If there is any doubt remaining about the power potential of the Gen III LS1/LS6 engine architecture, the following real-world engine buildup should clear that up. Simply put, there is no other production 5.7-liter small-block pushrod V-8 engine design in the world that is as easy to build and responds to a set of race-inspired CNC-port cylinder heads and an aggressive camshaft with a streetable 500+ hp.
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Now, this engine will have the hardcore lopey idle and need for premium gasoline that any high-performance, naturally aspirated engine would exhibit, but the powerband and peak numbers will more than justify those realities. This chapter will show you the details required to assemble any Gen III V-8, while presenting a standard combination of parts to create 500 hp.
The Gen III V-8 engine upgrade components used here were originally developed from GM Powertrain components by the people at GM Racing. The aftermarket industry then refined this package. This engine is being built by Wheel to Wheel Powertrain (W2W), in Warren, Michigan, for use in a road racing Corvette, but it isn’t much different from the street Gen III V-8s they build every day for hot rod daily drivers. The big difference between their street engines is this one has some aftermarket components in the short block, like a forged crank, billet rods, forged aluminum pistons, and other performance pieces.
Many of the 500+ hp street engines W2W builds don’t have anything changed in the short block — a testament to the Gen III V-8 capability. But the aftermarket additions are shown because it’s a good thing to show how aftermarket components are integrated into the Gen III in case more than 530 hp is desired — as that seems to be the limit for some factory components like the pistons and rods. In this chapter, you’ll see the machine work and finesse needed to assemble a 500+ hp Gen III V-8 engine. Then, whether you choose to build this engine with the stock short-block or add even more aftermarket performance components, you’ll have enough info to understand what it will take to get the engine together.
While W2W does have some tricks and refined processes they perform to extract the maximum performance and durability from these packages, almost all of the processes shown here can be repeated by anyone with similar results. And W2W is quick to give this engine design its due — they acknowledge the ease with which power is unleashed from the LS1/LS6 Gen III V-8 as a direct result of the excellent engineering by the people at General Motors Powertrain and Racing.
External Pump Oiling System
As you will see, the engine built in this chapter is assembled with a dry sump oiling system that uses a two-stage external oil pump as the scavenge pump with the factory oil pump on the pressure stage to make sure oil flows to the engine in high-G cornering situations. This system is being used because the vehicle and driver this engine will service run hard through corners and experience high G-loads for sustained periods. If you are building an engine for a more street oriented application, you can save the money this system costs and use the factory wet-sump oiling system instead.
The term “dry sump” comes from the fact that the oil is not stored in the bottom of the engine anymore. There is an external oil sump holds more oil than would normally be used in a production oil pan, which allows the oil to cool and let the air percolate out of it. Storing the oil somewhere other than the bottom of the engine allows the oil pan to be much more shallow, which allows the engine to be mounted lower in the vehicle. Since the oil is not allowed to sit in the bottom of the engine, the chances of the oil roping around the crank, eating horsepower, and getting more air whipped into it, are minimized.
The choice between the dry-sump and wet-sump system usually is driven by how oil needs to be drawn out of the engine, not how oil is pumped into it. The two-stage external oil pump is actually two oil pumps that run off a common shaft. Each pump, or stage, draws oil from a different area of the oil pan. Many drysump systems use a three-stage pump, with one of the stages pressurizing the oil and the other stages sucking it out of the engine. The system used here is designed this way because of the rules in a road racing series mandating that the factory oil pump be used in the oiling system.
Dry-sump systems are mostly used in engines that will go in vehicles that can achieve high lateral grip for extended periods, like a road race car. They are expensive, but are good insurance the engine won’t starve for oil at the end of a long cornering experience, which would obviously result in a more expensive problem. Wet-sump oiling systems don’t have the same amount of oil and control of the oil in the oil pan as the dry sump systems, which can lead to starvation of oil to the oil pump.
W2W has built 500+ hp Gen III V-8 engines with both the dry and the wet sump oiling system for the street and have never had a problem with durability in either case. It does depend on how you drive the vehicle, but in general, if you do not drive multiple race laps with the car on a road race track, the wet sump system should be acceptable.
W2W uses either the LS1 or LS6 engine as their starting point to build this 500+ hp engine. The only real difference between the LS1 and LS6 engine short blocks is the pre-’01 LS1s didn’t have ascast “windows” between the mains in the bottom end of the engine block for highrpm air and oil-vapor flow. If you plan on spending sustained periods of time at high rpm, the later LS6 block (casting number 12561168) is the correct choice as it has better crankcase oil control.
Beyond the block, since the cylinder heads, camshaft, and intake are being swapped out, it doesn’t matter whether you start with an LS1 or LS6 engine or even a 4.8-, 5.3-, or 6.0-liter iron-block truck engine. Most performance enthusiasts prefer the aluminum block LS1/LS6 engine for the weight savings, but the iron-block engines are similar in design and cost less if weight is not that big of an issue for you. Obviously, the smaller-displacement engines will make less overall power, while the 6.0-liter should make just a little bit more power than the 5.7- liter LS1 engines.
The CNC cylinder heads W2W prefers to use are the GM Performance Parts CNC heads. There are two versions, the more aggressive 11.2:1 compression head (PN 88958622), or the just released 10.5:1 compression heads (PN 88958665). Ron Sperry, the GM Racing engineer that originally designed much of the Gen III V-8 cylinder head ports and chambers, did the development of these CNC-ported heads.
The 8622 heads have a small 62-cc combustion chamber, while the 8665 heads have close to the production 65-cc chamber. Both heads have 250-cc intake ports, 85-cc exhaust ports, and can support north of 500 hp. They come with the impressive LS6 factory valvetrain — hollow-stem stainless-steel valves (sodiumand potassium-filled on the exhaust side), chromium-silicon (Cr-Si) ovate beehive valvesprings, and other equipment.
The milling of both of these heads means they will probably need different length pushrods to maintain good alignment of the pushrod tip and rocker cup. The 8622 heads often end up with a 7.325-inch pushrod, while the 8665 heads mostly run with the factory-length pushrods. Maximum lift is considered to be 0.570 inch.
There are plenty of CNC cylinder heads available, but W2W’s feeling is the GM people, especially Sperry, probably know best how to maximize performance with CNC-ported heads. After all, they understood what they had to start out with, and had a tremendous amount of technology available to make the improvements.
Besides these heads, this engine is loaded with aftermarket components for increased durability and performance. The forged steel Lunati crankshaft used here is the stock 3.622-inch stroke of race rules, but the cranks can be ordered with up to a 4.125-inch stroke to increase displacement. If a longer stroke is desired, sometimes the block will need to be clearanced for the big end of the rods to clear the bottom ends of the bores and bottom of the engine block. This usually depends on what brand rods you are using — often there is no clearancing required. Also, a groove will need to be machined on the number-8 piston so it will clear the reluctor wheel on the crank.
A nice touch is that the Lunati crank comes with the GM factory 24x crank trigger reluctor ring installed on it, so the factory crank trigger will work without any modifications.
The 3.897-inch diameter (for a 3.901-in bore) forged aluminum JE pistons used here offer advantages in durability and performance production over the factory eutectic cast-aluminum pistons for a 500-hp engine. They are machined to accept a standard hotrod/racing ring package of a 1.5-mm top, 1.5-mm second, and 3-mm oil spacer/separator ring pack.
The production eutectic cast-aluminum pistons are a low cost alternative to the forged aluminum pistons, which is good if you are building tens of thousands of 400-hp mass-production engines. But, since this is a performance engine and saving a few pennies on each piston isn’t the main concern, forged pistons are a good choice. This isn’t to say cast pistons won’t work on the street, but the owner of this engine was willing to spend the money for a little increase in insurance against a failure.
The reasoning against eutectic castaluminum pistons for peak performance applications is based on experience. These pistons are less forgiving to the pounding of detonation and preignition, and have a tendency to break into pieces instead of just lifting a ring land or melting slightly, as forged pistons usually do when stressed beyond their limit. While many enthusiasts think they aren’t going to come close to causing one of these issues, we all know that high-performance engines live in danger.
Peak horsepower is made with the air/fuel ratio and ignition timing set where the engine is just on the edge of detonation, what many hot-rodders call the “rattle of power.” Near this fine line, a forged piston offers a considerable safety net, which is why their cost should be considered the price of entry when building a powerful engine.
W2W likes to use JE or CP pistons in these engines. If you are going to use the stock rod and crank, W2W recommends JE PN 194884. These pistons are set up to work with the stock LS1 6.094-inch rod length, 0.944-inch piston pin, and 3.625- inch LS1 crank. If you are going to use an aftermarket rod and piston, W2W recommends the JE PN 194883 pistons so they can use a 6-1/8-inch connecting rod and a 0.927-inch floating piston pin with locks.
Controlling it All
As with any Gen III V-8, the engine is run by either the production powertrain control module (PCM) controller, or by an aftermarket electronic controller. A F.A.S.T. electronic controller runs the engine being built in this chapter with a program developed by W2W. At the time this engine was built, the F.A.S.T. controller was not yet reading the 24x crank trigger, though it will be able to by the time this book is published. Because of this, W2W installed one of their 4-point magnetic pickup systems. The pickup sticks through the bellhousing on the oil filter side of the block to read four magnets embedded in the W2W-modified flywheel.
By the time this book comes to market, pretty much all the aftermarket controller companies should be able to plug in to the factory crank trigger senders to run the engines, but right now only a few can run off the factory crank triggers.
Take a look at the last chapter in this book for more details on how to alter the calibration on the Gen III factory controller. Also discussed in Chapter 10 is how the aftermarket is modifying the factory calibrations to work with performance components and how to get a Gen III running on an aftermarket controller.
Every Last Detail
Simply put, this chapter, and complimenting info throughout this book, thoroughly documents the procedure needed to build a 500+ hp Gen III V-8 street engine. By that, we mean the information presented elsewhere in this book is not repeated in this chapter, but referenced here for you to find. This way, space is not wasted covering information that is already shown. Some examples of this are the processes of degreeing a camshaft, aligning the stressed-member oil pan with front and rear covers, and installing an intake manifold. From there, attaining the pleasant roar of a small-block Chevy Gen III V-8 coming from under your ride’s hood is up to you.
Hanging the Pistons on the Rods
Installing Rings on Pistons
Installing the Crank in the Block
Installing a Camshaft
Installing the Connecting Rods/Pistons
If you plan on using the stock short block with heads that have been machined more than 0.050 inches and a camshaft similar to the one used here, be prepared to spend some money buying aftermarket pistons with valve reliefs or having small valve reliefs cut in the stock pistons. The early Motorola Cup rules this engine was originally created for required stock pistons, but they didn’t limit valve reliefs, so the engine designers put as much compression, valve lift, and duration in the engine as possible. The piston on the left with the valve reliefs is a remnant from W2W’s days of supplying these early racing engines. The piston on the right is a stock unit.
Actually, if you need valve reliefs, W2W recommends installing a set of aftermarket forged aluminum pistons. This is because the cost difference between a set of stock pistons with the valve reliefs machined in them and the forged aluminum pieces is a few hundred dollars — a small price for a lot of insurance towards keeping your engine together. W2W has used heads milled about 0.040 inch, which nets a 62-cc chamber size, on the street with no problems. They’ve also cut heads up to 0.060 inch, which produces about a 57- cc chamber size, and had no problems in racing applications.
Piston: In the Hole or Popup?
The next important step is to check how much the piston comes out of (or stays down in) the bore during the crank stroke. This is a good parameter to check even if you haven’t changed anything on the stock short block. Here’s how you do it:
Oiling System and Water Pump
Building Cylinder Heads
Installing and Torquing the Cylinder Heads
Written by Will Handzel and Posted with Permission of CarTechBooks