This is the first post on this forum of this Yanmar engine "problem". I'm hoping that there is a former Yanmar tech or engineer that can give me a clue as to what, for lack of a better word, happened on this engine. I'll skip the back story and get right to the issue. This is the info tag on the engine, JD series 220 s/n CH4020D191240 model 4TNE84-EJT45C. Here's the problem. 3 years ago I acquired this tractor, a JD4510. It had overheated and the head gasket was blown. I decided to overhaul it, not being sure whether the rings had suffered enough heat to take the tension out of them. Cylinders looked good. Pistons looked good. Ordered necessary parts to do the job. Went to put the pistons in and the top ring wouldn't go in the bore. Called JD and Yanmar to confirm they were correct. I determined that the ring groove in the piston was too shallow. I had my machinist search and find a top ring with the correct measurements to fit. I assembled the engine and it is running in the tractor, but consuming oil. I should have checked to see if the groove for the oil ring was the correct width, but I didn't. I want to tear it down this winter and fix the problem, probably with new pistons, a .010 bore. No-one at JD or Yanmar can or will explain why the oe rings are incorrect and I am concerned that if I order a kit to overhaul this, that I might have more issues. Can anyone explain this. My assumption is that it is a reject engine that JD installed to cut costs.
Yanmar engine fiasco
- Thread starter Grizz54
- Start date
Smilingreen
Well-known member
It sounds like you either ordered the incorrect rings or they sent you the incorrect rings. Third option would be somebody had been into this engine before, changed out pistons and sleeves with a aftermarket set.
You would think that. But, no. JD and Yanmar confirmed that the ring set which I purchased from JD and came in a Yanmar package were the correct rings for that engine. The tractor had 1700 hours when I purchased it, so no, I'm reasonably sure it has never been apart. And I can't remember for sure, but I think that I went through that scenario and the pistons had Yanmar numbers on them. But thanks for the input.