Low compression / weak cylinder

[rScotty]

So after trying the oil trick today compression didn't hold and it even sounded a little worst after a few min of running so I went on and pulled the head. One medium and 2 or 3 light vertical scratchs in the cylinder pretty sure broken ring or piston or both... Now to figure out how to drop the front drive shaft to access the pan!

Good on you for pulling the head. Most of the time when I've had one cylinder go weak it's been a head gasket. How did that look?
rScotty

 

[radios1]

So after trying the oil trick today compression didn't hold and it even sounded a little worst after a few min of running so I went on and pulled the head. One medium and 2 or 3 light vertical scratchs in the cylinder pretty sure broken ring or piston or both... Now to figure out how to drop the front drive shaft to access the pan!

that happening at 600 hrs. is very suspicious!. maybe a manufacturing defect?.

 

[rScotty]

So after trying the oil trick today compression didn't hold and it even sounded a little worst after a few min of running so I went on and pulled the head. One medium and 2 or 3 light vertical scratchs in the cylinder pretty sure broken ring or piston or both... Now to figure out how to drop the front drive shaft to access the pan!

I've seen lots of leaky head gaskets, some leaky valves, but rarely have I found broken rings. Minor vertical scratches in the cylinder wall are surprisingly common. I don't know what causes them. On the other hand, any time the head is off I now consider it normal procedure to have an automotive machine shop take a very light cut on the head to make it absolutely flat.

I've come to believe that a lot of cast heads have a little bit of manufacturing stress locked into them that shows up as warpage when a new engine is first run torqued down and run up to temperature. The gasket should be elastic enough to seal in spite of that movement, but that's not always the case. But once the head has aged and been flatted, it seems to last just fine.
rScotty

 

[Shaneard]

Have you ever used ether on this engine to crank it?

 

[4wheelfurry]

Have you ever used ether on this engine to crank it?

I have never however I loaned it out a while back and I suspect he did. The fuel solenoid went out while he had it, he was trying all sorts of things to get it up running not knowing what he was doing... I went and got it back going, needless to say I was not happy about he handled that situation but he was afraid I'd make him pay to repair it which the solenoid was not his fault. So I suspect that is the culprit to my situation now!
The head gasket was sealed up tight to the head and block, everything looked as it should. I plan to pressure was and clean the head Saturday I will put a straight edge on it once it's clean. I am going to go on and lap in the valves while its down too.
Today I will try to figure out how to drop the front drive shaft and pan, I will post an update once its completely down.

 

[radios1]

I have never however I loaned it out a while back and I suspect he did. The fuel solenoid went out while he had it, he was trying all sorts of things to get it up running not knowing what he was doing... I went and got it back going, needless to say I was not happy about he handled that situation but he was afraid I'd make him pay to repair it which the solenoid was not his fault. So I suspect that is the culprit to my situation now!
The head gasket was sealed up tight to the head and block, everything looked as it should. I plan to pressure was and clean the head Saturday I will put a straight edge on it once it's clean. I am going to go on and lap in the valves while its down too.
Today I will try to figure out how to drop the front drive shaft and pan, I will post an update once its completely down.

ether these days have a lubricant to prevent washdown..

 

[RickB]

ether these days have a lubricant to prevent washdown..

Some but by no means all. And most ether damage is caused by the violent explosion that occurs before the actual fuel injection timing, not cylinder washdown. Broken rings and melted and broken ring lands are not caused by a lack of cylinder wall lubrication.

 

[rScotty]

I have never however I loaned it out a while back and I suspect he did. The fuel solenoid went out while he had it, he was trying all sorts of things to get it up running not knowing what he was doing... I went and got it back going, needless to say I was not happy about he handled that situation but he was afraid I'd make him pay to repair it which the solenoid was not his fault. So I suspect that is the culprit to my situation now!
The head gasket was sealed up tight to the head and block, everything looked as it should. I plan to pressure was and clean the head Saturday I will put a straight edge on it once it's clean. I am going to go on and lap in the valves while its down too.
Today I will try to figure out how to drop the front drive shaft and pan, I will post an update once its completely down.

Is that a wet sleeve motor or a bored block type?
I'm a great believer in hand-lapping.

No,I don't like ether either. I almost didn't buy our JD310 (used with 6000 hrs) because it came is set up from the factory with ether injection. There's a place on the manifold to screw in an ether cylinder triggered by a solenoid from a button in the cab. I've never used it, but suspect that the previous owner used it a lot. The tractor had 6000 hours when I got it. Luckily, that engine is still tight, quiet, fuel efficient, and quiet and starts on the first crank. So maybe JD's ether start system doesn't inject enough ether to hurt. Or maybe this is just a blessed engine.

Which reminds me that I've still got an old German .22 cal. pellet rifle that uses ether to boost the velocity. I guess that makes it a diesel rifle.
rScotty

 

[4wheelfurry]

Piston is out. Broken second ring and middle lan. Which is quite unusual, pre-detnation usually effects the top ring and lan.. top ring and oil ring were both free and fine. No chunks missing or even big scratches to the piston beats all I ever seen. Assembly error perhaps? Anyway I have one bad push rod too so all parts ordered. Will clean this weekend and wait reassembly.

 

[RickB]

That would be an assembly error at 40 hours, at 600 it is not. Sounds like ether damage and you had better pull #1 and #2 and inspect them.