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

[stownsen914]

Hi all,

I posted this question on the Pelican board, and would like to get opinions here as well.

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, which I understand can explain the high lead level in the oil
- 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?

In addition to the oil analysis report, I'm also including some pics of the Canton oil filter element that I run in place of the stock oil cooler on the engine. I have not changed or inspected this filter in a long time, as I use an coarser screen element nspection filter in the scavenge side of the oil system (definitely a mistake to not have checked the filter on the engine more often). Note a significant amount of metal bits, with some of them being magnetic (last blurry pic shows a magnet I trolled around on the filter element). Could this be acceptable given the extended period of time this filter was in service?

Thanks in advance for your opinions!

Scott

[john914somers]

Hi all,

I posted this question on the Pelican board, and would like to get opinions here as well.

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, which I understand can explain the high lead level in the oil
- 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?

In addition to the oil analysis report, I'm also including some pics of the Canton oil filter element that I run in place of the stock oil cooler on the engine. I have not changed or inspected this filter in a long time, as I use an coarser screen element nspection filter in the scavenge side of the oil system (definitely a mistake to not have checked the filter on the engine more often). Note a significant amount of metal bits, with some of them being magnetic (last blurry pic shows a magnet I trolled around on the filter element). Could this be acceptable given the extended period of time this filter was in service?

Thanks in advance for your opinions!

Scott

Hey Scott,
SO you have reached the correct person as I am a petroleum chemist for a private laboratory. In looking at your data you are missing a crucial element to your study, you have no controls. What I would recommend is to analyze a brand new sample of the exact same kind of oil, as a background sample, because all oils have some metals in them. This will tell you if the metals in your oil are from your engine or not. To determine if the lead is coming from your fuel, change your oil and run some unleaded fuel. If you are using a good laboratory they should be able to tell you what the metals concentrations are in milligrams per kilograms of oil or parts per million. This may be prudent instead of merely rebuilding your engine. Good luck!

[stownsen914]

Hey Scott,
SO you have reached the correct person as I am a petroleum chemist for a private laboratory. In looking at your data you are missing a crucial element to your study, you have no controls. What I would recommend is to analyze a brand new sample of the exact same kind of oil, as a background sample, because all oils have some metals in them. This will tell you if the metals in your oil are from your engine or not. To determine if the lead is coming from your fuel, change your oil and run some unleaded fuel. If you are using a good laboratory they should be able to tell you what the metals concentrations are in milligrams per kilograms of oil or parts per million. This may be prudent instead of merely rebuilding your engine. Good luck!

Thanks very much, John - much appreciated. Based on input from a few different people, I am considering running the engine cautiously this coming weekend, and inspecting the filter after the first couple runs to make sure nothing new is showing up in the filters.

I called Blackstone today to discuss the results, and got the impression that 58 ppm of copper is to be watched but not necessarily a reason to not drive the car. I am waiting on input from one more person whose opinion I would really like, but I'm leaning toward running it.

[Matt Romanowski]

Having done lots of oil changes with metal in the filter like that, I would say take it apart sooner than later. Will one more event hurt it - probably not, but you've got something going on in the motor.

Also, my personal opinion is to only use the Canton filters for float tests and run a regular, quality filter like a Wix, Mehle, Mann, etc. Then cut it open every couple of events to see what is in there. You should not find much if anything in the pleats of a filter.

[stownsen914]

Thanks Matt. I'm planning a club race later this week, and I think that'll be the last event on this motor.

Re: the Canton filter, I'm using the tall, canister style ones, one with a coarse screen and a second with an 8 micron disposable element. Are you thinking this is too coarse, or not up to the task in some other way?

I'm planning to do filter inspections after each of the first few runs to make sure no significant new materials is being shed. Otherwise I just park it.

[Matt Romanowski]

Thanks Matt. I'm planning a club race later this week, and I think that'll be the last event on this motor.

Re: the Canton filter, I'm using the tall, canister style ones, one with a coarse screen and a second with an 8 micron disposable element. Are you thinking this is too coarse, or not up to the task in some other way?

I'm planning to do filter inspections after each of the first few runs to make sure no significant new materials is being shed. Otherwise I just park it.

I don't think they are designed to flow enough. We had trouble with those filters on a couple of different motors and they are now banned in our shop. I think their filtering is probably fine, just not enough of it.

You're plan is probably a good one.

[stownsen914]

Interesting about the flow on Canton filters. I wonder if we're talking about the same one? The ones I have claim to flow 40 gal of oil at 180 degrees F, which seems well in excess of what our engines need. In fact it's why I chose that filter (many years ago) when I built my car ... I'm referring to the big cannister style filter like the pic below. Is that the one you had bad experience with?

[Matt Romanowski]

Those are the ones. I know they sell a ton and some people really like them, but we had bad experiences.

[J P Stein]

Race engines don't last forever. I got 7 years out of my AX motor before it got noticeably tired.

[Matt Romanowski]

Race engines don't last forever. I got 7 years out of my AX motor before it got noticeably tired.

Tired and metal in the oil are different things. Tired is dying valve springs, worn rings (and lands), increasing (or decreasing) valve margins, worn valve guides. Most motors race motors, when properly designed and built, don't kill bearings (intermediate shaft excluded).