so is this the dreaded glyco rod bearing issue?

[jwasbury]

Doing a top end refresh/upgrade on my 3.0l race engine. Pulled the rods to have a look at the bearings and found this. All 6 bearings have this mottled cratering as if a coating has failed and you can scratch it away with your fingernail. Obviously I am putting new bearings in. I read in the Rod Bearing Controversy thread that the 3.0l Glyocs were supposedly OK, but perhaps that has changed? It seems the GT3 bearings are the ticket.

[DSPTurtle]

Just got in two sets of the Clevite rod bearings and man do they look nice!
What's the date code on the back of that bearing?

[JFairman]

How does the crank look and feel with your fingernail?

[jwasbury]

The bearings are currently at the machine shop with the rods. I gave them a call and the date code is 9-02. Thus it seem these bearings were made prior to the quality issues people have experienced. My original plan was to do the top end only but I suppose I am splitting the case now to check the mains and properly inpect the crankshaft. A couple of the rod bearings also show some FOD in addition to this "fatigue" wear pattern. The crank journals look ok and I don't feel any grooves with my fingernail.

Will be pulling apart the oil filter to have a look and having an oil analysis done. I would like to determine the cause of this before I put things back together.

[jwasbury]

This does look like surface fatigue failure to me. One of the causes of surface failure is excessive loading from lugging the engine.

I have a theory that it could be lugging that killed these bearings. My race car has always been a bit cantankerous driving around the pits, for two reasons:

One is that it had a sloppy shifter and it was hard to find 1st gear...frequently you'd think you're in 1st when starting out from a stop, but you'd actually be in 3rd.

2nd is that the ECU was tuned on an engine dyno for higher RPM operation, but the "driveability" tuning was never well dialed in. I've made some small adjustment to improve the idle, but its not very well manner launching from a stop and it bogs a lot.

Once you're out rolling on track, the thing runs brilliantly...its just tooling around the pits that the lugging has happened. Could a couple of seasons worth of this type of thing kill the rod bearings? What do you guys think?

[Lapkritis]

Is the lugging more of a bucking/surging? If so, I would first and foremost, tune that out. It shouldn't take long but I have noticed it's fairly common for stand alone management to be tuned in such a fashion. Dyno time and paying a tuner for part throttle mapping is a perceived cost that can be reasoned into as unnecessary for a race car... the truth is it's worth it for reducing fatigue on hardware that is often expensive. It may seem less racy but as a tuner, I take note of how well other people pay attention to such a detail as a reflection of their capabilities. A tune for WOT only is far easier than taking the time and effort to tame the entire operating band.

As for the bearings - looks like they use a coating that is perhaps incompatible with oils/fuels/pressures. When opening an an engine, I expect some type of wear on the bearings every time. I would be far more concerned with a rotational scuff or FOD... in this case, I would replace with a different manufacturer to avoid that coating pictured that doesn't stand up.

[E Sully]

Here is an interactive site they have to help determine various bearing problems.
MAHLE Clevite - Bearing Analysis - BETA v3 Option 14 is the over loaded engine problem.

[jwasbury]

Inspected the filter element, and found only a small amount of tiny metal bits captured there (hard to see in the photos, but there). I suppose this is a positive sign.

[mattC2993]

Originally Posted by E Sully

Here is an interactive site they have to help determine various bearing problems.
MAHLE Clevite - Bearing Analysis - BETA v3 Option 14 is the over loaded engine problem.

Overlay fatigue. Are they referring to the coating?

[JJ 911SC]

Good info here: Glyco vs clevite rod bearings - with data

[jwasbury]

I got the results of an oil analysis for this engine:

[Lapkritis]

Interesting lead readings

[jwasbury]

Originally Posted by Lapkritis

Interesting lead readings

wouldn't that likely be the bearing material?

[KTL]

Originally Posted by jwasbury

wouldn't that likely be the bearing material?

Yep. Lead is one of the soft materials in bearings that provides that sacrificial effect of allowing material embedment when debris is in the oil.