TR4/4A broken TR4A exhust manifold; weld or replace?

[Steve P.]

Hi Gang, Spent the first day with my new toy yesterday (triage). The only major problem I've found so far is a broken exhaust manifold. The rear pipe going to the head is broken away (cleanly) from the rest of it. I've heard that cast iron parts like this can be welded these days fairly easily, but I've never had this work done. My question to the group is whether to look for a good, used manifold or get this one welded. I guess I'm concerned about how strong the welded manifold will be.

 

[Bugeye58]

If you take it to a competent welder, the weld should be stronger than the original piece. Make sure the gasket mating surfaces are true after the weld, and you shouldn't have any trouble at all in running that manifold.
Jeff

 

[Mark Jones]

Jeff makes a good point. I'd suggest having the exhaust manifold planed after it is welded to ensure that it is flat. If the welding warps the manifold any, and you then reinstall it, there is a good chance that the manifold will crack again due the stress of being bolted flat. This is what I did to the used exhaust manifold I found for my Spitfire 1500, which are know for cracked exhaust manifolds.

 

[Bruce Bowker]

As already said - a competent welder - and make sure that person knows what they are welding. There are many good welders but not necessarily competent with certain pieces.

I would look for a good used one and compare price of welding and planning. Might be a lot cheaper to buy one.

You might want consider a nice set of headers since the manifold has to come off anyhow.