HMSK80 Minimum tolerance on Crank - Snowblower Forum : Snow Blower Forums
 
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post #1 of 5 Old 02-08-2016, 07:43 AM Thread Starter
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HMSK80 Minimum tolerance on Crank

I've been rebuilding small engines for nearly 20 years and usually a manufacturer will specify the "new" tolerance for a crank pin or journal (usually a .0005 spread) but then call out a max wear limit. Example: Kohler K series crankpin is 1.4995/1.5000 dia. with a max wear diameter of 1.4990, which is .0005 under minimum New specification.

Now, for the Tecumseh Gurus, I have an 8hp where the thrust diameter of the crankpin (most wear) measures up to .0010 under min New spec and at 90 degrees measures within spec.

The engine threw a rod and I crocus clothed it to remove a slight nick it had from a rod bolt.

Do I chance putting it together? Will it knock being .001 under min?

Looking for some advice from someone who has done this.

If the Connecting rod split line wasn't jagged, I would just grind a thou off of the cap and have a nice day.

(Ref: I worked in the Machine Tool business for years so to me tenths matter!)

Love this forum, always willing to share my knowledge with the gang.

Thanks,

Kenny in CT waiting for the snow to fall!

Last edited by KennyW in CT; 02-08-2016 at 07:45 AM.
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post #2 of 5 Old 02-15-2016, 07:41 AM Thread Starter
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Wow, I thought I would get at least some comments! Anyhow, I found an NOS crank for what It would cost me to grind the old one to -.010 so I bought it.
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post #3 of 5 Old 02-15-2016, 07:51 AM
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engine specs start on page 93 of the L-head service manual...go to town!


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post #4 of 5 Old 02-15-2016, 09:26 AM Thread Starter
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Tecumseh gives you max and min but, unlike Kohler (in the K series manual), they do not give maximum wear limits (under min).
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post #5 of 5 Old 02-15-2016, 09:47 AM
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If the rod and cap are equal a thousandth or so is all you can take off, after that it will egg.The unequal rod and cap is more user friendly. I can't imagine what the wear is in my 50 yr 6hp Tech, seems quieter tan the newer Techs with the valve unloaders.
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