Looking for opinion on welding exh manifold ON-CAR

[ralfwho]

95 Riv 3800. Exhaust manifold is tubular steel.

I have developed a small crack between one of the port tubes and the collector. What does anyone think about MIG welding it ON THE CAR? The crack is about 3 inches away from the head.


I propose this:

1) Run the car until the manifold is hot.
2) Disconnect the battery
3) MIG weld the crack.

Opinions?

[TheSilentChamber]

If its not cast you should be able to weld it with no problems. Running it till its hot wont really matter.

[curtis73]

Agreed. Be careful with it though. It probably cracked because of heat cycling which has added carbon to the steel. It probably started life as cold-rolled which is a medium carbon content. The years of heat and carbon have basically turned it into hardened steel.

Therefore the threshold between a nice little hot puddle and a major blowthrough might be really quick Do you have a torch? Brazing might do well. Tig would probably do well too.

[jveik]

heat-resistant duct tape lol... but anyways, the same company that makes the famous POR-15 rust inhibitive paint also makes tons of other stuff, including exhaust manifold crack repair kits, i shit you not. Try google and type in por-15 and click one of the higher up sites and you should find it pretty easily. the only problem with the resto-motive or whatever stuff is that they are very expensive.

if you weld, i bet you could easily do it still bolted to the head. that would probably also help keep the flanges from warping and not sitting flush anymore. if all else fails, go to the junkyard, pay the 2 bucks entrance fee, and chuck a wrecked one's manifold over the fence and come back at night to get it lmao jkjk some people actually have morals and principles lol