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Question for engine rebuilders

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I have a K341 that gave up a rod a while back. talk about "Big Bang Theory..." anyway, I tore it down to see how bad it got inside and to my surprise other than the rod, and the very bottom of the piston skirts the inside looks great!

the crankpin looked like it might have taken some abuse but i used a white stone (lightly) and some polishing paper and it must have been debris from the rod or piston because it came right off.

i took some measurements and it does show some wear. the crankpin measures 1.498 to 1.499 (low limit is 1.499) and out of round a full .001 (spec calls for .0005 max)

the bore measures .002 out of the wear limits and is out of round about .005. going to need a new piston anyway and i can bore it at work ;). no problem there.

 

my question is, would you re-use the crank in that condition? I can't grind a crank at work...  lol

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I usually don't comment on engines but something I realized many years ago is as an engine wears the load on the rod and crankshaft is reduced so they stay together. When the valves or pistons/rings get some attention the load on the rod and crank is increased and if not in the bottom of the wear limit they soon fail.

I say do the crank/rod first and the top end second.

 

Garry

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These kohlers are great engines, but crankpin / rod failure is more common than you would think.  I think boring out the rod and using an insert bearing like an automobile is very superior.  

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I would think so too. Has anyone done that?

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The insert bearing, I think will work on the larger K engines...10, 12, 14 hp.  I had both cranks turned to .010 under in my rebuild of the K181S's.  You then order the rod .010 over.  It is worth doing it right.  :)

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2 hours ago, stevasaurus said:

The insert bearing, I think will work on the larger K engines...10, 12, 14 hp.  I had both cranks turned to .010 under in my rebuild of the K181S's.  You then order the rod .010 over.  It is worth doing it right.  :)

:text-yeahthat: I would do a complete rebuild.

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I have one of the bored rods in my Raider 12 K301. Sent two of them to Brian Miller for rework. My local NAPA machine used to do this but machine shop no longer around.

Used to be a shop in Ft. Wayne,IN that did this. The insert I believe was from a 4 cylinder Continental engine. Have the crank turned to the first undersize it will cleanup at. 

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