930 head stud torque values

[Alan L]

Thought I posted this y/day - but must have got lost somewhere.
I'm assuming the 930 has higher head nut torque values than the 911. Searched the forum and found values of about 40 ft/lb quoted for ARP studs. Is this the norm for a stock 930?
Thx
Alan

[spuggy]

Nope. Torque values vary, they're very specific to the materials the fasteners are made out of.

I wouldn't be surprised if 993 or divilar studs need different values to stock 930 - which my factory manual gives as just over half what you quote for the ARP studs, applied in a two-step process.

What studs do you have, and what year/type of engine?

[Alan L]

It is an '82 930, but I don't know what type of studs. Have yet to receive the car - in transit. But it has just had head work done on it 500km ago, and I intend to use it on track - so would like to go through all these things prior too.
I think the Dilivar studs are non- magnetic? Otherwise, how will I be able to determine what type I have?
The 911 torque value is 23 ft/lb - which sounds very similar to what you are quoting. Is that for the 930?
Thanks
Alan

[spuggy]

Originally Posted by Alan L

It is an '82 930, but I don't know what type of studs. Have yet to receive the car - in transit. But it has just had head work done on it 500km ago, and I intend to use it on track - so would like to go through all these things prior too.

I don't know jack, but it's my impression that the factory con rod bolts are much more of a worry than the factory head studs, unless you're making very silly power (in which case there's a lot of other things you'll be doing, doubtless).

Of course, that might just be me being over-sensitive because I had a rod bearing spin 3 weeks after an over-rev, 8,000 miles into ownership.

But my wrenches say a long-time 3.2 owner whose car they look after (same crank, rods, rod bolts as the 3.3) had exactly the same thing happen last year with 115K on the motor. And he doesn't over-rev.

I think the Dilivar studs are non- magnetic? Otherwise, how will I be able to determine what type I have?
The 911 torque value is 23 ft/lb - which sounds very similar to what you are quoting. Is that for the 930?
Thanks
Alan

Lots of good threads on identifying head studs in the rebuild forum.

Of course, they're qiute easy to identify when all you have to do is look at the invoice, heh.

I ordered SuperTec studs because I was still considering twin-plugging at the time, because they're relatively cheap from our host, include the nuts & washers, and the nuts (not by accident) won't foul the lower spark plugs. And if Henry doesn't know what he's doing, I might as well give up, was part of my reasoning.

My factory manual (you're gonna need one or more of those) gives stock studs as 7.5 ft/lbs, followed by 23.5 ft/lbs, with Optimoly HT applied to the contact surfaces of the nuts and stud bolt threads.

Spec booklet (mine only covers up to '81 models) gives 33 Nm where the factory manual gives 32Nm, and omits the two-stage and lubrication info.

[Alan L]

Many thanks Spuggy.
Looks like I need to find a manual.
Regards
Alan

[spuggy]

You have a PM.