- Jun 9, 2003
- Sequim, WA
Are the turbo bearings ball or journal? If journal, they are brass. That's a possible source of the copper. The zinc would be masked by the additive package. Some brass alloys use a bit of lead. That could explain the lead that may or may not be there.I'm used to Ford using Alumisil (bi-metal) bearings, silicon is really high, but aluminum isn't, which would lead one to conclude it isn't bearing material. I also don't see enough lead/tin for it to be a tri-metal bearing to explain the copper, so that's likely coming from something else (chelation), but where is the question! Also, your metal particles didn't look like copper, though if they are big enough to see, they are too big for the UOA to see them. Silicon is probably coming from silicone sealant from your timing set job if I had to guess.