Loose Header Bolts - How to keep em tight?

They keep loosening?

any Suggestions that you have tried already that work?:

These are on APN headers and the studs are in good shape. They either vibrate or harmonically loosen.

Bellville washers.

knock the studs out and replace with bolts with locking nuts. thats what i did. works great!

The problem is that headers heat and cool and that causes them to expand and contract. A Bellville washer acts somewhat as a spring and maintains pressure (doesn't loosen) even as the header changes. They are standard issue on most engines.

Most hardware stores that carry the Sharon line of fasteners will have them. McMaster Carr is another online source.

Also, header bolts are normally not plated, they are a different alloy to handle the heat and to not rust in place. I still use a high temp anti-seize.
http://en.wikipedia.org/wiki/Belleville_washer

yeah a belville washer is what alot of the older gm TBI motors had on them they worked until you stripped the stud.


you can also double nut them...

Did you tighten them hot? I know it's difficult - especially the lower ones, but exhaust fasteners need to be tightened while the engine is hot or they will keep loosening. Do this sooner than later if you don't want to replace gasket. I wore leather gloves and an old sweatshirt to protect my arms. You can get access to some of the lower nuts from the bottom. Be careful not to get burned.

The Bellville washers take care of that.

My Jeep came with Bellville washers from the factory.

Just buy a set of Stage8 locking header bolts!
In the case of the 4.0 they are nuts only.

A modified (about three times as thick) Belleville should have been there OEM, and damned sure should have been reused!

LocTite #272 will work - and it's the only grade that will work.

You can also replace with studs Loc-Tited into place, and use Keps nuts (they're designed for use with exhausts - they look weak but aren't) or use "staked" self-locking nuts (they'll have indentations on the top where the upper thread was deformed.) Don't bother with the Nylon collar locknuts - the Nylon just burns out.

Keps nuts can usually be found with performance automotive hardware and some aeronautical surplus hardware vendors. I'm not sure about staked nuts yet - but you can make them yourself with a little patience, a hammer, a vice, and a rounded-off cold chisel or punch.

5-90 said:

A or use "staked" self-locking nuts (they'll have indentations on the top where the upper thread was deformed.) Don't bother with the Nylon collar locknuts - the Nylon just burns out.

Click to expand...

staked nuts, fine pitch (24 TPI) FTW....

Jeff

Staked nuts are in use on a LOT of XJ stuff, off the top of my head, the LCA/leaf eye/shackle nuts are all staked, so is the steering wheel retention nut. I am pretty sure if you want to poke around a lot there are probably staked nuts that will fit the exhaust hiding somewhere in the XJ.

including, of all things......the exhaust studs

I just had to replace both studs on my TJ because the rear one snapped off.

Jeff