Torque of manifold nuts

[William2]

I am wondering whether torqueing the exhaust nuts to 12 - 15lbs/ft seems a bit high considering the nuts are brass and I'd hate to pull an exhaust stud out of the head as one or two of my stud head threads aren't too brilliant. If a stud did ever strip the head is it possible to do any type of repair with the head/engine in the car?

[TroonSprint]

I don't know what your exhaust header is like, but on my car there is no way a socket could be applied to most of them, so a torque wrench is out of the question. The second one from the front is hard to get any spanner on at all. So mine are just done up tight by hand, mostly with an open-ended spanner. I have no signs of exhaust leakage. I would just use your common sense!

Mike

[rgh0]

You can fit helicoils if you strip a thread in the head in situ. Been there done that

cheers
Rohan

[nigelrbfurness]

I replaced all my manifold studs on my twin-cam heads years ago with (I think) 5/16" UNC stainless caphead allen screws. Maybe a 1/4 UNC - I'd have to take one out to check it! Makes removing both the manifold and cylinder head much easier. I never use a torque wrench on them either, just pinch them up tight so the manifold gasket seals. Never had an exhaust leak, either.

Nigel F.

[alan.barker]

imho it's best to stay with studs which have been coated with copperslip when fitting.
Fitting caphead screws and screwing in and out into alloy is only asking for trouble.
Studs and brass nuts is best with spring washers
Alan

[john.p.clegg]

"Fitting caphead screws and screwing in and out into alloy is only asking for trouble."

..not when you've helicoiled them....

John

[alan.barker]

maybe that's why they were helicoiled because of caphead screws going in and out damaging threads

[john.p.clegg]

no , no , I can assure you I heli-coiled them first after finding my hands would not contort to the nut-space...

John

[alan.barker]

o.k. John,
it's your choice as you like.
Imho i like the studs because i can put the gaskets in place which don't move out of position, slide the manifold onto the studs which does not then need supporting. Take my time fitting spring washers and brass nuts, not needing to support manifold and stop gaskets moving at the same time.
But then again i'm a bit like Miles Wilkins and like to keep things original design.
Alan

[john.p.clegg]

Alan
Another option is longer nuts..

http://www.ebay.co.uk/itm/Brass-UNC-UNF ... X8CUSNPKvQ

John