Hi Mike,
The problem I have run into is although you might tend to be forgiving for seeing the rings at the top of the stroke along with the piston reduced diameter in the ring area....fact is the rings are working themselves to death to make up the taper and it's a pretty sure bet the ring land clearances are out of spec. Gets progressively worse as you reach the maximum allowable bore at the top of the liners.

Those tractors that take forever to warm up and start or ether is required are the result of lost compression due to these worn conditions.

True, The top ring is a keystone if I am remembering right and it is probly way past spec. I can't see the damage he has but I did recommend replacing the sleeve assemblies...

The Keystone rings were an up grade (replacement) from the original on older engines but I think in later years engines were equipped with them as standard. Have installed lots of them but don,t have any more info on it than from memory.

The original poster may put up some pics soon and we can see how it looks. None of us have any idea how much wear he has at the top so at this point we don't know if the rings are actually expanding and contracting in the distance of the stroke. If they are then new rings will not help the problem.

i will!! tommorow hopefully...

hey all got some pics...Here are some pictures of the bores (with scary looking spider) .....the gap is evident in some of the pictures....take a look and tell me what you think!

some more pics of the bores...

AND finally some pics of the tractor in general...

data plate

I have to admit the bores in my D2 5J2115SP are looser than that. It was the first Cat I bought, I think I was 19 at the time. After I brought it home I noticed an intermittent misfire on cylinder #2. I started tinkering on it and when I removed the valve cover found every outer valve spring broken and coiled around itself, and cylinder #2 intake valve with the inner spring also broken allowing the valve to drop enough to hit the top of the piston. I don't know how it ran as well as it did. The valve had contacted the piston so many times that it wore a perfect impression in the piston top. The bores were so worn I remember seeing an excessive ring gap, so much that measuring would mean nothing. After seeing all that I figured the whole thing was so worn out I really didn't have much to lose, and no money to do it up right. I got another 5J head that I overhauled and installed and fired it back up, it ran pretty good all things considered. It's still running that way today. It's really something to see, the steady flume of blue smoke from the exhaust eclipsed only by the horrendous amount of blow-by from the crankcase breather.