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.
Since we wanted to maintain as much recognition as possible with the new Z06, we chose to use the OEM dry-sump reservoir. It also has provisions for the dipstick and tank vent lines to the engine. However, the stock tank is too tall to fit within the C2 engine compartment, and so we contacted Line Precision who makes the OEM tank. working with them, we were able to retain the original upper and lower cast portions, along with a new center section that was shorter and wider in order to maintain the original 10.5-quart capacity of the stock tank.
In researching the details of the dry-sump setup, we found quite a few details on the stock system. There are two fittings on top of the tank. The rear fitting on the reservoir runs to the "dirty-air" connection on the front passenger side of the engine and to the PCV. The forward fitting runs to the clean-air fitting ahead of the throttle body. The tank contains a volume of 10.5 quarts, which is the minimum required to run an 8-quart service fill with the LS7 engine. When 8 quarts are added to the tank, 1.2 quarts fill the lines and cored passage in the oil pan, leaving 6.8 quarts of oil in the tank. The remaining volume of the tank is intended to provide for oil conditioning, de-aeration, and a fresh-air provision to prevent sludging and PCV separation. If you use an aftermarket tank, it's important that you create these provisions for crankcase pressure equalization and PCV system flow. The LS7 uses two oil pumps: the scavenge pump pumps 25-percent more volume into the tank than the supply pump draws out. This extra volume is air, which will pressurize the tank if you don't have a way to equalize the pressure with the crankcase. It will also draw down the pressure on the crankcase to unacceptable levels, so there should be a line connecting the tank to the crankcase for pressure equalization. It's also recommended that you provide fresh air to the tank and draw foul air off the crankcase through the PCV system.
The oil lines from the engine to the oil reservoir are unique fittings. If you can run the OEM lines, these will work fine. If not, or if you are using an aftermarket reservoir, such as that from Peterson Systems, you can get adaptors that convert the lines to an AN12 fitting. There are several sources for these fittings, such as Street & Performance.
To mount the tank, two lower brackets were made that fit into tabs welded to the frame and one upper bracket that mounts to the firewall.
To gain space for the oil reservoir, which was placed in the rear of the passenger side of the engine compartment, the battery location had to be moved. In some cars, the battery could be placed in the trunk area (if we had one!) or the rear of the passenger compartment. However, we didn't like the idea of a battery in that location or running the cables that far from the engine. We decided to fabricate a new battery mount on the driver-side framerails just behind the inner fender panel. For access to the battery, a panel originally used on A/C-equipped, big-block midyears was used in the rear of the inner fender panel.
You may be able to use the stock exhaust manifolds. They do have a unique outlet though, which makes making the rest of the system more difficult. You may also run into clearance issues with your frame or engine mounts. Street & Performance made a set of headers for us with larger primary tubes, a flange to match the LS7 port shape and with the necessary clearance. Stainless collectors were used, which will be mated to the rest of the exhaust system that we will cover in a future installment.
Since the car will be used for shows, we wanted to do something special in detailing the engine. It was sent to Street & Performance where Adam Gunn performed his work. The heads, throttle body, and water pump were polished. To help retain their finish, they were coated with Zoops Seal. The front engine cover, oil pan, starter, coil mounts, and valve covers were chromed. Even though the block is aluminum and could be polished, we wanted to have a contrast to the polished and chromed pieces, so the block was smoothed and painted in our custom red paint. All the mounting bolts were converted to 12-point polished ARP bolts.
There will be several other custom pieces made for the final detailing; these will be shown in a future installment. This will include the cold-air intake system, the custom cooling-system radiator, and expansion tank made by the Pro-Fab shop at Be Cool. Mark Walkowiak from Mark VII Machine and Fred Militello from Be Cool have worked from our diagrams to make these units, and their work is outstanding.
In our first installment, we mentioned there would be some equipment you may not have that would be helpful in the project, such as an engine hoist and leveler. We also found a hydraulic table came in handy when it was time to line up the transmission. some extra hands and eyes are always helpful when you are lining up the motor and transmission mounts. Luckily for us, Frenchy Bernier and Ray Zisa from Corvette Center made a house call.
This is probably a good place to mention the fuel tank . The stainless tank is from Rock Valley and has a built-in fuel pump. Note that this tank has the main and return lines on the top instead of the bottom as is usual since we wanted to keep the bottom of the tank free of fuel lines (photo 09). The tank has been polished (we've made a note that this is another one of those jobs we never intend to do again). As we write this segment, we are looking for the best location for the fuel filter (C5-style with a built-in regulator), and then we will route and mount the main and return lines with a combination of braided-stainless and hard-stainless lines.
A Tremec T-56 transmission from Keisler Engineering was chosen. We've had good luck with that unit in our '62, and like the smooth shifting and gearing. To improve its appearance, we decided to smooth and polish the transmission and bellhousing. That involved approximately seventy-five hours of polishing and is not something we're likely to do again! The skip shift solenoid was eliminated as was the backup light switch. The reverse lock-out unit was also polished, rear cover plates fabricated, and the brackets were painted. All the bolts were converted to 12-point ARP polished stainless. To help retain the finish, the entire unit was coated in POR 15 Glisten, which should stand up to the heat. The urethane transmission mount is from Energy Suspension.
Flywheel/ Clutch/Pressure Plate & Hydraulic Unit
Since the engine comes with the flywheel, clutch, and pressure plate, we saw no reason to go with aftermarket units. To activate the clutch, a hydraulic unit used in the F-body cars was used, along with a custom bracket mount from Alf Ebberoth of Performance Automotive.
A Dana 44 differential was chosen for its strength, along with a gear ratio of 3:90 that works well with the double overdrive of the T-56 transmission. The unit was smoothed, and then painted in our custom red color for contrast to the chromed differential carrier. A custom torque arm from SRIII Motorsports was used. The welds were smoothed, and the unit was chromed. Urethane bushings from Energy Suspension were used for both the differential carrier and torque arm. They were mounted using six-point polished stainless bolts from Totally Stainless.
Drive & Halfshafts
Driveshaft ::: A custom driveshaft from Denny's Driveshaft was used. The welds and yokes were smoothed, and the unit was chromed. Spicer universals were used. For further detailing, the universal joint centers were powdercoated in red, the bearings were polished, and the retainer rings were chromed. That made assembly an interesting exercise!
Halfshafts ::: The halfshafts were shortened. You may recall from the last installment that we wanted to retain the stock body profile, but still use wider wheels and tires; this required narrowing the halfshafts, differential carrier, rear toe-rods, and camber rods. We wanted to smooth the welds and finally thought of a way to do that job more easily. We don't have a metal lathe, but do have a wood lathe. We decided to make wooden dowels, which were turned to the diameter of the yoke, to mount the shafts in the lathe. Then, turning at a slow speed, a series of files and grits of sandpaper was used to smooth the shafts (photo 13-shaft mounted in the lathe; photo 14-before and after turning perspective). The shafts were then chromed, and the universal joints treated to the same process of finish as the driveshaft.
In the last installment, we mentioned keeping the suspension parts loose at that point. When you begin to install the halfshafts, you won't have to loosen as many bolts as you have to move the hubs outwards to gain enough space to get the halfshaft universals into the differential and spindle yokes. we found that temporarily removing the rear toe-rod at the hub and the camber rod at the differential bracket can help get enough free area to get the halfshafts in place.
Brakes: Calipers, Rotors, & Boost
Calipers ::: As they say, "once you have plenty of power, you will also need plenty of stopping force." There are many choices for brakes these days, ranging from the stock Corvette units to Wilwood and Baer aftermarket components. Since we are trying to use as many current Corvette parts as possible, we decided to use the stock C5 Z06 calipers up front. Since we are using the C5 front-suspension components, these bolt right up without the need for adapters. We considered using the C6 Z06 calipers, however, we were concerned they might not work as well in combination with the C4 rears. We were also concerned there was not enough clearance with the 17-inch front wheels we are using. In the rear, we used the calipers from the '96 C4 Corvette. One reason for using these calipers is they have an integral parking brake. Braided-stainless lines to the calipers were used, along with stainless hard lines. These were polished and coated with Zoops Seal.
To add more detail to the calipers, the "fins" were smoothed and polished; the calipers were painted in red, and then clearcoated. The brake brackets were smoothed and chromed, as well as the emergency-brake parts. We also had polished stainless plates made to cover the brake pads for a final touch.
Rotors ::: We like the look of the two-piece Baer EradiSpeed rotors, which are slotted and drilled. To add more detail, the rotor hats were chromed, and stainless bolts were used. Also, the outside edge and insides of the cooling vanes were powdercoated in red by Anvil Power Stryke powdercoatings, a division of Har-Conn Chrome in Newington, Connecticut, for appearance and to keep any rust from forming.
Boost System ::: We've used vacuum-boost systems in the past, but wanted to try something different this time. We had heard of a new system from ABS Power Brake, www.abspowerbrake.com. It's an electric/hydraulic unit, and the power unit mounts remotely on the frame, which allows more space on the firewall. The package comes with a billet master reservoir, polished booster pump, accumulator, and a hydraulic stop-light switch. The accumulator stores power should the unit fail.
For mounting it to the frame, a plate was made and welded in place low on the driver side. Lines were run to the front and rear brakes, and the pressure line runs from the pump to the master unit. The electrical connections are straight forward: battery, ignition, and ground wires.
Since we are trying to retain as much of the original appearance as possible, we chose to keep the original, pull-style, parking-brake lever. To do this, we had to adapt it to the '96 C4 rear-brake calipers, which have an integral parking-brake mechanism in the caliper. We used the underdash parking-brake housing from a '64 Vette because we like the way it mounts, and its pulley mechanism allows the cable to run closer to the firewall. A stock parking-brake arm mount was welded to the new frame in the same location as the stock unit. A stainless-braided cable from Lokar was used to make the connection from the parking-brake handle to the arm on the chassis. From that point, Lokar braided-stainless cables were used to run to the calipers.
So Here We Are
Photo 20 will give you a good idea of where we are at this point in the project. We couldn't resist mounting the wheels from Mid America Motorworks on the chassis for a look. There are also many other things going on simultaneously, such as the bodywork at Corvette Center, interior work at Interior Motives, machine work at Mark's Machine, exhaust work at Patten Cycles, and the daily UPS delivery of countless parts.
In upcoming installments, we will get into more detail on several systems (exhaust, cooling, heating/air, and so on), as well as the body and interior. Since we are writing the articles as the car is being built, there will be a few month's adjournment while we complete more work on the car. Building a car is similar to building a house-the frame seems to go up quickly, but it's the interior plumbing, electrical, fixtures, and so on that take the majority of the time.
We hope what you have seen so far has been of interest and help if you are considering a similar project. In the meantime, you can find additional photos and links to sources on our web site at www.corvetteforum.net/c5/richs7/.