After draining the crusty break-in oil, I ran a conventional 10w30 oil for 250 miles then changed it out and sent a sample to Blackstone Labs for analysis - see report below. This is my second oil sample sent for analysis. Comparing the prior results with the current sample I noticed the aluminum and copper content increased: In 2024 aluminum content was 10ppm and copper 67ppm; the latest sample shows aluminum content at 24ppm and copper at a whopping 242ppm. I didn't think to cut open the filter this time around so I don't have any empirical evidence to support the lab results.

Should these numbers be concerning? I've been pushing the timing advance a little looking for more off-the-line acceleration; does the AL number indication detonation or pinging (pistons are aluminum). Could the copper be coming from the spark plugs (again, thinking detonation/pre-ignition) or could this be coming from the bearings? Thanks in advance for the advice of the CO community; this is my first performance engine build, trying not to screw it up.

Thanks,

Rodney

 

Detonation beats up the rod bearings. I doubt enough aluminum got past the ring gap to show up as piston.

 

Is this the first 250 miles other than break in?

 

Is your radiator aluminum? Shouldn't be getting into your oil but could be a source.

 

The engine oil history is as follows:
Break-in oil - Lucas 30wt break in oil
1st oil change - 10w30 conventional (tested 6/8/24)
2nd oil change - 10w30 conventional (tested 7/3/25)
I have about 500 miles of driving on the car now.

For more history, see my Crusty Break-in Oil thread here:

https://classicoldsmobile.com/forums...ak-oil-175445/

Rodney

 

Bearings contain both aluminum and copper.
As mentioned detonation will beat em up pretty quickly if it’s bad enough.

 

I'd cut the filter and have a look. I wouldn't get too concerned about the sample at that stage of post rebuild

 

The change in these analysis results are not statistically significant. Remember that this is reported in PPM (parts per million). If you took seven samples of the same drained oil, you would likely see this level of variation. I would not have any worry at all.