Stuck yanmar 165D

[etpm]

If the rod bearing caps were removed can they just be bolted back on and torqued properly? I ask because since the pan is off and the rod ends are exposed why not just unbolt the bearing caps and then try to push the pistons up. If they can't be moved then the problem is stuck pistons. It may even be possible to tap on the underside of the pistons if they are stuck to try to get them moving.
Eric

 

[careyo63]

I seen a front pump for aYM276. It was nice looking. I have a front mount on my ford. What I couldn't find was the chain Driven YM165. Never seen that one before.

 

[rScotty]

I seen a front pump for aYM276. It was nice looking. I have a front mount on my ford. What I couldn't find was the chain Driven YM165. Never seen that one before.

I wouldn't call it a chain drive, just an axial coupling using a duplex chain.

It is an oddball way to drive a pump, but mechanically it makes a lot of sense to couple two axial drive shafts that way. It allows for a bit of mismatch so the shafts do not have to be perfectly in line.

You see it a lot when coupling pumps of all kinds, irrigation pumps espeically.

I've got a tech paper from Yanmar somewhere that talks about chain couplers when they started using them. Mostly for the early two cylinder models that didn't have a high flow hydraulic pump. If there is any interest I can dig for it.

Here is a photo on our old YM165D. Can you see the chain coupler?
rScotty

 

[rScotty]

If the rod bearing caps were removed can they just be bolted back on and torqued properly? I ask because since the pan is off and the rod ends are exposed why not just unbolt the bearing caps and then try to push the pistons up. If they can't be moved then the problem is stuck pistons. It may even be possible to tap on the underside of the pistons if they are stuck to try to get them moving.
Eric

Yes. I just didn't want to get into the tricks about removing and refitting used rod caps with someone that I'm not familiar with their mechanical confidence. Frankly, I don't like to ever remove rod caps on a new engine except as a very last resort.

 

[etpm]

Yes. I just didn't want to get into the tricks about removing and refitting used rod caps with someone that I'm not familiar with their mechanical confidence. Frankly, I don't like to ever remove rod caps on a new engine except as a very last resort.

I understand. That's why I asked. What about just planning on buying new bearings? I don't know what bearings cost but new bearings wouldn't be a bad thing. The OP needs to determine if it is the rings that are stuck. Pulling the bearing caps off would certainly be cheaper than sending the tractor to a shop. Easier too. I'm surprised someone didn't suggest this when he removed the pan. If the rings are indeed stuck then bumping the pistons up will need to be done anyway in order to replace them or to make sure they are moving freely in the ring grooves. And if the pistons move up freely then at least the OP knows the engine is in good shape. So far the poor guy has been reduced to guessing, he really needs to find out if the rings are stuck.
Eric

 

[millard762]

I do have those 2 chains but can't remember if there was a master link. Will check when I get off work

 

[millard762]

I wouldn't call it a chain drive, just an axial coupling using a duplex chain.

It is an oddball way to drive a pump, but mechanically it makes a lot of sense to couple two axial drive shafts that way. It allows for a bit of mismatch so the shafts do not have to be perfectly in line.

You see it a lot when coupling pumps of all kinds, irrigation pumps espeically.

I've got a tech paper from Yanmar somewhere that talks about chain couplers when they started using them. Mostly for the early two cylinder models that didn't have a high flow hydraulic pump. If there is any interest I can dig for it.

Here is a photo on our old YM165D. Can you see the chain coupler?
rScotty

View attachment 878198

That is exactly what I have

 

[millard762]

So, if the rings were stuck, would the ATF/xylene mix move past them that fast?

 

[rScotty]

So, if the rings were stuck, would the ATF/xylene mix move past them that fast?

Sure it would..... once it dissolved some carbon or crud so that the mix could flow through the ring end gaps. If the gaps were as open as stock, a shotglass of your mixwould flow right through in a few minutes, Except for the amount of mix that formed a boundary layer due to close clearances. That boundary layer of your mix is all you can expect to remain, and is all that is doing the work. because of the xylene (I use acetone sometimes) the mix degrades - evaporates - too quickly, Renew it daily or even more often..

One of the critical things you do when installing rings is setting the proper end gaps on the rings. The ring end gap has to be close enough so that it seals well enough to develop enough compression to start a diesel, but not so close that heat expansion will cause the gap to close completely and scar the cylinder bore. And they are generally set 180 degrees (rotation) in opposition to each other.

Re: the lower end rod bearings. We will get to those in a bit. But I am not yet satisfied the engine is free of end constraints. We have to disconnect the hydraulic pump on the front, and the transmission on the back.
Put it in neutral and see if the PTO shaft turns. A PTO shaft problem combined with a frozen clutch could certainly cause these exact problems. The frozen clutch means that any transmission malfunction also locks the motor. Have you put it in neutral and not in 4wd while raising both rear tires off the ground & tried to rotate the engine via the front crankshaft nut?
Consider taking off the shifter cover and have a look around,

If this were 40 years ago I would say take it to a shop. But unless you personally know an old stye gentle and educated experienced mechanic who hasn't retired, lets first try some easy things at home.

Gotta go do some work today....
rScotty

 

[careyo63]

Looking at the top of the Cyl. No Scars. Then when you posted the Excellent Pics. of the Bottom End even on here there is no sigh of of piston problem or a broken ring. Chk. the Cyl. pressure going to find out if there is a problem. Your ordering at least one head gasket so might want to make it 2. JS,,