Welding cracks in iron exhaust manifolds

[Dipstick]

The soot inside exhaust manifolds will likely contaminate any weld. Hot tank it first.

 

[wyrmrider]

yep has to be both chemically and mechanically clean
we checked and re-machined may repaired blocks

 

[BSB67]

Couple Items KD.

1) I believe that the driver side C body hp manifold works, or can be modified to work on A body 383 cars.

2) I had a manifold actually break in two (A Body 383 driver's side interestingly enough). This was almost 40 years ago. Had a well seasoned guy braze the two pieces back together. I still have it and worked for many years until I put headers on the car. If it worked seeming well on a manifold that broke into two pieces, certainly crack repair would be effective if done properly.

 

[zyzzyx]

Here's the first one I did on the Mercruiser block:

 

[POMONAMISSEL]

heat it too , cherry red , after you've v'd the crack well . then weld it with a ac/dc ark rod made for cast iron , its a high nickel rod . you can also knock the flux off the rod and tig weld with it , you still must keep the part cherry red and let it cool slowly .

 

[Ceedawg]

Sure will! I had a buddy that bought a used boat up here in Illinois.
It was an Inboard/Outboard Mercruiser four cylinder. He found out that
the one side of the block had been pushed out from frozen water left in
the engine. It opened up the whole top of the water jacket just below
the deck bolting surface. Freeze plugs were still intact! I V'd out both
edges and beat everything back with a dead-blow to where it all looked
good. Welded it up with 224 and that was it! So far I've fixed three more
IO's the same way. The owners were told they needed a new engine. Ha!
This stuff really beads up nicely, and is very easy to apply. I'll look for
some photo's and post them.

Great, where do I buy these rods? Did you say you tiged or stick welded?

 

[Curiousyellow71]

We have had good luck with Muggy welding supplies. They have rod for specific for exhaust manifolds. We have used their rods to repair cast iron heads. Follow their instructions and I haven't seen anything easier. We've brazed, welded with stainless and nickel and even cast iron rod with heat before muggy.. This stuff is slick it doesn't crack.. do small beads with the stick welder walk away for a bit and come back weld a little more till the crack is gone...brazing will need to be cleaned out first. https://www.muggyweld.com/wp-content/uploads/2017/01/Manifold-Kit-3-32.jpg

 

[33 IMP]

I wish i had access to this kind of info years ago. I have an exhaust manifold from one of my imperials that was so badly repaired (brazed, all over!) that if you hold it up in the air by one end you can see it sag of its own weight. I replaced it with one from a 1950, the newest flathead eight available, but i had to change the intake and carb to match.
I would like to have the original repaired, but i think it is much too far gone.

 

[Curiousyellow71]

35 years ago a old school blacksmith shop repaired a pair of exhaust manifolds on a cat engine for us that were completely burned out, warped and cracked with holes.... Somehow he put carbon back into the manifold(no idea how) before repairing them. The manifolds were burned out piles of junk and he not only made them look like new but also moved the dump flange to the other end of the manifold. I remember him working the manifolds over a forge. I wish I knew his art...but I doubt I'd have enough patience to do those old school repairs.
Some of these new rods work so well I would not be afraid of trying to repair anything.

 

[Kern Dog]

I finally took a few pictures:

The Right side is the one that was brazed.

 

[Kern Dog]

All I have here is a MIG welder. No TIG, no torches.
I might check with a welding shop to see what kind of $$$ they'd want to fix these. I don't know what a good used pair of B body Magnum manifolds costs but if they could fix these for under $150, that seems like I'd be dollars ahead. I'd still need those weird manifold sleeve bolts though.

 

[Curiousyellow71]

The specialty rod is surprisingly easy to work with. With the specialty rod you can stick weld it cold....do small 1 or 2 inch beads...let it cool...repeat. Start welding the crack with no brazing first so you know how its suppose to weld..

Might be a good excuse to add a stick welder to your shop KD... Try to find a DC welder. The old ac buzz boxes could work...but they don't weld as nice.

 

[dadsbee]

It can be done... without the hype... and despite the fact I have a TIG that I weld aircraft engine mounts with, a MIG I do other **** with... I still went old school and used a simple ARC welder with some cast rods to weld the flange back together on my numbers manifold on the Bee when I broke it off disassembling the car for restoration. As noted Greg.. stop drill the ends if you can, grind a "V" into the crack and work your way out of it with small filler beads, being sure to thoroughly cleaning each one before the next bead is laid down. Peen each bead before the next... then once above "ground" grind and blend and if you can sand blast it to make the repair disappear.

 

[wyrmrider]

Kern
keep me posted
I have several C and B Magnum drivers side manifolds
at least I did unless my **** clean up brother scrapped them
last ones I installed was on a late B Body which takes different drivers side than early B-E body D body Imperial takes B body IDK about A body
I thought you were by Kern river and I could drop one off...
cheers

 

[Kern Dog]

Kern
keep me posted
I have several C and B Magnum drivers side manifolds
at least I did unless my **** clean up brother scrapped them
last ones I installed was on a late B Body which takes different drivers side than early B-E body D body Imperial takes B body IDK about A body
I thought you were by Kern river and I could drop one off...
cheers

Hey man...I wish that my name meant that I owned property in Kern County!

 

[Moparnocar]

They make a propane heated rod too, the aluminum version is called aluminoy

 

[Jc cooper]

Brass has been used on cast iron for many decades , but the ad vice to drill both sides of crack is correct plus bevel the crack bring repair area up to at least 400* the secret to brazing is the parent metal needs to be hot enough to accept the brass and the flux needs to be applied,which is not a problem today because most supply houses carry flux coated rods for accey welding , this is usually a core for an experienced welder , all the brass junk in there problematic needs cleaned up with a grinder before repair begins , remember brass typically doesn’t handle stress very well so go easy reinstalling parts , this is how we the old timers have done it for years, my professional opinion,FYI not saying others will or could have a different one ! Btw us very dark very dark glasses so you can see what your doing keep the brass clean and solid !