Exhaust Header Mounting Help

[Farenheit251]

I got a SS header from John and the 8 mm nuts that hold it on keep backing off. I don't want to overtighten as I already broke off one of the mounting studs trying to put a standard nut on a metric stud,fortunately John was able to tap in a new stud.

Is there something like LOc tite that will hold up to the heat or do I need to be looking for a specific type of nut that won't back off?

 

[dgardner]

http://www.bestnutsbolts.com/hexnut.html

If the stud is long enough you can also use a "jam nut" arrangement. run the first nut down and tighten to your regular torque. Hold it with an open end wrench so it can't turn. Run a second nut down on the first and tighten it down with a second wrench, "jamming" the two together. Works great.

 

[Johnny]

There are locking nuts and washers, but it sounds like you have a thread mismatch. Check with John.

I wasted a lot of time last night drilling out two Loc-Tited bolts that snapped when I tried to remove them.

 

[Farenheit251]

There is not much stud left over for a 2nd nut. I checked with John on the size after I broke off the stud.

 

[dgardner]

Then one of the deformed thread types in the link I posted will be your best bet. You should be able to find them locally at a well stocked hardware store.

 

[glenboy]

go to GRAINGER.COM to find jam nuts so u do it rite

 

[Larry Cobb]

Brian;

The best retaining nut for the exhaust manifold is a flanged type with the deformed thread (as Dan mentioned).

You didn't say if the stud was US or metric. Which engine is it ??

Metric will be harder to find.

Also, make sure the stud is not loosening up in the head (assuming it is aluminum).

There are some hi-temp ceramic locking compounds also available.

Larry

 

[Shawn Forsythe]

If the design of the manifold is such that Manifold Nut Keepers will mount, then by all means use them. Deformed nuts make exacting the proper torque impossible, as the deformation adds an unknown fifferential, that also varies nut to nut.

Install under the nut, bend two of the ears down along the edge of the manifold. Once the nut is tight to spec, you bend up three remainder of the ears around the nut.


Another option is Nord-Lock http://www.nord-lock.com/.
They are sold at McMaster Carr, and they work great for exhaust manifold nut retention.
http://www.mcmaster.com/#nord-lock-washers/=1f1fcl