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andyrv

Well Known Member
Not the best pics but here are all 4 cylinders. Superior XP-IO-360 at 770 hours. My question is the amount of oil in the bottom of 3 of the 4 cylinders. I seem to be going through oil at a faster rate these days. Comments?

Thanks,
Andy

cylinder4_zpsa7bdda71.jpg


cylinder2_zpsa59dd7c0.jpg


cyl3_zpsb3d8ca53.jpg


cyl1_zps100a30c5.jpg
 
Major ugly.....

Pretty sure you got some problems for sure. Personal opinion here is that I would not fly with that on my plane. I have borrowed the worse looking photo as an example, but all show some issues.

Not only do I see score marks, but the crown and also the edge of the piston appears to be damaged like it was pounded by something floating around in the cylinder----broken ring maybe?

Also, the cross hatch is totally worn away.

cylinder2_zpsa59dd7c0.jpg


Are you running without an oil filter------or air filter??
 
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Another view

Another view of the same cylinder. Dental cam is hard to work with but here you can see the crosshatching in the cylinder. Pretty sure the ugly looking stuff on the pistons is lead deposits being brightened and magnified by the camera. Yes to both oil and air filter. Last annual 100 hours ago and all 4 76-78 out of 80 on compression.


cly2-2_zpsf2ab86a2.jpg
 
andyrv said:
Another view of the same cylinder. Dental cam is hard to work with
Click to expand...

Wow, hard to work with is quite an understatement-----that looks like a different cylinder, not just a different view of the same one.

Perhaps you should have a mechanic with an actual borescope take a look at it??
 
Please see the thread about what happened to my Superior XP 360 with 900 hours in this same section of the forum.
 
DanH said:
Yeah, right. You never did tell us the rest of the story.
Click to expand...

Yes, I'm been hammered with an immense amount of work in the real world as well as with the airplane, in addition to studying for and passing (91%) the commercial written.

I never did determine what caused the piston damage, I have a number of theories and no definitive answer.

Ultimately I sold the core to someone who wants to rebuild it, and have purchased a brand new engine which I am installing now. I hope to start it for the first time tomorrow and fly this weekend.

I plan on doing a write up on the engine I chose, the trials and tribulations of the installation, and my experienced with both the motor and the vendor once I get over this hump.

Here are the related threads:
http://www.vansairforce.com/community/showthread.php?t=116604
http://www.vansairforce.com/community/showthread.php?t=117119
http://www.vansairforce.com/community/showthread.php?t=117119
http://www.vansairforce.com/community/showthread.php?t=117603
 
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... the amount of oil in the bottom of 3 of the 4 cylinders....
Click to expand...

I've seen that much oil collect at the bottom of a cylinder before in an engine that was running normally and not consuming a large amount of oil.

You could have some scoring, but my experience with the dental cameras is that they tend to magnify the appearance of problems that aren't really there.

I'm a long way from saying everything is okay - if you have doubts, ask an experienced mechanic familiar with lycoming engines to look at it first hand. I think the photos, good as they are, lack the detail to make a good call.

One thing you mention that is really hard to see and is potentially a concern is the edge of the pistons - the potential for heat or other damage.

Dan
 
Oil

Thanks Dan and Weasel for the comments on the oil. I'll finish taking a look around in all 4 cylinders and do compression checks (Annual) tomorrow. Engine has been great since hour 1. Was running about a quart of oil every 8 hours but seems to have increased a little.

Found one valve cover dripping a little and screws were not tight enough. Also had one of the rubber oil return line connectors dripping that needed a little tightening. Fixed up a connector in crankcase vent line that was dripping a little. Hopefully that will help clean things up a little.

Pulling the cowl again in a week or two to add sump heater for this winter so I'll take another good look after running a few hours.

Andy
 
which Dental cam?

Andy, nice pics....which dental cam? I have seen very few posted that are that sharp, with good depth of field!
please share exactly the model and where you got it?
thx
 
andyrv said:
Thanks Dan and Weasel for the comments on the oil. I'll finish taking a look around in all 4 cylinders and do compression checks (Annual) tomorrow. Engine has been great since hour 1. Was running about a quart of oil every 8 hours but seems to have increased a little.

Found one valve cover dripping a little and screws were not tight enough. Also had one of the rubber oil return line connectors dripping that needed a little tightening. Fixed up a connector in crankcase vent line that was dripping a little. Hopefully that will help clean things up a little.

Pulling the cowl again in a week or two to add sump heater for this winter so I'll take another good look after running a few hours.

Andy
Click to expand...

Hmmm.. a quart every 8 hours? I see 1.5 quart use in 50 hours max. If it were me, I would look deeper. YMMV, JMHO. :)
 
andyrv said:
........ Was running about a quart of oil every 8 hours but seems to have increased a little. ......... Andy
Click to expand...

How many quarts of oil are you keeping in the engine? Or, said another way, when do you add oil?

If you try to keep the oil full, you will likely use more. Most 4-cyl Lycoming engines seem to be "happy" at about 6 Qt.

Lots of discussion on VAF on this topic.
 
Oil quantity is bit excessive, but I wouldn't ground it for that. I would be most concerned with the vertical scoring in the second picture. Tough to tell with the poor photos, but they look somewhat deep. That type of scoring is consistent with ingesting foreign particles. It can lead to a bit more oil consumption and blow by. I also see signs of corrossion.

I would more closely examine that cylinder for the extent of scoring.

Larry
 
lr172 said:
Oil quantity is bit excessive, but I wouldn't ground it for that. I would be most concerned with the vertical scoring in the second picture. Tough to tell with the poor photos, but they look somewhat deep. That type of scoring is consistent with ingesting foreign particles. It can lead to a bit more oil consumption and blow by. I also see signs of corrossion.

I would more closely examine that cylinder for the extent of scoring.

Larry
Click to expand...

This needs some investigation as to the conditions of oil consumption. The scoring looks like carbon scoring from the top piston land. (still could be ingestion) This is typical of higher hour engines with high oil consumption coming past rings. Get a good picture of the ring turn around area at the top of the stroke to evaluate the crosshatch. It will wear down at that location first due to higher cylinder pressures and temperatures at that region of the stroke.

Although worthy of investigation, it does not seem to be a flight issue.
 
People seem to flip out about scoring. Don't unnecessarily. Its like rat **** in flour - a certain amount is acceptable (and always present). The real proof in the pudding is what does your engine cylinder monitor say about that cylinder? Whatever your CHTs and EGTs are telling you is what is happening during operation and that's where your diagnostics start. Readings are same as all the other cylinders? I'd keep flying, but each to his own.

FWIW a quart in 5-20 hrs is ok. Cont even says quart in 3hrs is ok. At that point though you do have to do the math as to whether carrying around a case of oil and burning it up is worth it to you. In the end though, no engine quit because it was burning oil past the rings - and its most likely still making rated HP or so close to it you can't tell the difference. Besides, you can run a motor without any rings and it'll make good power. But oil consumption? Yeah, you better have it on constant feed. And have a squeegee and a 55 gal drum of oil-dry for the rest of your plane.

One other note - the life of oil at 3hr/quart, yeah you'd want to shorten your oil changes up since its absorbing a lot of combustion products quicker and youre subsequently pumping those around the motor. How short is your call.
 
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As PCHunt inquired, "How much oil are you keeping in your engine?"

On my O-320, if I fill it to 7 quarts it'll blow most of a quart out of the breather in the first 5 hours, and I'll spend another five hours on the ground lying on my back afterwards cleaning it off the belly.

Then it'll slowly run from 6 quarts to 5.5 quarts just in time for the 25 hour / 4 month oil change.

Is it burning a lot of oil, or just blowing it overboard?

- mark
 
Oil

I try to keep it around 6 quarts.

Added a separator last year but no significant change so I assume the engine is just burning a quart every 8 hours.

I am comfortable with the 8 hours/quart as this engine is a dream to fly behind and all chts/egts are very consistent. I took the pics to show the oil in each cylinder so the lighting, magnification make things look worse than they are as shown by the repost of the same cylinder from a different view.

My consumption did go up slightly recently but I did find a few small leaks as noted. Going through the rest of the annual this week then will keep an eye on things.

Andy
 
Could this oil be entering the cylinder through the valve guides after shut down?

I find it hard to believe that this much oil could get past the rings during the few rev's at shut down.
 
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