Oil analysis on a 911 race engine, elevated lead/copper?

[stownsen914]

Hi all,

I'd like to get your input on the oil analysis I just had done on a 911 race engine from my 914/6. It shows elevated lead and copper, which I'm guessing could mean bearing wear. Does this mean the engine is just moving toward rebuild time, or does it mean "don't drive it anymore, rebuild now"?

A few details:
- I do use leaded gas.
- The engine is a short stroke 2.7 (93 x 66), is revved to 7500 with no overrevs, and has about 55 track hours on it.

The summary mentions "cautionary" about the lead but doesn't use as strong language about the copper. It also says that lead seems may be explainable from the leaded gas. I was expecting a little more time before a rebuild, but maybe time's up?

Thanks in advance for your opinions!

Scott

[turbo owner]

Past the lead and into copper, don't risk it. The repair cost will only go up from here.

[stownsen914]

In doing some research after posting, I've read that if there were significant bearing wear going on, I would expect to see elevated tin and manganese as well. Yet those seem more in line with averages. Any thoughts on this (or other potential sources of elevated copper)?

[Steve@Rennsport]

The source of lead & copper in these engines are main, rod, and IS bearings. Without the ability to know precisely WHERE this material is coming from, you really need to disassemble the top end and look at each rod bearing shell.

I would also cut open the oil filter and lay out the media for close inspection.

[manbridge 74]

My 2 cents...

First penny: After using OA on heavy equipment and various other engines I'd look at trends. Meaning one grab sample is not enough to know, especially if nothing is found in filter media.

Second cent: OA companies are hesitant to say all is perfect when your engine might grenade next time out. Seems there is ALWAYS some slightly elevated level of material present.

[stownsen914]

Thanks guys for your thoughts.

Re: looking at the filter, I've done that. I should mention that I run two filters in this car. Both are Canton remote filters. I have a 180 micron screen "inspection" filter on the scavenge side before the cooler and tank. I check that regularly. I usually see a few flakes of non-metallic stuff there. Same thing this time.

I also run an 8 micron Canton filter in place of the stock oil cooler, similar to what the factory did on 911-derived race engines, and I think on the 993 as well. Since I check the inspection filter frequently and it's always been clean, I have not replaced or inspected the 8 micron one as frequently (which was a mistake now that I want to use this to judge current engine condition). I pulled the 8 micron filter apart, and see what I assume are many hours of random crap dating back to when I built this engine. It includes what appears to be small non-ferrous bits. No copper-colored bits evident.

Nothing on the magnetic drain on the engine sump, and nothing of significance evident in the "cup" in the drain plug on my aftermarket oil tank.

What should I look for?

[stownsen914]

Well, here's what's in my filter. This is from the fine filter mounted in place of the cooler on the engine. A key point is that this is many oil changes' worth of debris, as I've generally focused my filter inspections on the other filter in the scavenge side, as I thought that's where I'd trap most of the debris.

The third pic is shows that some of the debris is magnetic (sorry for the blurriness).

Is this ugly?

[manbridge 74]

I'd be concerned but only way to know if that is from normal break in (I think you said you hadn't changed it) or signs of a more serious issue is to get a look at a bearing shell.

[Rusty 356]

Was this your first oil analysis? I guess pulling and inspecting is good advice. I would drain the oil and change the filters and run it and do another analysis. A piece of debris could cause the increased levels of the material found from first analysis.
Let us know what you find going forward.

[Eagledriver]

Leaded fuel will give you readings like that for lead. Copper is high but could be from valve guides. Why not do what Blackstone suggests. Run for a few more hours and test again, as well as inspect the filter. Keep an ear out for rod knock and lower oil pressure.

-Andy

[KTL]

I agree that not having a number of pressure filter inspections makes it tougher to gauge your situation. That said, that IS quite a lot of material on that filter fabric. You could put another filter cartridge in there & do a short "recon" run to see what that filter shows. It'll only cost you the filter & some time to see what it shows. I'd proceed very cautiously because a busted engine from bearing failure gets really expensive really quick. Been there done that & I don't wish it on anybody- even that cheater Tom Brady

[otto_kretschmer]

Originally Posted by stownsen914

What should I look for?

what's the oil pressure and leak down numbers look like?

oil analysis is only one tool in your tool box