Hi everyone my 1979 corvette 350 cubic inch had one of the header bolts loosened while on a 1300 mile round trip to SC. It loosened on the way home some where around Spartanburg SC. The bolt is on the left side rear header flange and is turned out about 1/4 inch from the flange and the bolt is loose enough that you can turn it by hand. The 1979 Corvette Shop Manual indicated to tighten bolts to 17 ft. lbs. Is there a thread locker material that can used on the bolt threads to keep it from turning out again and should I get a new bolt to replace the current bolt or replace all the bolts and gasket.

 

Typically you want to use never seize on the bolt. As far as a new bolt, I would inspect it and replace if necessary.

 

Blue LocTite. But you may have difficulty removing the bolt later.
Anti-seize will release the bolt later, but may come out sooner.
Anti-seize reduces corrosion between two unlike metals. Such as steel bolts into aluminum or cast iron heads.

Somebody needs to invent a Thread Lock Anti Seize. Here is your chance to make a million.

Are you using ARPs 12 point header bolts with built in washer? They seem to hold on the header flange better.

 

Tom, if you are using actual tube headers, these Stage 8 Locking Header Bolts should do the trick. If you have aluminum heads, be sure to put a dab of anti-seize on the threads when you install them.

https://www.jegs.com/i/Stage-8/868/8911/10002/-1

Stage-8 Locking header bolts are made of grade-8 quality steel and use a patented 3 piece system that consists of a grooved bolt, a retainer and spring clip. The retainer fits over the head of the bolt, the retainer fits up against the header, and the clip snaps into the groove for a secure fit that won't wiggle loose. Bolts with a 6 point DHH (Double Hex Head) feature a recessed 3/16'' allen head inside the hex head for installation in those tight spots.

another version...

https://www.jegs.com/i/Stage-8/868/8911B/10002/-1

Good luck... GUSTO

 

I have used Stage-8 and these "split lock" type locking header bolts. I prefer the "split lock" type. Percy's used to make them and it looks like they're now made by Summit: https://www.summitracing.com/parts/sum-910120

You can see how they work here:

 

Ive tried all the remedies for loose header bolts. The loctite wont work becasue it will heat up and release, the lock washers heat up and exand but not as much as the bolt will so they release as well, whether they are split or star washers. The best thing I found for my small block was lock wiring the bolts. I had to use extra long allen head bolts due to the headers I had. I used some marine spacers to move the headers away form the spark plugs because I would have needed to massage all the tubes due to the angle plugs and the stage 8s were too short. The solution I am using on my big Block is the Stage 8 lock bolts with the pointy washers, the second ones Gusto showed. If you cant get them close to a tube to lock them you can bend the point over the flange. They are tricky to install, you just need to have plenty of time and patience and some tools to puch them in. Some will be easy adn some will make you curse like a sailor.

 

French lock washers will do the trick. Use hex head bolts tightened over the French lock washers; then pull up one of the flats against one of the hex flats.

 

I use the stage 8 lockers.End of your problem

 

I used the stage 8 bolts as well. Had to modify some of the locks a little with a grinder to get them to go on in the right position. I used the 6 point hex head with the allen wrench in the end version. The allen wrench hole makes it a whole lot easier in some of the positions. I wouldn't try torqing the bolts down with them too tight as allen wrench stuff likes to wallow/strip out easily. I drove the car a couple times and re-torqued before I installed the locks.

Have never had my header bolts come loose and consequently have not had to replace the gasket either.

 

I went back to my aircraft mechanic days and drilled my header bolts to accept lock wire. My bolts have never backed out.

 

Brilliant!

 

Yeah. I like them. Stage-8's work also but these Split-Locks are a LOT easier and work just fine.

 

Never heard of the split locks before this. I like the idea and it does look a lot easier.

How are they on aluminum heads I wonder. Any tendency to bind and sort of cut new threads on the way out?

 

It's really unwise to use any kind of BOLT especially in aluminum heads. Unwise is a nice term! Exhaust header studs from arp is the correct answer.

 

I've had my Headers on/off several times with aluminum heads and bolts (the stage 8 ones) have yet to have a problem. Two sets of aluminum heads. Just gotta use anti-seize with dissimilar metals. I use anti-seize with all exhaust components and dissimilar metal contacts, if loctite or sealant is not being used. If I used studs I'm not sure I could get the headers off/on the engine on the drivers side. Using side pipes.

 

Why use inferior products. When you can hang the gasket on the studs and then hang the headers.

Very simple

 

When I started out as a young kid everyone had header bolts always going loose. So the fix was wisdom at the time told you to double up on your crappy Mr. Gasket exhaust gaskets. It might have delayed the fequency of loose header bolts. Then along came Stage 8. I jumped on them when they first came out. Somewhat better. But your still have to be holding the gasket and header and trying to line up the stupid bolts to the threaded head hole. The other problems with them are: You have to line up the half moon cut in the washer. So you tighten the bolt and might have to back it off to line up the washer cut to the rounded primary tube. Then I bought Hooker S?C headers and they only fit smaller 1 5/8th headers! Then I did safety wire on tiny 12 point bolts. I broke a bunch of tiny drill bits trying to drill grade 8 bolts.

Then I found ARP universal stud kits with the tiny 5/16th nuts that had all kinds of pipe clearance when I first started traveling with a Sprint car team. It's like so easy to install studs, hang the gasket, hang the headers. No more fighting and cussing to line up bolts and leave them loose to get them all in and dork around. Why would you continue to use crap?

 

well, I like the idea. I guess I haven't had mine on and off enough times to hit that frustration wall. If studs makes it that much easier I might give it a go next time I have the headers off.
I do know it's a close fit on the drivers side with the side pipe headers and the steering box. So I'd have to see if the flange can clear both or be manipulated to clear them into place with studs sticking out.

 

Ive worked on cars with stud clearance problems.

You can install problem clearance studs individually after hanging the headers

Studs are only installed hand tight. Or double nuts to remove loctite red ones

 

I use anti-seize. Works every time.