In our last installment, we covered the chassis and suspension. Now we will address the engine and its accessories, the drivetrain, and the braking systems.
Engine: Test Fit, Accessories, ECM, Dry Sump, Headers, Detailing, And Installation
Since the theme for our car is the combination of the first Z06 model offered with the latest Z06 engine, our plan from the beginning has been to use the LS7 engine. We have followed the development and availability of the GMPP engine and placed an order with Dobles Chevrolet in Manchester, New Hampshire, for one as soon as it was available. After some delay from the original introduction target date of August 2005, the engine was delivered in October 2005.
The engine comes assembled, along with the throttle body, injectors, flywheel, clutch, pressure plate, starter, exhaust manifolds, oil filter, spark plugs, and water pump. Several key components are not included, such as the dry sump tank, oil lines, ECM, wiring harness, accessory brackets, and alternator.
Our first step after the arrival of the engine was a test fit to see what issues we might face for the chassis, motor mounts, and engine accessories. as you might expect, we found several issues. The first was the pilot bearing needed to be changed. Through 2004, a needle roller clutch pilot bearing (No. 14061685) was used in the Y-Car. In 2005, a ball bearing design (No. 12557583), which is used on trucks, was released on passenger cars and is the one used on the LS7. This bearing is positioned approximately 10 mm further aft, and it doesn't allow the transmission shaft to seat all the way. Fortunately, the crankshaft still has a provision for the earlier-type bearing, which works fine. It may take a little doing to get the bearing out, so be sure to use a bearing puller designed for that purpose.
We also found the chassis cross-member under the engine needed to be modified to clear the dry sump pan. The cross-member was cut, and a new piece was welded in place. The last major change needed was to move the rack-and-pinion mount by a half-inch as the power-steering pump pulley would interfere with the intermediate steering shaft.
The good news was the engine fit well otherwise, as did the motor mounts and engine accessory brackets. We also tested headers for clearance of the chassis using the LS1-style, street-rod-style units since there were no sources for LS7 specific headers at the time.
Accessory Drive ::: Our accessories had to serve three purposes: function, fit, and appearance. There are several sources for serpentine-belt systems and brackets today. We chose Street & Performance (S&P) for the alternator, A/C compressor, power steering, and idler brackets. We also used the engine mount adapters from S&P for the motor mounts, which allow the use of small-block mounts. We used the mounts from Energy Suspension to match the other urethane bushings we've used.
Engine Systems ::: The LS7 is a bit more involved than other engines when it comes to setup, particularly because of the 58x reluctor and the dry-sump system.
Computer And Harness
For the engine management, we used the reprogrammed ECM and engine harness from Speartech, www.speartech.com. It's well made and the customer support is top notch. John Spears made it to function with the fly-by-wire throttle (we are using a C6 throttle pedal), which eliminates the need for a hard-wire cable.