JD 950 engine rebuild

[TimberHole]

My old liners had corrosion above the top o-ring also. I think it’s because people don’t take care of their coolant. I think the JD rings are worth the extra money but that’s just my opinion and you know how those are. I would also consider some locktite when installing the studs in the block. These engines are pretty good at blowing head gaskets and I have come to believe the studs are not staying tight in the block.

 

[83regalsx]

My old liners had corrosion above the top o-ring also. I think it’s because people don’t take care of their coolant. I think the JD rings are worth the extra money but that’s just my opinion and you know how those are. I would also consider some locktite when installing the studs in the block. These engines are pretty good at blowing head gaskets and I have come to believe the studs are not staying tight in the block.

Like I said before, I don’t really like the oil ring that came in the weaver kit but I’m sure it’s fine. Not worth the extra $150 to me.

As for the head studs, I’ll keep it in mind. Thank you. I normally like to re-torque after a few heat cycles. Especially on an engine like this that’s so easy to do so.

how many hours were on your engine when you went through it.


I picked up some John Deere lube today. For anyone who has looked into the controversy around liner seal lube you may find it interesting that this stuff is a coconut based oil.

 

[rScotty]

Well, I can't find the info I had on sleeved engines needing coolant with the anti-cavitation additive.
But having a coolant that doesn't form cavitation bubbles does make sense.

Ditto with the loctite on head studs. I have never done that, but we all know that really picky engine builders will often replace all the old head studs with new when they rebuild. I don't go there either.... so using the appropriate loctite seems a decent middle ground.

What is the deal with the JD oil control ring being different? I would have thought that the OEM Yanmar oil control ring would be the best quality - or are we not talking OEM? Yanmar is a huge company in diesel engines.

What do you think on facing the block or head?
rScotty

 

[83regalsx]

Well, I can't find the info I had on sleeved engines needing coolant with the anti-cavitation additive.
But having a coolant that doesn't form cavitation bubbles does make sense.

Ditto with the loctite on head studs. I have never done that, but we all know that really picky engine builders will often replace all the old head studs with new when they rebuild. I don't go there either.... so using the appropriate loctite seems a decent middle ground.

What is the deal with the JD oil control ring being different? I would have thought that the OEM Yanmar oil control ring would be the best quality - or are we not talking OEM? Yanmar is a huge company in diesel engines.

What do you think on facing the block or head?
rScotty

I purchased an aftermarket rebuild kit My pistons and rings are not John Deere or Yanmar. I won’t get the block decked and my head is brand new so no need there.

 

[TimberHole]

I did an in frame with a blown head gasket at 1200 hours. Excellent machine and no cracks in head.

Split another 950 for full overhaul at about 2800 hours. Had a rod knocking. Crank barely turned and head had 3 cracks. Shop pinned the cracks.

As for the rings, the Deere rings I bought were the exact same as the rings I removed right down to the markings. Upon close inspection the aftermarket rings were yielding when installed and would not return to there original shape, even using a good ring expander.

 

[83regalsx]

Got the liners dropped in tonight and started cleaning up and swapping pistons. I found two spun wrist pin bushing and one was broken in half. The other is severely worn but not spun. These things saw some heat and poor lubrication, surprising with how good the rod bearings look. Anyway, I ordered new wrist pin bushings and will wait for them to come in to see if the rods need to go to the machine shop.

I also started checking rod bearing clearances and they were all great. On the low end of the factory spec actually. This may not matter though if I send them out.

 

[TimberHole]

I had to send my rods to the machine shop. I have a lot of tools but did not have the tools/equipment needed to ream those bushings.

 

[83regalsx]

My new head and Bushings came in as well as new rod bearings. Got the rods to the machine shop on Thursday to get the Bushings pressed and honed to fit the pins, should be done early next week. In the meantime I’m swapping parts over to the new head and cleaning things up. Shouldn’t take long once I get parts back from the shop.

 

[yanmars]

The mention of coolant. Will you use the green stuff as perhaps originally used back in its time or extended use coolant? I have a similar tractor, the Yanmar 336d and wondered about the same.

 

[bmaverick]

The mention of coolant. Will you use the green stuff as perhaps originally used back in its time or extended use coolant? I have a similar tractor, the Yanmar 336d and wondered about the same.

Use the old standby green coolant OR the Prestone OAT formula for ALL vehicles, old and new. Prestone keeps the corrosion inhibitor additives at the old levels for the best protetion.

The Extended Life coolants are engineered with minimal corrosion inhibitor additives. Thus, in our older tractors, using the Extended Life coolants would bring on the internal corrosion and a cooling system pumping brown sludge around.