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Engine Swap: GM Gen IV L92 Makes Big Power

Gm L92 Engine
Jay Kopycinski | Writer
Posted August 1, 2012

Bolt in a Generation IV Engine

GM introduced the LS engine family of V-8 engines in 1997 in the Chevrolet Corvette as an all-aluminum engine, and the company has built upon this line ever since. These original versions, some with cast iron blocks and some with aluminum, were known as Generation III engines.

In 2005, GM introduced the Gen IV engines. The newer line brought larger bore sizes (for up to 7.0L displacement), different camshaft position sensor locations, and the addition of casting areas for GM’s Active Fuel Management cylinder deactivation methodology.

We got news that the guys at Crocker Off Road Performance in Phoenix, Arizona, were doing a unique GM swap into a ’98 Jeep TJ owned by John James from Cottonwood, Arizona. What stands out is their use of a 400-plus-hp Gen IV L92 engine transplanted from a Cadillac Escalade. The L92 is a 6.2L Vortec engine used in the Escalade and several other GM SUVs and trucks. It boasts an all-aluminum design with traditional pushrod technology, but utilizes variable valve timing. It was rated from the factory at 403 hp and 415 lb-ft of torque.

To make things ever more interesting, John backed this potent powerplant with a 6L80 six-speed automatic with full automatic and manual shifting options. When all was done, the Crocker guys made this engine look like it belonged under the hood from day one.

Going forward, the Gen IV engines will be a popular powerplant option for those wishing to swap in a modern engine with the latest technology. This class of motors offers improved fuel economy, efficiency, horsepower, and smooth drivability. Here’s a quick rundown of things to consider when swapping any non-stock engine into your rig, and also some details specific to how you can put GM Gen IV technology under your hood.

01.Typical late-model engines have eliminated the ignition distributor completely and use one coil per cylinder. The L92 has four coil units mounted atop each of the valve covers. Using a dedicated coil per cylinder allows the manufacturer to precisely fire each coil and spark plug as needed. The engine computer can adjust the ignition timing for each individual cylinder, improving both power and fuel economy.

02.You’re staring down the throat of a 90mm throttle body for this 6.2L V-8. To the throttle body, the shop crew added a custom intake boot and filter to fit the available area under the hood.

Fuel pressure to the injectors for the L92 should be about 58 psi, so a healthy pump that can move good volume is needed to keep this engine happy. A Bosch 040 in-tank pump was mated onto a 2005 Jeep TJ fuel pump sender and dropped into an aftermarket fuel tank for this particular build. A C6 Corvette regulator was used downstream.

03. Setting an engine such as this between the frame rails depends on just how much room you have in the engine compartment. Crocker used a set of M.O.R.E. engine mounts in this case. Depending on your particular swap and recipient vehicle, you may have to build custom mounts, or aftermarket pieces might be available. When doing an engine swap with new mounts, it’s vital to make sure the engine, transmission, and T-case mounts are compatible. That is to say, you don’t want one end mounted solidly while the other end sits on soft rubber mounts. Mounting point failure is likely to follow in this scenario.

04. Crocker ordered a custom built Ron Davis aluminum radiator with integrated transmission cooler to fit within the confines behind the grille. The water outlets were positioned to best align with the outlets on the engine. Sometimes, it’s possible to find a formed hose to fit a conversion, but often a universal flex hose will offer the smoothest fit, as was done here.

This engine came with a typical factory mechanical fan, but it was removed in favor of using a single large diameter SPAL electric fan behind the radiator. The Ron Davis radiator/fan/shroud assembly was custom built based on the rated engine HP and operating altitude for the vehicle. The cooling system is not the place to skimp when dropping in a high-horsepower engine.


Crocker Off Road Performance
Speartech Fuel Injection
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