QUOTE(ClayPerrine @ Mar 8 2023, 06:49 AM)
The only difference between a /4 flywheel and a /6 flywheel is the crank mounting surface. They use the exact same clutch disk and pressure plate. So the dimensions for turning a flywheel are the exact same.
That's good info Clay. Thanks!
So, the step between disc surface and pp mounting surface is 22.5mm or "A" in the diagram.
This is the important measurement to get correct.
Many times in the past I've found inaccuracies in published OEM data...
Why would anyone cut the ring gear upper surface?
That diagram shows different values for "B" which is the total thickness of the flywheel.
In my world this figure would never change as I see no need or gain for machining the face of the ring gear, just extra cost as that would be a third cut at the machine shop.
My unmachined 73 flywheel measures 40.4mm for B and the back surface is not flat as shown in the diagram. It has a small chamfer on the outer edge.