Exhaust manifold repair

[Greg L.]

Here is an interesting one... I was derusting one of my manifolds in some muratic acid the way I derusted all of my other cast parts and when I pulled it out I noticed a small "rust pit" that seem rather deep. Then I rinsed it off with the garden hose and to my suprise the rust pit turned into a hole about a 1/16" in diameter! I know I didn't leave it in too long so all I can think is that there was some contamination in the casting when it was cast back in 69.

Anyways....now what? What would be the best way to fix it? It's on the R/H outboard side but it's far enough down that any proper repair would be hard to see. I was thinking to just braze the hole shut but I don't know if the brass will stand up to the high temp. I could also get it welded but my luck the manifold would crack and seeing as they are original, I don't really want that to happen. Any thoughts???

[Joe L.]

Re: Exhaust manifold repair

greg-----

Brazing will usually work fine. For a non-structural type of defect, I think that it's probably the way to go. I don't recommend repairs, at all, to exhaust manifolds if there is a structural problem (flange, brackets, etc.).

By the way, some original factory castings were repaired for just such as the type of situation that you describe. They did not use welding or brazing, however. I don't know what sort of process was used.

[mike mccagh]

Re: Exhaust manifold repair

agree with joe that brazing way to repair the hole. however, i've got a 32 Dodge with 8 cyl engine(original) whose exhaust manifold fractured 360 degrees. no original replacement to be found. took the two pieces of the manifold to a very experienced cast iron welder(he works at the local CSX repair facility welding railroad cast iron). the manifold was placed in a furnace and the pieces then re-welded with cast-specific welding rod. i then surfaced the repaired manifold and re-installed it on the dodge engine. it's still holding 5 years and 5K miles later. the cast iron of 1932 is of poor quality. mike

[Verle R.]

Re: Exhaust manifold repair

A shop called Arc Angle in Tulsa specializes in "hard to do" repairs. They have successfully welded exhaust manifolds for me, including BB Corvette manifolds.

They can be reached at 918-838-0047.

Verle

[Barry K.]

Re: Exhaust manifold repair

you might want to try Jerry MacNeish. He seems to do a good job or repairs and a lot of people recommend him.

http://www.z28camaro.com/restosvcs.html

[Mike McKown]

Re: Exhaust manifold repair

Drill, tap, install threaded slug and grind flush.

[Craig S.]

Re: Exhaust manifold repair

Greg - I think Joe has mentioned this firm before as well.....but this would be a do it yourself operation vs taking somewhere.......Craig




Cecil B Muggy Weld

[Rob A.]

Re: Exhaust manifold repair

I had an exhaust manifold repaired locally at an engine rebuild shop. The trick, evidentally, is finding someone that knows how to properly "heat up" the manifold, as mentioned in another response. The repair can be ground down to match the immediate area of the repair. The hole I needed repaired was about 1/4" dia. The size of your problem should be very easy for the right person to repair.

[Terry F.]

Re: Exhaust manifold repair

There is an ideal repair for cast iron. They spray it with hot steel or some aloy. It works great and the bond is incredibly strong. More expensive than traditional repairs but a superior fix for cast iron. It is great for surfaces that are subject to wear because the new surface is very hard and durable. I think it is called spray welding. I have had it done on some tractor parts that are cast iron. Once it is repaired it really sort of looks like the surrounding cast iron. Just a thought, Terry

[Joe L.]

Re: Exhaust manifold repair

Terry-----

I believe that the original factory repairs were done using a process something like this. This sort of repair is what the factory-repaired areas look like.

[Tracy C.]

Greg, fix it yourself with brazing rod... the only

challenge will be the small size. You may need to countersink it a bit to create a cavity the brass will swim into.

Grind it flush after the fact and shoost a little high temp cast blast over the repair area and all will be well.

tc

[Terry F.]

Re: Exhaust manifold repair

Interesting that they took the time to repair them. But, new cast iron is nice and clean (no prep work really). Probably had a set-up running all the time. If they came across a pin hole or something they just spray welded it and moved on. Thanks for your comments, Terry

[Greg L.]

Re: Exhaust manifold repair

Thank you very much for all of your advice. My initial solution was to braze or if that wouldn't work drill, tap and plug as Mike suggested. Seeing as the hole is so small I'm going to just braze it over. I've repaired the odd casting in the past with brass and it has always held up but I was a little unsure if the brass would last on an exhaust manifold but now tend to think that this is the way to go with this repair. Thanks again.

Greg

[Mike McKown]

Re: Greg, fix it yourself with brazing rod... the

Most paint doesn't like to stick to brass.