Does anyone know of a good source for an old school vw beetle to ADC L91-4003 adapter plate and couple for a non clutched system?
Thanks a lot EVfun, just to confirm these are the exact reference dimensions? I'll be doing all my CAD design around them so I just need to make such I have exact references before I get parts made or $$$ down the drain.The aircooled VW Beetle bell housing is a simple design. The motor is located with a centering ring that is 11.100 inches in diameter around the motor shaft. The outside diameter should be at least 12.400 inches but could be larger without interfering with anything. The motor shaft location can be used as the center for everything.
The top 2 bolt holes are located 4.328 inches above the horizontal centerline and 3.897 inches to either side of the vertical centerline (42 degrees to either side of the vertical centerline.) The bottom 2 bolt holes are located 4.117 inches below the horizontal centerline and 4.117 inches to either side of the vertical centerline. The 4 holes should be 7/16 inch in diameter.
You get to set the holes and locating ring for the motor based on what you have chosen. I used a Prestolite MTC-4001 so mine is a step cut with a 8.5 inch diameter to fit the motor locating ring. Most motors have a locating ring diameter smaller than the bolt pattern so the plate can have a through hole in the locating ring diameter.
My shaft coupler is machined from a VW Bus input to mainshaft coupler turned down to 1.125 inches (for the hardened splines that fit the input shaft) and a Ruland shaft coupler is used to connect the splined coupler and motor shaft. The clutch pilot shaft is cut off the input shaft. Here is a picture of the motor installed. I don't have any pictures of the motor and adapter out of the car.
Yeah I was working on the assumption that everything would be metric and the designers used rounded off numbers. I checked the little counterbore step and I got 282mm off my transmission. I also re-checked my other numbers and got very close figures to the ones you mentioned. Here's an image of what I have.I double checked my typing and verified they where posted without error. I think the bolt holes are a few thou off, but the bolts fit without issue. I suspect the correct dimensions would be 11mm holes and the holes located on radius 148mm from center with the top 2 located 42 degrees on each side of the vertical center line and the lower ones located at 45 degrees from either side of the vertical center line. I bet the locating ring is actually 282 mm instead of 11.100 inches too. You will notice how that would move things just a few thou, and would make more sense since the old VW Beetle is metric. The locating ring should be about 3mm deep.
I want to point out that if you choose to go without a clutch you will want the shaft coupler to be as small in diameter and light as practical. The inertia of the armature and everything attached to it are what the syncros have to bring to speed when shifting (diameter kills shifting speed.) It will not shift race car fast, but the old Beetle transaxle seems to be quite up to the task of going clutchless and I wouldn't put one back in if someone else volunteered to do it for free. I've been running my adapter without issue since 1999.