awilson40

Here is a pic of the original exhaust manifold studs next to
the replacements I received.
Notice that the end that screws into the head has much fewer threads
and will not screw in very far.
Is this OK ??? Anyone used studs like this with no problems??

'Rule of Thumb' for aluminum is 1 - 1 1/2 times the diameter
in thread length for thread engagement which these have
that.
I dont want to risk pulling the threads in the head.
Thanks

pikey7

replacements you received from where?

I've always used 1-1/2 times thread diameter for steel raterials. I would have gone for at least 2x for Al, but I guess if they are the saturn units that people have already used successfully, then no panic.

Do you recall the torque needed on the header nuts? If it's over 12Nm (the standard for M8 in Al) then it's a risk IMHO.

brad-cam

Andrew, I've used replacement studs like the ones you have with no problems. Are those stainless steel? Good if they are as corrosion on these studs is a bad thing. I would also recommend you use some high-temp anti-seize compound on the threads.

awilson40

Thanks guys,
They are the studs Lindsey Racing sells. Dave Lindsey says they use them on all
their heads so I guess I'm just being ****.

Tom M'Guinn

Won't they make it harder to remove the headers -- since they will stick out further?

Tomas L

You could use the long thread against the head. You just have to check how much it should protrude so the nut don't run out of threads and cut the inside accordingly.
Otherwise I reckon the stock Porsche studs can't be that expensive?

Tomas

awilson40

according to Lindsey...they are Porsche studs

Waterguy

The Porsche stud I bought looked like the one on the right, not the one on the left.