Were Broken Head Studs ...

[Norm K]

... common to the 930 or is this limited more to the 911?

I've seen conflicting information (imagine that, conflicting info on an automotive forum!) as to whether it's as common in 930s as in 911s, if it's largely limited to earlier cars (and even then to those with magnesium cases), if it's a Divlar thing, etc...

I suspect this has been hashed out here many times but a search for some sort of definitive answer, should one exist, certainly doesn't pop right up.

Norm

[81Kremer930]

I had one broken on my 81 930....Mag case.

From what I've read it's common with early Divilar application, whether it's a 911 or 930, from the late 70's early 80's up until the 993 application when the studs were then coated to prevent the corrosion at the base of the case.

Someone may chime in with more knowledge than this, as this is my personal experience.

[quattrorunner]

I bought an engine that was torn apart because of broken head studs. 77 930 3.0

[herman maire]

Originally Posted by 81Kremer930

I had one broken on my 81 930....Mag case.

Your 81 has a mag case I thought for sure they were aluminum cases.

[81Kremer930]

Originally Posted by herman maire

Your 81 has a mag case I thought for sure they were aluminum cases.

That's what I thought, but the machinist told me that the case was Magnesium. He may have been wrong however. Considering he doesnt deal with Porsches on a regular basis. He had the case to take care of the remaining piece of stud in the case.
We found out the hard way that these studs cannot be drilled successfully. He removed the stud with an EDM machine... It's been a very expensive process from there...

[JFairman]

Originally Posted by herman maire

Your 81 has a mag case I thought for sure they were aluminum cases.

They are aluminum.

[81Kremer930]

Originally Posted by JFairman

They are aluminum.

Meaning that all 930's were aluminum?

[JFairman]

All the 3.0 liter and bigger engines are aluminum.

A friend has a '77S and it's the last of the magnesium cases. Those usually or maybe always need to be line bored when rebuilt.. expensive.

The SC replaced the '77S in '78 and it had the aluminum 3.0

[jsveb]

The carrera 3.0 ( 930/02 )
Was also made out of alu. It is identical to the early turbos.
My 76 Carrera does have a mag tranny case though.

[timspu]

My 1988 Euro engine had a sheared head bolt. Engine was popping under boost only.
Very expensive repair. Had all replaced whilst engine was stripped. Also needed new valve guides. Motor had done 80K miles on it.