Do you know the bearing composition in...?

[Curious Kid]

...all those UOAs that one might use to help them in their oil selection? I seem to remember a person or two mentioning that not all bearing inserts are lead or lead-faced, and thus show no lead in the UOA report(s). I thought it unlikely that steel would be used due to the higher strength of the material and how this might interact with the crank's bearing surface. I suppose silver is a possibility.

How might one be able to find the specific bearing composition for their or any other engine for that matter, to make a more educated observation/selection?

 

[Kestas]

Only by reverse-engineering a known bearing. This data is not commonly available even to the automotive engineer, let alone a shadetree mechanic.

The generic bearing is typically a layer sintered powder metal copper on a steel backing. The steel is plain low carbon steel. The copper is infiltrated with lead, and the finished bearing is plated with tin.

I've seen other bearings where aluminum was used instead of copper/lead. The aluminum matrix has fine dispersion of silicon, which makes up 12% of the alloy. Aluminum galls on steel - not a very good choice for sleeve bearings.

I've also heard of some premium bearings used way back when on Cadillacs, which contained silver.

 

[hone eagle]

Most have gone to all aluminum,lead is a no no now.
cant have workers exposed

 

[Curious Kid]

Thanks for the quick response.

I was taking a break and remembered some of the discussions that were going on in response to other's UOAs. Some would comment on there being no lead in this or that engine, and that this weight was a great choice. I'm not trying to shake the thicker/thinner is better sense, but how about knowing just what those bearings are in the engines that use 20 wts., spec.ed so or other?

Just a thought.