Exhaust Manifold Repair

[ponypastor]

Has anyone successfully repaired a small crack on an exhaust manifold for a 429 CJ/SCJ? If so, how did you do it?

Thanks. 

 

[Don C]

Not specifically for a 429, but I have had several repaired or modified. I knew a father and son that were old school blacksmiths, they could weld just about anything. They started by notching the crack, then heated the manifold, then arc welded them. I don't remember what rod they used. My point, if you're not experienced at welding cast iron, don't practice on rare or expensive items, find someone that has the expertise.

 

[mjlan]

I'm with Don- it can be done with success, but not without proper technique and equipment.

I would start with asking engine builders or restorers who they use for block repair. The process is the same as  the material is the same- furnace to pre-heat the part and then the right materials for the welder.

There are a couple of videos this guy put out there and its crazy how good they turn out...

 

[mjlan]

Sorry, this is part two, the above is just the old boy tongue waggin

 

[Carolina_Mountain_Mustangs]

For sure you can weld cast iron. I had a Ford van with 351 HO engine and the exhaust manifolds cracked. I actually brazed them. In the tool & die shop we welded castings all the time. There are special rods you get and pre heating the parts is important and hammering the weld as it cools expands it and keeps it from cracking. We had die crashes with huge tools weighing 10's of thousands of lbs. We usually sent them to MPD Welding in Michigan. The put the castings on huge heat tables to slowly heat them up and they would vee out the back side and braze it there and on the working surface they would weld. The brazing rods they used were like 1/2" in diameter. The welders / brazers would switch off and never stop. One would duck under the other and take the rod and torch and the went 24 hours day nonstop.
Back in the 60's in the shop I worked in the racers that could not afford new everything would buy used engines from the big shops. We brazed the web with the thrust bearing in 427 side oiler block that Cecil Gordon ran. He cut pulp wood for a living and raced almost every NASCAR race back in the 60's. When you hit the wall the crank shifts forward and breaks or cracks the web because of the thrust bearing being there.

 

[rio1856]

For informational purposes, check out this video

 

[71Rustang]

I have fixed them.Stick welding with high nickle content rod.Pre heated using a torch,properly prepped crack,weld,throw in pile of play sand to cool.

 

[OMS]

When I called around to get one repaired years ago. The shop said it had to be furnace brazed

So I V'ed out the crack, put the manifold in the barbeque grille and cooked it for of a couple of hours to get it as hot as possible.

Had everything ready, shut off the grille, brazed the crack, fired the the grill back up and then slowly kept dropping the temp

Worked well, only issue is when you paint them you can see the smooth repair line 

Have done a couple this way

 

[Q1SVT]

Has anyone successfully repaired a small crack on an exhaust manifold for a 429 CJ/SCJ? If so, how did you do it?

Thanks. 

Ever stick weld?

Use a 1/4 grinding oval burr, follow the crack 1/8" deep and just past the ends of the crack...

https://www.mcmaster.com/4292a65

Get some stick welding rod trade name ENi-CI (Ni99) 3/32"

Mc Mster has in in 1/2#, 3/32 dia   https://www.mcmaster.com/7973A612/

You can [SIZE=12.17391300201416px]pre-heat little [not require] but liker to heat 200-250 around general area [/SIZE]

[SIZE=12.17391300201416px]Try to weave the weld back & forth in the 1/4" grove as you run the [/SIZE][SIZE=12.17391300201416px]length in one pass. [/SIZE]

[SIZE=12.17391300201416px][/SIZE]

I use Cronation 211, but they do not sell it in smaller poundages...