M4A2 Sherman clutch shim question

[Perry Kitson]

The old timers always said, "the only thing keeping the oil in was the paint".

[Jesse Browning]

Are there match marks on the parts? Supposed to be, but my clutch didnt have any either.

[Malcolm Towrie]

Originally Posted by Jesse Browning

Are there match marks on the parts? Supposed to be, but my clutch didnt have any either.

You mean match marks to identify which parts come from which engine? Didn’t know that so I haven’t been looking for them.
Malcolm

[Jesse Browning]

The match marks are usually for keeping everything balanced, but if marked differently could give a clue to origin.

[Lynn Eades]

Malcolm, so based on what you have said, then the purpose of the shims might be to prevent over bending the spring and risking breakage ( as well as the travel)

[Malcolm Towrie]

I have to confess, guys, since we removed a total of 0.020” total from both the flywheel and pressure plates to clean up the heat checking, I decided to install both clutches with just the one 0.032” shim per bolt. My justification is that my experience working on GM engines and transmissions is that the design engineers were way too anal about setting allowable specs and wear tolerances. I defy anyone to notice any difference between a 6-71 running with spec 0.016” valve clearance (4 valve head) and say 0.018” clearance.
Also the GM spec of 1.460” for the injector timing, with no tolerance specified, has at least one guy on YouTube making the effort to get it that exact spec, I seriously doubt if +/-0.010” makes an detectable difference.
If we find out I’m wrong on the shims when we get the engines back in the Sherman, I will of course not be posting it here.
Malcolm

[Malcolm Towrie]

The clutch release bearings have been installed. And also the transfer case inner housing with the release forks, and the outer housing.
Much to my relief, there was some free play on both clutch release forks, indicating that the setup with just one 1/32” shim under each clutch cover bolt was allowing the release bearings to unload.
The sketch in post #1 above above shows that if bolting up the transfer case had left no free play on the clutch forks, we would have had to pull the t/c off and add more shims to move the diaphragm spring inner bore towards the flywheel.
Malcolm

[Michael R.]

Originally Posted by Malcolm Towrie

I have to confess, guys, since we removed a total of 0.020” total from both the flywheel and pressure plates to clean up the heat checking, I decided to install both clutches with just the one 0.032” shim per bolt. . . .

If we find out I’m wrong on the shims when we get the engines back in the Sherman, I will of course not be posting it here.
Malcolm

Good effort Malcolm. Nice to see you catch a break.