PTT flywheel fits ok, on the LX9 flywheel
This is primarily because the LX9 flexplate has a reinforcement plate on it that spaces the flywheel away from the flexplate. part number 12579453
the PTT flywheel can't stack on a LA1 3400 flywheel
it doesn't have the reinforcing plate. so it doesn't sit flat.
the flexplate is only part of the problem though, it also needs a means to center on the crankshaft. The reinforcing plate on the LX9 flexplate pushes the flywheel out far enough to only contact the flexplate at the mating flange, but it also puts the entire flywheel beyond the register on the end of the crank. so I need to find a way to keep center the flywheel. the fastest, simplest solution is to make a centering ring, much like the hub centric ring used on a wheel, the issue with that, is that can lead to stacked tolerances and sub par alignment.
one of the other ideas was to machine the flexplate side of the flywheel down, but leave a ridge at the ID to register on the crankshaft. the ridge could fit inside the ID of the reinforcing plate, and around the OD of the crankshaft register. I'm not super fond of this idea, unless I could talk PTT into making me a blank flywheel with a thicker mating flange. I'm going to take some more accurate measurements and call to try and talk to one of their engineers and see what they say about that plan.
I'm OK with modification of both the flexplate, and to a degree, the flywheel, the flexplate is a brutally simple part, that doesn't really wear out, the flywheel, requires machine work to fit the engine either way. I do not want to modify a crankshaft in any way to fit this. at this point, a centric ring looks preferred, the cut required to make the reverse register on the flywheel would be pretty meaty, to go the full depth of the reinforcement plate, the cut would be about ~2.5mm, on a flange that's only ~7.25mm to begin with.
anyone have another idea?
also, fwiw, PTT flywheel, resting on a LX9 flexplate, has a stack height of about 1.05"
this information should be pertinent to any internal balance 60V6, but my information thus far is based on an LX9 3500.
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