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KT17 damage


Snojetter

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My brother in law had a conrod let loose on his 7117.  Damage to the cylinder is shown in the attached photo, outlined in red.  Everything else appears to be ok internally, so let's just assume this is the only issue.  The thought is to clean up the jagged edges of the break, hone the cylinder to eliminate any micro-edges on the inside of the cylinder at the break line, and then re-assemble.  Being the piston is still fully contained in the cylinder, it would seem this missing piece shouldn't cause any problems...but would like other's opinions.

Has anybody tried this?  Can you think of any problems this would cause?

Tractor1.JPG

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Never tried - it might work but the rest of the piston may be weakened and cause problems later.  If I had the $$ I'd replace while it's apart anyway and hopefully avoid another overhaul later.  Depends on whether the cylinder and crank etc. still worth the rebuild.  With that much of the piston skirt missing there is likely to be more slop as the piston moves up and down.

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I had the same issue with a Kohler magnum. The broken area at the bottom didn't interfere where the piston rode in the cylinder. I showed it to a couple of mechanics and both said they would have no issues using it. Like you, I cleaned up the edges and had the cylinder honed. Put the engine back together and it runs like a charm. Can't say what will happen in the long run as I just did this recently. I did read other posts, I believe on this forum, where this question/issue was asked before and most said there should be no issue using the cylinder. But, it is up to you.

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Providing the piston does not travel that far down it should work ok but you need to determine bottom dead center on piston , you should be able to look in and see other piston to determine BDC

Some engines the piston protrudes out of bottom of cylinder when at bottom dead center.  Just my $.02

Edited by 720nut
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16 hours ago, 720nut said:

Providing the piston does not travel that far down it should work ok but you need to determine bottom dead center on piston , you should be able to look in and see other piston to determine BDC

Some engines the piston protrudes out of bottom of cylinder when at bottom dead center.  Just my $.02

Lloyd, I'm not sure I understand what issue/problem this would bring up if it did?

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  • 4 weeks later...

The KT17 series I had issues with oil starvation if it was operated on a slope. It was corrected with the Series II , but if you decide to rebuild a Series I engine, make sure you be careful about operating it on a slope..

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I agree that as long as the piston doesn't travel into the damaged area, it should be ok at the top end.  But one thing no one has mentioned is that it will probably blow oil from the crank case.  Even with a healthy coating of Permatex, there isn't much surface area to seal it in the bottom half.

I saw a pair of jugs on ebay for  $150 plus shipping ($50) and a couple of singles.  

Throw it back together and see what happens but I'd be prepared to ask Santa for some new cylinders.  Of course now we are talkin' about an upper half rebuild.

PS:  If you do get used cylinders, ask the seller to mic them for you so you know if you can even use them.  If I recall, there are 6 micrometer readings required: two at the top, two in the middle and two at the bottom.  Each pair of readings are at 90 degrees of each other.

Edited by wwbragg
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