VW Motor mount and Coupler, do I cut the drive shaft?

3623 Views 7 Replies 4 Participants Last post by Max57TBird, Jan 20, 2011

matthiaswm

Discussion Starter · Jan 18, 2011

I need to mount my Kostov 10" on the VW Bus/Beetle tranny. The transmission drive shaft has about two inches that stick out beyond the geared part. Should I cut that off?

Cutting it would move the motor two inches closer to the gear box and make the coupler 2 inches shorter as well, but It feels kind of "wrong". What did you guys do?

Also, with the motor hanging off the back of the transmission (just like the old ICE), should I add another motor mount at the rear, or is mounting it on the gear box enough?

Thanks,

Matt

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EVfun

· #2 · Jan 19, 2011 (Edited)

I take it you are referring to the input shaft? If you are not running a clutch it is possible to cut off the smooth part of the input shaft but you should never cut the splines. What type of motor shaft adapter are you using?

My VW shaft adapter consists of a Ruland shaft coupler and the input to mainshaft coupler from a late model VW bus that was turned down to 1.125 inches in diameter and had a key slot cut in it. I cut off the pilot bearing section of my input shaft.

The Beetle doesn't require a rear motor mount. I believe the Bus and Type 3 do require a rear mount to be fabricated. The motor itself can usually be supported by just the shaft end, though I am not familiar with the Kostov motors. The Prestolite MTC motor in my VW based beach buggy is only supported by the transaxle.

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matthiaswm

Discussion Starter · #3 · Jan 19, 2011

Thanks for all the details! I will get a clutch disk on Monday and the motor in a week or so and try around a little. When I asked the question, I was not aware that most people seem to leave a working clutch in place. Cutting the end off would ruin that option.

I'll check again if I find an old motor mount in the ca. It came without engine... .

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Tahoe Tim

· #4 · Jan 20, 2011

I cut mine back close to the splines and then used a grinder to sneak up as close as possible. Without a clutch, that part of the shaft which usually fits into the pilot bearing on the vw flywheel is not needed.

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· #5 · Jan 20, 2011

I would do a set up that does not require you to cut that shaft. Once cut that transmission is only good for your application. It would not be good for a gas engined vehicle again if for any reason it needed to be used for that. Otherwise just go ahead and cut it off if needed. My setups use the clutch and need that part to remain in place.

Pete

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· #6 · Jan 20, 2011

EVfun said:
I take it you are referring to the input shaft? If you are not running a clutch it is possible to cut off the smooth part of the input shaft but you should never cut the splines. What type of motor shaft adapter are you using?

My VW shaft adapter consists of a Ruland shaft coupler and the input to mainshaft coupler from a late model VW bus that was turned down to 1.125 inches in diameter and had a key slot cut in it. I cut off the pilot bearing section of my input shaft.

The Beetle doesn't require a rear motor mount. I believe the Bus and Type 3 do require a rear mount to be fabricated. The motor itself can usually be supported by just the shaft end, though I am not familiar with the Kostov motors. The Prestolite MTC motor in my VW based beach buggy is only supported by the transaxle.

68 Busses and up and 69 Squarebacks and up need the extra mount. The Mount on the early type III's are not really a supporting mount but they do help a bit because the motor sticks out much further than like a Bug engine would. The Bus requires a mount because they removed the transmission frame horns in 68. They removed them from the type III in 69. All type IV require that extra mount in the back.

Your buggy only needs the transmission to hold it in place. Just like my Ghia. If the chassis has frame horns you don't need that extra support.

Pete

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matthiaswm

Discussion Starter · #7 · Jan 20, 2011

gottdi said:
68 Busses and up and 69 Squarebacks and up need the extra mount.

Great help. Thanks!

About cutting the shaft: this car will never go back to gas, but it may have to go back to having a clutch... . Thanks for the thoughts.

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Max57TBird

· #8 · Jan 20, 2011

matthiaswm said:
Great help. Thanks!

About cutting the shaft: this car will never go back to gas, but it may have to go back to having a clutch... . Thanks for the thoughts.

Matt,
Never say never - - suppose you want to sell the motor later (Upgrade or whatever) it would be easier to sell an unmodified motor.

I chose not to cut mine but rather put some 1.125" spacers between my home made adapter plate and the motor. You can see the gap and almost see the spacers in the photo:

http://www.chieftain.com/news/local/article_71792c86-fc3e-11df-acd9-001cc4c002e0.html

The assembly was quite stable in its cantilevered configuration, but I had an easy way to add a support to the rear of the motor so I did.I also had an ulterior motive for the gap (I want to play with a regen idea in the future) so that was part of my decision.

That having been said, the car is not yet running so I cannot give you a final report.

Lane

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