K241 Burning Oil Problem

[litlmikeyl]

Originally Posted by dbuck

It maybe a optical illusion, in the picture of the piston and valves. It looks like the piston is tight to the cylinder on the valve side and there is is a gap on the non valve side. That piston being marked as + .020, was it miced for size and what piston to cylinder clearance did you use? With the MMO leaking down past the rings, what ring gap did you use?

Don,

You're right about the picture making things look off. Couldn't get a good picture from straight above the cylinder.

The piston was miced a couple of times during the machining process. I do not recall what the piston to cylinder clearance measured.

I don't recall the actual gap measurements that I ended up with. I did need to file one ring slightly to bring it farther into spec. I was concerned it would be too tight otherwise.

[J-Mech]

Originally Posted by litlmikeyl

Don,

You're right about the picture making things look off. Couldn't get a good picture from straight above the cylinder.

The piston was miced a couple of times during the machining process. I do not recall what the piston to cylinder clearance measured.

I don't recall the actual gap measurements that I ended up with. I did need to file one ring slightly to bring it farther into spec. I was concerned it would be too tight otherwise.

You know there is a spec on skirt clearance right?

Did you tear it down yet? We're waiting......

[litlmikeyl]

Update - I didn't tear the engine down as some had suggested. Found the head was warped, so the typical. 040" mill job was done to straighten that out. Also fixed my breather issue and got a new carb to replace what I had which was in need of almost everything.

Results - The amount of smoke has gone down a bit and some of the blue is gone. It's more of a whitish color but you can smell oil if you walk past the muffler outlet. Also I don't get the oil spatter out if the exhaust like before. Either way, the motor gets to come out. Bummed I am.

[bocephus1991]

It sucks but better to tear back into before it hand grenades. Good luck and let us know what you find inside.

[austin8214]

Originally Posted by litlmikeyl

Update - I didn't tear the engine down as some had suggested. Found the head was warped, so the typical. 040" mill job was done to straighten that out. Also fixed my breather issue and got a new carb to replace what I had which was in need of almost everything.

Results - The amount of smoke has gone down a bit and some of the blue is gone. It's more of a whitish color but you can smell oil if you walk past the muffler outlet. Also I don't get the oil spatter out if the exhaust like before. Either way, the motor gets to come out. Bummed I am.

Are you certain that your rings were put in correctly?

[olds45512]

Not suure if someone already pointed this out but if I had to guess its a valve problem. Its seems to be where the majority of the burnt oil/carbon is and even the oil on the piston looks like it ran down from the valves. Regardless I would disassemble it and double check everything, all that extra oil in the combustion chamber probably aided in the rapid loss of the crosshatching.

[J-Mech]

Originally Posted by olds45512

Not suure if someone already pointed this out but if I had to guess its a valve problem. Its seems to be where the majority of the burnt oil/carbon is and even the oil on the piston looks like it ran down from the valves. Regardless I would disassemble it and double check everything, all that extra oil in the combustion chamber probably aided in the rapid loss of the crosshatching.

How is it going to suck oil up the valves? The lifter galley is drained, and there isn't much vacuum on the intake. Never seen a flat-head Kohler suck THAT much oil up the intake. It's not the valves.

Excessive oil WILL NOT cause a crosshatch to disappear. Too tight of ring gap, or incorrect skirt clearance will. OR the crosshatch wasn't deep enough, and didn't last through ring seating.

[olds45512]

Originally Posted by J-Mech

How is it going to suck oil up the valves? The lifter galley is drained, and there isn't much vacuum on the intake. Never seen a flat-head Kohler suck THAT much oil up the intake. It's not the valves.

Excessive oil WILL NOT cause a crosshatch to disappear. Too tight of ring gap, or incorrect skirt clearance will. OR the crosshatch wasn't deep enough, and didn't last through ring seating.

Unless the drian is plugged, or somethings creating excessive pressure. Im sure im not the only one that's seen a kohler blow the dipstick out. I respectfully disagree about too much oil not wearing the crosshatch. When the oil gets burnt in the combustion chamber it can lead to a gritty paste that will act as sandpaper in the cylinder. Like I said before, regardless of all the theories I would disassemble it and go over every piece to find the cause, I do agree that ring fit and skirt clearance could be a cause but I was just throwin out an alternative idea.

[J-Mech]

Originally Posted by olds45512

Unless the drian is plugged, or somethings creating excessive pressure. Im sure im not the only one that's seen a kohler blow the dipstick out.

I'm not going to disagree that it may have a vent problem. But, on a fresh rebuilt, the drain better not be plugged because if it is, there's bigger issues. Now, the reed valves in the vent may be in wrong, but if that were the case, I think either the dipstick would have blown out, or a seal. So, probably not a vent problem.

Originally Posted by olds45512

I respectfully disagree about too much oil not wearing the crosshatch. When the oil gets burnt in the combustion chamber it can lead to a gritty paste that will act as sandpaper in the cylinder.

I don't disagree about this point on merit. But, this is a fresh rebuild with only 26hrs. There is no way that carbon from burnt oil wore the cylinder out in 26hrs. That would take nearly 100hrs on an old engine to wear it that bad. No way a new engine with 26hrs burning oil would do that. Besides, it takes quite a while on a hard load for a motor to burn oil efficiently enough to make carbon like that. Most guys don't run these engines hard or long enough to occur that kind of damage from carbon. Now, a big tractor pulling a disk..... different story.

My assumption is still improper clearance, either on ring gap, or skirt clearance, which caused pre-mature cylinder wear. Damage was done before oil consumption/carbon was an issue.

[dvogtvpe]

Originally Posted by J-Mech

I'm not going to disagree that it may have a vent problem. But, on a fresh rebuilt, the drain better not be plugged because if it is, there's bigger issues. Now, the reed valves in the vent may be in wrong, but if that were the case, I think either the dipstick would have blown out, or a seal. So, probably not a vent problem.

vent problem would blow oil past the crank seals before anywhere else. been there seen that.




I don't disagree about this point on merit. But, this is a fresh rebuild with only 26hrs. There is no way that carbon from burnt oil wore the cylinder out in 26hrs. That would take nearly 100hrs on an old engine to wear it that bad. No way a new engine with 26hrs burning oil would do that. Besides, it takes quite a while on a hard load for a motor to burn oil efficiently enough to make carbon like that. Most guys don't run these engines hard or long enough to occur that kind of damage from carbon. Now, a big tractor pulling a disk..... different story.

My assumption is still improper clearance, either on ring gap, or skirt clearance, which caused pre-mature cylinder wear. Damage was done before oil consumption/carbon was an issue.

that's allot of wear in a short period of time. I've probably worked on more engines than the majority of the posters here combined have seen in their life . probably rebuilt 6-700 of them. when you see that kind of wear in a short period you think 2 things. dirt wipeout of improper clearance.