Spare Parts

How A Bunch Of Guys Scrounged Up This Sick LS1

By Will Handzel

As if just building a 1,700hp LS1 wasn't enough. If you can believe it, this engine was built from spare parts in a bunch of guys' spare time as a dare to be the first to run 6 seconds in the quarter-mile with an LS1 V-8, which they achieved in a borrowed race car. As unbelievable as it sounds, it's true, and you're going to find out how this wild LS1 went together and what it means to the future of making power with the LS family.

In case you don't know, the latest version of GM's small-block V-8 engine has been powering new vehicles since it was introduced in the '97 C5 Corvette as the Regular Production Order (RPO) LS1. This engine family has shown itself to have great potential, but until now, max effort LS1s were only making about 1,200 hp. So how one builds an LS1 to survive while making over 200 hp per cylinder is a real story!

WHERE TO START
While many would think the engine block would be the most important component to get right, they would only be partially correct. While block prep is important, this band of shop rats found that the oiling system was the key to making the engine package live under the 30-plus psi boost from two massive turbochargers. But before we get to the oiling system, let's talk about what work was performed on the engine block. For starters, the original 5.7L, 99 mm (3.897-inch)-bore aluminum LS1 engine block is not being used here. The aluminum blocks have not proven themselves capable of handling over 1,000 hp, so an iron 6.0L, 101.4 mm (4.000-inch)-bore truck block was used as the starting point.

These iron blocks, with a few modifications, have been handling over 1,200 hp in quarter-mile trim for a while now, so this is another test of their capabilities. They are about 90 pounds heavier than the aluminum blocks, but in this case, the iron piece is the only option, and the added weight is negligible.

To add strength, the bottom 2/3s of this engine block was filled to just about 1-inch below the deck on each side with Moroso's Hard Blok cement. This way, when the engine is running, water will still circulate through the heads and the 1-inch cavity in the block during its short runs. While this is not a suitable setup to maintain temperature in a street application, it is a fairly common practice in ultimate-performance quarter-mile engines to stabilize the bores under the extreme loading. Before pouring the cement in the block, a torque plate is bolted onto the deck with factory head bolts so the block is in it's stressed state when filled.

To further improve the stability of the block, a main cap girdle was carved out of a 3/4-inch-thick aluminum plate and bolted to the main caps and engine oil pan rail with ARP studs and bolts, respectively. Also, the block was drilled and tapped for custom, oversized ARP studs at the deck and main caps.

OILING FOR BIG POWER
To give you an idea how involved the oiling system is for this 1,700hp engine, you should know there are actually three separate pumps evacuating or pressurizing oiling cavities. Why, you ask? Well, Billy Briggs, Wheel to Wheel Powertrain's (W2W) chief engine builder, and Kurt Urban, W2W's Director of Operations, brainstormed this oiling system in an effort to achieve "stability and a solid oiling wedge" under the extreme conditions of making about five times as much power as this engine made from the factory.

The stability end of this equation is in terms of getting the piston ring to stay locked onto the ring lands. Evacuating the crankcase increases the chances of keeping the rings sealed tightly on the ring lands in practically any situation. This is important because engines that operate under extreme boost closely resemble ticking time bombs because the air/fuel mixture finds its way into many places it shouldn't be, such as the crankcase and valve covers. Pulling a vacuum has the added benefit of minimizing the amount of vaporized and liquid oil that is slopping around inside the engine cavities, robbing horsepower as it drags on the rotating and reciprocating components.This vacuuming aka savaging) responsibility falls on a Dailey three-stage, external dry-sump oil pump that spins the same speed as the crankshaft. Now, 1:1 is a really blistering pace for an oil pump on an 8900-rpm engine, but so far, the Dailey unit is handling it. The pump draws three stages of oil out of the ARE dry-sump pan with -12 braided lines and sends it to the Peterson dry-sump oil tank. This system was intended to pull 20 inches of vacuum in the crankcase when the engine is seeing its maximum 30-psi boost--which it did accomplish. Both Briggs and Urban credit the Total Seal piston rings with allowing it to accomplish that feat.

A second Dailey oil pump, this one a single-stage unit, spins at half-crank speed. It pumps pressurized oil from the dry-sump tank through an oil filter via -12 braided steel lines into a fitting on the front of the engine block that taps into the stock oiling system passage. This pump makes about 70 psi at 8900 rpm. Once the oil is inside the engine, Briggs and Urban experimented with rerouting the oil flow in a few key areas. First, to restrict the oil into the heads, the lifter bores are bushed with bronze guides drilled with only a 0.060-inch oiling hole (vs. the nearly 1/2-inch-diameter galley in the block passage). This is because the oil going to the top of the engine is only needed to oil the mating union of the lifter, pushrod, and rocker arm. The valvesprings and other top-end components are lubricated via an oil mist that comes from 0.020-inch holes drilled in an oiling passage in the roof of the cast ARE valve covers. This passage is fed in each valve cover by a -4 braided steel line that taps into the main oil galley at the back of the block.

Also, to make sure there wasn't a problem with the front cam bearing, a -4 braided line was plumbed internally from the back of the block to the crossover passage at the front of the block, which was also opened up with a die grinder. This was done because on some wet-sump engines, W2W has seen the driver-side main galley low on oil pressure. The company feels this is because that galley feeds the main bearings, whereas the passenger-side galley just oils to the lifters and valve train. This added responsibility could sometimes drain off pressurized oil to the point it leaves the driver's side lifters and front cam bearing a little short of pressure. Early dyno testing showed pressure was more than sufficient at this area. So, because of that, the internal -4 line is not being used to pressurize the front galley-but at least they know the oil distribution is pretty impressive throughout this engine!

The third oil pump is the stock gerotor oil pump that spins on the snout of the crankshaft. It is used to evacuate the copious amounts of oil being pumped into the turbo bearings to both cool and lubricate them. Pulling the oil from these bearings is important because it minimizes the amount of oil that might be sucked into the intake tract on the

pressure side of the turbos. This scavenge is something both Briggs and Urban have been interested in trying for a while and have found it makes a dramatic difference in the amount of oil that ends up in the engine.

THE TOP END
The 30-plus psi of boost this engine will operate under would destroy the stock valvetrain components, so major modifications were made to handle the loads. Some of the changes included a 0.650-inch-thick Jesel rocker shaft (compared to the 0.500-inch-thick stock piece) that provides increased valvetrain stability, but also raises the rockers up 0.150-inch. For improved clamping capability, the bolts holding the rocker shaft to the cylinder head were also increased in diameter to 7/16-inch. The rocker bodies are also oversized Jesel billet pieces with the pivot point moved inboard to reduce the force required to open and close the valves. This is another especially important issue on big-boost engines, as closing the intake valve against the 30-psi breeze is very challenging. The rocker adjusters are solid-ball nosed instead of the usual drilled type that allows pressurized oil to pass through them to oil the valve train. The solid adjusters are required to handle the increased loading on the valve train in an area with very limited space to package larger components.AFR's groundbreaking LS1 cylinder heads received copious welding by W2W to increase the diameter of the valvespring pad, move the pushrods holes inboard and weld up the water jacket ports in the deck surface. Then, the ports and chambers were CNC-machined by ET Performance, in Walled Lake, Michigan. ET also installed beryllium seats and added a 15-angle valve job in preparation for the Del West titanium valves.

In an effort to improve deck integrity where the heads and engine block meet, W2W also completely welded up the coolant holes, then drilled the holes to exactly match the coolant passage openings in the copper SCE head gaskets.

HAIRDRYERS AND PLUMBING
Let's be clear-two 80mm Precision Turbo hairdryers on this beast make it all right. At the 8900 rpm, these babies are honking 30 pounds into the intake manifold. That's after the air goes through a Precision Turbo intercooler, dropping 130F degrees and losing a little boost pressure in the process!Yup, the turbos and all the beautiful Dera and Brown-built tubing and mounts are a sight to behold. But more importantly, it all works to make impressive power.

So, the engine has made an incredible number on the dyno and the car has run just as good, which is the icing on the cake for all involved. No, they weren't sure it could be done, but they had a hell of a time dreaming up the idea, overcoming the challenges, and achieving their goals. Not bad for a side project, huh?