scooty

The exhaust manifold on an LX is not cast iron as is popular belief over here! It is steel which means it should be easy to MIG weld.

I took my manifold off to have it welded and the guy told me it's not cast iron. The manifold and converter are actually made of 2 pieces of steel welded together in 2 halves. If you look carefully you can see the weld seems along the edges. The tubes are welded very cheaply to a steel flange that bolts to the engine.

Cast iron manifolds are made by pouring liquid pig iron into a mold. The steel halves used for our cars' manifolds are most likely sheet metal pressed into a die.

My manifold cracked all along one of the welds joining the #1 tube to the mounting flange. The guy showed me how the welds were done very cheaply with a machine so they end up looking like paste smeared along the joint. A proper quality weld should look like a row of overlapping circles.

So if your manifold is welded no need to buy an expensive new piece. Just have it welded. It's steel!

04 Honda Civic

iTrader: (2)

Where did you read that it was cast iron?

Regardless of the materical they are not even casted.

scooty

I read it on a several different threads on here, for example:

https://www.civicforums.com/forums/3...m-options.html [POST #4]

https://www.civicforums.com/forums/3...-question.html [Post #1]

It's crazy the amount of misinformation you can sometimes get. I almost bought a whole new OEM manifold because I was under the impression the manifold is cast iron and cannot be welded properly.

pwnsauce

from what i read, on hondatech i believe, welding a crack doesnt hold up and your better off getting another manifold or aftermerket header.

04 Honda Civic

iTrader: (2)

Yea, welding still is no guarantee either. I mean its a cheap fix, but certainly not a permenant one. At least in my opinion.

scooty

Why not? The factory welds the tubes to the mounting flange after all, and in a very cheap manner I might add as this is where my manifold cracked. It was cracked almost all the way around one of the tubes where it joins the mounting flange.

They guy did a good job of welding it. The joint itself should be stronger than the surrounding metal. Now if it cracks again at the other factory welds or some where else I wouldn't be too surprised. But the weld itself is a solid repair.

So far so good, time will tell I guess, but my point is not to automatically dismiss a cracked manifold as junk and attempt to have it repaired professionally.