VW W12 to Porsche G86.20 transaxle

Mounting a starter in place other than OEM can be done. For the Coyote engine in my Miura, the starter needed to be moved over to the other side of the engine to provide clearance for the transaxle.

P1140660 - web.jpg

An aftermarket, gear reduction starter commonly used for SBC was used. The bellhousing bolts were dual purposed to hold the starter by using longer bolts and a set of nuts on the long tails. An adapter plate was made on CNC mill and a bunch of aluminum carved off of the engine block to allow the starter gear to pass through to the flywheel/ring gear.

It took some time to work out how to do it, but in the end wasn't all that complicated. It feels a bit weird taking a die grinder and burr to the engine block but once the chips start flying it's just another custom bit to a custom car.
Thanks for the replies.

Measured up the W12 and designed the adapter this evening. The green 20mm thick plate mounts on the G86.20 transaxle, the blue 40mm thick plate mounts on the W12 engine. Does it make sense to mount a custom flywheel directly on the flexplate? If I use the flexplate as is - I have the starter issue sorted as well as the trigger wheel situation. Unfortunately I do have an additional length now of 20+40=60mm which is counterproductive to using the W12 in the first place.

If I remove the flexplate, the green flange is enough to connect the transaxle to the engine. But then I need to find a solution for the starter gear. What do you guys think?

Could have done this easier but the sound of a 12-piston engine is just something I dont want to miss in my Countach (re-)build. [/QUOTE said:
Excellent reasoning!
Although the W12 is a different sound than a V12. Seems like the W12 "flywheel" adapter is only 40mm or about 1.6" not reallty a space killer when it comes to packaging. Or is it?
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The flex of a flex plate is needed when you have a big soggy torque converter, but not what you want for a clutch.

Looks to me like you have the tools and knowledge to make an aluminum flywheel that you can mount the trigger and ring gear salvaged from your flex plate to on the front side and a clutch and pilot bearing on the back. I suggest aluminum because of weight (inertia) considering it's size.
Okay, found somebody that makes a flywheel for the W12 with a manual clutch:


I hope they are willing to help me here. I would need a different version of that flywheel so that it can accept this clutch:

Clutch Masters 20-707-HDFF-R Clutch Kit 00-04 Porsche Boxster S 3.2L

It reads "FX300" and apparently holds 110% over stock - which should be 480 lbf*ft. The W12 makes 430 lbf*ft. This should work.

There are more extreme clutches available:

SPEC writes " 671 lb-ft"