Question Metal found in oil filter

  • Aaron Kahn
  • Topic Author
  • Offline
  • Junior Boarder
  • Junior Boarder
More
16 Jan 2024 10:18 #4177 by Aaron Kahn
Replied by Aaron Kahn on topic Metal found in oil filter
During the scoping of the cylinders, we didn't see anything that looked suspect.  The only scuffing on the wall of the cylinder was exactly where the wrist pin plugs would be on the piston.  There has been no change in fuel consumption or oil consumption in the prior flights.  I have not done anything different prior to this metal issue, other than it happened after returning the aircraft to service after annual inspection.  

We did check the surface of the valves with the scope and the intake and exhaust valves all looked great.  The heat pattern on the exhaust valve surface looked healthy.  The valves appeared to seat properly when actuated by turning the prop.  The surface of the piston appeared healthy as well, apart from some buildup on the face of the piston.  The carbon material found in the oil seemed to match closely with the build-up seen on the piston face.

The only other item of interest is during a run-up recently a plug appeared fowled.  I leaned the mixture and let the engine run at a higher RPM for a minute and the rechecked. All was normal after the recheck.  I suspect a small amount of lead fowling in the plug.  

I will keep the group informed with what I find after the next oil change.

Aaron

Please Log in to join the conversation.

More
10 Jan 2024 08:00 #4174 by STEVE ELLS
Replied by STEVE ELLS on topic Metal found in oil filter
Hi Aaron,
Thanks for posting these results.
You and your mechanic ran through a very thorough trouble shooting menu.

I'm not sure why a wrist pin would move enough to cause the rubbing, and if that rubbing came from the bottom of the piston.

Did you change the operation spectrum of your airplane prior to the appearance of the metal? Were you flying from a different airport? Did you change the brand and weight of oil? 

During the borescope was #3 more oily than the other cylinders?

Did your fuel consumption numbers go up prior to the appearance of the aluminum?

If you have an engine monitor, please download the engine temps data--look for increased, or temperature changes esp. in cylinder #3 during recent flights.

Please pull the valve cover of #3 and see if there's any evidence of excess heat, such as cooked on crud on the valve spring cap. I'm thinking that it's possible that carbon broke loose from a valve guide and was sucked into the combustion chamber, got between the cylinder wall and the piston, and that caused the piston to relocate slightly.

Please keep me in the loop on what you finde after the 10 hour fly off.

Best,
Steve

Please Log in to join the conversation.

  • Aaron Kahn
  • Topic Author
  • Offline
  • Junior Boarder
  • Junior Boarder
More
10 Jan 2024 03:55 #4171 by Aaron Kahn
Replied by Aaron Kahn on topic Metal found in oil filter
Update to the situation:
  I had the filter analyzed and the metal found in the filter was indeed aluminum.  I flew the plane over to my mechanic and we drained the oil, checked the suction screen, cut open the filter, borescoped all the cylinders, and performed a compression check.  The borescope inspection of the cylinders showed #3 had some scuff marks where the wrist pin plugs are located.  The scuffing did not look bad enough to pull the cylinder.  All the other cylinders looked good.  All compressions were we in the upper 70's.  
  The oil and filter checking showed no further sign of metal, but there was a large amount of carbon or other grit in the filter and suction screen.  Some of the carbon flakes in the suction screen were quite large.  I had the filter sent for analysis and it came back with very little metal.  
  My mechanic and I have a theory about what might have occurred:  1) the wrist pins are floating and the one in #3 must have shifted slightly.  2) Once this moved, the cap rubbed against the cylinder wall producing the aluminum and wore into the new position.  3) After the pin moved, any carbon buildup on the underside of the piston broke loose, resulting in the large amount of carbon flakes in the oil.
  What next?  My mechanic said to follow the Lycoming suggestions, and fly the plane for another 10 hours and then change the oil and check the filter.  If not further metal is found not to worry.

Aaron

Please Log in to join the conversation.

More
27 Dec 2023 09:11 #4165 by STEVE ELLS
Replied by STEVE ELLS on topic Metal found in oil filter
Hi Aaron,
I'm interested in what steps you took, did you fly for a few hours and inspect the filter?

Was it clean?

Or did the metal amount increase?

Steve

Please Log in to join the conversation.

More
04 Dec 2023 09:40 #4160 by STEVE ELLS
Replied by STEVE ELLS on topic Metal found in oil filter
Hi Aaron;

OOPs!

That's a little alarming!

Lycoming service bulletin SB480F contains guidance from Lycoming on metals discovered during changes or inspections:

I have attached Lycoming Service Bulletin SB 480F. In it you'll find recommendations on what the next action should be--this depends on the amount and type of metal found.

I'll also refer you to an article from the Piper Flyer magazine archives: www.cessnaflyer.org/magazine/article-arc...-this-in-my-oil.html.

Check out the bulletin--determine the amount and the type of metal; those factors will guide to the appropriate action.

I believe the bulletin tells owners, if the amount of metal is less than 1/4 teaspoon, to add new oil, install a new filter then fly for 10 hours and re inspect.

Your plan to re inspect a new filter in 5 hours seems very sound. 

It may be that one of the aluminum connecting rod/piston pin end caps is being abraded.

Please let me know what you find.

Steve

.


 

Please Log in to join the conversation.

  • Aaron Kahn
  • Topic Author
  • Offline
  • Junior Boarder
  • Junior Boarder
More
04 Dec 2023 04:19 #4158 by Aaron Kahn
Metal found in oil filter was created by Aaron Kahn
All,
  I have been flying my '67 PA-28-140 with a RAM 160hp STC regularly sense the engine was overhauled about 280 hours ago.  After cutting open the oil filter from the last oil change I was shocked to see a "large" amount (10 - 15 flakes) of fine aluminum flakes in every pleat of the oil filter.  The oil analysis showed only a slight increase in aluminum over the prior samples.  The particles found in the filter were thin, and about 1mm wide, and 1 to 4 mm long.  It looked like shavings.  Up until this time the engine had made no metal.  I am going to cut open the new filter as the engine as about 5 hours sense the last oil change to see what it looks like.  Was wondering where this sudden metal could come from.  I am 99% sure the material is aluminum and not tin (shiny silver flakes which are hard).

Thanks for the help,
Aaron

Please Log in to join the conversation.

Time to create page: 0.098 seconds