All engines are stamped with an engine identification label. Place number one cylinder on TDC of compression stroke. Ensure timing mark on damper and front cover are aligned. Back off adjusting nut until lash is felt at pushrod.
Rotate pushrod while tightening adjusting nut until lash is removed. Rotate crankshaft one revolution and align timing marks. Adjust remaining valves in same manner. Cylinder No. Valve No. Loosen fuel tank filler cap. Connect Fuel Gauge J to fuel pressure connection mounted on fuel rail, right side of fuel pressure regulator. Wrap shop towel around fitting during installation to avoid spillage. Install bleed hose. Turn gauge valve and drain fuel into a proper container.
NOTE: For reassembly reference, label all electrical connectors, vacuum hoses and fuel lines prior to removal. Match mark engine hood and all other major components prior to removal.
Battery negative cable. Pressure cap. Drain coolant. Each VDF generally covers multiple vehicles that use similar engine controllers. Once you have purchased a VDF, you may tune as many vehicles of that type as you like — there is no per-VIN licensing.
In fact, if you want the software to run properly we highly recommend that you use Windows XP as this is the only operating system that has consistent behavior without a fuss. Moates Support. Search for:. The cylinder liners were specially matched to their bores, into which they locked via a simple slip-fit. The interior surfaces were coated with Nikasil, a nickel-silicon alloy that provided an extremely durable but plaint surface for the specified lightweight cast-aluminum Mahle pistons.
The connecting rods and crankshaft were forged of steel to maximize their strength and durability. To enhance the overall strength of the engine as a whole, the block was heavily ribbed and gusseted. The usual five main crankshaft bearings were supported by a special one-piece aluminum cradle that attached to the block by no fewer than 28 bolts. The bearings were oversized at 70 millimeters, which was considered necessary for reliable, sustained operation at 7, rpm. While the engine was fabricated to incorporate exacting standards and minimal tolerances between moving parts, a great deal of effort was also placed into ensuring proper lubrication within the engine.
The LT5 crankshaft was cross-drilled for internal centrifugal oiling from the front of the crank to the conrod pin bearings and main bearing journals.
The engine included a separate oil cooler with thermostatic control, and the crankcase consisted of a two-piece aluminum assembly with an integral pickup that assured proper feed and bottom-end oiling during hard cornering, when sloshing oil might otherwise leave part of the oil sump momentarily dry. From an engineering standpoint, one of the most fascinating aspects of the LT5 engine is the unique three-stand engine induction system.
A large, forward mounted air cleaner would feed a cast-aluminum throttle-body assembly with three throttle blades — a primary blade of 0. The throttle body, in turn, connected to an aluminum plenum chamber that branched into 16 individual runners, one for each intake port. Eight of these would feed the primary ports and would operate continuously; the other eight had individual throttles for supplying the secondary ports under certain conditions.
Each runner was given its own fuel injector that was supplied by twin tank-mounted electric fuel pumps and was activated in sequence by the engine control module ECM. The injection system of the LT5 actually operated in three, progressive stages. During this stage, the secondary throttle blades remained closed below 80 degrees approximately of the primary blade opening, which equated about 70 miles per hour on the road.
In that event, the ECM would trigger the vacuum actuator to open the secondary runner throttles. Because the engine management system operated in stages that were mechanically controlled, the second stage performance could literally be locked out with a key.
The new fuel injectors provided improved fuel atomizing and spray control. They also claimed to require less operating voltage for improved cold-weather cranking performance and were less susceptible to clogging than earlier fuel injection designs. The LT5 came with a total of four camshafts, two per cylinder bank, one for each set of intake and exhaust valves. Valves were actuated directly from the lobes on the cams, and the intake cams featured distinct primary and secondary lobe profiles to match the valve operation of the staged induction system.
An ECM-governed fuel shutoff limited the engine to a maximum rpm of 7, rpms. Engine valves were canted at 11 degrees to their respective ports in a classic cross-flow cylinder head. Essentially a modified pentroof type, it allowed the spark plugs to be centrally placed for good flame propagation and thus faster, more complete combustion, for better efficiency and emission control.
Despite this, the fast burn design combined with the new injection system enabled the LT5 to run easily on regular 87 octane unleaded fuel. As with before, Russ Gee instructed Midgley to again seek outside help. Although he reached out to a number of companies, including Lotus and another British firm known as Coventry Climax, none of these facilities offered the required production capabilities.
Ultimately, Chevrolet contracted with Mercury Marine , a company based out of Stillwater, Oklahoma that specialized in marine engines, to build the LT5 engine for the ZR1.
Given the anticipated low production numbers that were anticipated for the ZR-1, it was reasonable to assume that Mercury Marine would have no issues keeping up with the demand for these specialized, high performance engines.
This practice would continue through the end of calendar-year , at which point Chevrolet assumed all service responsibilities for the powerplant. The LT5 engine weighed in at only 39 pounds more than the L98, which was amazing since it produced a noted 60 percent increase in horsepower over the base model Corvette.
These new engines would turn even the largest cynics into believers. The engine was mated to the rear axles and, in turn, the rear wheels by a brand new six-speed transmission. In both the standard Corvette and the ZR-1 variant, the ZF gearbox offered two important new features over the previous Corvette transmission. First, its gears were arranged to minimize synchronizer loads. The CAGS system was not solely intended for the Corvette, but was also used on Chevrolet Camaros and Pontiac Firebirds that were equipped with a six speed manual transmission.
The CAGS system utilized an integral-rail shift linkage with a solenoid actuator that guided the lever from first gear directly to fourth whenever the car was running at miles per hour with at least a partly warm engine and a throttle opening of no more than a third.
From the onset however, Reuss and McLellan knew that a new look would be required to differentiate the ZR-1 from the base model Corvette. Ultimately, the ZR-1 Corvette featured a variety of subtle, but notable changes to the base model Corvette.
These tires, which measured 11 inches wide, added 1. Aside from the rear fenders, the only notable cosmetic change to the car was the introduction of a new rear bumper.
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