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Lycoming piston pin plug failure and collateral damage?

Kooshball

Well Known Member
I?ve come across an engine with an 0-360 in it that has recently suffered the abrasion of the aluminum piston pin plug. It was identified by aluminum in the filter and confirmed by inspection. The engine was topped, crank and cam inspected, oil lines and cooler flushed and retuned to service. That was 12-hours ago and at that time the oil was changed, analyzed and filter inspected and they all look clean.

the question is that with that kind of failure and subsequent repairs is the engine likely to have suffered some kind of damage not yet detected and be headed quickly for overhaul or is it likely to continue on without collateral damage? This issue isn?t uncommon as there is a service bulletin or similar from Lycoming but I am not able to find reports of what ultimately happened down the road with impacted engines that were repaired.

If anyone here has experience with this issue it would be of great assistance,
 
My 320 started eating pin plugs. I replaced and re-ringed at 100 hours. Currently have 650 hours with no issues on my engine. Fine alum particles are not serious risk when floating around in the oil stream. First, the filter will catch most of it and any that make it to bearing surfaces will create no damage to steel parts and only limited damage to bearing surfaces. Even if they embed in the bearing, it shouldn't damage the steel surfaces (Al is much softer than steel). The key problem area is the oil cooler, as oil flows through the cooler before the oil filter and will catch and trap small particles potentially clogging it or reducing flow.

Larry
 
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My 320 started eating pin plugs. I replaced and re-ringed at 100 hours. Currently have 650 hours with no issues on my engine. Fine alum particles are not serious risk when floating around in the oil stream. First, the filter will catch most of it and any that make it to bearing surfaces will create no damage to steel parts and only limited damage to bearing surfaces. Even if they embed in the bearing, it shouldn't damage the steel surfaces (Al is much softer than steel). The key problem area is the oil cooler, as oil flows through the cooler before the oil filter and will catch and trap small particles potentially clogging it or reducing flow.

Larry
Thank you. The logic makes sense and I?m glad that you have been trouble free for a while now.
 
Oil Cooler

In the race car world, if an engine made metal, first thing we did was throw the oil cooler away; they proved impossible to clean.
 
Like John, I was about to comment on the oil cooler. I would either replace it or send it off for an overhaul. At a bare minimum flush it in a parts washer both directions for 24 hours each session.

Regarding the original posting. You are asking for a reason. You have concern. If you find yourself flying the airplane less or have a subconscious aversion to flying it then do a full TDI. It's about a $6K to $9K deal but cheaper than the alternatives (could be cheaper since you have all new cylinder assys). Unless the work was in fact a TDI (you mentioned crank and cam inspection). On the other hand if you are satisfied with the answers you get here or other sources to keep running it "as is" that's fine, too. It's probably okay, especially if you run oil analysis every change to monitor things.

The point is not whether or not the engine needs more mechanical attention. It has more to do with your own peace of mind and that of your family and loved ones.
 
Like John, I was about to comment on the oil cooler. I would either replace it or send it off for an overhaul. At a bare minimum flush it in a parts washer both directions for 24 hours each session.

I have had them flushed and ultrasonically cleaned. Proper flushing alternates direction and as described is at least 24h
 
My experience with piston pin plug failures was that you were never really sure if the cooler was clean. Even with professional overhaul/ servicing... the only way to tell for sure, was with an Xray. Maybe they have another means of internal oil cooler inspection since I got out of the business but I wouldn't rely 100 percent of any kind of flushing. If the service place can't prove and guarantee the cooler to be clean then I would find someone that could or get a new cooler. I absolutely don't think flushing at the local airport by running a solvent through it under pressure will be effective. No matter how long you flush it for. My two cents. Seeing aluminum in the filter again in 25 hours and wondering if its residual or new from all the cylinder work you just did, isn't my idea of a good day.
Good Luck,
Mahlon
 
I spoke to the manufacturer of my oil cooler (Niagara) after my O-360 made metal and was told that there no guarantee of getting all the metal out with flushing due it's construction. I figured it was not worth the risk so just bought a new one. FWIW.
 
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