Does anyone have any ideas of why the flywheel bolts have been ground down as in my attached picture? This motor came out of my 1976 - 914. I am in the process of cleaning up and painting the car. The engine as per the serial # is an early 73 2.0. Ser # GA000605. The heads as per the casting numbers are 2.0 L off a VW bus. I am thinking the motor was put together after the OE 2.0 L gave up. The OE 901 5 speed tansaxle is bolted to the current 73 2.0 L.

The flywheel looks like a 914 flywheel and the clutch plate looks correct but someone who put this engine together shaved the flywheel bolts for a reason. It looks like the bolts were ground down on the bench and then installed and torqued to the crankshaft. The bolt shoulders are 1/2 the OE height but with the right socket I would think they were able to get 85 ft lbs on torque. The clutch plate would have contacted or come very close to contacting the full length flywheel bolts if they had not been ground down 1/2 in height. And if the clutch plate over time wore down to the rivets you would have clutch plate contact with the bolt heads at full length.

My thoughts are the flywheel may have been surfaced down so much they had to grind the bolt heads if the outer bolt up surface point for the pressure plate was not also machined down at the same time. It may also be possible the flywheel is a different depth at the flywheel bolt center point Click to view attachmentClick to view attachmentand maybe a VW bus flywheel or they may have a bus clutch plate installed.

It does have a new Sachs clutch plate stamped with P/N 1861540033.

Anyone have a good explanation of why the shortened flywheel bolts?
Thanks.

My guess would be the flywheel has been resurfaced too many times and lost much of its thickness, requiring the bolts to be shaved.

when you resurface the FW, you "should" grind those bolts down a bit or the friction plate will do it for you (sometimes with disastrous results).

If they contact the plate that is bad.

It is obvious that those were ground off the car.
The plate did not for it for you or all of the scratches would be aligned circumferentially

The recess in the center of the wheel gets shallower every time the wheel gets turned. Then the bolt heads stick out.

They appear to have been ground down by hand as the scratches are not uniform. .
Best assumption is the flywheel has been surfaced too much or that someone
used an incorrect clutch disc [maybe upside down??]

I'd suggest you measure the clearance with the clutch disc installed and find out
what the clearance is now. . Then replace 1 bolt and see if the disc actually hits.

The hardest part of figuring out an issue is trying to know what the previous owner was thinking. That is why they are sometimes known as DAPO's

its normal practice to grind those down when the flywheel is resurfaced (as everyone stated above)

I prefer to go with a cap screw, metric allen head to replace those bolts when they get thin like yours.

(easy to do now while you have things apart, they can be ground also)

Maybe a new flywheel would be in order? I know they are spendy, but if you have it apart you are probably buying parts. Is that dumb? Is that much grinding a way of getting a lightened flywheel and OK as long as the relative dimensions are proper?

Do a search, new flywheel specs are about the same as an old fly that's be reground a few times.
I always keep my eyes open for flywheels that haven't been over ground too many times.
I have quite a few of them now.

Grinding down the bolts is an acceptable practice, you can take off a fair bit.
At minimum I remove the top outside ridge.
I've seen them ground down to the point that you can jut get a socket on them, I've never seen one fail do to this practice.
When doing this use only the 6 spring 911 clutch disc, 4 spring will interfere with the bolts.
You also will have to put a flat washer behind the release arm pivot. One washer only and don't over torque the pivot.