thebowl

Jake, if I correctly understand your thinking, the real problem with the IMS may not lie at either end of it, but instead in the middle, i.e., the trueness of the shaft itself.

Mark Henry

Your cams all run on the casting, no bearings, so do aircooled 911 cams.
Cams, IMS are all spinning at half the speed of the crank.
I'd have to look to see if the IMS has a oil galley, but if it doesn't I'd say the pump leaks enough to lube the journal by design. IIRC it has a groove for oiling.

nickdee62

Its just one of the surprises I found when rebuilding my engine. And yes, there is a lot of oil fed to it. But, as you can see by the gear, that end drives the timing chain for the left side head. There's a good bit of axial tension on it, so I'm wondering why it doesn't end up egg shaped.

I was not as amazed at the cams not having bearings. Even though you have the tension of the valve springs, it seems the journals in the heads and valve covers are more than up to the job. You'll find many oil passages there.

I didn't do much research before I bought my 996. I never considered the term "disposable engine" possible. After doing my rebuild I can fully understand why the Porsche dealers do engine swaps on these and not rebuilds.

I must admit that coming from a background of simple V8s, this thing was an eye opening challenge. But I had fun and enjoyed it!

Mike Murphy

I really wish that these engines - all engines - had pre-oilers and focus more on filtration and using a pre-oiling system to reduce wear, since most wear is during startup.

Balu

Or out for a train inspection at 3am after an undesired emergency application
when the lamp beam illuminates a caustic soda tank dug into the ground
surrounded by twisted broken rails and the glowing remains of the truck
and journal assembly.

Been there with the coal train also.
Sixty miles an hour on double track.
No flashbacks but the occasional "train dream".
All in the past once we pulled the pin and carried on.

Nothing to add regarding bearing surfaces.
Just sharing ribbons of steel stories.
Move on...as you were.

wildbilly32

Yep! Me too...