Well, sorry for the delay... I had to pursue the flywheel maker to the point that I was worried that he wouldn't want to do them or that I would give up and work around a stock dimension flywheel. Good news on two fronts: first, custom aluminum 12# flywheels will be under 400$ delivered in very small quantities. next, while waiting we did look into a budget setup that uses the stock fw and it appears that this will work very well, too. I'm not looking to make any money on this so we're sharing all our information but flywheel supplier and part number. that said, i won't even appologize if you use the following information without verification and then run into problems
Here's the low down: bolting a NA Z32 flywheel to a VK56 for use with the Z32 trans poses four surmountable problems (the requirement of an adapter plate is a given).
1) the starter ring gear is 4mm or about 3/16" too far away from engine to trans flange (back of the block) so that the VK starter will not properly engage.
2) the starter ring gear on the OEM flywheel is designed for a rear-engaging starter drive gear which is the opposite of the VK starter. you can't simply flip the ring gear on the flywheel, either.
3) the clutch wear surface is 6mm or about 1/4" too close to the engine to trans flange (back of the block).
4) the input shaft crankshaft bushing depth is wrong (similar to 3 above).
a custom flywheel with the correct OEM ring gear fixes all but number 4 which is a simple matter of a custom bushing, and since the VK crank has extra support length from the factory this is easy.
to use a stock flywheel requires these mods: Disassembly of starter and simple machining in a lathe to mount 4mm deeper in the block. this looks to be very safe with the starter we used for mock up. the flywheel wear surface dimension can be remedied by machining an extra .240" off the bell housing for the adapter plate. this forces you to weld the adapter to the bell housing, but that is really not a big deal; the adapter on my buddy's 10 second L28 powered 510 is welded to the trans. a 55$ new ring gear can be pressed on to fix the issue of engagement direction. it appears that an OEM bushing works for the input shaft with this set up. in a z32 chasis the passenger side head may have a clearance issue unless the trans is moved forward a small amount; no way to tell for sure until we have one in the car.
it looks like the adapter plate will be o.5" 6061. thicker than that compromises the strength of the bell housing flange where it bolts on. we can machine a nice bevel into the id of those adapters slated for welding so that a deep filling weld is provided for without extra prep work.
another idea occurred to me last night at the shop regarding crank angle sensor mounting that I'll share once I have a cad drawing finished. it allows the stock ecm or a custom tooth wheel to easily mount up without machining to this adapter.
next big project is cnc'd parts for building a good intake manifold. ironically, this will be one of the most expensive and time consuming parts of this project for us.
Here some links to the record setting land speed z32 we sponsored as well as the ’28 model T that we swapped a vg30dett into for racing on the salt.
http://www.scta-bni.org/Bonneville/BNIrecs_cat_e.htm
http://www.scta-bni.org/El%20Mirage/ELM%2006/May/photos/friday/IM000620.JPG
http://www.turbohoses.com/ken_carlson.htm Click on the thumbnails for large images
next update with pics