Uneven piston gap to Cylinder walls

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Uneven piston gap to Cylinder walls

Postby rcupka » Wed Jan 16, 2019 9:34 pm

Hi Guys,
Just started working on my new Model 70 with Kohler K161S 7hp I got a in December. I took the carb off to clean / repair it, it showed a low of wear in the hole on the Governor linkage, but more concerning was that one of the throttle plate screws was missing, Must have been a long time before it was put away because the throttle
plate was loose and there was wear where the plate had vibrated against the carb. throat.

Took the head off today to see if the screw cause foreign object damage to the valves at it passed through the engine. Fortunately the valves showed no damage from the brass screw, however I noted that the piston to wall gap was larger for about 30 degree near the exhaust valve. When I cleaned away the carbon I can see the top ring is making good contact on the wall. It just appears to be from the top ring on up?

Is this common on high time engines? Perhaps piston wobble from skirt wear. I do not see any scoring on the cylinder walls, I notice a , 0.010 on the top of the piston top. I can put it back together and see what happens or change a piston and rings while I am this far.

Appreciate the benefit of your experiences

Dick Cupka
Last edited by rcupka on Fri Jan 18, 2019 9:55 am, edited 2 times in total.
Dick Cupka
Cub Cadet Model 70
1949 Farmall Cub
1972 International Cub Lo-Boy 154
2005 New Holland GT20
1960 Lincoln Continental Mark V
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Re: Uneven piston gap to Cylinder walls

Postby rcupka » Wed Jan 16, 2019 9:51 pm

Trying to post a picture now
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Dick Cupka
Cub Cadet Model 70
1949 Farmall Cub
1972 International Cub Lo-Boy 154
2005 New Holland GT20
1960 Lincoln Continental Mark V
rcupka
 
Posts: 11
Joined: Thu Dec 27, 2018 8:52 pm
City and State: Saline, MI
First and Last Name: Dick Cupka

Re: Uneven piston gap to Cylinder walls

Postby dale campbell » Thu Jan 17, 2019 5:35 pm

the piston is worn at the top due to carbon build up at that area , if you tear it down it will probably need bored , might as well just try it the way it is and see how it runs
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Re: Uneven piston gap to Cylinder walls

Postby rcupka » Thu Jan 17, 2019 9:31 pm

Thank You Dale, I think that is likely what I will do.

Dick Cupka
Dick Cupka
Cub Cadet Model 70
1949 Farmall Cub
1972 International Cub Lo-Boy 154
2005 New Holland GT20
1960 Lincoln Continental Mark V
rcupka
 
Posts: 11
Joined: Thu Dec 27, 2018 8:52 pm
City and State: Saline, MI
First and Last Name: Dick Cupka

Re: Uneven piston gap to Cylinder walls

Postby rcupka » Wed Mar 13, 2019 8:54 pm

I haven't posted in a while due to travels and other projects I have been working on. I installed a new head gasket, new carb, battery, air filter, new points and condenser, cleaned the tank and the Cub started right up! Now just seems to be routine work to continue to improve the Model 70.

Drove her the other day and everything seems to be working, haven't checked charging yet. Not sure if PTO is okay or not, took of the 38 inch deck and will service it and then try the PTO.

Set her aside while I worked on a Cub 154 Lo-Boy that I picked up. Looking forward to spring to continue working on all the Cub projects. I am tired of heating up the baen so warmer temperatures will be welcomed.

Thanks for all the help from the forum members, will report progress as it happens.

Dick
Dick Cupka
Cub Cadet Model 70
1949 Farmall Cub
1972 International Cub Lo-Boy 154
2005 New Holland GT20
1960 Lincoln Continental Mark V
rcupka
 
Posts: 11
Joined: Thu Dec 27, 2018 8:52 pm
City and State: Saline, MI
First and Last Name: Dick Cupka

Re: Uneven piston gap to Cylinder walls

Postby ksanders » Thu Mar 14, 2019 8:34 pm

Good deal. Even worn a lot of those engines will run well. Sounds like yours was bored once already. Easy way to check front pto is try to turn it by hand with motor off and the pto lever forward. It shouldn't turn without turning the motor. Pull the lever back to disengage the pto (push against the center button of the pto) and it should turn by hand without turning the motor. If it won't free turn double check the adjustment on the rod coming from the handle to the front rockshaft. If that checks out only other issue could be slipping under load. A common issue with those sitting a while is freezing up and always staying engaged.
From the first Original to the last x82 Series... you can't beat an IH Cub Cadet!!!
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