Secure Exhaust Flange Studs

[Paul Ahnell]

What's the best way to secure the Exhaust flange studs? Is there a super heat-resistant thread locker out there, and what is it? Or, is there a better solution?

[Martin Benade]

You could use split lock washers. Generally the nuts stay on fine with no special care.

[Mike Wilson]

I've used red Loctite with good results. I'm sure others will have their favorite thread locker.

Mike

[Martin Benade]

Loctite (including red) releases when it gets warmed up, I think the nuts stayed on regardless.

[Paul Ahnell]

All: Thanks for that, but I'm concerned with securing the studs in the head so they don't back out if I have a tight nut. What's th ebest way to do that?

[Martin Benade]

You could put some punch marks on the threads, or crunch them a bit with vise-grips before forcing them in. Personally I would be most comfortable leaving them as designed, they usually stay in place. Instead, if you come across a tight nut, deal with that using heat or a good penetrating oil such as Blaster, and a little back-and-forth exercise.

[Vic Skirmants]

I would definitely NOT intentionally damage the stud threads; that will only cause machining of the aluminum head.
If a stud comes out with the nut, double-nut the other end of the stud and remove the tight nut. Then insert the stud using the double-nutted (?)end to screw it in. I do use Red Loctite. You could also use JB Weld to be sure.

[Herlin E. Woolery]

Paul,
I use LOCTITE 243 and holding very well .

Herlin Woolery
'58 A Coupe

[Jeffrey Leeds]

How about chasing the header side stud threads to make sure they are clean, first. Then I like to use a copper flange nut
(https://www.belmetric.com/hex-with-flan ... p-189.html) to secure the exhaust headers. Not correct but peace-of-mind when it comes time to R & R

- Jeff

[Martin Benade]

The instructions say 500 degrees F will release red or blue Loctite, I think that is about half the running temp of an exhaust port. Jeffrey's idea is a good solution.

[Paul Ahnell]

All: Thanks again for your replies and suggested solutions. I just ordered the Belmetric copper nuts and may use a just a touch of JB weld as Vic suggested. There are a lot of different hi-temp thread lockers out there. Will also use Remflex gaskets. Expect it will be good until I go toes up.

[Vic Skirmants]

The instructions say 500 degrees F will release red or blue Loctite, I think that is about half the running temp of an exhaust port. Jeffrey's idea is a good solution.

Has anyone measured the temperature of the exhaust area of a 356 head? When using exhaust temp gauges on the race cars, we tried for 1400 degrees about 2-3 inches from the mating surface. That is of course at the tip of the flame; the hottest part.
I really doubt the head gets to 1000 degrees! Doesn't aluminum melt around 700 or so?
Using an under the spark plug sender, we can see up to 400 degrees; trying to keep it closer to 350 with jetting and cooling.

[Martin Benade]

I looked up some generic numbers for exhaust temp and manifold temps, which sometimes glow red. Probably I was totally wrong to infer this on a Porsche.

[Dick Weiss]

I've found that the rounded end of the exhaust stud(s) are for the nut(s)--and flanged nuts may not properly get tight due to the exhaust flanges are welded on the outside: That's why the 12mm hex nuts will (or should) clear the bead.
The other flattened end of the stud may be very slightly larger in pitch which will get tight when inserted into its hole in the head.
I used to made some special over-sized studs to suit. I also 'peened' the outside of the port casting to kinda shrink the tapped hole and use either Loctite or J.B. Weld, and use Hi Temp anti-sieze to prevent the nut from "rusting in place" over the years.

[Al Zim]

Your situation is solved very simply. Use a thread chaser (not a die) to remove the rust from the stud (the studs remain in the head). You can purchase Brass metric nuts with 13mm hex or you can get some 5/16 brass nuts at the local hardware store and tap them to 8 MM. I use a 1/4 inch drive to install the exhaust flanges where possible. al zim You always have to file the exhaust flanges flat. Check the welds to see if there are any visible leaks between the exhaust pipe and the flange. Sometimes you have to heat (red hot) the pipe to insure a proper fit to the head. I always use double gaskets and orange silicon on assembly.
The gaskets currently available are half the thickness of the original gaskets and do not have the wire reinforcement in them. al zim