IH8MUD Home IH8MUD Forum IH8MUD Gallery CruiserFAQ

21.2.3.2 GM Diesel Swap Specifics - Aaron Leach ([email protected])

The GM 6.2L mounts very similarly to a GM gas V8. The back of the engine has the same bolt pattern as the 350

Most of the same directions that come with the small block kit from Advance The engine can mount so that it is about three inches from the radiator, and then the centerline of the engine was placed at 12 inches from the left inside frame rail to the center of the engine--essentially the same as the small block Chevy engine. One thing to remember is that the 6.2 is a wide engine. The stock steering box has to be removed to make the engine fit. Installing a power steering conversion, such as the Saginaw box is required. Also, because of the width of the engine, the steering shaft should be lengthened an extra eighteen inches. That prevents the U-joint from hitting the exhaust manifold. The cruise control mechanism can be removed, and part of the air intake system must be removed for hood clearance. There is a spacer between the engine mount and the block that is needed to fit the engine properly.

What You Can Use, and What You Cannot

Here is a list of things you can use with the conversion, and what you cannot:

-you can use all GM Chevy transmissions: TH350, TH400, 700R4, SM420, SM465, etc.

-you cannot use a gas engine torque convertor, you have to use a diesel one.

-you cannot use a gas engine flex plate or flywheel. The diesel's is balanced.

-Also, when using a flex plate, there are two kinds, a lock-up type, and a non lock-up type. Each uses a different torque convertor.

-the injector pump has an overflow tube. You will need to run a return line to the fuel tank.

You will want to install a diesel tachometer. These run off the alternator. Diesels use their own starters--you will not be able to use a gas engine one. Diesels also use their own engine cooling fan. One battery will probably fit, but two might be difficult. You can get a box made that fits behind you seat that will hold two batteries. It might be wise to already have a lift installed because the drive line might hit the oil pan. With the automatic transmissions, you might have drive line problems in the rear. My drive line for the TH350 is going to be about twelve inches. The TH400 and the 700R4 are about 5 inches longer than the TH350. You will need a filter that takes water out of diesel fuel. The diesel RPMS top out around 3500. An over drive transmission, higher differential gears, or larger diameter tires will help with this situation.

Wiring the engine up

The engine is quite easy to wire up. First of all, the wires going to the starter are the same as they are on the gas engines. Secondly, the coil wire goes to the injector pump. There are two prongs on the injector pump. Which ever prong you put the coil wire on, you will need to jump a wire from there onto the other prong. You can throw the coil away, you will not need it. Also, the wire that went from the coil to the distributor is not needed.

To wire the glow plugs up, you can run a wire to a push button switch, then from there to two 70 amp relays, one for each side of the engine. If you don't want to hold the button down to control the glow time, you can add a timer relay.

You can also hook this up to the ignition. The only difference is that the ignition would be your push button switch part of it.

11/30/02