Kohler K301 Burning Oil

[SShields27 11]

I am rebuilding a Kohler 12hp, k301. The tractor had been sitting for about 20 years. When I first got it I thought maybe it just needed some run time, possible a stuck ring. I've had it for a couple months and there has been no change. I have recently took the engine apart and can't find a definite reason for the smoking. Piston and ring appear to be in good condition. The cylinder is very clean and is not really worn. It does measure 3.377" at top of bore, and right on size at bottom, but not egg shaped at all. It does not smoke too bad at an idle or at a constant rpm, but when the rpms ramp up, or tractor gets under a load, it smokes like a train. It will occasionally backfire at an idle and blow a little puff of smoke but not a lot. If anybody has a bit of advice on where to look, I would love to hear it. I do not know a lot about the valve guides, if they are worn, could this cause this issue?

[SShields27 11]

I just went out and checked. The intake valve fits the guide nicely. The exhaust valve does have a little slop in it

[Fordiesel69 219]

Normal for the EX valve.  Leave it for now.  Use a three stone rigid hone first on the cylinder to even it up.  Then switch to a dingle ball hone, or hand sand the areas the 3 stone misses.  Put a new set of rings in and run it hard for 5 hrs.  Trust me when I say it will stop.  I just did an M12 and it took 6 hrs for it to stop smoking, but it did.   Its all in the rings most of the time.  Use a 3 piece oil ring if you can.

 

Is there any knocking?  I find that in most but not all cases, when the cylinder and rings are worn, the crankpin / rod is too.

 

Hear the knock on my video:

http://youtu.be/I6bVzrxQRAU

 

Mine is quite severe, but the PO did not maintain properly.  Shame shame.....

[SShields27 11]

Thank you for the advice. I will give it a shot.

And no there is no knocking, I was actually surprised at how well the engine ran.