5.9 Magnum MPI swap flywheel idea
not sure where the idea of using a flex plate and fly wheel came from,,,the flex plate is balanced for a convertor,,and mounting the fly wheel to the flex plate is going to move the fly wheel out farther away from the crank im not so sure the balance would be correct,,,and you would have to do some adjusting on the clutch fork for proper throw out bearing travel just my 2 cents
The idea came from trying to find a cheap way to use a 130T flywheel with Magnum MPI setup. The computer needs to see the tone ring that is on the flywheel and I was hoping to not have to buy a 143T flywheel and associated 11" clutch and big bellhousing (see the first post).
The theory was that if a flexplate would sandwich between the crank and flywheel, I could use the tone ring on the flexplate to run the computer, but still keep my small flywheel and 10.5" Centerforce clutch. That hasn't shone much promise.
Still in question is whether or not the crank lip is tall enough to center the flywheel with the flexplate behind it. I was hoping the 1/16" (or 1/8") of material in the flexplate wouldn't upset the clutch and fork relationship. If it does, then a similarly sized spacer between the bell and block should fix that right up. That's what they do with the 5.7 Hemi to fit the crank offset difference.
The flexplate carries the balance weight for the motor, that's why I thought I would use a 5.9 flexplate. The converters on the Magnum motors are neutrally balanced. Don't see why it would matter if there was a converter with a neutral balance or a flywheel with a neutral balance behind a flexplate with the correct inbalance for the motor. Also, I did find out that the v6 flexplate has no weights, so in theory, the v6 flywheel would also be neutrally balanced.
So, the parts list outlined above should be easy to find and should bolt together without any real machine work involved. I found a flywheel locally for $27, a flexplate for $12 and a bellhousing for $50. Bonus that I wouldn't have to even pull any of it.
BTW, there are 130T flywheels for 5.9 Magnums, but they are just early 360 flywheels with the correct inbalance for a 5.9 Magnum. They don't have the tone wheel for the computer.