Cam bearing failure

[Roert42]

I’m rebuilding a Ford 3.8 V6.
I tore the engine down yesterday and everything seem in very good shape, except the cam bearings.

The journals on the came were in great shape, so I was very surprised to see this. Looks like the tops of off the cam bearings are pitted heavily.

 

[Roert42]

Does anyone know if this is common for this engine family?

Looks like oil starvation, but there doesn’t seem to be any signs of overheating or excess wear.

 

[dvdswan]

Are the oil galleys lined up with the bearing hole?

 

[Roert42]

Yes, check all the bearings orientations.

150k factory bearings by the way.

 

[Fast Eddie]

I may be out in left field but that looks like corrosion? Almost an acidic corrosion. Anti-freeze in the oil at some time maybe? I have seen this once before.

 

[Roert42]

Interesting idea. Never had issues with coolant.

Only thing I could think of. Has had an issue with #6 plug fowling up while the others were fine. Maybe an issue with that injector or ring causing gas in the oil.

 

[superj]

Bearing Damage: Cavitation Erosion - Waukesha Bearings (waukbearing.com)

 

[55trucker]

If one is intending to *rebuild* the engine the state of that cam bearing is really mute.
The block has to have the cam bearings removed before the block goes into the caustic tank to be cleaned.

 

[Fast Eddie]

That depends? Maybe he's trying to understand the cause so it doesn't happen again? It could be anything from substandard material, to improper installation, to failed associate component. I sympathize with the guy. I'd want to know.

 

[Roert42]

really I was going to do a hone and gasket job so I could get this whore back on the road.

This has put the project on hold because it does need an actual rebuild….

 

[MISWFL]

I've seen the same thing on water cooled VW ( 1975-1992 gas and Diesel ) intermediate shaft bearings, which are pressed in one piece bearings like that. Not sure of the cause, but the VW factory bearing seemed like crappy quality compared to aftermarket replacements, which don't have to be reamed to size like the factory ones do. IIRC, the VW bearings could be flaked apart by using your fingernail on the side. The VW main and rod bearings were much better quality.

 

[19Walt93]

One year some 3.8's had a chirping noise from where the rocker arms rode on the aluminum sleds/stands. Ford's fix- that I didn't like- was to add a can of acidic mystery stuff to the oil, run the engine for a while, then change the oil. The mechanic-in-a-can was supposed to etch the rocker sleds so more oil could get in. Those bearing look like the might have been exposed to that stuff. Late 80's/early 90's 3.8 often had head gasket failures that let coolant into the oil but I'd expect the rods and mains to look bad, too. The 3.8 worked great in Mustangs, Granadas, T Birds, LTDs, and even F100's- other than being doggy as a truck engine. When they changed the coolant flow to use them in front wheel drive chassis things went down hill fast.