Yep, used the alignment pins on installation.
Virtually no ridge at top of cylinders, but there is wear. I.E., the original swirl marks from honing the cylinders was barely discernable and the bores were shiny and clean looking. Didn't mike them and since I could hardly feel a ridge and didn't take the pistons out I didn't check for taper of the cylinders.
No hyd fluid in crankcase. Have checked that. Also, when the valve cover fills up and blows out, it almost drains the crankcase. That's what originally caused me to see the problem, and be very concerned.
The way the head cracked it blew out a chunk externally and simply drained the water onto the ground. No water got into the engine. Now the 8200 was different, it filled the crankcase with water, but that's a different engine and it's the one that I replaced the block on. Did a complete overhaul but reused the original pistons after miking them to be sure of clearance.
As for the cylinder wear, I suspect the block, and rings, are pretty tired. I'm just thinking with relatively easy starting and clean running and comparing it to the 8200 blow-by, I wouldn't jump on the blow-by as being the problem. Plus, in talking to the local Kubota people they reinforce the idea that it "should" smoke and/or be hard to start if there was enough wear to cause excessive blow-by. BUT, at this point it is the only thing I can come up with that makes any sense at all.
There are other problems with the 7100 block, and if / when I do an overhaul I'll have to replace that block. I'm toying with the idea of brazing up the crack in the 8200 block (the crack is in an accessable spot that is not structurally nor pressure sensitive), replacing the 7100 pistons with 8200 pistons and rings, and turning my 7100 into an 8200 cross-breed. I've been studying the parts, the books, and I can't find any differences between the blocks EXCEPT the bore. Don't have specs to compare the valve diameters between the two engines, and that concerns me a bit. Also can't be absolutely certain about the bolt holes for the gear box and the front cover, but I'd lay odds both engines were from the same casting and the same tooling set-up with the exception of the bore.
I've got several more weeks of other major projects before I start back on tractor repairs - probably won't be until October or later. After that I guess I'll have to start by tearing the 7100 engine down. Have just been trying to postpone it for another year or two. Besides, I'd planned to use the 7100 to power my log splitter. I need to split a lot of wood before winter!
But thanks for all the thoughts! If nothing else it stimulates my own thinking.
D.A.M.
