Exhaust Suggestions for loose exhaust studs/bolts

[StrontiumEthics]

My exhaust studs on my engine keeps coming loose, its the second time after i tightened it. I don't want to over tighten the cheap Chinese studs in the block because I don't want to strip it. I was thinking of cutting a grade 8.8 automotive M6 bolt and using that as the two exhaust studs. But I am wondering what kind of nuts I should use. After using lock washers, and watching the Bolt Science video posted by pucksterpete, I dont know what else I should trust! lol. I was thinking Nylon but I maybe the heat might tamper with it.

 

[GearNut]

You could always drill a hole through the portion of the studs that extends past the nuts holding the exhaust on and then safety wire the studs together. It would not have to be wired tightly at all, and a bow in the wire to clear the exhaust pipe would be quite acceptable, just twist the 2 strands around each other. Safety wire in this type of application would not need to be strung tight to do it's job. The studs would be prevented from unscrewing out of the cylinder, and the nuts would be prevented from unscrewing past the safety wire (like a cotter pin application).

 

[motorpsycho]

oh man...come on!
take out the junk chinese studs as long as they're loose, and put in some good quality studs using loc-tite to keep them tight in the block. use flat washers, lock washers and standard nuts with loc-tite.

 

[StrontiumEthics]

Oh ok. That sounds like a great idea! But what about the Nylon nuts? I have a couple of them now. Wondering if the heat will mess them up?or perhaps make them better with Loctite?

 

[Fulltimer]

The nylon would probably melt.

Terry

 

[kerf]

How about a star lock washer with your studs? Will Loctite even stand up to the exhaust temps?

 

[StrontiumEthics]

This is the exact thought process im going threw! lol i was thinking of Loctite but what about heat from exhaust.

 

[andreasklapp]

you can get high heat loctite. you can also use a sort of washer with two arms on it, one folds over the nut to prevent it from turning, the other over your manifold. i don't know exactly what your setup looks like, but my ford v8 has something similar on it, and i used to use the same things on skateboards to keep them from going loose.

 

[StrontiumEthics]

EUREKA!! I found out why my bolts are getting so darn loose. It has to do with the Muffler. There are 2 kinds of mufflers. One type has a Long M6 stud going through the center bolted onto a the muffler Cap, the other has 2 very small bolts bolted through the muffler and cap to keep the cap on. I have the one with the long M6 stud going through the middle. When the M6 bolt holding the cap gets loose it VIBRATES LIKE ****, which is where Im getting some of the vibration from, possibly loosening the Exhaust nuts! Tell me what you guys think of that, and a possible solution.

 

[GearNut]

That very well could be causing enough vibration to loosen up the mounting nuts at the cylinder head. Solution? I would run a castellated nut and a cotter pin.