What's the right amount of end play for the crankshaft?

[cwhuntersr]

I know that my .042" is way out of spec, but so far I've found:
"The Bible": no more than .015"
"Rebuilding the Model T Ford Powerplant (Vic Zannis)": .003-.004"
"The Engine (MTFCA)": no more than .007"

Just to be sure before I pay for an expensive rebuild: Am I doing this right? https://youtube.com/shorts/iQwQctgZ9nw

[TXGOAT2]

My take:

.015 is the Wear Limit... the point at which service is needed to maintain full function.

.007 is the maximum clearance you'd want in a new assembly.

.003 to .004 is a good initial clearance in a new or rebuilt engine with a straight crankshaft.

If I was assembling a rebabbited engine, I'd go for .003 to .005 with a good shaft, then break in carefully with a good light bodied oil.

I'd expect to find that a newly assembled engine set at .003 clearance would measure about .004 to .005 after a few miles of running.

It might be wise to set up a used crankshaft a little looser... maybe .006.

A performance engine might call for a little more clearance.

4th main alignment is critical.

[Ron Patterson]

I strongly suggest youfix .042 endplay or your gonna have a problem that could run $5-7 thsound to fix.
See attached.

Failed Magneto.jpg (39.36 KiB) Viewed 1317 times

Ron Patterson

[cwhuntersr]

My take:

.015 is the Wear Limit... the point at which service is needed to maintain full function.

.007 is the maximum clearance you'd want in a new assembly.

.003 to .004 is a good initial clearance in a new or rebuilt engine with a straight crankshaft.

If I was assembling a rebabbited engine, I'd go for .003 to .005 with a good shaft, then break in carefully with a good light bodied oil.

I'd expect to find that a newly assembled engine set at .003 clearance would measure about .004 to .005 after a few miles of running.

It might be wise to set up a used crankshaft a little looser... maybe .006.

A performance engine might call for a little more clearance.

4th main alignment is critical.

Thanks Pat. Great information. I'm in the process of tearing down the engine to give it to a rebuilder

[cwhuntersr]

I strongly suggest youfix .042 endplay or your gonna have a problem that could run $5-7 thsound to fix.
See attached.
Failed Magneto.jpg
Ron Patterson

It's already running that much and the only bad thing to happen was the loss of a magnet plate!

[Allan]

CW, you should not waste money on a lottery ticket. If you lost a magnet plate with no extra damage, you have already won the lottery!

Alan from down under.

[cwhuntersr]

.042" endplay and only a plate? you are absolutely correct