Here are pictures of the piston out of the 12 hp Kohler that blew up this summer cutting grass, some of you may remember. I am going to put a new piston and rod in. The bore looks good, but have not got a good look at it yet. So, I figure that it wont need to be bored out, so no going to a 14hp from a 12hp. That was just a thought if it needed boring. Pictures not so good, but gives you the idea as to what happened. So I will do some measuring and then start looking for parts. Good to have a spare engine. Thanks for looking, Noel
Pictures of pistion out of my Kohler 12hp
Posted December 28, 2014 - 01:07 PM
I think this is what happened to my K341 in the Ford. Haven't pulled it yet to see though.
- tinbender7 and propane1 have said thanks
Posted December 28, 2014 - 01:48 PM
Split the top right off that piston... wow.
I'd check your bore carefully. No way that it didn't get chewed up some. I'd also check and make sure it isn't worn out of specs. I've seen a piston split like that twice, one time due to overspeeding the engine and the other time due to the bore being worn oversize from use and the piston slapping around freely.
Check it carefully.
That's the old style piston, the newer styles were different. They called the new ones "Mahle" pistons.
- Alc, Texas Deere and Horse, KennyP and 4 others have said thanks
Posted December 28, 2014 - 04:14 PM
I agree with Ben I would have it bored. It's had to believe the cylinder isn't damaged.
- superaben and propane1 have said thanks
Posted December 28, 2014 - 04:47 PM
Looks like it should be repairable. There should still be parts kits available on EBay for those motors Noel. Genuine Kohler parts are pretty pricey if you can get them.
- propane1 said thank you
Posted December 30, 2014 - 06:45 PM
Edited by propane1, December 30, 2014 - 06:54 PM.
- Sawdust said thank you
Posted December 30, 2014 - 09:33 PM
No damage to cylinder. Had better look at it tonite. And any measurement I do are good , but I am not an engine professional. New ring gap is .024 top to bottom and the same if turned 90 degrees. Bore measures 3.379 top to bottom and turned 90 degrees. Book says 3.375. Rod measures 1.501. Have not measured crank yet. Noel
.024" End gap on new rings does not sound right.
A common guideline is .003"-.004" gap per inch of cylinder. .....So, 3.375 x .004" = .0135" End gap. ...Yours is almost twice that amount.
What rings are you using?
- Sawdust and propane1 have said thanks
Posted December 31, 2014 - 05:54 AM
Your answer should be 0.0135 I think, if I did it right. Noel.
Edited by propane1, December 31, 2014 - 06:20 AM.
Posted January 20, 2015 - 09:46 PM
- olcowhand said thank you