Rod bearing wear.

[reclino]

1986 911 turbo. #6 rod bearing is the only one with damage. Others looked good.


I guess some bit of carbon from the turbo scavenge pump found its way here.
Bummer

[reclino]

[reclino]

The other bearings looked like these.

[reclino]

So the conservative side of me says just replace them all with Clevite 77 bearings. The frugal side say replace this one with a Porsche bearing.

[stownsen914]

Rod bearings are cheap compared to the mess bad ones can make of your engine. After all the bad reports of Glyco rod bearings, I plan to play it safe and use Clevite. And I'm pretty frugal.

[Henry Schmidt]

Although we sell Glyco and Clevite, we use Clevite exclusively in all our rebuilds.
With one caveat, We also like the GT3 factory bearings when they are appropriate.

[m42racer]

Originally Posted by Henry Schmidt

Although we sell Glyco and Clevite, we use Clevite exclusively in all our rebuilds.
With one caveat, We also like the GT3 factory bearings when they are appropriate.

Why?

Could you please explain why?

[Henry Schmidt]

Originally Posted by m42racer

Why?

Could you please explain why?

After experiencing consistent low quality of Glyco bearings we sought a different source for the engines we build.
So far the Clevite and GT3 bearings have measured up to our standards.
We also sought a source for undersized bearings so we could start using .010/.010 cranks in lieu of repairing cranks(welding or chroming) or discarding damaged cranks altogether.
Our crank exchange program is taking off. We have .010/.010 cranks of every flavor and the bearings to accompany them ready to ship. At a reasonable price as well.
The crank shop we use is doing a tremendous job manufacturing Porsche cranks.
Magged
Plugs are pulled holes threaded for new plugs.
Ground .010/.010
Cross drilled
Ion Plasma nitrided
Straightened if necessary.
Polished
Balanced

[Ollies930]

Is there a difference in thickness between the Clevite and GT3 bearings?
Will one give measurably more clearance than the other, and if so, how much?

[AVI_8]

Originally Posted by Henry Schmidt

Although we sell Glyco and Clevite, we use Clevite exclusively in all our rebuilds.
With one caveat, We also like the GT3 factory bearings when they are appropriate.

Hi Henry,
Does the above statement apply to the factory Glyco's from OPC, I've read about the problems regarding the Glyco's from the South African plant.
With my engine rebuild starting soon I'll need to get bearings and noticed that the Clevites are cheaper than the OPC bearings, without taking cost into consideration would you still have Clevites over the original porsche bearings?
Thanks

[DRACO A5OG]

Porsche will mic them to insure they are within spec evidenced by mic marks out of the box that is why they are more than Glyco's from aftermarket providers.

[AVI_8]

Hi Draco, thanks I'm aware of that I've seen the micrometer marks .,., they charge a hell of a lot for checking though!
I was more wondering if the Clevites were in some way better than the original bearings, in the way that ARP head studs are better than dilivar which break often etc.

[DRACO A5OG]

My 2 cents Clevites and Porsche Glycos are equal but priceswise Clevites win.

[3rd_gear_Ted]

Porsche = Six Sigma in process deviation during the creation and manufacture of ALL components.
Costs $$$, but you get the product performance and reliability as it was designed when its all put together.

Typical manufacturing standards for airliners, rockets, satellites, etc.

[stownsen914]

Does anyone worry about Glyco main bearings? Totally understood why they are less of a concern than rod bearings, but does that mean poor tolerances/quality is OK and just go with Glyco for the mains?

[Henry Schmidt]

Originally Posted by stownsen914

Does anyone worry about Glyco main bearings? Totally understood why they are less of a concern than rod bearings, but does that mean poor tolerances/quality is OK and just go with Glyco for the mains?

We sell aftermarket Glyco mains but generally use Factory bearings.
For engines 78 and later GT3 mains come in three different standard sizes making it easier to fit a used crank.

My suggestion when it comes to using after market Glyco bearing is to measure and inspect for anomalies then dry film coat. For dry film coating we use Tech Line CCL and CT1.

[WERK I]

Originally Posted by reclino

1986 911 turbo. #6 rod bearing is the only one with damage. Others looked good.


I guess some bit of carbon from the turbo scavenge pump found its way here.
Bummer

reclino,
Was that the only area that suffered damage on your engine? Nothing on the top end?

[reclino]

There are a couple of cam lobes on the drivers side head that were pitting, and the matching rocker arms had excessive wear. I am cleaning the cam carrier's right now. None of the oil spray bar holes were clogged all flow well, have been pumping filtered parts washer solvent though them all day.
David