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My First Stroker Part 3 - LS1 Engine Build
Our garage-built 383 gets its final parts installations, making this stroked LS1 ready to run!
Nov 1, 2006
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My First Stroker Part 3 - LS1 Engine Build
Jesel offers a specific version of its J2K Shaft Rocker System for just about any Gen III cylinder head on the market-including our ETP 215cc units. ARP hardware and a shotpeened surface are strength-enhancing features that come standard. Carrying PN K2A-SP1218, they retail for $1,525.
Jesel includes a pushrod length checker in all of its rocker kits. This handy item can be finely adjusted within a length range of six to nine inches. The particular model included in our rocker kit is a two-piece (four, if you count the ball ends) not only to enable a wider range of adjustment, but so that the length of each aluminum segment falls within the measurement range of a typical caliper (6 in).
The instructions included with the rockers list a proper preload operating range of .25 to 2 turns on the lash adjuster. Jesel specifies one full turn is the ideal location for the adjuster, so before beginning any measurements, we loosen the adjuster's lock nut, back the adjuster all the way out until it can't turn any more (the adjuster being all the way up in its bore), and rotate one full turn using an Allen key. The adjuster's lock nut is then tightened so that the adjuster will remain at one full turn while we perform our measurements.
Now, the billet steel Jesel rocker stand is bolted to the cylinder head. The supplied 8mm bolts thread into the same holes (helicoiled by ETP) where rocker studs would normally go, making the Jesel shaft rocker system a true bolt-on piece. Before putting the stand in place, you might want to re-torque your head bolts or studs one last time (it should be done a few times as the gasket slowly seats); once installed, the rocker stand will obstruct access to some of them.
After making sure cylinder numero uno's lifters are riding on the base circle of the cam (use the procedure we detailed last issue), Jesel's pushrod length checker is inserted. Here we put it in the intake position-both intake and exhaust must be checked, but which to do first is entirely up to you. You can see that the black adjustable end of the checker is capable of being turned with a wrench, but just your fingers will suffice.
The Jesel rocker assembly is placed loosely on the rocker stand. As you can see, there is one shaft assembly for each cylinder, on which ride an intake rocker (left) and exhaust rocker (right). At this point, roughly adjust the checker so the rocker assembly can sit flat on the stand. You can see the adjustable end of the checker beneath the lash adjuster; though in close quarters, there's ample room to get at it with your fingertips.
Now bolt the rocker assembly to the stand. Each set of rockers is secured by a total of three bolts through its shaft: two stainless 5/16-18 bolts turned with a 3/8 12-point socket, and one 3/8-16 bolt turned with a so-called T50 Plus-a better version of Torx that has more rounded edges at the points. (Jesel is nice enough to supply a T50 Plus socket for you to use.) Again, all of these are quality ARP bolts.
With the rocker shaft bolted to the stand, adjust the checker so it butts squarely against the inside of the rocker's lash adjuster cup seat. Note: during this process, the lifters should not have any oil in them as this will throw off the reading. But if you've already soaked them (as we did last time), the lifters are easily bled down. Simply hold the checker down against the lifter plunger; the lifter will bleed down over the span of just a few seconds. Sometimes this won't work as you can't generate enough force: in this case, pull up on the tip of the rocker and you'll see it slowly lift off the valve further and further. Alternatively, turn down the adjuster and the oil will get squeezed out; it won't tighten firmly until the lifter plunger actually bottoms (just make sure you bring the adjuster back to one full turn after this).
With the lifters free of oil, you'll note that tugging upward on the rocker will allow it to tilt backward, pulling its tip off the valve. This isn't because there's any physical space between the valvetrain components anymore: rather, you're compressing the lifter plunger's internal spring. Unlike solid lifters, hydraulic lifters have a range of travel that allows the rocker tip to stay in contact with the valve, compensating for the expansion and contraction of metal that occurs at different engine temperatures. When adjusting the valves once we have our real pushrods in hand, we'll set the rocker adjuster to put the lifter in its correct "preload" range. But there's also the operating range for the adjuster (.25 to 2 turns): so we're making sure we buy pushrods that will put us within the relatively narrow window where both the lifter plunger and rocker adjuster can be at their proper positions.
Enough with the theory, back to practice. The range of possible hydraulic lifter preload can be confusing (pushrod length measurement is much easier for solid lifters), but just adjust the checker so it's firm against the inside of the adjuster cup and the end of the checker is difficult to spin (thanks to friction). Remove the rocker assembly, take the checker out, and measure its length using a caliper like our Powerhouse unit. We get an overall length of 7.850 inches. Repeating the process on the exhaust, we wind up with 7.890. It looks like we're in the range of 7.900 for the correct pushrod length (they're normally sold in increments of 0.050 inches).
To make sure the 7.900 number is right, we're going to experiment a bit. We'll now set the checker out of the engine; then, in lieu of playing with the length of the checker while installed, we'll alter the position of the rocker adjuster instead. Here you can see this rocker system's cup-seat adjuster in action; turning it clockwise reduces clearance (lowers the adjuster out of its bore; right) and counterclockwise increases clearance (pulls it into its bore; left). Be sure during the following process of turning the lash adjuster that you're actually bottoming the lifter plunger and not simply hitting the adjuster's lock nut against the rocker; have a 12-point 3/8 wrench ready to back this nut off as far as needed.
First, we adjust the checker to 7.950 (the next possible length pushrod we could buy) and see if it'll work. It doesn't: the adjuster causes the lifter plunger to bottom out at only a turn and a half. After adjusting the checker to 7.850, we try again and find that after two full turns on the adjuster, there's still a ton of plunger travel left before bottoming it out. In fact, the plunger doesn't bottom until almost 3 1/2 turns of the lash adjuster-way past Jesel's proper spec. (Here you see us backing the lock nut off even further to get to this extreme 3 1/2 turn position).
Bringing the checker back to 7.900 inches and putting it in place, we find that at a quarter turn on the rocker adjuster, there's too much play in the lifter plunger; but at exactly two full turns, the plunger bottoms out. This means that where we'll need to be on the lash adjuster is somewhere between .25 and 2 turns (2 1/2 when tested on the exhaust)-just about what Jesel specifies. We double-checked on cylinder number eight (passenger side rear) and got near-identical results: so 7.900 is as good as we are going to get!
Our pushrods of choice are Manley PN 25712-16 Swedged End Pushrods. Retailing for $140, these suckers are made from heat-treated 4130 chrome moly and feature a 0.080-inch wall thickness and a black oxide finish. While these particular pushrods are 5/16 in diameter, larger diameters are available for truly sick valvespring pressures. They're manufactured in Manley's Lakewood, N.J. facility for top-notch quality and are readily available in length increments of 0.050 inches (and in some cases 0.025).
After a thorough cleaning, slide all 16 pushrods into their holes. It's critical that you look through them to make sure no crud occupies their center oil passages; otherwise, the upper valvetrain could be starved of oil and accelerated wear will result.
We need to install and adjust each rocker arm set one at a time since at any given point in the crank rotation, different valves are open on various cylinders. Remember, each rocker assembly can only be bolted on when both valves on that cylinder are closed. We begin with cylinder number one. Before popping the rockers atop the stand, we lube the tips of both pushrods with Jesel's provided extreme pressure lube; this will ensure proper break-in of the pushrod tip/rocker adjuster surface meeting (an area that experiences a large amount of force). This is the only area of the Gen III engine where any sort of "break-in" lube is required.
To ensure we are at the number-one firing position (where both valves are sure to be closed), we can again look through this convenient hole in the lifter valley and see whether both cylinder one's lifters are on their cam lobe base circles. Recall that you might have to press down on the pushrods to get the lifters to come down out of their trays.
Now, after putting some more extreme pressure lube under the rocker lash adjuster cup seats (which Jesel makes out of super-tough tool steel by the way), adjust them all the way up into their bores and bolt the rocker assembly in place. The T50 Plus stand/shaft bolt gets 45 lb-ft and the two 12-point ARP 2000 stainless steel 5/16-18 shaft bolts receive 35 lb-ft of torque. With the rockers secured, we can adjust the rockers one at a time using the above-mentioned decades-old procedure...
Spin the pushrod between your fingertips while slowly tightening the adjuster with a 1/8 hex wrench. When the pushrod becomes difficult to spin, stop; you've just taken all the "lash" out of the lifter, meaning the pushrod is now seated on the lifter and pressing against its plunger. Make sure what you're feeling here is tension from the lifter plunger's internal spring and NOT the plunger being bottomed out! At this point, Lunati's valve adjustment instructions state to add another 1/2 turn on the adjuster, which we do. Just as a double-check, remember this "proper" position and keep turning the adjuster until the plunger bottoms; the proper location should be at least .75 to one full turn back (in this author's opinion).
After bringing the adjuster back to its proper position, the lash adjuster's lock nut is then torqued to 25 lb-ft. Jesel says overtightening this nut is the most common cause of rocker failure, so make sure it's tight to spec (but get it pretty tight before putting the torque wrench on so you know the adjuster itself won't spin while the nut is being secured). Having addressed both the intake and the exhaust rocker, cylinder number one's rockers have been properly adjusted, so we'll move on to the other cylinders.
We chose to go along with the firing order of the LS1 engine (1-8-7-2-6-5-4-3) but you can go in whatever order you'd like; just don't confuse which rockers have already been bolted on and adjusted! For cylinders where you can't see the lifters (3, 5, 4, 6) it's hard to know when they're on the cam's base circle, so you'll need to spin the engine and watch the pushrods and/or rockers move (noting again that pushrods without rockers won't go down without pressure on them due to the GM lifter trays holding the lifters up).
Watch for any minor interference issues as you go through the process of installing and adjusting the rockers. When bolting on the rocker assembly for cylinder seven (driver's side rear), we found the exhaust rocker was in close proximity to the head's valve cover rail. The area was meticulously masked off and lightly ground with a die grinder, with care being taken not to go so far as to potentially affect the sealing of the valve cover gasket. With the rocker assembly reinstalled, the engine is spun over to make sure no interference exists at any point in the rocker's range of motion. Success!
The remainder of the rocker assemblies were bolted on and adjusted without problem, and the installed Jesel J2K Shaft Rocker System looks just as good here as it does under the hood of the C6R. You'll note in this final photo that we've masked off all the intake and exhaust ports; with the valves now operational, we don't want anything accidentally falling into a port and finding its way inside a cylinder-necessitating head removal (both of the cylinder, and perhaps that of the clumsy perpetrator)!
The valley cover includes provisions for the LS1's two knock sensors to be isolated from the oily engine interior. GM recommends that new knock sensor grommets be installed in the valley cover ($3.41 for a set of 5, PN 12558177), which we do here after knocking the old ones out with a socket and hammer. They're lightly lubed with oil before installation.
Here's a look at the LS1's driver side (bottom) and passenger side (top) valve covers. One can see the PCV baffling located on the underside of each, which in our case prevented them from being reinstalled as-is. A good bit of material removal, trial-fitting, followed by more material removal will be required until the valve covers will fit. We've got our fingers crossed!
The underside of the driver side valve cover has a stamped metal baffling piece running along its top edge, which the adjusters of our rocker arms bashed right into. It comes off by a light grind of the aluminum tabs holding it down, followed by simply yanking it out.
Many of the cast-in aluminum tabs that held the metal baffling to the underside of the driver side cover will need to be ground away, and most significantly, the far rear rocker (number seven exhaust) interferes heavily since the cover sits lower here in the vicinity of the PCV system grommet. Significant grinding had to be done, but we were very cautious not to go too far and break through to the outside, rendering our valve cover useless (save for a possible JB Weld fix).
As to the passenger side valve cover, things aren't as bad; in fact, none of the aluminum underside of it actually hit the rocker arms. Rather, the black plastic baffling-and aluminum vanes holding them-jut very deep and hit the actual shafts of the rocker system. It's a simply matter of snapping off the plastic, then cutting and breaking out the aluminum vanes, as shown here.
Once clearance is checked and verified to be OK, the valve covers are thoroughly cleaned of all metal shavings and set atop the heads. Being sure to use a new GM valve cover gasket (PN 12560696), torque the stock valve cover bolts to 106 in-lb. Turn the crank over at least twice (one cam revolution) and make sure you don't hear any contact under the covers. If it sounds OK and there's no binding as you're trying to turn the crank, you should be good to go!
We weren't able to get our hands on a new GM valley cover gasket (PN 12558178) in time for our engine assembly, so we were forced to reuse the stock one. Like the oil pan and front/rear cover gaskets, it's a controlled compression aluminum carrier design like we described in our gasket sidebar last issue. After thorough cleaning of all surfaces, the valley cover is set in place and the bolts torqued to 18 lb-ft. Though ARP has bolt kits available for the valley cover (PN 434-8001, $36.04 for stainless hex-head bolts), we had to use our F.A.S.T.-supplied button-head cap screws which, with their flatter heads, give enough clearance for the thicker-than-stock F.A.S.T. intake to sit above.
By virtue of their location in the valley area between the cylinder banks, the LS1's knock sensors are excellently positioned in the block to sense engine acoustics. They look the same as the knock sensors GM has been using since the TPI days, but are specially tuned for the acoustic signature produced by abnormal combustion in the LS1's aluminum-block engine. They are torqued to 15 lb-ft with a 7/8 deep socket. Don't overtighten these suckers, they're sensitive pieces of equipment! The piece of wiring harness that connects to these two sensors must also now be installed as the intake manifold is soon to go on atop them.
The main upgrade we chose for our ignition system is a set of MSD's Multiple Spark Coil (MSC) LS-1/LS-6 Blaster Coils. The coils are sold for $578.60 under PN 82458 and fit nearly all Gen III engines; MSD also has available a PN 82468 "MSC II" coil kit for Gen III engines that use a different factory wiring harness connector (such as GM trucks). Also pictured is a custom-fit MSD 8.5mm Super Conductor Wire Set that retails for $59.30 (PN 32823). Also available in red, this particular wire kit actually is designed for GM trucks and is a bit longer than the Camaro/Corvette wire kit; this helps make up for the extra coil-to-plug distance caused by our ETP heads' raised valve cover rail.
We picked up a set of ARP stainless hex bolts (PN 434-2302, $68.56) to attach the stock coil brackets to the valve covers, not realizing that MSD actually includes new plated bolts with its coil kit (see the sidebar for more detailed info on this kit; the provided bolts are high-quality but not quite as good as stainless). GM wants threadlock on the coil-bracket-to-valve-cover bolts, so we oblige; the bolts-five per cover-are torqued to 106 in-lb.
The coils then bolt atop the brackets. To get them to work, some light grinding to the bracket is required, as these coils are slightly larger than the OEM units (thanks to the beefier electronics inside). Also, you'll need to use washers under the coils (some more than others) to space them off the bracket a touch, or else they'll contact the valve cover bolts and other raised parts of the valve cover. Fortunately, we had extras thanks to our duplicate set of bolts from MSD.
We then connect the factory coil wiring harness to each coil. It's a bit of a stretch, but it'll reach with some slight adjustments. While currently capped off with an MSD-supplied plug end, a close look will reveal an extra wiring connection in each coil; it's for an upcoming MSD ignition controller. This controller will reportedly feature automatic nitrous timing retard and other goodies LS1 enthusiasts have been sorely lacking for some time. Look for a test of this item in an upcoming issue!
With the coils in place, we install new NGK spark plugs (since this is a new head, they'll get 15 lb-ft of torque) and pop on our MSD wires, being sure to use adequate dielectric grease on each end. We'll of course have to disconnect the wires from the plugs to get our headers to go on, but you can see here how these wires are more than long enough to reach the plugs. The plug end of each boot is also bendable to just about any angle, which helps orient the wire to clear all exhaust header primaries and other obstructions-a very nice feature.
We were a little confused when we discovered that ARP's engine mount bolt kit includes only six bolts, while each engine mount requires four. Never fear; two of the GM bolts need to be reused on the driver side as they have studs sticking off the top to hold a heat shield. After torquing all eight engine mount bolts to 37 lb-ft, install and torque the stock heat shield nuts to 89 in-lb.
SLP sells this PN 100221 Harmonic Balancer/ Underdrive Pulley kit for 1998-2002 LS1 F-bodies ($236.85). It meets SFI spec 18.1 and as such is engraved with a unique serial number. SLP's 25 percent underdrive design frees up horses while also maintaining proper cooling system operation and alternator voltage. GM demands that a new bolt always be used in the front of the crank (as this bolt is apparently torque-to-yield), and SLP includes one. Not included are new, shorter serpentine belts; our belts ran about $55 at the local (rather high-priced) auto parts store.
SLP says to follow the GM service manual directions and use a J 41665 Crankshaft Balancer and Sprocket Installer tool, but we borrowed a proven-to-work system that includes a longer crank bolt (M16 x 2.0 x 120mm versus the stock 103mm length) and some washers. You can buy a longer bolt like this from a well-stocked local hardware store or an industrial supplier like McMaster-Carr. Also pictured is our LS1's old crank bolt to use in the installation. But the longer bolt is key: if you try to install the balancer using just the old crank bolt, you'll strip the first few threads out of the crank snout.
Position the balancer on the end of the crank, then insert and turn the longer crank bolt to slowly push the balancer onto the snout. Don't lube the crankshaft front oil seal, it is designed to be dry at startup. But you'll probably want to lubricate the underside of the head of the bolt and any washers you have under it (the washers facilitate bolt turning and also prevent the bolt from prematurely bottoming out). Do not lube the threads of the bolt, however. Once the longer bolt bottoms out, insert an OLD crank bolt and tighten until you hit-get this-240 lb-ft. If you can't get it that tight (this would likely take a torque wrench designed for a dump truck), at least make sure you meet SLP's depth spec.
After removing the old crank bolt and ensuring that the crank snout is recessed about 2 1/2-4 1/2mm into the bore in the balancer, the final step is to install the NEW SLP-provided GM crank bolt. Torque to 37 lb-ft, then put on a breaker bar with a torque angle gauge like this one from Snap-On (not properly zero'd here, you'll note). The bolt must be turned an additional 140 degrees. If you don't have a torque angle gauge, just draw some lines with a magic marker and watch them as you turn (140 degrees is about 3/8 of a turn). Though you will need to apply some real force to get the bolt to turn far enough, don't worry about stripping the threads in the crank snout-so long as most of the threads are engaged, they're not going anywhere!
The stock water pump is reinstalled using new GM gaskets (PN 12559271, $4.84) and new, stainless steel ARP (PN 434-3201, $36.25) bolts torqued to 22 lb-ft. You can also see we've put in the stock coolant air bleed pipe here, which runs between the front portions of the two cylinder heads (with rubber hose that will eventually run to a port on the radiator attached). New air bleed pipe gaskets from GM are a good idea too (PN 12551933). Some earlier LS1 engines had a four-point pipe that also ran to the back of the heads, but it can't be used with most aftermarket intake manifolds as they are generally thicker and sit lower; owners of these cars will have to convert to the two-point pipe with GM blockoff covers in the rear.
An SLP 160-degree thermostat was chosen for this build in the interest of gaining the efficiency and power benefits that come along with lower engine running temperatures. Carrying PN 100223, it fits all 1997-2003 LS1 engines and retails for $56.60. The thermostat is installed onto our GM water pump and its ARP bolts (included in PN 434-3201) torqued to 89 in-lb.
Now's a good time to mention an item that could potentially save a whole lot of headache. Though many cooling systems will seal properly when water/antifreeze is poured into the system, once in a while a leak occurs-most often in the head gasket area. This sometimes even happens before the car is run, with water pouring into the cylinders or onto the garage floor as coolant is dumped into the radiator. At less than $5 a pack, these GM Cooling System Seal Tabs can be had at your local dealership under PN 12378254 and will help ensure all coolant-related gaskets in the engine seal properly. Drop them into the radiator, and they'll circulate helpful particles the first time the engine is run.
After removing the masking tape from the intake ports, clean the cylinder head surface thoroughly and look into the ports one last time to make sure no foreign material is in there. Although the LS1 intake manifold uses durable rubber port seals instead of old-style gaskets, they still need a clean surface in order to seal properly. You can see the wiring harness for the knock sensors in the foreground; this is your last chance to install this item before it's hidden beneath the intake manifold!
The F.A.S.T. 90mm top shell (PN 30-54005, $549.95) is drilled and tapped for our nitrous nozzles and assembled to our existing F.A.S.T. inner and lower shells. The manifold is set in place using the existing rubber port seals, but keep an eye on them while you set the intake down as they may want to creep out on you. The stock intake bolts are installed with some threadlocker and torqued in sequence to 44 in-lb and a final pass of 89 in-lb. You'll note that we've already reinstalled our nitrous and fuel lines running to the nozzles. If you're putting a direct port nitrous system on your new stroker motor, now is the time-you'll recall that installing one under the tight cowl of an F-body is quite a task!
Our throttle body of choice is a 90mm Holley LS Series Throttle Body designed for four-bolt mountings (GM LS2, 90mm F.A.S.T. LSX, and other intakes). This anodized aluminum unit features a contoured inlet and a throttle shaft that is fully rollerized to prevent annoying throttle sticking. It even includes a new throttle cable bracket (not shown). Carrying PN 112-576, it can be yours for $475.
We couldn't use Holley's provided throttle body bolts because they were apparently designed to screw into the built-in threads of a stock LS2 manifold; the F.A.S.T. uses through-bolts that require nuts on their ends. Fortunately, we had a PN 54014 hardware kit from F.A.S.T. on hand and used its bolts. The factory IAC and TPS are also transferred to the new throttle body; as for the Holley-provided throttle cable bracket, we'll attach it once we have the engine in the car.
An engine hoist is another must-have for an engine build, and even though the F-body's engine installs into the car from below, such a hoist is still needed to drop it from the engine stand into the subframe. The best way to lift any small-block is with a chain attached from the rear of one cylinder head to the front of the other. We used a bellhousing bolt at each location and made sure to adjust everything so that when all slack was taken out of the chain, the chain did not contact any breakable parts and the engine lifted in a neutrally balanced manner.
An assistant is required for the final lowering of the engine, as he or she will provide delicate guidance as you drop the hoist mechanism millimeter by millimeter. (Note that the subframe will need to be sitting on a rolling dolly to enable you to wheel it around and get it all lined up as you are lowering the car onto the subframe; a trip to Lowe's will allow you to acquire the materials for one). Get the engine mounts lined up with their attachment points, and slide in the through bolts; tighten to GM spec. At this point, take the tension off of the engine hoist-the engine will probably want to rock backward a touch, so you might want to use a wood block or two under the back of the engine so as not to overstress the mounts.
Our Speed Inc. fuel rails. There are two PN's here: RGR500, the LS1 High Flow Fuel Rails ($139.99); and RGR501, the Plug & Play LS1 Fuel Rail Installation Kit ($99.99), which includes an LS1 Feed Line Quick Disconnect Fitting. Together, these items make for a fuel rail system that features -6 AN lines and adapts directly to the stock fuel delivery line and just about any intake manifold, making for a very straightforward installation. The provided fittings are top-quality Aeroquip and other brand pieces-a nice touch.
After slipping our 60 lb/hr injectors into the anodized aluminum fuel rails (available in silver, black, blue, or red to match your engine bay), they can be popped atop the intake manifold. Don't forget to lubricate the fuel injector O-rings (both top and bottom). The provided fuel rail bolts get 89 in-lb of torque; be sure to use some locking compound on the threads.
Installation of the Speed Inc. kit involves cutting braided line. Anyone who's done this before knows it can cause some aggravation; but once you get the technique right, you'll appreciate how you can get the fuel lines to just the right length for your application. Wrap some electrical or masking tape tightly around where you want to cut. The best way to slice is with a cutoff wheel. Though we're using one here, a hacksaw won't work very well unless you have one with extremely fine teeth. A couple of trial runs were enough to show us that we needed to switch to a different tool. The key is to cut all of the stainless steel braids cleanly without pulling on them with the tool you're using-any stray braids will make installing a fitting a real hassle.
After the line is cut and any out-of-whack braids dealt with, remove the tape. Though technically improper, a tiny width of tape left on the end can prevent braids from popping out; they are like a Chinese finger trap and will want to increase in diameter with any force pushing on them. (If you do this, make darn sure there are no fuel leaks once the system is pressurized; there shouldn't be if you use a thin enough piece of tape, but you never know.) Lube the socket end of the fitting and use a twisting/pushing motion to insert the line; it will take a substantial amount of force. Then, the hose end portion of the fitting can be inserted into the socket and tightened, all the while making sure the line does not back its way out.
With a fitting on each end, the crossover fuel line is attached to the rear of each fuel rail. The fuel line coming from the tank will fasten to the front of the driver side rail, but we'll have to wait until the engine is in the car to attach this. Note that we are not using a fuel pressure regulator on this engine; according to Speed Inc., such an item is only necessary on a forced induction application.
With the fuel rails in place, we've installed all of the aftermarket parts we acquired for this "My First Stroker" project. Our 383 LS1 looks pretty badass, if we must say so ourselves! Once in the car, most of its beauty will hopefully still be visible; though with the notoriously cramped F-body cowl, there's only so much we can expect!
The positive crankcase ventilation (PCV) system can't simply be unhooked from the engine intake without creating massive vacuum leaks. Therefore, one must install blockoff caps at all locations where PCV lines formerly connected to the manifold and throttle body. Rubber caps like these are readily available at your local auto parts store.
In addition, a PCV system cannot just be disconnected from the valve covers and capped off. There needs to be a way to vent the crankcase pressure that is found in any engine (predominantly due to the gases that inevitably leak past the rings under power). If this pressure is not vented, various seals will be compromised and you'll have oil leaks galore-in addition to potentially damaging the engine otherwise. Our method of choice is to install a valve cover breather, like this one available from Speed Inc. (PN IZM0003). It screws into the factory oil fill cap location and can be had for $44.99.
As the valve cover breather will install into the passenger side valve cover, we still lack a way to bleed pressure buildup from the driver side. Though expert opinions differ on the necessity of such a provision, the LS1's lack of an open lifter valley made us think twice about simply letting pressure naturally find its way over to the passenger side. After all, all of the LS1's valve-cover-to-intake hookups occur on the passenger side, and the factory felt the need to connect the two covers. You can see here how we've left the factory balance pipe between the valve covers intact (with some lengthening needed thanks to increased valve cover height), but have cut and blocked off the tube (finger pointing) that originally ran all the way to the intake just aft of the throttle body.
We won't go through our flywheel and clutch installation in detail as you can read about it in a recent issue (see "Forward Motion," March 2006). Here's the short version: we picked up a set of ARP's PN 330-2802 LS1 flywheel bolts ($34.34) for our SPEC flywheel. They were Loctite'd and tightened to GM spec in sequence. A new pilot bearing (GM PN 14061685, about $16.00) was installed in the back of the Lunati crank. Our clutch alignment tool was put in place and the SPEC pressure plate was tightened atop the clutch disc using ARP's PN 134-2201 LS1 pressure plate bolt kit ($18.87). By the way, this Stage 3 SPEC clutch is rated up to 680 lb-ft so it'll be capable of handling the newfound torque of our stroker-at least while naturally aspirated.
With the clutch bellhousing in place, our long-tube Dynatech headers can now be bolted to the heads. For a full installation and review of these headers, see "The Sound! (And The Fury)" in our May 2006 issue. Since the ETP heads have a relocated spark plug, we were concerned about interference with the header primaries; but our worries turned out to be unfounded, particularly as the angle adjustability of the MSD wires' boots make creating clearance with any header a cinch. The factory air pump and fittings can then be attached to the engine and headers.
It makes things a lot easier if you bolt the transmission to the back of the engine before lowering the car onto the subframe, avoiding any need to futz with a trans jack in the cramped F-body trans tunnel. Now's a good time to install a new throwout bearing too. Carefully line up the tranny and gently slide it into the clutch; the transmission bolts get 37 lb-ft.
Most engine accessories can also be installed onto the engine while it sits in the cradle/subframe. Here we've already attached the alternator and are bolting on the power steering pump. Note that the power steering pulley must be removed for pump removal and installation, which is easily done with a generic pulley puller/installer tool (they're widely available).
Of all the conveniences the F-body's removable-subframe system makes possible, perhaps the best is the ability to install the wiring harness onto the engine and transmission prior to its insertion. The overworked/underpaid-looking dude you see here is viewing a pre-removal photograph (perched atop the strut) for guidance on where all of the wires are to be routed. We'll also note that while the engine has been out of the car, the A/C compressor has been left hanging under the vehicle; you can see it above said dude's head. This avoids having to decompress the system and buy new R-134a (along with getting moisture into the A/C system and possibly destroying it).
Time to lower the car onto the engine! You'll definitely need an assistant or two to help, as someone needs to operate the lift while another makes sure the cradle is going in straight. Many fine adjustments to the location and pitch of the cradle will be needed as the vehicle is slowly lowered (small wooden blocks are a big help); use extreme care to make sure nothing gets crushed, bent, pulled, or otherwise screwed up. Areas of particular note to watch are the steering shaft and twisted mess of brake lines near the driver side strut tower; they'll need to be lined up and slipped into place as the car is lowered. Botch them up too badly, and you'll be dropping the subframe again!
With the right amount of finesse, the dowel pins in the cradle will line up with those on the frame and the cradle can be attached (only six major bolts hold it in). This is the mess you'll be left to deal with once the engine is in place: a not-insignificant portion of the wiring harness, currently piled atop the intake, must be snaked over to the computer location behind the passenger side front wheel. You'll also need to connect all coolant hoses, bolt up the A/C compressor, attach the torque arm to the back of the transmission, and reinstall lots of other little things before you're ready to run.
As the inlet location for the Speed Inc. fuel rails is at the front of the driver side rail, the OEM rubber fuel line won't work (it's attached further back on the stock rail). Since we're leaving the purge canister system functioning on this vehicle, we separate the rubber fuel line from the fuel vapor line by delicately slicing the heat shielding wrapping them together.
The stock rubber fuel line segment is removed from where it connects to the factory hard lines adjacent to the shock tower using a 3/8 fuel line disconnect tool available at just about any auto parts store (it's just a small piece of plastic). You can see we've cut the correct length of braided line, attached its fittings, and are now tightening it to the fuel rail inlet. Speed Inc.'s included LS1 Feed Line Quick Disconnect Fitting enables the finished line to snap directly onto the factory hard fuel line coming from the tank. As to the front of the passenger side rail, Speed Inc. supplies a plug for it; but since our nitrous system needed a fuel source, we acquired the appropriate adapter fitting locally (only $6 for a steel 3/8 to -4 AN).
After pouring in 5.5 quarts of 10W-40 Pennzoil conventional oil (see our discussion of break-in fluids and procedures next time), our Speed Inc. helix-mount breather is then affixed to the passenger side valve cover. The polished aluminum mount is twisted in by hand (a strap wrench may come in handy) and the breather simply pops on top. This washable breather comes off easily for when you need to add oil, yet stays put thanks to a beveled edge machined into the inside of the mount.
We found that the stock throttle cable bracket wouldn't work with our new Holley throttle body, as it sat too far back to allow the throttle to completely close (even messing with the cable adjuster wouldn't give us enough slack). Never fear: Holley's provided throttle cable bracket (absent from our previous photo thanks to us "misplacing" it) provides the solution. It bolts not to the molded-in location on the manifold, but to the upper left throttle body bolt and the front intake bolt. This moves it forward enough to allow the cable to properly reach. Holley also includes a longer bolt and spacer to move the throttle cable bracket even further forward if need be (nitrous plate being used, etc.).
Home at last! After a few final adjustments to get the airlid and MAF on properly with our new throttle body, this 383 LS1 is good to go. You can see fingerprints and hastily routed wiring lingering here and there, but we're not looking to hit any car shows right away: we want to get this sucker running, tuned, and ready to kick ass! Hate to leave you hanging, but make sure you pick up a copy of the next issue of GMHTP for full dyno and track results, a breakdown of all the parts and funds we spent on this project, as well as a synopsis of computer tuning and other issues that go along with any new engine.
383 LS1 Stroker Epilogue - GM High-Tech Performance Magazine
Our "My First Stroker" 383 LS1 Stroker project engine is finally ready to run. Check out what kind of horse power this small block makes. Only at GM High-Tech Performance Magazine.
LS7 Camshaft & Power Package Install - GM High-Tech Performance Magazine
Read all about the LS7 camshaft and power package installation we perform on this Chevy Corvette Z06. Only at www.gmhightechperformance.com, the official website for GM High-Tech Performance Magazine!
LS Engine Build Part 3 - GM High-Tech Performance Magazine
Read part 3 of this comprehensive LS1 stroker build project in GM High-Tech Performance
Carbureting an LS1 - Tech Article - Chevy High Performance Magazine
Read how Chevy High-Performance converts an LS1 from fuel injection to carburetion.
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