REBUILD: 2nd ADVICE REQUEST - STUDS
 

Just begun the long block tear-down:
1980 911SC 3.0 Bought in May 2005; 188K Miles

Although this beast seemed to run ok in the one month I ran it before chassis strip and engine drop, I've now found:

Broken Head studs: 4 total (2 on each side)

Questions:

> Is that (4) an unusually high number of broken-off head studs?

> Considering the number of broken head studs, and the likelihood that over-torquing contributed, I intend to replace all head studs - Correct decision?

> I notice almost ALL studs (Valve Covers, Chain Covers, other studs) exhibit corrosion/rust/oxidation. Although not originally planned, I'm now feeling compelled to replace ALL studs - Correct decision?

And, considering the number of broken head studs, and not yet to the head gaskets to check for leak/blow-by evidence, but suspecting there must have been SOME compression loss, are there any other side effects that should be - more than usually - anticipated or inspected for? If yes - what?

All experienced perspectives and advice is gratefully appreciated!

Thanks!
Jim

4 is not unusually high number, but I would replace them all with the steel studs. The rest of the studs don't carry a high torque load so unless the are rusted to the point where you think they will break off I would just use a scotch brite pad to clean them up.

I cleaned up the non-head studs with a wire brush on a dremel. Works very quickly with minimal effort.

No, yes, and it depends. Four is not unusual, once, one goes, others do too. Yes replace them all with steel ones. The other studs will clean up but will rust again faster. The new ones may be zinc coated. If you do you will be happy with the result. You are looking ar a top end rebuild. Goos luck. It will be nice when you complete the project.

Regards,

Only the bottom studs need to be replaced. They are made of a different material called Dilavar and are prone to breaking. Replace these 12 studs with steel like the top row. All other studs will be fine just clean them up with a wire wheel/brush.

-Andy

once again i belive there are strong arguments for both sides

If it were me and i just went through all this with my motor

i was there already it didnt cost me a ton of cash i changed everything. to me it is a piece of mind thing. i did it so i wouldnt have to think about it down the road.

yes you can clean parts and they can and most likely work just fine.

Just replace the bottom row with steel.

If I ever hear of a steel stud breaking, I'll agree that there are strong arguments for both sides.

-Andy

I had one steel stud break, four dilavers, and one steel on the top side. I'd replace all 24 of them if it were me.

David,

Thanks for the input. This is the first case I'd heard about. I wonder if a broken stud on the bottom put enough stress on the top stud to cause it to break also.

-Andy

well any time a nut or bolt breaks it will extra stress on the remaining studs it is possiable that it caused another stud to break