LS Engine Final Assembly

LS Engine Final Assembly Tips



LS Engine Rebuilds: Final Assembly Guide


SHARE THIS ARTICLE: Please feel free to share this article on Facebook, in Forums, or with any Clubs you participate in. You can copy and paste this link to share:


We’ll, it’s finally time for the main event: engine assembly. The good news is that we’re on easy street from here on out, and though it may sound ironic, you’ll probably find the final engine assembly process downright simple in comparison to some of the tasks you’ve performed thus far. Not that this is a time to completely relax; a great amount of care and attention to detail is still required! Nonetheless, chances are that this is the phase of your rebuild project you will enjoy the most, as all the hard work you’ve done thus far will, at long last, begin to pay off!


Before You Begin

At this point, a few last words are appropriate. Before beginning final assembly, you should have all of the applicable tools listed in Chapter 2 in hand and ready to use—read through this chapter first to see which ones you will need if you’re unsure. Also, it should go without saying that before getting started, you should have performed all applicable pre-assembly procedures listed in Chapter 7 and had any and all additional machine work performed on your parts, as appropriate. And even though you went through the component cleaning process (Chapter 6) before embarking on pre-assembly, you will need to have cleaned all of your engine components one last time before embarking on final assembly. Remember, contamination left on parts can ruin your engine!


Final Assembly Supplies

The following supplies are either necessary or helpful during the final assembly process, and they apply to several steps. Without further ado, they are:

Assembly lubricant

All friction surfaces inside the engine will, of course, require lubrication so that they are adequately protected at startup. Though a thick engine oil is acceptable to use on bearing surfaces, additional protection can be had with a specialized assembly lubricant designed with bearings in mind. Another type of assembly lube is so-called high-pressure lube, which is designed to be applied at points where significant friction occurs, such as the pushrod cups of rocker arms (this stuff is sometimes moly-based and is usually included with aftermarket rocker arms). Use of all the right lubrication in all the right places will ensure a trouble-free break-in and long life for your LS. Also note that the term “assembly lube” can also apply to the lubricants used on the threads of some aftermarket fasteners, and as mentioned previously, small packages of this stuff are normally included by the fastener manufacturer. Refer to the product information for any assembly lubricants you pick up so that you’re familiar with the approved uses of each before applying.



A dedicated bearing assembly lube (top left) will help protect your bearings and crank journals during initial startup, while a high-pressure lube (bottom right) will do the same for your pushrod seats. The Royal Purple assembly lube at top right “bridges the gap” between bearing lube and high-pressure lube, and can be used on both types of surfaces. Finally, fastener assembly lube (bottom left) assists in achieving proper torque readings, and this stuff is nearly always moly-based.


Engine oil

Regardless of whether you’re using purpose-formulated assembly lube on your bearing surfaces, engine oil will still be needed during final assembly. Usages range from lubrication of certain fasteners (for proper tightening) to coating of surfaces like cylinder walls, lifters, and cam lobes. Thicker-weight conventional oils such as SAE 30 are preferred. Do not use thin weight oils such as 5W-30: a thick enough layer of it may not cling to metal surfaces between now and startup! Also, despite what you may have heard about GM putting together some of its high-output LS engines using synthetic oils, they are not recommended for our purposes.


An oiling can will prove useful when applying engine oil to your parts so that they (and your hands) stay as clean as possible. A small set of brushes is another option, as we talked about in Chapter 7.

An oiling can will prove useful when applying engine oil to your parts so that they (and your hands) stay as clean as possible. A small set of brushes is another option, as we talked about in Chapter 7.


Threadlocker, thread sealant & anti-seize

Certain fasteners and engine block plugs will require thread locking or Teflon-based sealing compounds. Each of these will prevent loosening over time and unwanted fluid seepage, respectively. Note that while you should pick up some anti-seize compound, this stuff should only be used on spark plug threads.

RTV Silicone

Assembly of a Gen I or II small-block would require an entire tube of this stuff or more. Fortunately, modern gasket technology means that only a few dabs are needed when bolting together an LS, so a small tube is all you’ll need.


You can’t put together an LS without these: thread sealant (also known as pipe thread compound or “Teflon paste”), threadlocker (medium-strength recommended), RTV silicone, and anti-seize.

You can’t put together an LS without these: thread sealant (also known as pipe thread compound or “Teflon paste”), threadlocker (medium-strength recommended), RTV silicone, and anti-seize.


Parts organizer trays

Though not an absolute necessity, it’s nice to have something to safely hold your soon-to-be-installed engine parts while you are going through the assembly process. Parts organizer trays are great because not only do they make items less likely to fall off of your worktables, but they keep numbered parts in order, helping prevent inadvertent mixups of cylinder-specific items like pistons and rods.


Goodson is a great source for parts organizer trays like this so-called block organizer. Piston/connecting rod assemblies are especially likely to tip over once assembled, so why not have them lying safely atop your worktable?

Goodson is a great source for parts organizer trays like this so-called block organizer. Piston/connecting rod assemblies are especially likely to tip over once assembled, so why not have them lying safely atop your worktable?


Supplies to stay clean

We’ve already reiterated that your parts must have been cleaned following the procedures in Chapter 6 before beginning final assembly (and frankly, you’re probably sick of hearing it). But you’ll also need to make sure they stay that way as your engine comes together. Hand cleaner should be kept nearby to clean your paws frequently during assembly. Some of the usual cleaning supplies we’ve seen before will be needed as well, particularly assembly wipes (which should always be used unless otherwise specified), which will allow you to give the surfaces of engine parts one last wipe before they’re hidden inside your LS forever.


While you’ve hopefully been keeping your hands clean throughout all stages of your rebuild project, it’s more important than ever to do so now. The life of your LS depends on it! You may also consider wearing disposable rubber gloves during the final assembly process.

While you’ve hopefully been keeping your hands clean throughout all stages of your rebuild project, it’s more important than ever to do so now. The life of your LS depends on it! You may also consider wearing disposable rubber gloves during the final assembly process.


Final Notes

Before getting started, one last note: it should be obvious that there will be a lot of bolt tightening to perform during final assembly. You will need to have all fastener tightening specs—torque, torque angle, bolt stretch, etc.—ready and verified before beginning. The reason for this is that although we’re quoting typical GM specs in this chapter, you must always use the specifications supplied by the manufacturer when using aftermarket fasteners (as well as any special instructions supplied with any aftermarket parts). Do not apply lubricants, sealants, or threadlocker to any fasteners unless specified herein or by the fastener manufacturer! In addition, the final caveat is that since there are so many variants of the LS engine architecture (a pool which continues to increase by the model year), it would be impossible to guarantee that all fastener tightening specs quoted herein are correct for each and every LS engine. We will attempt to note any such differences as we go along, but it doesn’t hurt to have your GM service manual at hand to verify or look up values unique to your engine.

Step-By-Step Final Engine Assembly Procedures

Step 1: Ready to Begin Assembly

7The most exciting time of the engine build is now upon you, as all of your shiny new or refurbished parts will come together to make what you’ve been dreaming of: a fresh LS engine!Don’t let the adrenaline get the better of you, though: follow the below steps carefully (and in order) to ensure you don’t make any mistakes.

Step 2: Install Screw-In Engine Block Plugs

8Flip the engine block upside down on its stand. Install any and all block plugs of the screw-in type, including oil gallery and coolant plugs. You should have noted where they all came from during disassembly. All of these are safe to reuse if their sealing washers are in good condition, but be sure to use Teflon-based thread sealant on the threads and under the sealing washer (new plugs include sealant on them). Torque this style of plug to 44 ft-lbs, or 30 ft-lbs if one of these plugs is an engine block heater.

Step 3: Install Press-In Engine Block Plugs

9Install a new front oil gallery plug into the front driver side of the engine block. Apply medium-strength threadlocker to its circumference, and tap it in place using a flathead punch or similar instrument. Its outer lip should be recessed about 0.01 inch when fully installed. At this time, also install the rear oil gallery plug (a.k.a. barbell restrictor; use of a new one is strongly recommended). This item can simply push into place by hand, and will protrude just slightly when installed properly. Use no sealant on this plug, just make sure its O-ring is intact and lightly lubricated with engine oil.



Step 4: Install Main Bearings

11Wipe each bearing shell seating surface in the block or main cap, as well as the back side of each shell, before proceeding. The upper main bearing shells (grooved) must now be installed into the engine block and the lower main bearing shells (solid) into the main caps. Be sure to install the thrust bearing shells into the center block bulkhead (bottom of first photo) and #3 cap. If you established the need to make one or more of these bearing shells undersize or oversize during pre-assembly, ensure each is being installed in its correct location. Each shell has a tab that fits into a recess in the cap or block, preventing backward installation (finger pointing in second photo). Make sure each shell is fully seated with its edges flush with those of the block or main cap—crooked bearings could spell disaster! Also ensure that your main cap locating dowels are in place in the block at this time (only certain engines have these; for example, the LS7).



Step 5: Insert Crankshaft Into Block (Professional Mechanic Tip)

13Give the seating surfaces of the block and main caps, as well as the bearings themselves, a final wipe. Lubricate the upper main bearing shells. Do not forget to lubricate the thrust faces of the #3 main bearing! Spread some lube on the crank’s main journals, too. Now, grasping the crankshaft by the snout and rear flange, slowly lower the crank into the block. Use care not to nick any of the crank journals. Just as the crank is about to rest on the bearings, it may get stuck; slight adjustments in angle of the crank will likely be needed to get it to seat, as it will only go in just the right way. If gentle wiggling does not coax the crank to seat, pull the crank slowly upward and start over; excessive jostling will damage the crank journals or bearings. It may help to rotate the crank slightly as you lay it in.



Step 6: Install Main Bearing Caps and Bolts

15After lubricating the lower main bearing shells, lay the main bearing caps in place, being sure to install each numbered cap in the correct location. The “wings” at the edges of the caps all face toward the rear of the engine, with the exception of the #5 cap (you can see this in the accompanying cap numbering photo). The caps likely will not seat fully by hand, as remember they are a tight fit between the deep-skirt oil pan rails. Insert the M10 main cap bolts and start them by hand. To guide the caps down, alternate tightening the bolts side-to-side to ease each cap all the way into place (don’t do this on caps that use locating dowels—tap the cap in place with a rubber mallet). The longer, non-studded main bolts go toward the center of each cap, while the studded ones go toward the outside. Only snug these bolts for now, then install the side cap bolts loosely. If you are re-using your old side bolts, apply some RTV sealant under the heads to prevent oil leakage.


Important Notes:

(1) Though GM recommends these M10 bolts be installed dry, some engine builders use a small amount of oil on the threads to help prevent any possibility of thread damage during tightening (you can put some under the heads of the bolts, too). This is only permissible because these bolts use the torque-plus-angle method; doing this would destroy a proper reading if relying on a torque spec only!

(2) If not using GM bolts, follow the lubrication instructions provided by the manufacturer.





Step 7: Tighten Inner Main Bearing Cap Bolts (Torque Fasteners)

19Torque all M10 inner main bolts (numbered 1-10 in the accompanying diagram), in the sequence shown, to 15 ft-lbs. Before proceeding further, you must use a rubber mallet to hit the crank rearward, then forward, with a rubber mallet. This aligns the thrust bearing surfaces and it is important to note that final thrust of the crank must be in the forward direction! Then use your torque angle gauge to twist these inner main bolts in sequence an additional 80 degrees. (See “Utilizing Fastener Stretch” on page 118 for reasons why this “torque plus angle” methodology is used by GM.)







Step 8: Tighten Outer Main Bearing Cap Bolts and Side Bolts (Torque Fasteners)

23Now, torque all M10 outer main bolts (numbered 11-20 in the first picture), in sequence, to 15 ft-lbs. Once this is done, use your torque angle gauge to add an additional 51 degrees of twist to each outer main bolt, again in sequence. With all M10 main bearing bolts now tight, the main cap side bolts can be addressed. Torque each to 18 ft-lbs; there is no required sequence for these bolts save to say that you should tighten one side bolt and then the other before moving to the next cap. There is also no angle to add to the side bolts.





Step 9: Assemble Pistons to Connecting Rods

26Unless you are using a press-fit piston pin (in which case your machine shop will already have put together your piston/rod assemblies for you), now is the time to assemble your pistons to your connecting rods. Read “Piston and Connecting Rod Orientation Rules” on page 113 before proceeding. Piston pin retaining clips vary in style; some are c-clips that install with snap ring pliers or similar tools, while others are spiral-type and must be stretched open to ease installation (shown in hand, such a spiral-type lock must then be worked into one side of the piston pin bore by simultaneously rotating and pushing it into its groove). Once you have a clip in one side, lightly lubricate the piston pin as well as the friction surfaces in the piston and rod with clean engine oil. Slide the pin through the bores in the piston and rod until it hits the clip on the far side of the piston. Then install the other clip atop the pin. Make sure these pin retaining clips are fully seated—they’ll normally click when they’re all the way in (a flathead screwdriver comes in handy for this)! Repeat for all pistons and rods, remembering to install any piston “notched” for reluctor ring clearance onto your #8 connecting rod (see Chapter 5)! At this point, we suggest marking the face of each piston with magic marker to correspond with any number previously scribed onto the rod.





Step 10: Determine Piston Ring Clocking

29Most piston or piston ring manufacturers will provide specific guidelines as to ring “clocking,” or placement of the end gaps about the piston’s perimeter. If no clocking recommendations have been specified, you should follow the ring clocking diagram shown here during the below steps of piston ring installation (compression rings can easily be repositioned once installed on the piston, while oil rings are a little more tricky to slide against one another). The most important thing to note is that the oil control rails must be placed about 1-inch to either side of the expander end gap. Most modern ring packages don’t require precise clocking other than this, but you should still space the end gaps of the top and 2nd rings approximately 180 degrees apart.

Step 11: Install Oil Ring Support (Performance Tip)

30Some high-performance LS pistons with a short compression height have an oil ring groove that intersects the piston pin bore (see the Appendix). Such pistons require installation of an oil ring support, which sits beneath the oil rings and provides the necessary structure in the area of the piston pin. An oil ring support must be installed before any piston rings, and this is most easily done using ring expander pliers. Oil ring supports will often have a dimple (pointing) that must face down in the area of the piston pin bore. This dimple prevents the support from rotating out of place while the engine is running—you do not want the gap in the support entering this area!

Step 12: Install Oil Rings

31It is easiest to install rings if your piston is standing upright (so that you have two hands to work with); your rod vise lying flat on the surface of a table works well for this purpose. Beginning with the #1 piston, lightly lubricate the surfaces of all rings with clean engine oil. Install your oil ring expander into the bottom ring groove, which is the wavy-looking ring (it may have a piece of thin wire connecting its ends, like this one). Note that some ends of expanders simply butt together, while others lock in place. Then install one oil ring control rail below the expander and another oil ring rail above the expander. Oil ring control rails are easily installed by hand using a light twist (set one end in and hold it with your thumb), and ring expander pliers are not required. Note that if your piston has a small opening beneath the oil ring groove (near left thumb in second photo), you should move the rail endgaps past this area, i.e., further apart than just the 2:30 and 3:30 positions shown in step 10.



Step 13: Install Compression Rings (Special Tool)

33Proceed to lightly lubricate and install your compression rings one at a time, being sure you are using the appropriate compression ring pair for the #1 piston (they should have been marked after ring fitting). Start with the 2nd ring, which sits in the lower of the two compression ring grooves and normally has a duller finish. Be sure to install the correct side facing up: this will be noted on the instructions included with your rings and is normally indicated by a small dot or a beveled/grooved inner or outer edge (which may face either up or down depending on your ring set). Use ring expander pliers to expand the ring just enough so that it slips around the piston; too much can damage the ring. If you do not have ring expander pliers, you can use your thumbs to push the end gap apart. Now install the top ring, again making sure to follow the ring manufacturer’s instructions on any bevel or dot placement. Once in their grooves, the compression rings should stick out a bit; this is normal and will help the rings put tension on the cylinder walls. Repeat steps 11-13 (as applicable) for pistons #2 through #8.





Step 14: Install Crank Turning Tool (Professional Mechanic Tip)

36As with pre-assembly, a lot of crankshaft turning is required during final assembly. For this reason, it helps to install your crankshaft turning tool (if you have one) onto the crank snout at this point. Depending on the style of your tool, you may have to install your oil pump drive gear (which may be part of your crank sprocket) onto the crank snout before putting the crank turning tool on—see step 27. Again, if you do not have a crank turning tool, we recommend simply installing your old crank bolt and using a 24mm wrench to turn it.

Step 15: Install Connecting Rod Bearings (Critical Inspection)

37If your rod caps are currently installed tightly to your rods, remove them in accordance with “Proper Connecting Rod Cap Removal” on page 96. Start with the piston/rod assembly for cylinder #1 (remember, each is unique!). After ensuring the bearing shells and their seating surfaces on the rods are clean, install the lower connecting rod bearing shell into the rod cap and the upper shell into the top portion of the rod. As with main bearings, each bearing shell will have a tab that will fit into a recess in the rod or cap, and the shells must be fully seated with their edges flush with those of the rod or cap. Also note that rod bearing shells are not always the same, and your rod bearings may have a top and a bottom half. This is especially true when using chamfered rod bearings to match high-performance filleted cranks. If this is the case, check the back of the bearing shells, which are often stamped with a “U” or “L,” indicating upper and lower shells. As a double-check, watch that the chamfer in the edge of such a bearing will face the filleted edge of the crank journal (i.e., the chamfer must face the front of the engine on odd-numbered cylinders and the rear of the engine on even-numbered cylinders). Lubricate the bearing shells with assembly lube.





Step 16: Turn Engine on Stand and Turn Crank to BDC (Professional Mechanic Tip)

40Turn the engine on its stand so that the cylinder deck surface is as horizontal as possible. Give the appropriate cylinder wall one final cleaning, and lightly lubricate it with clean engine oil using a lint-free towel or assembly wipe. Then turn the crankshaft so that the rod journal for the cylinder you are working on is at its furthest point below that bore (bottom dead center). This will give the most room to guide the rod onto it. Also lubricate the crank rod journal with assembly lube.



Step 17: Adjust and Prepare Ring Compressor (Special Tool)

42No matter what type of ring compressor you are using, lightly lubricate its inside surface with engine oil. If you have a tapered-sleeve ring compressor, set it roughly atop the bore. Adjustable sleeve-style ring compressors need to be adjusted until the cylinder liner can no longer be seen around its inner circumference. (Many machine shops make a slight chamfer in the top of the bores to ease ring installation, and you can see this in the first photo). As for band-style adjustable ring compressors, they should be wrapped snugly (not tightly) around the piston at this time, leaving the piston skirt exposed. Note: Use of band-style “oil filter wrench” compressors that do not lock to a set position is not recommended and can result in ring breakage!



Step 18: Install Piston/Rod Assembly into Ring Compressor

44After verifying ring clocking, lightly lubricate the skirt of the correct number piston/rod assembly and insert it into your sleeve-style ring compressor (or simply insert the piston skirt into the bore if using a band-style compressor). Start pushing the piston very lightly downward by hand. Further minor adjustments to adjustable-style ring compressors may be needed so that the piston can slide through it while still holding the rings firmly. When using a sleeve-style compressor, you will probably need to use your fingers and press each compression ring into its groove, to allow it to enter the tapered section of the sleeve (shown in left photo).



Step 19: Avoid Rod Interference Problems (Important!)

46Once the piston skirt has entered the top of the bore and all rings are being compressed, look underneath to ensure the connecting rod is roughly centered and not about to contact any part of the crank or block (or another rod, if one has already been installed onto the journal). Shown is a rod hitting a crank counter weight, a common occurrence. Twist the piston as necessary to get the rod at a 90 degree angle to the crank centerline, and you may also need to slide the rod to center it along the piston pin. Failure to correct these problems can destroy the rod or other components!

Step 20: Install Piston into Bore

47Hold the ring compressor against the deck surface and begin tapping downward on the top of the piston with the rubber butt end of a hammer. If the piston stops at any point, do not force it! The ring compressor may be improperly adjusted and a ring may be hanging up on the bore lip. Some moderately forceful taps may be needed to get the piston to move, but anything more than this should be a red flag—in which case you’ll need to stop, pull the piston out, and make any necessary adjustments before trying again. Once you are certain the piston is going into the bore properly, reach underneath and begin guiding the end of the rod with one hand while continuing hammer taps with the other (you may remove the ring compressor at this point if you wish).



Step 21: Guide Rod Onto Journal and Install Rod Cap

49As the piston moves down, some further slight twisting of the rod may be needed to help guide it past the crankshaft counterweight (and other rod, as applicable). As the rod nears the crank journal, use extreme care, as any part of the rod touching the journal surface could cause a scratch. Hold your hand around the journal with your index finger and thumb, keeping the rod bolt holes centered on either side of the journal (shown, be prepared to get a little lube on your hand). Once the rod is seated onto the journal, install the rod cap (remember to do so in the correct orientation). On aftermarket rods that use locating dowels, it is recommended that you tap the cap in place using a rubber mallet (in lieu of drawing it down with the bolts) to seat the cap. Either way, install and tighten the bolts until snug. Repeat steps 15-21 until you have installed piston/rod assemblies into all cylinders.



Step 22: Tighten Connecting Rod Bolts (Torque Fasteners)

51Note: The procedures described in this step apply to engines using GM connecting rods and rod bolts only. If using aftermarket rods or bolts, follow the tightening procedure specified by the manufacturer, and read “Utilizing Fastener Stretch” below for more information. Flip the engine on its stand so that the oil pan rails are facing up. Starting with the #1 connecting rod, turn the crank so that both rod bolts are easy to access (the crank will be substantially more difficult to turn now that pistons and rings have been installed!). Torque each bolt initially to 15 ft-lbs. Then install your torque angle gauge and give each bolt an additional 75 degrees of twist. Mark on or near the bolt so you know you’ve tightened it, then ensure the rod can slide back and forth on the crank journal (if not, the rod bearings may be crooked). Repeat for each connecting rod until you have secured all sixteen rod bolts.





54Important Note:

Early-style GM rod bolts must only be twisted 60 degrees (instead of 75). The most foolproof way to determine whether your bolts are of this type is to look at the area between the bolt head and the threads: if the bolt has a thick shank with a series of shallow, vestigial threads starting just below the head, it is an early-style bolt. Later-style bolts all had a narrower shank interrupted by a larger-diameter sleeve somewhere between the bolt head and threads (exact location varied). The photo compares an earlier (left) and later-style (right) bolt removed from a rod, but you can have a look now just by loosening the bolts and pulling them out enough to look at the shank. Early- and later-style bolts should never be mixed on the same rod!

Step 23: Install Crankshaft Position Sensor

55Being sure to use some oil on its O-ring (replace if damaged), install the crank sensor into the passenger side rear of the block. Torque its retaining bolt to 18 ft-lbs. Make sure you are using the correct sensor for your engine and computer: black sensors are for 24X reluctor rings, while lighter colored sensors are for 58X rings.

Step 24: Short-Block Final Assembly Complete

56The assembly of the short-block (or “bottom end”) is now complete! Take a well-deserved break, but be sure to cover up your engine while you’re gone to prevent contamination from airborne dust, bugs, and other unwelcome substances. Then, move on to the next step.

Step 25: Install Camshaft (Professional Mechanic Tip)

57With the engine right-side-up on its stand, lubricate all cam bearings in the block that you can reach. Before continuing, be sure your hands are very clean, as it will be impossible to avoid contact with the camshaft’s journal and lobe surfaces during installation. The front of the camshaft is recognized by its bolt hole(s) and sprocket locating pin. Lubricate the two rearmost cam bearing journals (and the lobes between them) with engine oil, then insert the cam until it can rest these journals on the front two cam bearings in the block. (Please note that there is no need for moly-based “cam break-in lube” on LS camshafts thanks to their rollerized design!) The fact that Gen III/IV small-blocks use five equally-spaced, equally-sized cam bearing journals allows insertion of the cam segment-by-segment like this, meaning you can lube the journals and lobes as you go along, making the process a bit cleaner. When well on its way in (and little remains exposed to grab onto), an LS cam’s hollow construction lends itself nicely to the use of one or more long 3/8-inch extensions inserted into its central bore for added leverage (longer bolt(s) of the appropriate size and thread pitch can also be used, this is the only option for most single-bolt cams). Continue to insert the cam slowly and carefully (lest you mar the lobes or cam bearings), noting that more and more upward pressure will be required as the cam gets deeper into the block. When it is nearly all the way in, you can even insert a long 3/8-inch extension into the rear of the cam to help guide it the last few inches. Once the cam is in, remove the extension(s) or bolt(s), but be careful—the slight backward tilt of most engine stands means the cam may want to slide its way out the back of the block!





Step 26: Install Camshaft Retainer Plate

60Lightly lube the built-in gasket at the back of the cam retainer plate (check once more that it’s in good condition). After wiping the corresponding surface on the front of the block, lubricate the thrust surface of the cam (its outside edge, which is inset slightly) and set the cam retainer in place. Use care not to accidentally push on the cam or it will slip backward and fall onto its lobes. Install the four cam retainer bolts and torque to 18 ft-lbs. If your cam retainer bolts are of a TORX-head design, the specification is 11 ft-lbs.



Step 27: Install Crankshaft Key and Sprocket (Special Tool, Professional Mechanic Tip)

62Install your crank key into the crankshaft snout’s keyway using a rubber mallet. Be sure that it goes in squarely or it will be difficult to slide the crankshaft sprocket and/or oil pump drive gear over it. You may have installed your timing set’s crank sprocket onto the crank snout during pre-assembly, but if not, do so now. Spray some lubricant such as WD-40 onto the snout to help this process. Some aftermarket sprockets will simply slide over the snout and only require a few light hammer taps to seat fully on the crank. Factory-style sprockets should be started with light hammer hits, but will need to be pressed on the rest of the way using a crank gear installing sleeve (possibly combined with a harmonic balancer installer tool). The alternative to buying a sleeve is to simply use your old crank sprocket (shown)! This method will also require your old crank bolt and is easier and cheaper than buying a special sleeve. Press the sprocket on until it firmly seats against the crank, then remove your old sprocket, it should just come off by hand.


Important Notes:

(1) Some cranks (expecially aftermarket ones) use a second key located further outward on the snout (to properly index aftermarket harmonic dampers and prevent any chance of it spinning on the snout). If using such components, install the second key at this time as well.


(2) If using an adjustable timing set, be sure to install the crank sprocket using the correct keyway you determined during pre-assembly.

(3) Do not use hard hammer hits to install the crank sprocket, this can cause severe engine component damage!

Step 28: Install Camshaft Sprocket and Timing Chain

65Turn the crankshaft until the alignment mark on its sprocket is at the 12:00 position. Spin the camshaft by hand until the cam locating pin is facing to the right (roughly 3:00), making sure not to push the cam backward at all. This pin placement will help get the cam sprocket locating mark roughly where it needs to be. Lubricate the thrust surface at the back of the cam sprocket and soak the timing chain in oil. Once this is done, take your cam sprocket and hang your timing chain on it. Reach behind the engine with one hand to hold the cam from moving backward (this also allows you to turn the cam slightly if needed). Put the cam sprocket in place while simultaneously wrapping the timing chain around the crank sprocket. You may have to take the cam sprocket and chain on and off of the engine a few times until you get the marks on the cam and crank sprockets to line up vertically (they should be at 6:00 and 12:00, respectively). Start the cam bolt(s) by hand (some aftermarket timing chains afford very little slack, making this difficult); torque to 18-26 ft-lbs (cams with three small retaining bolts) or 66 ft-lbs plus 40 degrees (cams with one large retaining bolt).


Important Notes:

(1) Be sure to use the correct sprocket markings determined during pre-assembly if using an aftermarket adjustable timing set.

(2) Engines equipped with VVT have the cam phaser mounted to the front of the cam sprocket, and the assembly is secured to the camshaft by an actuator solenoid valve in lieu of a bolt. It must be tightened to 48 ft-lbs plus 90 degrees.


(3) The timing chain tensioner (on engines so equipped) may need to be installed before the chain and cam sprocket. In this case, the tensioner will need to be temporarily deactivated using a pin or similar instrument while the chain and sprocket are put in place.(4) Engines equipped with a timing chain dampener (which sits in the area between the cam and crank sprockets) should install it at this time, torquing its bolts to 18 ft-lbs.



Step 29: Install Oil Pump

69If your crank sprocket does not have the oil pump drive gear built-in, slide this item onto your crank snout now. Wipe the mating surfaces on the front of the block and back of the oil pump, then set the pump in place over the crank snout. You may have to twist the oil pump’s gear teeth so that they align with the teeth on the crank sprocket (or separate oil pump drive gear). No gaskets or other sealants should be used between the pump and block surfaces. Torque spec on these bolts is 18 ft-lbs. Once the oil pump has been installed, flip the engine over on its stand.


Important Notes:

(1) If you are using an aftermarket double-roller timing chain, be sure to place any supplied spacers between the pump and block (and use any longer bolts supplied). Most aftermarket oil pumps do not require spacers as they are designed with the thickness of a double-roller chain in mind.

(2) While most pumps self-align properly to the block, LS7 oil pumps must be held flush or no more than 0.04-in. above the oil pan rails at the bottom of the block—no protrusion below the rails is acceptable! A straight edge or the GM J 41480 can be helpful in determining this—this is the same tool used to align the front and rear covers to the block (see steps 33-34). The procedure is similar for the LS9.

Step 30: Oil Deflector Tray Modification (Performance Tip)

71Note: this step applies to high-performance applications only. For stock rebuilds, skip to the next step. When using a crankshaft with a larger-than-stock stroke, modifications to your oil deflector tray may be required to obtain adequate rotating clearance. To check for contact between your rotating assembly and the tray, set it loosely in place atop the main bolts and rotate the crank, watching and listening for any interference. Most commonly, this occurs between the tray and the heads of the rod bolts. To correct for this, mark the tray at all points of interference, then take it off of the engine and use a hammer and chisel to bend the tray in these areas. Do not close off any gaps in the tray completely—this will create oil flow problems. Reinstall the tray and ensure you have adequate clearance, noting that some extra space will be necessary to account for crank stretch at high RPM!As an alternative to modifying the oil deflector tray, you may also install a set of aftermarket tray spacers (see “SLP Performance Parts” on page 122), but be aware of the following: because the oil pump pickup tube mounts atop the tray on most engines, some modifications (i.e. slight bending of its bracket) may be required in order to correct for decreased clearance between the pickup tube’s screened inlet and the floor of the oil pan. This is easy to check with clay later during oil pan installation. A final note on oil deflector tray modification is that if you are using aftermarket main studs, they may require some of the holes in the tray to be enlarged slightly, which is easy enough to do with a drill or die grinder.





Step 31: Install Oil Deflector Tray and Pump Pickup Tube

74Lay the oil deflector tray atop the main bolts, noting correct orientation (most are marked “REAR” at the back). It is a good idea to shoot some oil into the oil pump inlet at this point for initial lubrication. Install a new O-ring onto the end of the oil pump pickup tube. Coat the O-ring and the oil pump inlet opening with oil, then push the pickup tube into the oil pump. Ensure the tube is all the way in before inserting and tightening the retaining bolt, or else you may damage the O-ring or push it out of position. The retaining bolt gets 106 inch-lbs of torque, while the eight stock deflector tray nuts (one of which also secures the pickup tube bracket) receive 18 ft-lbs. If using aftermarket main studs and tray nuts (as shown here), use the torque specifications provided by the manufacturer.


Important notes:

(1) There are at least two different styles of pickup tube used on LS engines. Some tubes neck down near the end before bumping up to a flange. These tubes require a thicker O-ring, which is normally green in color. Other pickup tubes do not neck down and require a thinner (usually blue or black) O-ring; it is this type that is shown in the photos. An incorrect O-ring can cause loss of oil pressure and severe engine damage, so be sure you are using the correct type!


(2) If your oil pump has been spaced forward for use of an aftermarket double-roller timing chain, slight bending of the pickup tube bracket will be required for proper fitment.

(3) On dry sump engines (such as the LS7), the pickup tube is part of the oil pan, so only the deflector tray is installed at this time.


Step 32: Install Crankshaft Oil Seals into Front/Rear Covers

77The crankshaft’s front and rear oil seals should not be reused, and must be removed from the engine covers and discarded. A hammer and flathead screwdriver can be used for this, though care must be taken not to score the aluminum surfaces of the covers. GM recommends waiting until the covers are on the engine to install new seals, but this requires special J-tools (which are invariably expensive or hard to get a hold of). The front seal is fairly easily tapped into place about its edges with a rubber mallet; do this slowly and gently or the seal will be destroyed. While the same can be done with the rear seal, you can also use this tool made by now-defunct Wheel to Wheel Power-train (which tightens to squeeze the seal into place, second photo) to make the job more fail-safe. A thin film of oil applied to the engine cover surfaces will help the seals press into place. However, the seals themselves are designed to be installed dry—do not lubricate their inner rubber surfaces! If you are afraid of botching this step, know that new front and rear covers are available from GMPP with seals pre-installed (see “GM Performance Parts” on page 125 for more information).



step 33: Install Rear Cover (Special Tool Used, Precision Measurement)

79Before installing the rear cover, make sure the rear oil gallery plug (barbell restrictor) is still in place at the driver side rear of the block (see step 3)! Set a new gasket in place on the rear cover, using the first couple of threads of each rear cover bolt to hold it there. Wipe off, but do not lubricate, the crankshaft’s rear flange. You must be very careful when sliding the rear cover onto the block, as it is easy for the lips of the rear crank seal to become misaligned while doing this, resulting in an oil leak (updates to GM’s seal design have made this much more foolproof, though). The aforementioned Wheel to Wheel Powertrain tool’s aluminum “donut” helps ease an earlier-style seal’s transition onto the crank. Once all rear cover bolts are started by hand, you have a choice. The first option is to use a GM cover alignment tool (J 41480) to align the rear cover’s cover-to-pan sealing surface with the block’s oil pan rails before torquing the rear cover bolts to 18 ft-lbs. As an alternative, you may visually align the cover-to-pan sealing surface with the pan rails, tighten the bolts, and then verify no more than a 0.020-inch drop between the pan rails and rear cover using a straight edge and feeler gauge (any protrusion of the cover beyond the pan rails is unacceptable). This latter method will usually provide acceptable results since contact between the rear seal and crank flange helps roughly align the cover to the block.







Step 34: Install Front Cover (Special Tool, Precision Measurement)

83The front cover goes on next, being sure to use a new gasket behind it. This cover is most easily aligned using the same alignment tool used for the rear cover, along with an additional J 41476 tool to help align the cover side-to-side.(This latter tool was not used in the previous step since the rear seal had already been installed and was basically serving the same purpose). Install the J 41476 hand-tight using your old crank bolt before installing the J 41480. If you do not have access to these two tools, it is strongly recommended that you wait until after you install the harmonic damper (step 59) to tighten the front cover bolts. This will help align the cover side-to-side and will of course require the oil pan to be installed after the harmonic damper as well. Either way, the front cover bolts get 18 ft-lbs of torque, and you must also verify no more than a 0.020-inch drop between the pain rails and the cover-to-pan sealing surface.


Important notes:

(1) Some aftermarket oil pumps require grinding to the inside surfaces of the front cover for proper fitment. Be sure to clean all shavings from the cover and seal after doing this.

(2) The LS7 does not use the J 41476, but rather its own specialized set of cover alignment tools, which require that the front crank seal not be installed until afterward. Absent access to these tools, it is recommended that you take the route of installing the harmonic damper first to help align the LS7’s front cover. The LS9 installation is similar.


(3) Engines equipped with VVT have provisions for actuating the cam phaser mounted to the front cover (you should have noted their layout during disassembly), so be sure to install these components now as well.


Step 35: Prepare to Install Oil Pan

86Oil pan design varies substantially by engine and application, however all are installed using the same methodology. First, make sure any and all internal baffles, the oil filter adapter, the oil filter bypass valve, and like items that you may have removed during cleaning are in place and tight. Then set your new pan gasket atop the oil pan, using as many bolts as you can to hold it (it is not necessary to actually rivet the gasket to the pan, though you can if you wish). Now, apply a 1/4-inch bead of RTV silicone at each of the four meeting points of the block and front and rear covers. You will note that the front and rear cover gaskets protrude toward the pan gasket slightly at each of these points, but this RTV is for extra insurance.






Step 36: Install Oil Pan (Precision Measurement)

89Now set the oil pan in place on the engine block. Depending on the baffle design of your pan, it may not drop straight down, but rather require some wiggling and/or angling to install. A properly installed pan will sit flush on the engine block; if it does not, your pickup tube may be hung up in the oil pan baffle(s), so lift up and try again. Once you are confident the pan has seated correctly, tighten the bolts only snug and use a straight edge to measure the pan’s location with respect to the rear of the engine block. Because the oil pan forms a structural part of the driveline (heck, even some of the bellhousing bolts attach to it), this dimension is critical: the pan cannot protrude beyond the back of the engine block, and may only be set forward 0.010-inch on most engines. On some engines, a maximum of just 0.004-inch is considered acceptable! After making any necessary adjustments to get the pan location correct, tighten all the short oil pan bolts to 18 ft-lbs. and the two long pan-to-rear-cover bolts to 106 in-lbs (most engines; pan and bolt style may vary). After verifying pan alignment is still acceptable, replace any and all sensors you previously removed from the oil pan (for example, the oil level sensor and oil temperature sensor, these vary by application).





Step 37: Install Camshaft Position Sensor

92Turn the engine right-side-up on its stand. On Gen III engines, the cam sensor slides into the top rear of the block, and its retaining bolt is tightened to 18 ft-lbs. On Gen IV engines, the sensor is installed into the front cover, and its bolt gets 106 in-lbs. (the sensor on VVT-equipped engines is similar but not identical). With either style, be sure to use some oil on the O-ring. Many Gen IV engines also have a wiring harness extension and bracket (leading to the bottom of the cover) that you may wish to install now.



Step 38: Install Valve Lifters and Guide Trays

94The best way to install the lifters into the engine is to first insert them into the lifter guide tray. Apply some engine oil to the grasping areas of the tray, then slide the lifters in. Because the tray grabs onto the flat areas on either side of the lifter, the lifters will only go in one of two ways, with either being acceptable (orientation of the lifter’s oil hole on the side does not matter). Then spread oil on all surfaces of each lifter—roller tip included—and push the tray into place in the engine. Each lifter should slide easily into its bore. On some engines, the shape of the tray dictates that it can only be installed in one orientation, but on others this does not matter. Tighten the lifter guide’s retaining bolt to 89-106 in-lbs—do not overtighten and crack the tray! Repeat for the other three trays until you have installed all 16 lifters.


Important Notes:

(1) It is recommended that you not soak hydraulic lifters in oil before installation, as this can interfere with proper rocker tightening (stock rebuilds) or with valve lash adjustment (high-performance rebuilds using adjustable rocker arms).

(2) On AFM-equipped engines, the lifters for cylinders 1, 4, 6, and 7 look slightly different, mainly in that they have built-in springs that allow them to follow their cam lobe profiles while deactivated. Be sure to install them into their correct locations. The areas that the guide tray grabs onto are also of a different shape on these cylinders.

Step 39: Press in Cylinder Head Locating Dowel Pins

96There are two dowel pins for each deck surface of the block, one at the front and one at the rear. It’s best to not reuse your old dowels, so install new ones now. Each must be pressed into its hole as completely as possible, and light hammer taps may be needed to do this.

Step 40: Lay Head Gasket on Block

97Wipe the deck surfaces of the block clean one last time before proceeding. Tilt the engine in its stand so that one deck surface is horizontal. Take a head gasket and place it on the block, noting any markings on the gasket such as “FRONT” or “THIS SIDE UP.” Some gaskets are unmarked; to determine their orientation, note that because the rear portion of many LS blocks has more coolant passages between the block and heads, these must match any corresponding holes in the head gasket. Also, you may have to press down on the lower corners of the gasket to seat it onto the dowel pins.

Step 41: Inspect Cylinder Head for Gasket Incompatibility Recess (Critical Inspection)

98Some early Gen III heads have a recessed area along the edge of the deck surface, just below the number 3 or 6 exhaust port (the head shown does not have the recess, but it would be exactly in the area pointed at). If your head has a recess, you cannot use GM’s newer-style MLS head gaskets, but must rather use a GM graphite-layered steel core gasket. See Chapter 4 for a comparison photo of these two types of gaskets. In the case of aftermarket gaskets, consult with the manufacturer for head compatibility information. If your heads are not currently assembled, follow “Cylinder Head Assembly” Workbench Tip before proceeding to step 42.

Step 42: Install Cylinder Head and Bolts

99Make sure that the deck surface of the head is completely clean. Grasp a head along its sides (holding fingers inside the intake ports works well) and set it in place atop the head gasket. Ensure that it locates properly on the dowel pins. There are fifteen head bolts: ten that are large in diameter (M11 thread on most engines) and five small in diameter (M8 thread). Insert them at this time and turn them until they are just barely snug against the head.


Important notes:

(1) If you have a 2003 or earlier block, two of the M11 bolts are shorter than the rest, and these must be installed at either end of the top row of M11 bolts (locations #9 and #10 in the diagram shown in the next step; there is one shown being inserted in the photo to the left). On 2004 and later blocks, all M11 bolts are of the same length.


(2) While you must always install new M11 bolts, your old M8 bolts can be reused so long as you apply medium-strength threadlocker to the first several threads.


Step 43: Tighten M11 Head Bolts (Torque Fasteners)

102Refer to the accompanying image for bolt numbering. The M11 bolts must be tightened in three steps. These bolts require a substantial amount of force to twist, so you may wish to have an assistant help you hold the engine stand from rolling around while you’re doing this!

FIRST STAGE: Using a torque wrench, tighten the M11 bolts numbered 1 through 10 in sequence to 22 ft-lbs.


SECOND STAGE: Now use a torque angle gauge to add 90 degrees of twist to these same bolts, again in sequence.

FINAL STAGE: The specifications to use in this stage depend on the style of head bolts that your block uses.

2004 and later blocks with all-same-length M11 bolts: add an additional 70 degrees of twist to the bolts in sequence.


2003 and earlier blocks with long/short M11 bolts: add an additional 90 degrees of twist to the bolts numbered 1-8 in sequence. Then add 50 degrees of twist to the shorter M11 bolts in locations 9 and 10.


Important notes:

(1) For engines using M12 head bolts (such as the LS9), refer to your GM service manual.

(2) If using aftermarket head bolts or studs, refer to the installation instructions and tightening specifications of the manufacturer. However, the above tightening sequence should always be used.

Step 44: Tighten M8 Head Bolts (Torque Fasteners)

105Once all M11 bolts are secured, use a torque wrench to tighten the M8 bolts numbered 11 through 15 in sequence to 22 ft-lbs. There is no angle to add to these bolts. With all head bolts fully tight, repeat steps 40-44 for the other cylinder head.


Step 45: Mask Off Intake Ports (Professional Mechanic Tip)

106As the valves are about to become operational, you do not want stray bolts or other items accidentally entering the cylinders, requiring head removal. Avoid any chance of this by masking off the opening of each port—especially those of the intakes—with tape. Once applied, you may want to punch a small hole into each piece so that the engine can “breathe” as rockers are being installed and the crank is turned over (this latter concern doesn’t apply so long as you have not yet installed spark plugs).

Step 46: Install Pushrods

107Lubricate the lower tips of all sixteen pushrods with engine oil, then slide each into place through its passage in the cylinder head. Press down on each one as it is inserted to make sure the tip is centered onto the lifter plunger, and also to push the lifter down onto the cam. For the moment, do not lubricate the upper tips of the pushrods.

Step 47: Prepare to Install Rocker Arms (Important!)

108On engines using stock or small-duration aftermarket camshafts, it’s possible to install and tighten the rocker arm bolts eight at a time at just two different positions of crankshaft rotation. However, since long-duration cams can cause some lobes to command lift at these positions, we’re going to go through a procedure that will work regardless of camshaft used. First things first, though: thanks to the rollerized design of factory LS rockers, we suggest submersing them in engine oil to help lube the internal bearings. After this, you must lubricate each tip with engine oil and liberally lubricate the pushrod cup (a specialized assembly lubricant is strongly preferred over oil for this area because of the amount of friction that will occur here at startup). Also lube the area that will contact the underside of the rocker bolt head with oil to assist in proper tightening, and use your oiling can to squirt plenty of oil between the valve spring coils onto the valvestems. Then, for cylinder heads where the rocker pivot supports are not a machined part of the head (this is the case with most LS heads), lay the rocker stands in place on each head; some aftermarket stands get bolted in place. Please note: because our method of rocker installation does not involve installing all rockers simultaneously, the factory stands must have at least 2 rocker bolts inserted into each of them at all times (spaced as far apart as possible) in order to prevent the stands from shifting out of place—the built-in factory alignment tabs alone will not stop this from happening!





Step 48: Install Rocker Arms (Professional Mechanic Tip)

















116Note: this step applies if using stock-style rocker arms only. If using aftermarket adjustable rocker arms, skip to step 49. The rocker installation process will require some attention—along with an assistant—because of the tendency of the lifter guide trays to hold the lifters off of the cam once they are raised, which masks lifter movement. However, when done correctly, the results will be properly tightened rocker mounting bolts on any application! 1. Start off by having your assistant use your old crank bolt to turn the crankshaft clockwise (most crank turning tools can no longer be used thanks to the front cover being in the way). 2. Hold downward tension on the pushrods for cylinder #1. This prevents the lifter guide trays from holding the lifters up artificially. Wait until the exhaust pushrod just begins to move upward (the exhaust is the one on the right when looking from the side of the engine). 3. At this point, lube the pushrod tip and install the intake rocker arm (make sure the pushrod enters its cup on the underside of the rocker properly) and torque its mounting bolt to 22 ft-lbs. 4. Continuing to hold tension on the exhaust pushrod, have your assistant turn the crank until your newly installed intake rocker rotates the intake valve open and then almost completely closed. Now install the exhaust rocker arm, torquing its mounting bolt to the same 22 ft-lbs. 5. Repeat this step for every cylinder until all sixteen rockers have been installed.

Important notes:

(1) Gen IV-style heads use rockers with offset tips for the intake valves. If you have this type of head, remember to install these rockers in the correct locations. (Recall, though, not all Gen IV engines use “Gen IV-style” heads, see our “LS Cylinder Head Evolution” Workbench Tip in Chapter 4 for more information.)

(2) If using an aftermarket cylinder head where the intake rocker mounting bolt intersects the intake port, it is not a bad idea to apply some RTV sealant to its threads.

(3) If you’re getting confused about which lifter is on the base circle of the cam at any given point, it helps to verify by viewing the lifters through the cast-in “gaps” at the front and rear of the valley. See above, picture 6. Unfortunately, this is only possible for cylinders 1, 2, 7, and 8 since these lifters are the only ones visible through these gaps. The alternative is to wait until after rocker installation to install the engine covers; this way, the cam sprocket will be visible during this step to help you sort things out.

Step 49: Installing Aftermarket Adjustable Rocker Systems (Performance Tip)

117Note: this step applies to high-performance applications only. For stock rebuilds, skip to the next step. When using aftermarket adjustable rocker arms, the installation procedure is often very similar to that discussed in step 48, and you should always follow the instructions provided by the manufacturer when using such a system. However, here are a few helpful hints to guide you if you’re using a shaft-mount rocker system (this is not the only style of system available for LS engines, but they are by far the best). With installing an adjustable shaft rocker system, the main thing to keep in mind is to back the lash adjusters off all the way (i.e., as high as possible) so that they do not interfere with the process of tightening the mounting bolts. Also when installing and tightening their mounting bolts, since most shaft rockers are joined together as one pair for each cylinder, both lifters must simultaneously be on the base circle of the cam lobes (rotate the crank until a bit after the intake lifter returns to its lowest point). Once a rocker pair is installed, each rocker is then individually adjusted as follows: the lash adjuster is turned until it just contacts the tip of the pushrod (“zero lash”), then a specified number of turns (usually 1.5 to 2) are added to achieve the proper lifter preload. The lash adjuster is then locked in place via a nut.





Step 50: Install Valve Covers

120With all rockers installed and adjusted (as applicable), we can button up the top of the cylinder heads with the valve covers. Most LS cylinder heads use four centrally located bolts to hold the valve cover in place. These bolts must be torqued to 106 in-lbs in an inner-to-outer sequence. New valve cover gaskets are mandatory, though the grommets under each of the bolts are OK to reuse.




Step 51: Install Valley Cover or LOMA

122Set the valley cover (or LOMA on AFM-equipped engines) atop the block with a new gasket in place. Some aftermarket intake manifolds require substitution of the stock valley cover bolts, as their heads are too tall to afford adequate clearance from the floor of the intake. Either way, torque these bolts to 18 ft-lbs.

Step 52: Install Oil Pressure Sensor

123On Gen III engines, install the oil pressure sensor at the upper rear of the block (next to the cam sensor, shown); tighten to 15 ft-lbs. On Gen IV engines, the oil pressure sensor installs into the rear of the valley cover and receives 26 ft-lbs of torque. Be sure to reuse the sealing washer under the sensor (as applicable) and use some Teflon-based sealant on the threads (new sensors normally already have sealant applied).

Step 53: Knock Sensor Installation

124If your engine is a Gen III, the knock sensors mount into the top of block, in the valley cover area. Carefully lower each sensor into place and torque to 15 ft-lbs. If your engine is a Gen IV, the knock sensors install low on either side of block (not shown); the retaining bolt of each gets 15-18 ft-lbs.

Step 54: Installing Knock Sensor Wiring Harness

125Note: This step applies to Gen III engines only. For Gen IV engines, continue to the next step. Because the intake manifold is about to obstruct access to the top of the valley cover, the piece of wiring harness that connects to the knock sensors on Gen III engines must now be plugged in. Run the wiring to the rear of the engine, and make sure the seals seat properly in the valley cover as well.

Step 55: Install Coolant Air Bleed Pipes

126The last items to be installed before the intake manifold are the coolant air bleed pipes (or blockoff caps, if originally equipped at the rear—never install blockoff caps between the fronts of the cylinder heads!). As discussed when they were removed during disassembly, exact style of these pipes varies by engine; however, all are installed with bolts tightened to 106 in-lbs, making sure a gasket or O-ring is used in between.

Step 56: Install Intake Manifold (Torque Fasteners)

127Before setting the intake manifold in place, install new intake port seals (car intakes, shown) or clip new carrier-style gaskets (truck intakes) in place. The intake port seals may want to creep out of their grooves, so ensure they are seated correctly before proceeding. Remove the masking tape from your intake ports and wipe the sealing surface of the heads, then place the manifold on the engine. Start its ten bolts by hand (use some threadlocker on their threads). You will need to make sure any brackets that attach to the intake manifold (and were removed during disassembly) are returned to the same place before doing this, as some are held by the intake bolts. Torque the bolts, in the sequence shown, a first pass to 44 in-lbs and a second pass to 89 in-lbs. (Note: For factory-supercharged engines such as the LS9 and LSA, refer to your GM service manual for installation instructions.)





Step 57: Install Fuel Rails, Throttle Body and Intake Manifold Accoutrements

130Exact style of fuel rails and injectors varies by application, but they should be installed now using threadlocker on the bolts. Fuel injector O-ring seals should be lightly lubricated with engine oil to ease insertion, and again, if reusing your injectors, use of new seals is mandatory! Throttle bodies are installed via either 3 or 4 bolts, and a new seal should be used for this, too. Now is also a good time to install the MAP sensor, any PCV system hoses, brackets, throttle body sensor(s), and any other items originally removed during disassembly. The detailed notes and photos you took regarding these items will pay off big time here!



Step 58: Install Flywheel or Flexplate (Torque Fasteners, Special Tool)

132Line up the “extra” hole in the flywheel or flexplate with that in the back of the crankshaft (if applicable). Apply threadlocker to the threads of the six bolts and install them. Torque to 15 ft-lbs using the sequence shown in the accompanying diagram, then repeat this sequence for additional stages of 37 and, finally, 74 ft-lbs. A flywheel holding tool is suggested for this step, though you can also have an assistant insert a pry bar into the flywheel/flexplate’s teeth (as may have been done during disassembly). Note that some ultra-high-performance engines such as the LSA and LS9 use an 8- or 9-bolt crankshaft flange; in this case, refer to your GM service manual.



Step 59: Install Harmonic Damper (Professional Machanic Tip, Special Tool)

134Because of the high bolt torques needed for proper harmonic damper (“balancer”) installation, it is strongly recommended that you now install a flywheel holding tool to keep the crankshaft from turning over. There are two methods that can be used to press an LS damper onto the crank snout. The first involves using a harmonic balancer installation tool, which is fairly self-explanatory (not shown). But back in Chapter 2, we also mentioned that an alternate method is available, and here it is: acquire an M16 x 2.0 x 120mm bolt along with at least a few washers. Use this longer bolt (with the washers underneath to help it spin) to pull the damper onto the crank snout, switching to your old crank bolt if the longer one bottoms out. Watch to ensure the crank seal in the front cover stays intact during this process (do not lubricate the seal or the corresponding surface on the damper). With either method, once the balancer is on the crank as far as it will go, install your old crank bolt and torque to 240 ft-lbs. Remove it and ensure the crank snout is recessed no more than about 0.175-inch from the innermost ridge of the balancer. Only then may you install your new crank bolt, torquing to 37 ft-lbs plus 140 degrees of twist.


Important notes:

(1) Never attempt to press on the damper using just your old crank bolt! You will destroy the first few threads in the crank snout.(2) Some engines use a special locking washer between the front of the crank snout and the balancer (you should have noted this during engine disassembly). Be sure to install it during this step, as applicable.


(3) Because of the different length crank snouts used in some Gen IV engines (for example, LS4 and LS7), a different length bolt may be needed than that listed.

(4) While most factory cranks and dampers are not keyed to one another, many aftermarket ones are. In this case, you will need to align the keyway in the damper with the key in the crank for proper installation.


Step 60: Final Engine Assembly Complete

137At this point, final engine assembly is roughly complete. We’ve installed every key engine component, and basically everything that’s left is better considered an accessory! Your stage of desired completion at this time may vary; you’ll need to think back to engine removal and disassembly to decide “how much further to go” while the engine is still on its stand, since further component installations may hinder your ability to easily install the engine into the vehicle and/or onto the vehicle’s removable subframe. Some of the items you may wish to bolt up now, but which we will not go through in detail, include:

  • Starter motor
  • Engine mount brackets
  • Spark plugs
  • Ignition coils and brackets
  • Water pump
  • Other accessory brackets
  • Exhaust manifolds (use threadlocker on these bolts)
  • Oil filter
  • AIR system
  • Dipstick tube
  • Clutch pilot bearing/bushing

Most of these items are pretty self-explanatory to reinstall: just reverse the steps you went through during disassembly (see the Appendix for some helpful torque specifications). That said, move on to Chapter 9 for hints on installing, tuning, and breaking-in your newly-rebuilt LS!


Written by Chris Werner and Posted with Permission of CarTechBooks



LS Engine Asembly – from ChevyDIY

Borrowed from



The Ultimate Assembly Guide for LS1-LS4 Chevy Engines


When assembling an engine, a certain sequence needs to be followed. Don’t make any assumptions, as every detail must be checked.

Let’s start with your expectations, power-wise, budget-wise. You must remain realistic, as a 700-hp nitrous bullet with cast pistons and stock rods is not going to enhance your image at the race track when it comes apart in spectacular fashion.

The smart thing to do is to build an LT-based engine that is capable of driving to the track, racing for the day, and then driving home. The most popular sizes are 355 to 383 ci. For this book, we built a 355-ci engine that is almost as powerful as a 383-ci version, for a lot less money.

Prepping for Assembly

The only LT block options are whether you have two- or four-bolt main bearing caps. Otherwise, the blocks are the same. When starting to plan your project, try your best to get steel caps and straps, have the deck heights checked and corrected, and ensure the lifter bores are all measured (once in awhile you find one that is scuffed up).

The block must be cleaned before you begin. We use a method that bakes the block like cleaning an oven, and then it is shot blasted. Now it is ready to be checked for any cracks. If we are going to overbore the cylinders more than .030-inch, we sonic- check all the cylinder bores for wall thickness. The LT block easily goes .060-inch oversize for a normally aspirated application. We have built several LT-based engines at 4.100 inches (.100-inch oversize). In fact, my (Myron’s) personal 1954 Chevy Sedan Delivery is powered by a 409-ci 548-hp LT1 with a 4.100-inch bore. Something to keep in mind is that the thinner the walls are, the harder it is to keep cool.

 Line boring the mains.

To install the cam bearings, start at the rear and work forward. Make sure the oil feed holes are facing the crankshaft. All cam bearings face the crankshaft. This becomes obvious when you see the main caps with the oil feed hole facing you.

Main Bearing Caps and Straps Once the walls pass inspection, we tap the threads on all of the bolt holes in the block. Any damaged or stripped bolt holes are repaired. The block is now ready to have the main bearing caps and straps installed. You need to find the best-possible machine shop to do this work, where the technicians are familiar with the intricacies of this operation. When the angled (splayed) bolt holes are drilled, it is important that they do not go into the water jacket, which would lead to a coolant leak that would be difficult to locate. Another item that is often overlooked is the dipstick clearance near the fourth main bearing cap.

The block should now be ready to have the newly installed caps and straps align bored, leaving some material for finish align honing.


After a thorough cleaning, a Magnaflux inspection (for cracks), and a dimensional check, you have some options. If it is a very nice crankshaft, you can balance it and give it a polish on the machined surfaces. This includes de-burring and a good brushing of the oil holes. You may choose to have the crankshaft ground; if you do, be sure to specify the final journal size.

One option with factory cast or steel shafts is to have them nitride coated. This is a surface hardness treatment that helps a crankshaft last linger and survive in harsh environments. The first step is to have the shaft normalized, which makes it stable so that after grinding (when it goes to be heat treated) it needs only a minimum amount of straightening. The result is a crankshaft with a very hard surface that is scuff resistant. This is not cheap, but as a rule it is less expensive than a new aftermarket crankshaft. Of course if you are building a stroker with a new (longer stroke) crankshaft, you do not have do this.

Another option is to cryogenically treat the parts. This has been popular with top-of-the-line builders with good results. This ultra-cold treatment aligns the molecular structure in the metal, resulting in a stronger part.


 The next piece of the short-block puzzle is the pistons and wrist pin assembly. Custom pistons vary in quality. The most important dimension is the piston-to-wall clearance. The most critical surface is the bottom of the ring lands, because if the ring grooves are not ultra-smooth, combustion gases can blow under the ring and cause a large loss of power. That also means that the ring end gaps need to be set precisely.

The wrist-pin-to-piston clearance is usually set by the manufacturer, but it still needs to be checked. If it is too tight, it scuffs. If it is too loose, you hear a little noise that is a “double chuckle” under a no-load situation. For a mild street engine, something about .0005-inch is in order. A maximum effort drag racing engine commands .0009-inch clearance.

The piston rings are next. Again, all of the dimensions need to be checked. This includes groove depth and width and of course, the end gap when the bores are finished.

At this point we bore the block giving the pistons just enough clearance so that after a quick hone and run through the hot tank we can mock up the assembly. The reason for not finishing the bore at this time is to keep the piston stable in the bore, which makes an accurate deck- height check possible.

We’ve chosen to use a fullfloating-design piston pin in this engine. These require no special preparation techniques and make assembly relatively easy. If you have a press-fi t pin setup, you need to make a test pin out of aluminum to avoid ruining (and buying!) the wrong piston.

To check the deck height, put a piston and rod assembly in the four corner bores and measure the amount that needs to be cut. Today’s engine blocks are much better when it comes to the factory machine work. The target dimension is around .002 inch, end-to-end. For all cast-iron blocks with steel connecting rods, set the deck height at zero and use a .040-inch-thick head gasket. This gives a quench clearance that pro- motes a quick mixture motion, leading to a chamber that is not as octane sensitive. Also look up at the pin end to make sure that the small end of the rod has clearance in the piston. Once you’re satisfied that the reciprocating assembly has proper clearances throughout, run everything through the hot tank again.

Next, check for piston-to-valve clearance (we assume the heads are assembled and ready to go). Remove the springs from the number-1 cylinder and substitute a set of lightweight springs to make the job of checking easier. We use a set of old cam bearings that had the OD turned down so that they just slip in. Remember, we are going to go back to the hone to finish the bores and a final cleaning so we don’t want to drive in a new set of cam bearings only to take them out again.

The piston-to-valve clearance needs to be sufficient so the valves and pistons never make contact. There are several things to consider: whether you’ll be using an automatic or manual gearbox, whether the engine will be living on the street or the dragstrip, or both, etc. All of these factors have a bearing on your decisions regarding the finishing details. Let’s assume everything is average for this particular build.

The intake valve clearance is usually less than the exhaust valve clearance. The reason for this is that the piston chases the exhaust valve up the bore on the exhaust stroke. If you are at the limit of the valve- train’s ability to control the valve motion, things begin to crash. Conversely, the intake valve chases the piston down the bore, and this puts the intake components under compression. Therefore, less clearance is needed. A good number for the exhaust is .100 to .125 inch, and the intake only needs .060 to .080 inch.

At this time you should check the compression ratio to make sure that it meets your specification. You need a dab of oil on the top ring on the piston to help seal things up. We use a Katech Whistler tool to accomplish this, but you could use a CC tube to figure out the compression ratio the old- fashioned way—by measuring the volume of the bore, gasket, and cylinder head at both bottom dead center (BDC) and top dead center (TDC) and comparing them to create a ratio.

Bore Honing

 The short block is now ready for the bores to be honed to their final size. The piston-to-wall clearance that you end up with depends on the piston alloy. The block is run through

the hot tank for the final time, paying the most attention to the bores. Before using a compressed-air blowgun, wipe the block with a clean white cloth coated with a rust preventative, such as AMSOIL MP. This keeps a rust haze from forming in the bores and is also the only thing that we are going to use on the bores themselves during final assembly.

Ring Gap

Next, the ring end gap needs to be checked with a feeler gauge and corrected. This can be done with a fi le or with a specialty ring grinder. Follow the piston and ring manufacturer’s gap recommendation. With too little clearance, you take a big chance of pulling a ring land off when the engine gets up to temperature. With too much ring gap, you have excessive blow-by, oil burning, and lots of smoke out the exhaust pipe. The proper gap is critical, so take the time to ensure it’s right.

Piston Pin Locks

Begin final assembly with the installation of the piston pin locks. Once you have one set of locks in the pistons, add a drop of oil in the pin bores. Install the pin in the piston and move the pin in and out to

make sure the oil is spread evenly. Wipe a little oil in the small end of the rod. Hook the two together and install the remaining pin locks. The end play of the wrist pin needs to be near zero. Otherwise the pin can act as a battering ram and drive the locks out.


With the pistons hung on the rods and ready to install, you can prepare the block for them. Install all the galley and frost plugs. Next come the cam bearings, and then install the camshaft and make sure it turns freely.

Install a main bearing and torque the cap. Measure the vertical clearance. We like to set the clearance between .0018 and .0020 inch. This applies to most engines. Any more than this makes the rotating assembly fl ow too much oil, resulting in oil pressure problems, such as low oil pressure at a hot idle. We use the same clearance on the rod bearings. One note here is that some crank- shafts have very large radii fi lets. Be sure that the bearings do touch in this area; this means the rod bearings also.

All the piston and rod assemblies are ready to be installed. To prepare the bores, wipe each bore briskly with a clean rag soaked in some lacquer thinner until the rag comes out clean. Then coat the bores with Amsoil MP, leaving a light fi lm.

Next, put a small amount of Total-Seal (a quick-seal dry assembly lube) on your finger. This is a black powder that provides the proper lubrication during the critical break-in period. It virtually eliminates cylinder-wall burnishing and glazing. Rub the top 2 inches of the bore with your finger. If you have done a good job and the bores are clean, the surface has a greenish cast to it.

Bottom End Assembly

Once you’ve accomplished all of the prep work, you can begin the bottom end assembly process. The actual assembly process doesn’t take nearly as much time as the preparation. Knowing everything will fi t correctly and that all of the bearing clearances are correct means you can simply put the parts together. Remember to use a quality assembly lubricant on all of the bearing surfaces prior to assembly.

Once you are happy with the clearance on the main bearings, it’s time to install the crankshaft. For years we have used Amsoil synthetic gear lube as the assembly oil. We use it everywhere. You don’t need much. Our rule is that if it drips on the floor, you have used too much.

There’s no real trick here; just be careful, as you need to make sure that you have proper end play, and that the rear of the thrust face on the center main is seated against the thrust surface on the crankshaft.

You are now ready to install the piston and rod assemblies. We use very little lube because when an engine runs there is very little oil above the ring travel. In the old days, dipping the piston in a can of oil was overkill. We put just a drop of oil on the skirt of the piston and rub it around, and make no attempt to lube the rings; that job is for the Quick Seat lube powder.

Install your tapered-ring compressor over the rings, being sure to space the ring end gaps evenly. Put a spot of oil on the rod bearing and install. At this time do not torque the rod bolts, just snug them. When you have all eight pistons installed, torque the rod bolts. Once this is done, be sure to move each rod pair back and forth to make certain that the rod seats against the crank cheek. Some of today’s aftermarket crankshafts have extra-large radii fi lets, which causes an interference between the edge of the rod or main bearing and the fi let. Also many of today’s rod bearings have a top and a bottom.

It is now time to install the front cover with the Optispark along with the damper and water pump. The rear seal is next. It is important to note that some seals on the engine are installed dry and others need to be oiled. Read the instructions that come with the seals.

More often than not we fi nd there is too much oil pressure when setting up the oil pump. The old rule of having 10 pounds for each 1,000 rpm is okay up 5,000 rpm. After that, it gets to be too much. My (Myron) World Challenge competition Camaro was about 40 psi at 7,000 rpm. After two years of racing, the bearings looked like new.) The spring that comes in a standard oil pump is usually set to bypass at about 40 psi with hot oil. This should be enough. You might shim the spring with one washer.

The next thing is to set the clearance between the bottom of the pickup and the pan. This dimension should be 1/4 to 3/8 inch. As for the oil pan, we typically use a road-race style as most of our customers run F- and Y-Body cars.

Top End Assembly

Installing the heads is pretty straightforward. There are just a few things to think about. We typically use new head bolts; it is cheaper than cleaning the old ones. As for head studs we do not use them on blocks with bolt holes that go into water. They almost always weep coolant into the crankcase or dribble down the outside of the engine. We use CMD Extreme Pressure Lube Number 3 under the head of the bolt. On the threads, we use silicone sealant or a Tefl on sealant. The heads are torqued in the normal fashion in accordance with the factory circular torque pattern.

On new aluminum heads, we use a brass drift and a large hammer to give each bolt a medium rap after the initial torque. Then, we loosen each bolt and re-torque. The aluminum compresses and work-hardens. This technique allows the bolts to remain at the proper torque setting.

When installing the valvetrain, it is important to make sure that the rocker arm geometry is correct. One of the major factors that determine the correct geometry is the length of the pushrods. Pushrod length is directly affected by the length of the tappet and the installed height of the valvestem, and needs to be measured carefully prior to assembly to ensure proper length Once the geometry is set and the valves are adjusted, it is time to prime the oil pump. This needs to be done before the stock LT1 intake is installed, because there is no provision on the intake to use the traditional oil pump priming tool. Be sure to install the oil filter, plug the oil pressure port, and that the drain plug is tight with a new gasket. Put in your oil of choice. Once you have primed the pump install the oil pump drive before installing the intake.

Next, install the intake manifold. Start by doing a test fi t without any sealant. Use the gaskets that match your port size; the LT has little plastic dowels that hold the gaskets in place. There should be around .040- inch clearances under both ends of the manifold, as this allows the manifold to settle. Check for both bolt hole alignment and intake port alignment. Once you are satisfied, put a little silicone around the water ports and the bottom of the intake ports along with a bead at each end of the block. Set the intake manifold in place and just snug the bolts. We are going to come back in a few hours and finish tightening the bolts to the specified torque.

Bolt the intake manifold into place. Install the throttle body, fuel rails, and injectors as shown.

Step-1: Inspect Oil Galley Plugs

1The galley plugs here are the factory style, pressed in and then staked with a chisel. This motor is mild-performance, so factory plugs are just fine.














Step-2: Inspect Oil Galley Plugs (Continued)

2There is an important galley plug at the rear of the engine not to miss. If you do, oil squirts all over the place, requiring you to remove the head and install the plug.





Step-3: Note Drive Type

3The rear plugs are screw-in types. Notice the Allen-key- style drive.






Step-4: Choose Lube

4We swear by this type of lube for our assemblies.






Step-5: Tighten Bolts

5Use the lube on the threads and under the head of the bolts; tighten to 70 ft-lbs of torque.




Step-6: Measure Clearance

06The correct way to measure rod or main bearing clearance is to use an inside and outside micrometer. Although it’s common practice to use Plasti-gauge, we feel that the micrometer is far more accurate.







6This is a very delicate operation and requires “feel.” If you are ham-fisted, try not to do this on your own. For this build we had a clearance of .0018 inch, which is what we want for a solid build. We want it below .002 and over .0018 inch of clearance.






Step-7: Choose Break-in Lube

7It is very important that you use a break-in lube with high zinc content, so the zinc acts as a barrier between the metals.












Step-8: Lube Bearings

8A small dab of lubricant on each bearing should do the trick.




Step-9: Check Galley Plug

9This series of photos shows the hidden galley plug that is inside the marked hole. Without this, the oil travels from the oil pump directly to the bearing, essentially bypassing the oil filter. This will cost you a motor! Triple check that this plug has been installed.


















Bore Preparation


Step-1: Inspect Machine

1This scale and fixture is used for determining the big-end weight of the connecting rod.






Step-2: Use Belt Sander

2To get all the end weights of the connecting rods consistent, we use a belt sander.












Step-3: Create Balance Sheet

3All the rods are weighed to find the lightest. The other seven are then machined to make them all weigh the same. The rest of the components of the connecting rod assembly are also weighed as a unit. Notice on the balance sheet that we use two big ends as part of the calculation because there are two big ends on each crank journal along with two sets of rod bearings. For the rest of the components, we use one of each and then 5 grams for oil. Add the column and divide by 2. Each number is now half of the bob-weight.


Step-4: Disassemble Bob-weight

4Here’s how a bob-weight comes apart. Great care must be taken installing them to get them evenly spaced across each journal. (The crank is then spun to determine the crank balance throughout the RPM range.)













Step-5: Tighten or Loosen Connecting Rod Bolts

5The wrong way (top left); the “just OK” way (top right) to loosen rod bolts. This (bottom left and bottom right) is the correct way to loosen them.






Step-6: Measure Rod Bearing Clearance

6The correct way to measure rod bearing clearance is to use an inside and outside micrometer.






Step-7: Insert Ring into Bore

7Tip the ring into the bore carefully.







Step-8: Square Ring

8Use ring-squaring tool to level the ring inside the cylinder bore.






Step-9: Measure End Gap

9Use feeler gauge to measure end gap. Minimum end gap is 4.5 x bore diameter in thousands of an inch.





Step-10: Adjust End Gap

10Piston ring end gap is adjusted by grinding the ends of the ring until the proper gap is achieved. The proper way to do this is by using a piston ring grinder (shown). It can also be done by hand fi ling (which should still be done after the ring is gapped very close to the target dimension), but the grinder saves a lot of time. Remember, you can make the end gap larger, but you cannot make it smaller. It’s best to creep up on the proper dimension slowly, making regular measurements until you’re within a couple thousandths. Then, finish the work by hand to ensure a smooth surface on both sides of the gapped ring.


Step-11: Clean Inside of Bore

11Use Amsoil Metal Protector or similar product to clean the inside of the bores.









Step-12: Check Ring Seat

12You can use dry assembly lube to ensure that the rings seat properly. Doing this gets a much faster ring seal than ever before. In the old days, builders dunked the pistons in oil prior to installation. Today’s modern cylinder bores are miles ahead of previous years of engine building due to modern machining tolerances. When the lube turns green, it is done doing its job.


Crankshaft Installation


Step-1: Choose Gear Lube

1We use Amsoil gear lube to assemble the motor.








Step-2: Align Bearing Tangs

2Align the tangs of the bearings together for proper alignment. Make sure the back of the bearing is completely dry before installing.



Step-3: Prepare to Torque Bolts

3Running the bolts down saves time before torquing them.





Step-4: Torque Bolts

4Spin the crank as you torque down the main caps to check for freedom. Start torquing the caps at 45 ft-lbs and then proceed to the final torque rating of 70 ft-lbs.





Step-5: Align Crankshaft Thrust Surfaces

5Force the crankshaft forward (as shown with a screwdriver between the main cap and the crankshaft, arrow) and gently tap the rear cap to the rear. When completed, set up your dial indicator and determine crankshaft endplay. You should have approximately .003 to .005 inch. The crankshaft must turn freely with no sticking points.










Piston and Rod Assembly Installation


Step-1: Lubricate Piston

1A small dab of oil should do the trick to make sure the piston is lubricated properly while you run it home.




Step-2: Check for Interference

2Under certain circumstances, some components may have interference between the crank journal and the rod bearing (left). If this is the case in your build, you must chamfer the bearings to avoid rubbing (right).







Step-3: Install Oil Rings

3Install the oil ring in its groove. We use a method of rolling it into place rather than spreading it. This is the same for the top and bottom rings.
















Step-4: Check Skirt Diameter

4Make sure that all rings go below the surface of the piston. The skirt diameter of the piston is wider by approximately .020 inch than the top lands of the piston. It is therefore important that the rings do not protrude beyond the surface.





Step-5: Use Alignment Marks

5If the rings are marked, the marks must face upward. All ring packages come with instructions, make sure to follow the specific instructions for your set.





Step-6: Install Top and Second Ring

06Install the top and second ring by inserting the tip gently and sliding the rings around the piston. Offset the ring gaps prior to installation.





6If the ring package tension is light you may be able to push the piston in with your hands.






Step-7: Tap Ring into Place

7Stiffer- tension ring packages may need to be rammed home with the butt end of a hammer.






Step-8: Guide Connecting Rod

8Guiding the connecting rod onto the crank ensures it does not knick the crank journal. There is a tool for this, but after forty years I use my fingers.





Step-9: Check Clearance Between Piston and Connecting Rod Small End

9Make sure that you have enough clearance between the two when installing your pistons. We have seen instances where custom rods, custom pistons, and custom crank shafts incur binding issues that can lead to catastrophic failure of the motor.










Step-10: Install Camshaft

10Installing the camshaft requires a steady hand, as not to damage or mar the soft cam bearing surfaces.




Step-11: Install Water Pump Drive

11Gently tap the water pump drive into place, being careful not to hit the sprockets, as they could gall.






Step-12: Add Loctite to Threads

12A dab of Red Loctite on the threads is plenty to keep the retaining bolts in place.






Step-13: Spin Bearing

13Spin the bearing to make sure it is free and does not hang up.






Step-14: Add Loctite to Cam Retainers

14Another dab of Loctite goes on the cam retainers.






Step-15: Install Camshaft Thrust Plate

15Cam retainer and fasteners are installed using loctite.





Timing Chain and Cover, Optispark and Rear Seal Installation


Step-1: Align Cam Gear Dot

1When installing the Cloyes timing set, make sure to align the cam gear dot with the crank gear’s round marking, which can be difficult to see. This is for the factory-specified timing. To advance the timing, use the triangle marking and the square marking to retard the timing, per the instructions.



Step-2: Install Crank Gear

2Use solid blows to install the crank gear; this may take a few jolts to get it seated properly.





Step-3: Install Cam Gear

3Set the motor to TDC and install the cam gear with the chain. Again, Loctite is your friend with the retaining bolts.







Step-4: Tighten Camshaft Retaining Bolts

4Tighten camshaft retaining bolts to 30 ft-lbs.







Step-5: Install Reluctor Wheel

5Install the reluctor wheel, keyed properly.







Step-6: Apply Lube to Seals

6Prior to installing the seals, it is always a good idea to apply a thin coat of lubricant such as grease on the sealing lip and shaft per the instructions from Fel-Pro. Press these seals in with a large socket or a fl at plate and a hammer. In this case, we use a press, which is ultimately the correct way. Be sure to put solid support under the cover to ensure that you do not scratch or mar the polished cover.


Step-7: Apply RTV to Cover Gasket

7Apply a thin layer of RTV to hold the cover gasket in place.






Step-8: Apply RTV to Cover

8Repeat the process on the cover.







Step-9: Tap on Timing Cover

9The timing cover may require some persuasion from a rubber mallet or, in our case, the plastic butt end of a hammer.






Step-10: Choose Timing Cover Bolts

10There are two lengths of bolts for the timing cover; finding the correct ones should be fairly straight- forward.






Step-11: Install Distributor Shaft Seal

011The distributor shaft seal is a PTFE seal and must be installed dry. Do not lubricate the lip or the seal. Put this seal in when the cover is installed on the motor. Caution: The seal tends to fold over itself and cause a lot of headaches for owners when the seal leaks.





11The best way to ensure that the seal does not leak is to work inward toward the gear prior to installation so that it does not hang up. We use a spare gear set to massage it into shape. You are not able to see if it is hung up until you start the motor.




Step-12: Verify Crank Timing

12We cut a keyway into the crank hub to verify that the crank is properly timed and to verify the accuracy of the timing. You may need to have a machine shop complete this task for you.





Step-13: Align Distributor to Camshaft

13Ultimately, it may be easier to remove the cover of the distributor to align it to the camshaft. The size for this is an E4 Torx bit.




Step-14: Install Hub

14Pound the hub into place until it seats flush against the timing gear.






Step-15: Add Lube to Rear Seal

15The rear seal gets a small amount of assembly lube to help drive it home and seal it well.




Step-16: Find Gasket Stud

16The rear main seal adapter gasket on the driver’s side should have a stud. The passenger side has an indexing dowel.





Step-17: Install Rear Main Seal

17Installing the rear main seal requires care so as to not let the seal fold upon itself. Do not use a screwdriver to do this; use your finger to massage it onto the crank, working it back and forth until it seats.




Oil System and Pan Installation


Step-1: Inspect Valley Pan Spider Spring

1Here, the valley pan spider spring is resting in position.








Step-2: Install Oil Pump Pickup

2Installing the oil pump pick up often requires a special tool and often requires welding to keep it in place.





Step-3: Test Fit Oil Pan

3Using a piece of clay and some plastic, we place the oil pan over the pump to get a satisfactory distance between the pump and pan. The ideal depth is 3/8 inch.



Step-4: Pre-Lube Oil Pump

4Pre-lubing the oil pump helps it prime faster. You must prime the pump before you start the engine for the first time.





Step-5: Add RTV to Oil Pan Gasket

5A good bead of RTV on both sides of the Fel-Pro one-piece oil pan gasket is needed.














Step-6: Install Oil Pan

6The bottom is capped off by the oil pan. (In this photo you can see that the cylinder heads are already in place. You can install the oil pan before you install the heads.)







Step-7: Add Oil Pan Straps

7Straps are added to make sure the oil pan has been evenly snugged into place. They should be tightened until compression is made on the gasket. We let the RTV set for 24 hours and then come back to retighten the bolts.






Head Installation


Step-1: Choose Gaskets

1We are using Victor Reinz gaskets (PN 5898). We did not deck this block, resulting in a .030-inch deck height. To compensate we use a .030-inch-thick head gasket, which gives a quench clearance of .060 inch, which is .020 inch more than what is considered ideal.




Step-2: Add Thread Sealer

2A small dab of Tefl on thread sealer on each thread helps seal the holes from water.






Step-3: Tighten Head Bolts

03Head bolts are tightened in three equal steps to 70 ft-lbs with a dose of fastener assembly lube. In the approved sequence, bolts are tightened in a circular pattern. The first lap starts at 30 ft-lbs, the second lap at 50 ft-lbs, and the third onto 70 ft-lbs. A smooth, careful motion with a quality torque wrench is your best bet.



3A couple firm taps on each head bolt and then another round of tightening to 70 ft-lbs saves you a lot of work later when retorquing the heads. This works best on new heads and less so on older used heads. This may seem a little crude, but it is quite effective and saves a retorque later.


Valvetrain Installation


Step-1: Add Lube to Lifters

1With a liberal amount of zinc-laden assembly lube, the lifters come next.








Step-2: Inspect Tie Bars

2These tie bars have the fl at end matching the fl at end of the lifter. Tie bars are essential and must not be omitted.







Step-3: Add Lube to Pushrods

3Zinc assembly lube is dripped on all the top and bottom of all pushrods.







Step-4: Add Oil to Valve

4A dab of oil on each valve does the trick.







Step-5: Tighten Spider Gear

5Tighten the spider gear, holding the lifter retainers in place.






Rocker Arm Installation


Step-1: Torque Rocker Studs

1Rocker studs come next and are torqued down to 55 ft-lbs.





Step-2: Install Exhaust Rocker Arm

2When the exhaust valve just barely begins to open, take the intake and run the nut down to zero lash (21198). Then roll the motor over until the intake just closes. Install the exhaust rocker arm and take it down to zero lash (21199). This procedure is used throughout the entire drivetrain. At this point you should be using this time to spin the crank shaft to notice any binds throughout the motor, i.e., camshaft ticks, connecting rod clearance, etc.















Step-3: Adjust Rocker Stud Alignment

003A quick check before you throw the valve covers on. You can use a fl at bar to see if the rocker studs are fairly equal. They should be within one turn of each other.





03One full turn of each rocker stud suffices. This is a quick way to make sure the rockers are properly snug and do not need to be fiddled with later.







3Finally, snug the lock nut tight, back off the stud nut about a 1/16 turn, then tighten both stud and lock nut as one.







Final Top End Assembly


Step-1: Prime Oil Pump

1Using a drill, the pump is primed prior to installing the gear drive to make sure the pump is functional and to pre-lube it prior to the first start up. This requires a special tool; or a modified distributor works just as well.






Step-2: Inspect Oil Pump Drive Gear

2A new gear is cheap insurance. Our old one (left) has seen a lot of use and is worn down and needed to be replaced.






Step-3: Install Oil Pump Drive Gear

3Install the oil pump drive gear.








Intake Manifold Installation


Step-1: Inspect Gaskets

1Make sure your gaskets are LT-specific with no coolant holes.



Step-2: Check Gasket Fit

2Inspect throttle body gasket for alignment and fi t.




Written by Eric McClellan and Posted with Permission of CarTechBooks