Rod Bearing Inspection

[Jcslocum]

I just pulled the rods out of my 100K 3.2 mile engine. The all look pretty good for the age but for 1 set. These marks can't be felt with the finger nail but they look a little scary.

Any thoughts or input??

Set 1





Set 2






Set3




Set4


Set5




set 6

[BURN-BROS]

Minor debris entered the motor. Typically the #3 rod is the one affected as it's the first one to see oil from #1 main.

If there is no damage to the crank, then new bearings are all you need.

Upgrade to a set of ARP rod bolts. 9mm rod bolts are Inneffective.

[Jcslocum]

Crank looks perfect and these marks cannot be felt with a bamboo pick. Funny how visible they are but don't seem to have any depth.

Has the issues with the Glyco rod bearings been settled or are these still a risk?

[Jcslocum]

I have the ARP bolts read to go BTW.

[Steve@Rennsport]

Originally Posted by Jcslocum

Has the issues with the Glyco rod bearings been settled or are these still a risk?

For these engines, I'll ONLY use Factory Porsche rod bearings in street engines. Race engines get Clevite 77's.

[Jcslocum]

Steve, safe to assume you have the good ones in stock???

It's a street engine to be used as a DD buy my daughter (who is doing the build with my guidance) and maybe just use the Clevite 77's just because the Glyco's are a known or unknown problem??

[BURN-BROS]

A Glyco Rep stated that the Babbitt formula are identical whether aftermarket or the fancy factory GT3 rod bearings....The only difference is the location that they are made. Porsche requires a vigorous QC department so the bearings that are purchased by Porsche are from the facility in Germany while the aftermarket bearing come from the Poland Plant.

[KTL]

The silvery coating that you can't feel or measure is an anti-corrosion protection. People often think that the bearings are severely worn when that silvery coating is scuffed off. Not necessarily true. That said, those bearings showing significant "smearing" would seem to have experienced something in the oil

When I measure the bearings with a bore gauge, that coating gets rubbed by the anvil (even when I lightly lube the bearing surface) but you can't really measure the lost coating with a typical bore gauge that measures to the 0.0001" For instance i've measured new #8 bearing inserts vs. used (new being a Porsche dealer bearing) and they measure out to be the same, despite the used bearing looking worn because it's silvery coating is rubbed away.

Those rods are BROWN. Castrol GTX oil???

[Jcslocum]

I can't say what oil for the life. I know I drained Brad Penn out of it. Coulda been Castrol before but at 25 years who knows what was in and out of it!!

Another picture zoomed. I think this looks much worse than it is. It's reall hard to feel anything... It would probably go another 100K!!

[Jcslocum]

I think I have found a set of NOS Porsche/Glyco rod bearings that are made in Germany. I'm not sure of the manufacture date yet but they are very cheap @ $25 for the set. I will buy them and inspect them for date and the marks that the OEM bearings have.

Is there a specific manufacture date I should be looking for? Is there a "bad" date range or will any bearing made in Germany do the trick for me?

[Jcslocum]

I can't get my damn 2"-3" micrometer into the crankcase to measure the crank :-(

Once I get the bearings in house, I will use Plastigage to measure clearances....

[KTL]

Into the crankcase, or do you mean onto the crank? My basic 2-3 mic fits on the rod & main journals no problem. In the crankcase, you gotta use a bore gauge at the bores you can reach. Also need to have the #8 main bearing insert installed to ensure proper alignment of the case at that end.

[Jcslocum]

Wanted to measure the crank at that one rod position with the crank IN there. Just for a data point but my Mic is too round. will go thru the spigot hole but not get round the journal...