sleeper_dave

I've been seeing slightly higher copper in my oil analyses. All was well for 200 or so hours after the engine rebuild, now i'm seeing copper increasing. Was consistently in the teens, now it's going up - last 6 samples showed copper at 14 (165 hrs), 17 (186 hrs), 18 (210 hrs), 45 (229 hrs), 54 (336 hrs, 37 hrs on oil), 61 (360 hrs). Note that I skipped a few oil analyses - about 3 oil changes over a 2 year period. No significant mechanical work done since it was rebuilt - stock 502 mag with a rebuild about 385 hours ago now. Blackstone says universal average is 49, but the slight increase at each change concerns me. No other wear metals are seeing any increase. Lead is staying low (5, 6, 4, 5, 5, 3 respectively in the samples above).

Wondering if anyone else has the same issue, and what it could be. Was there was a change in the merc 25w40 formulation that could have caused it? I have been running longer oil fills lately (still around 25 hours, but I'm using the boat less frequently the last few years so longer duration, except the one 37 hour fill) so the oil sitting in the cooler longer could explain this, if this is in fact the case. I did run M1 V-twin for a fill, but had a front seal leak so I switched back (after replacing the seal). That's the only significant work done on the engine. Other than that it was removed for a gasket replacement, but no work was done on it. The boat has a 16" oil cooler and an oil thermostat, and the timing advanced a wee bit, other than that it's a completely stock 502, carbureted.

mcollinstn

Don't sweat it. That's not high copper. If you were chewing a bearing, it would be much higher.
It is probably leaching from the oil cooler. How hot are you running your oil? When you rebuilt, did you change oilpumps or would there have been any reason to have changed the bypass spring?

When it goes over 150, start looking for a cause.
When it goes over 300, start worrying

MC

sleeper_dave

Thanks, that's kind of what I've been thinking, but just seeing it creep up a little bit every time concerns me. I did another change and have another sample to send in, hopefully it stabilizes or goes down slightly.