Talked to my mechanic today, he can't think of any such repairs that were made. I jokingly asked if maybe one of his silver teeth fell in, but no such luck.

Not concerned, just wondering.

I checked my race motor Blackstone results and I also have silver with acl race bearings.

Weird because looking at te cutaway on ACL site, I don't see silver. Now the question is how deep within the bearing is that layer. I have no noise and the silver isn't increasing. Can you post your results or tell me how many units they found over how many miles? How long have you been using the bearings?

Just trying to think, I'll keep an eye on it, but I somehow regret not getting clevite or King bearings for the longer lasting (as I hear)

My old motor with ACL bearings didn't show any silver in the UOA, I haven't run one on the new motor yet though.

--Ian

Found this on Bobistheoilguy

"Silver

Due to its exceptional thermal conductivity, it is occasionally implemented as a coating on bearings to help provide minimal friction. However, it is susceptible to corrosion from Zinc-based additives and is not commonly used in the U.S."

Could the Rotella be eating my bearings apart, or am I beng obsessive again?

Rotella won't eat your bearings.
But high silver usually means they are getting worn.

I'd be curious to see or hear some other guys running the ACL Race and what their readings are. 5ppm could indicate normal wear on the bearings (since there was no increase from last oil change), or it could mean a slow and steady destruction of the bearings as well. If it's the latter, I'd probably rather change them out sooner than later to avoid damaging other components. I might just wait for the next oil change and see what the readings are then.

T6
Attachment 233403

vr1 with more power and driven harder
Attachment 233404

But how much of that difference is from the oil itself, and how much from the residuals washing out? I was under the impression that break-in happened quickly, but as I'm seeing more and more blackstones on newer engines, the particles leaving the engine are quite a process.

I should add I also have the FM Oil cooler kit, so that might be retaining some things between changes as well.

Called ACL race this morning, finally got a reply. There is no silver in their bearings, and they basically gave me the same information as what's contained on their site in this photo


https://www.miataturbo.net/attachmen...ine=1445550451
Layers of an ACL Race Bearing

Based on this and the Nickel contents of both of my Blackstone samples, I would have to assume that the bearings are not wearing down at an abnormal rate. If all of the Nickel somehow got worn away during the original break-in oil change which we ran for about 10 miles, I would have super elevated Copper, Lead, and Tin numbers, but the Tin was also barely present in both samples. I can then only assume the bearings are OK, and that the higher contents of Copper and Lead from last time were break-in on the top layer of the bearing which is now washing away and decreasing.

I guess if I see a spike in the Nickel numbers, I'll know that the bearings are in need of replacement soon. Still not a clue on where the silver came from.

Its possible the alloy has a small amount of silver in it, thats a common alloying metal with lead/tin/copper.

Amazing how the ACL person I spoke to wouldn't have that information. I guess I am looking for tin as a sign of bearings needing replacement, but that layer is so thin I don't know how much I would really find.