Lycoming Oil Sample Allowable Levels

[paul m]

Help. I am looking after a high hour Lycoming fitted to a RV6. Just done an oil sample which has found a high Chromium count (30ppm). I can't find the allowable levels anywhere. I have found the Lycoming SB on sampling oil, but not the levels allowed.
Any help or direction to the publication, would be appreciated.
Thanks
Paul:)

[heated ice detector]

Try this site Home (http://www.sacskyranch.com/).
they sell a book with a lot of info re oil analysis,
How old is the engine, I am in the same boat with owners wanting to keep flying way past the man tbo, 10% maybe 20% over if its flown regularly seem to be a norm.

[hull city]

Most of the authorties will allow an extension to the engine TBO, and it will dependant on the type of operation. Check with your local authority.

[halabut]

I'm afraid there isn't any published limits, Lycoming are good like that.
Also what kind of oil sampling did you do? SOAP has kind of fallen out of favour, especially with modern fine filtration systems.
Do you conduct any oil filter debris analysis? I've seen some very good results on this, especially for catching cam follower failures.
On these engines (as with all aero engines, gas turbines as well) trending is generally better than go-no-go limits for metal in oil. Especially when you have the variables you get with Lycomings, normal, chromed or nitrided cylinders cylinders, what type of rings, OEM or PMA parts etc.
Think carefully before going over TBOs, they're conservative, but there for a reason. Ensure you have some kind of technical risk mitigation program.

[A and C]

tell us what type of cylinders you have fitted and I will try to make a comment that is not made on pure guess due to lack of data.

[NutLoose]

Have you tried contacting Lycoming, they are normally pretty helpful

BTW are these what you have found?

http://www.aircbs.gr/pdfsd/Lycoming_Engines/Airworthiness_Information/SL_L171-Spectrometric_Oil_Analysis.pdf

http://www.lycoming.textron.com/support/publications/service-instructions/pdfs/SI1492D.PDF

As said in the last one

If the origin of the metal contamination cannot be determined, a call may be made to the Lycoming Product Support Department. A good description (photographs, color and quantity, etc.) of the metal may result in placing its origin. When phoning Lycoming or when returning metal removed from engines, supply the complete engine model designation, serial number, history of engine, oil temperature, oil pressures, and any unusual behavior of the engine on the ground or during flight. Do not ship material to Lycoming without first calling the Product Support Department.
9. If examination of the oil filter or suction screen, per the above, indicates abnormal aluminum or iron content, contact a technical representative of the Lycoming Product Support Department at 1-800-258-3279.

Give them a call, without Engine make/ model/ cylinders/ rings etc as said we are all grasping at straws.

[On-MarkBob]

There is no published data because it depends on what is being found and how much as a percentage of the engine, if that makes sense. For example; in your case does the engine have chromed cylinders? if so you might expect a high count compared to an engine with steel or nitrided cylinder bores. The key to metal analysis is common sense, you need to find out what the metal is, (as you have done), then find out where it could have possibly come from. Also, how the metal has been treated in manufacture, for example; if the metal is 'case hardened' steel you could have a serious problem with a cam shaft or follower, even though the metal fragments might be small in number.

Bob

[Mike Echo]

Paul
I've P.M'd you due to a possible conflict of interest.
M.E.