JB Weld for Exhaust manifold?

[BradyA]

A friend of mine has a V8 engine in his boat (I'm not sure what kind) and asked me if there is a product that could seal a small maifold leak. Can JB weld to the job or is there an alternative (other than replacing the manifold)?

 

[Reel Poor]

Re: JB Weld for Exhaust manifold?

The alternative to not replacing cracked exhaust manifolds is usually a destroyed engine due to water intrusion.

 

[ZmOz]

Re: JB Weld for Exhaust manifold?

Maybe this stuff?
http://www.permatex.com/products/au...ir/Permatex_Hi-Temp_Metal_Repair_Compound.htm

 

[bomar76]

Re: JB Weld for Exhaust manifold?

If your friend's ultimate goal is to fill the engine with water and destroy it, JB Weld or something similar is an excellent choice.
If he wants to actually repair the problem he needs to purchase and install new manifolds and risers.

 

[riverjet502]

Re: JB Weld for Exhaust manifold?

Depending on where it is cracked, it can be welded with some nickle rod. I have done this in the past for a neighbor. Finding someone that "knows how to weld cast is another story". Post up some pics if you can and lets have a look see...

 

[MikDee]

Re: JB Weld for Exhaust manifold?

Depending on where it is cracked, it can be welded with some nickle rod. I have done this in the past for a neighbor. Finding someone that "knows how to weld cast is another story". Post up some pics if you can and lets have a look see...

This is true, if you are good at welding cast iron, and that's not easy!

 

[ziggy]

Re: JB Weld for Exhaust manifold?

i agree with real poor and bomar76. replace it or ya might really need to pay after ya ingest water.....

my manifold had a small crack on the outside that didn't leak. when the waterjacket was filled w/water on the bench. within a day it had all leaked into the exhust runner........ replace it......

this pic is just after i filled up the water jacket. the dark line is water leakin into the exhust...

 

[capecodder116]

Re: JB Weld for Exhaust manifold?

DON'T WELD IT....!!!....Speaking from experience....never weld cast iron....REPLACE IT....

 

[Cuyose]

Re: JB Weld for Exhaust manifold?

For what it's worth, or what the boat is worth to you, I had someone nickle weld my cast iron manifold a couple years ago and it has been rock solid. It was only a crack on the outside however, and I was sure of that before even attempting.

 

[dgopetactical]

Re: JB Weld for Exhaust manifold?

I bought a boat in the spring and found out that both manifolds had exterior hairline cracks from poor winterizing. (drip.....drip...) I used JB weld and all is well but I will have new ones on by next season... my opinion is jb weld is a good temp fix but a replacement should be in your future.

 

[Skinnywater]

Re: JB Weld for Exhaust manifold?

For years and years I've been told "you can't weld cast unless..."

Tried it one time since I didn't have much to lose and the result was
some of the prettyest welds that I've ever made.
A simple wire feed and argon, all the cracked exaust manifolds I've done are still holding years later.
I thought that at least one would crack again beside the weld, but they haven't yet.

 

[Scaaty]

Re: JB Weld for Exhaust manifold?

You Braze cast iron...but in this case, you give it the float test..

 

[Haut Medoc]

Re: JB Weld for Exhaust manifold?

Replace it.....​

 

[bomar76]

Re: JB Weld for Exhaust manifold?

He is not gonna be happy untill he cobbles some half azzed repair on it and destroys an engine.....

we can all look forward to the coming "Why is there water in my cylinders/engine won't turn over/is my starter bad" posts in a week or so.

 

[Wotknot]

Re: JB Weld for Exhaust manifold?

For years and years I've been told "you can't weld cast unless..."

Tried it one time since I didn't have much to lose and the result was
some of the prettyest welds that I've ever made.
A simple wire feed and argon, all the cracked exaust manifolds I've done are still holding years later.
I thought that at least one would crack again beside the weld, but they haven't yet.

Yes, you can successfully migweld some casts with SOME brands of S-6 wire, but are you saying pure argon?........or an argon mixture?