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What's the right amount of end play for the crankshaft?
Posted: Sat Jul 27, 2024 3:05 pm
by 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
Re: What's the right amount of end play for the crankshaft?
Posted: Sat Jul 27, 2024 5:43 pm
by 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.
Re: What's the right amount of end play for the crankshaft?
Posted: Sat Jul 27, 2024 5:56 pm
by 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 1324 times
Ron Patterson
Re: What's the right amount of end play for the crankshaft?
Posted: Sat Jul 27, 2024 8:05 pm
by cwhuntersr
TXGOAT2 wrote: ↑Sat Jul 27, 2024 5:43 pm
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
Re: What's the right amount of end play for the crankshaft?
Posted: Sat Jul 27, 2024 8:07 pm
by cwhuntersr
Ron Patterson wrote: ↑Sat Jul 27, 2024 5:56 pm
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!
Re: What's the right amount of end play for the crankshaft?
Posted: Sat Jul 27, 2024 8:17 pm
by 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.
Re: What's the right amount of end play for the crankshaft?
Posted: Sun Jul 28, 2024 9:34 am
by cwhuntersr
.042" endplay and only a plate? you are absolutely correct