welding cast iron exhaust manifolds

[kcombs]

I just purchased an almost complete 401 engine complete with 65 Skylark GS accessories (minus carb and aircleaner). One of the exhaust manifolds has a broken part where it meets the exhaust pipes. The walls look thinner than I expected so I am concerned about this being repairable. Does anyone have experience successfully welding these manifolds?

[54Rich]

I just purchased an almost complete 401 engine complete with 65 Skylark GS accessories (minus carb and aircleaner). One of the exhaust manifolds has a broken part where it meets the exhaust pipes. The walls look thinner than I expected so I am concerned about this being repairable. Does anyone have experience successfully welding these manifolds?

Years ago, I bought a 54 ford F100 that the exhaust and intake were cracked, bad. Anyhow, after many telling me that it was impossible to fix, I found a guy that specializes in cast repair. He is in Hudson, WI. Most of his work involves old tractors. When he is done it's hard to tell that it was broken. It's not cheep. I think mine were around $300.00 or so, but I could not find them anywhere. I'd say if you can find another set, that would be your best bet. If you want his number, PM me.

Thanks,

Rich

[doc]

Cast iron can be welded just like any other ferrous metal IF it is heated first, or it can be "cold" welded. both welds are done with an electric welder.
With the hot method the cast iron is slowly heated to a dull red and then welded with a cast iron rod. some use nickle or stainless steel rods.
cold welding is done like, 1 in. at a time on one end of the crack and then move to the other end and do an inch, no more. then back to the other end after the thing has had time to cool down. go slow and v grind the crack before starting.
two or three days ago there was a pair of 65 gs exhaust manifolds for sale on ebay.
dont throw the busted ones away, they probably can be saved.

[Hector]

Every good welder that I've worked with(shipbuilding) could weld cast iron by preheating to a determined temp. and using the correct metal for the job.Look for somebody with a heavy industrial welding background,they are out there and most have a shop at the house.Steel workers are everywhere :TU: .

[Mike Atwood]

I've welded alot of manifolds......I welded the exhaust on the rear side of mid kid's 95 regal last year, and it's held perfectly...... it was broken in half!
Make sure you get it glowing red! I used a wire welder on this one and had it on just about as hot as I could go.

[kcombs]

Thanks for all the replies! I am going to check out a local shop that specializes in welding cast iron. I wanted to make sure the repair would last before shelling out cash. Sounds like it is a do-able idea.

[bellhorsepower]

I may be putting headers on my 64 425 in the next day or so ,If you need a set of manifolds maybe we could make a deal.

[kcombs]

Are they originally from a 65-66 Skylark GS?

[bellhorsepower]

negative, 64 riviera but I think they are the same. But i'm gonna keep em a little longer, sorry ...TA perf. headers were too expensive w/the jet hot coating , so I may have my manifolds ported by Gessler.

[faster]

You can also braze them with brass rod successfully if you are "good" with a torch. You have to get the metal very clean and very hot but not molten and then work slowly and fill the v groove you cut in the place where you want to braze. You have to bolt or clamp them down flat so they don't warp. I have successfully repaired three with cracks and never had one crack again.

Mikey

[tlivingd]

You can also braze them with brass rod successfully if you are "good" with a torch. You have to get the metal very clean and very hot but not molten and then work slowly and fill the v groove you cut in the place where you want to braze. You have to bolt or clamp them down flat so they don't warp. I have successfully repaired three with cracks and never had one crack again.

Mikey


here is another tip. if welding or espically brazing a crack. it makes sence to drill at the very end of the crack, or where the crack is heading toward. it removes the stress concentration and will literally stop the crack in it's tracks, and should keep it from growing any further. I did this the the heat crossover in my intake 3 years ago with no problems now. You don't need to big of a hole either. 1/8" should suffice or maybe even 1/16" in some cases.

-nate

[sawblade]

I welded the exhaust manifold on my wifes car 4 years ago,still holding just fine.It was broke completely in half.Just be sure to use a high nickle content rod.Jeff

[faster]

Nate,

Good point, I forgot to mention that important little bit of info. Do what Nate says and drill the ends of the crack with a small 1/8" drill bit is fine before any welding or brazing.

Mikey

[tlivingd]

to add. if you have a crack in your exhaust manifold but dont have time to fix it the hole will keep the crack from growing further from heat cycling, alowing you to have more time till you can make the final repair.

[BBUZZ]

I do the same (torch preheat) when I braze or Arc weld with nickel rod, then Imediatley smother the part in warm Coal Ash or Lime and leave it there the rest of the day, this helps in cooling at a slow rate, I've done welds without slow cooling and have had them crack worse than the original crack I was fixing! BBUZZ

[kcombs]

Ok, it sounds like this will work. I appreciate all the responses to this post. The crack is actually a break, it is a "C" shape piece out of the manifold at the exhaust pipe flange area. It is probably one inch high and an inch and a half long. It begins and terminates in the gasket seat area and includes the stud. Seems this is do-able if done correctly; heat, bevel, nickel rod, and cool slowly. Thanks again everyone.

Kurt

[The_Dude]

Kurt, I am not sure if you completed your welding task yet, but here's another option. I found this when looking for an option to repair pot metal. I won't post the site here as I don't want to look as if I am advertising for this place. I haven't used it, but just saw it and wanted to pass along another option. Just do a search for "muggy weld" and you'll find their site.

Good luck...

[brians]

Just my two cents...

Be careful, cast iron is tricky. I would recommend you place the manifold on fire brick and place it in an oven at 350 degrees for around an hour. Take it out and immediately weld it then place it back into the oven (with the oven turned off) until it cools. This will prevent any cracking.

The fire brick retains the heat while the manifold is being welded. If it cools off during the welding process any new weld will have a tendency to crack. If it gets to cool just place it back in the oven. Any oven will do. Just make sure your wife/girlfriend isn't home if you use the kitchen oven. I have a lab oven in the garage which works great.

I like to TIG weld cast iron using "Jupiter B" welding rod. It's a bit expensive but it does a fantastic job.

Brian