Title says it all. They just keep coming loose. Are they supposed to have lock washers?

Do you mean exhaust stud NUTS..?????

Or are your STUDS backing out...???

CCC

Yea, I thought they were suppose to too.

Ron found loose bolts on mine this weekend as well.

One stud backs out. On all the others, the nuts keep falling off.

Loctight! I used the red on the studs and blue the removable type on the nuts, haven't had that problem again.

I have read many times where people us loctite on the studs. I find it hard to believe this can help. This stuff breaks down at temperatures well below the heat in the heads.

If the studs are working out, then the fit must be too loose. There are special copper plated nuts that should be used. These are one time only. If removed, they should be replaced with new ones. For that matter, if removed then the copper exhaust gaskets should also be replaced.

This is from the Loctite web site.

All I know is my studs have never come loose since I used this and the blue seems to hold up very well in high heat....

Hi Kelly

I think you are putting the heat exchangers on properly and all is fitting as it should. With or without the loctite. The last line on the specs you listed "removable with heat and hand tools" is the problem. The material is thermoplastic and not thermosetting.

You are not supposed to use ordinary nuts. There are special purpose nuts for this application that are self locking. I think most are the copper plated varieties as noted. Some are a bit pinched so that the hex is not perfect, and the threaded hole is ovaled. Others have a domed top that is 3/4 sliced underneath. If you use the correct nuts you won't have any issues most of the time.

http://www.pelicanparts.com/catalog/shopca...p_pg1.htm#item3

Check the tune up... Continually loose exhaust nuts are a symptom of extreme exhaust gas temps...

You might be lean or need some extra ignition advance..

Heads and oil can be cool and EGT can be elevated-

If they back out then you are ready to replace the stud with a new, non-corroded one and torque it to spec
If you are too cheap to get new nuts every time, whick shouldn't be too often, you can double nut the stud (not much room, but enough) which when tightened properly should not loosen.
Exhaust leaks smell, are loud, and could damage your heads I think

Just some thoughts on the subject. NEVER use lockwashers on exhaust components. They get hot, lose their tension, and it's as if they were never there, only looser. Loctite is a debatable question, and I won't weight in here. As for locking nuts, the factory never used them. The original nuts were standard nuts with helicoiled threads. 2 litre cats used thick nuts with a thick flange, 1.7s and 1.8s used conventional size nuts with a washer. If you're having a problem, I'd look to the integrity of the pipes and the rear support bracket. The flanges need to be intact and as parallel as possible, and the bracket MUST be there. The studs need to fit properly in the threads in the heads. The Cap'n

I prefer high grade stainless nuts double locked against each other (two per stud) with milk of magnesia for anti seize..

I do this when doing exhaust system testing to ensure that studs won't strip and to ensure we won't encounter problems during system swaps in the dyno cell.

I make exhaust systems gglow cherry red for hours and the locking nuts will weld themselves to the studs, I never use them. Keep in mind that at the port exit the temperatures can exceed 1100F on cars that are driven hard.

Thanks for the insight. I was worried about the lock washers anealing. I think I may go with Jake's stainless plan. I WAS using the flange nuts with the helicoiled threads. All of them on one side have fallen out at one point or another. The copper seems ok. But I can probably get some 12mm nuts with the right thread pitch from work in SS. And I'd prefer the 12mm. What a PITA to get a 13 mm socket in there!

Copper "crushed nutz" loosen too!

use a 12mm 1/4" drive socket. the thinner walls help.

k

I think someone is screwing with you and loosing them up at night when your sleeping soundly........

Next thing people will be following you around and complaining your car is too loud to the police

Not true, you dirty SOB.

I already set up a a camera and I've been monitoring it for a week.

Now your sleep deprived from watching the camera all week

I'm with Bruce on this one.
my guess is that its the work of underwear gnomes!

brant

WTF, Brant. Why all the southpark references?

You sound like someone who just got the whole collection and watched it all at once....!