280K on an 83 911SC

[Henry Schmidt]

We just disassembled an 83 911 SC with 280,000 miles on it and it was in amazing condition.
We expected to find worn bearings, bad P&Cs, shot valves or at least bad valve guides and the ever present broken Delivar head studs and we found none of the normal things.
When we pulled the strainer we found an unbelievable amount of metal.
The engine ran fine but leaked oil everywhere so when we found the metal the customer admitted to hearing some noise.
If I had not heard it run I would have sworn that the engine had exploded.
At this point a rebuild is in order but all we found were 4 broken valve springs (very unusual for an 83, pretty common in 78) and the chains were so worn that they were rubbing on the case.

For all you experts it certainly needs a rebuild but this is why the 3.0 is so desirable.

[MobileWrks]

looks like you panning for GOLD..

[mppickett]

Amazing. I'm impressed that the screen and filter were able to keep the engine alive.

[shbop]

Can't wait to hear the details of this build! Henry, are you going back stock, or are you going to get creative?

[ChrisBennet]

Hi Henry,
What was the condition of the intermediate shaft bearings? Any pics?
From the few motors I've done it seem like the intermediate shaft bearings wear a lot quicker then the other bearings for some reason.
-Chris

[Tinker]

Chris,

I have observed the same thing. The mains and rod bearings are usually fine, but the intermediate shaft bearing almost always start to show copper for some reason.

Tinker

[bbh03]

Why are the broken springs more common on the 78?

[Jeff Alton]

I agree with Chris also, that has been my experience as well.....

Cheers

[Henry Schmidt]

Intermediate bearings seem to show wear within the first few hours of running and stay that way for the life of the engine.
I have no explanation why this happens ( I'll let the "train drivers" figure that out) but it is what we see.
It is important to remember that I have never seen an engine failure do to intermediate bearing failure.

[911SCfanatic]

Originally posted by ChrisBennet
Hi Henry,
What was the condition of the intermediate shaft bearings? Any pics?
From the few motors I've done it seem like the intermediate shaft bearings wear a lot quicker then the other bearings for some reason.
-Chris

Funny, I was just wondering the same thing. I just broke down a '74 engine and the intermediate shaft bearings were showing copper everywhere but the rest of the bearings looked quite good.

[MBEngineering]

HI the valve springs in the SC engines from production date 25/04/78 had a quality control problem, engine numbers;638 3453>, 638 9153>, 678 0609>, look for code 4.78 inside triangle on spring.

regards mike