Who had cracked headers welded?
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Kinda depends on the crack. They're welded as part of manufacture, so they can be welded again (if in decent shape). I had a cast manifold welded on a Jeep that last 50k miles (when I sold it).
OTOH, buying used has gotta be cheap. Possibly cheaper than welding.
OTOH, buying used has gotta be cheap. Possibly cheaper than welding.
Melting Slicks
Joined: Mar 2002
Posts: 3,108
Likes: 126
From: S.L.C. UT
You should probably mention exhaust manifolds rather than headers. Headers are steel tube, and manifolds are cast iron. The repair work will be different between the two materials. Cast iron is harder to weld than steel.
Race Director
Joined: Jun 2004
Posts: 13,960
Likes: 707
From: WI
I had some welding done on a cast exhaust manifold on my old turbo car. I believe it should be nickle welded then the whole thing heated to relief stress. I had a local place do the work, it wasn't that much.
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Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
I've welded cast exhaust manifold before (not vette).
I've heard it can be problems due to a high silicon content in the metal but I had no issue. Used stainless steel wire on a mig and it was easy, strong, and lasted.
I've heard it can be problems due to a high silicon content in the metal but I had no issue. Used stainless steel wire on a mig and it was easy, strong, and lasted.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Slingshot
Joined: Dec 2001
Posts: 3,817
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From: Charlotte NC
Pro
Joined: Jun 2001
Posts: 520
Likes: 6
From: Elverson PA
I've had it done successfully. You should take it somewhere that knows how to weld cast, and has a good oven to heat and cool it in. I've seen someone else try to do a cracked Porsche header without heating it first, and it just kept cracking more and more.
Instructor
Joined: Feb 2005
Posts: 210
Likes: 0
From: Racine WI
TIG weld it
Have someone who knows how to TIG weld do it. Depending on where the crack is, they might be able to get to it and cut a 45 degree 'V' along the length of the crack with like a Dremel tool or small air powered grinder. Then they will fill in the crack with rod, and probably make another pass over the top of that (called a cover pass) to completely fill it up. If they do it right, it will be very strong. TIG welding is the way to go, because you have very good control and the heat affected area is very small.
Pro
Joined: Jun 2001
Posts: 520
Likes: 6
From: Elverson PA
Just use it as an excuse to upgrade. I only welded the ones I did b/c there was no other alternative other than a custom header (turbo Volvo). Otherwise, just go to the for sale/wanted section and ask for stock headers for your year. If they are cast, there are a million people who ditched them for aftermarket stuff and are willing to sell that to you cheap. I would pretty much give away my stock 85 manifolds. Maybe there are other years with better manifolds/headers that would bolt right up. My guess is not the 1985 year. TPIS longtubes were a huge upgrade on mine.
