Sealant For Studs In Water Jacket...

What kind of sealant do you use for the exhaust manifold studs that go into the water jacket on an f134?

what temp rating does it need to have, seems like since they touch the manifold, they would get really hot

I've used indian head and it bubbled out.. used permatex aviation and it still leaked a little..

 

I like Permatex also, but use their high heat thread sealant #59214

 

Permatex aircraft thread sealant.

 

going to try my luck with the permatex high heat thread sealant

 

Make sure to wire wheel the stud threads and chase the block threads with the proper tap to clear out scale. Blow it out with compressed air and if the motor is in vehicle as a final bit of insurance run a bolt saturated with acetone to prep/clean contaminants.
If it continues to leak suspect would be a crack near stud.

 

I've had good luck with pipe dope.

 

I've always used Ultra Copper with no leaks. Like NCRenII said, make sure the male and female threads are clean.

 

Also advisable is to put a slight chamfer / bevel at the block just to clean up the sharp edge as sometimes this may be what you need to create a seat for the stud to seal against................tried many things for years trying to seal race motors that ran studs into water jackets at 16-21 PSI water pressure..............Yama-lube made by Yamaha makes a good non hardening case sealing product that showed good results..........also Permatex makes a few good Anaerobic sealers that I also have used...........like mentioned above chase the threads, clean the studs and brake-clean all threads so they are perfectly clean and dry prior to assembly..................or do as we finally did and use only aftermarket blocks that had blind stud holes.

 

In the 70's many rebuild kits included plastic tapered washers (more like a triangular section o ring, usually yellow) to slip over the stud that would seal when the exhaust manifold was torqued down. They were a waste of time as heat stretch usually allowed any leak to re-surface.

 

And it wouldn't stop the threads from corroding.
I spent about two days last summer getting the studs out of an early Ford V8 flathead.

 

This is a good point. Prepping and applying the right sealant is important for not only preventing leaks, but, also to prevent metal bonding.
Also, what to do when fasteners seize or break off can be a thread on it's own.
some pointers I've used successfully:
-silikroil penetrant #1 in my book a day or several prior to attempting removal
-heat the stud with a torch
-if it's broke off flush or below, weld a washer the proper i.d. to the stud (weld won't stick to cast iron) and then weld a nut to the washer and use that to slowly back out the stud as it cools from welding (preferably do this after letting silikroil work).

 

on the brass nuts.
I had not tried ss studs, always been afraid of them popping when things heat up.

 

I use stainless steel bolts where ever I can. I look for 316, they come in 304, 308, and 316, each one has more nickel in it. The 304 seems soft like a machine bolt and stretch easily, and 316 seems harder. I used them in all the body bolts, floor panels, fenders, and steps that sort of thing, be sure to use oil or anti-seize on them the threads will stick and not go on or come off without a lubricant. Good marine shops have a good selection of them, they are good forever. Good Luck