Welding cast iron manifolds

[Coralsnake]

Anyone have any experiences repairing cast iron manifolds?

[Bob Gaines]

Anyone have any experiences repairing cast iron manifolds?

I was told part of the process is heating up the entire manifold to perform the repair properly. It can be done but depending on the repair you have to have realistic expectations . In other words you typically can tell where the repair has been done.

[shelbymann1970]

I've had manifolds welded before from my tool and die welder at work. I forgot the type of rod he used and wasn't there for the process but iirc on welding cast iron it has to be heated up. I welded up a crack in my PI manifold for my 68 Shelby GT500  and the area welded is covered up by the factory heat shield which SA left on the engine and never removed. I was then lucky to get a mint set of date codes correct manifolds off of Jim Wicks. If you want pics of the repair on mine or more detailed info on how it was done I can get that for you Pete. Oh, yeah, I carbide burred out the crack as per my welders instructions with a die grinder.

[shelbydoug]

I have done cast iron with 304 stainless electrodes. It didn't matter if the iron was preheated or not. Cast iron alloys vary. This was for Ford castings.

Most seem to be nodular iron.

[pbf777]

Cast iron alloys vary.

    And this has a great deal to do with whether the effort will be successful. 

    The next issue will be the condition of the casting, and note that generally the crack failure isn't something that 'just' happens, rather this often is a result due to fatigue.  In the case of exhaust manifolds the fatigue comes from the expansion and contraction due to the extreme heat differentials generated in the engines' periods of nonoperation vs. during those of operational, and isn't relegated solely to the immediate area of the crack. 

    Heating the casting is considered mandatory for success, this at least to that of a dark "cherry-red" color; and then after the filler material has been added, a controlled slow cool down that minimizes localized shrinkage that will impart stresses that may result in further cracking. 

    The stainless rod is popular for castings as it is high in nickel which aids in neutralizing some of the pollution present in the casting (cast iron is considered a "dirty metal" and another reason it is considered a non-weldable material) and reducing the gassing out, this making for a lesser effort requirement and better appearance and soundness in the welding.  It also is somewhat softer that the general steel rod filler materials which being more pliable aids with a reduction in the forces created by shrinkage particularly in the cooling-off period.  But it will definitely be visible! 

    The best filler material is cast iron; not just because it'll provide a less apparent repair, but because long term, a like material will move more equally with the parent casting and this will provide for less stress and the likelihood for a crack recurrence.   

    Now, some of the "miracle" welding rods for cast iron that "guarantee" success for the most novice of welders, most often actually don't provide for a true "welding" process, rather are a "brazing" process. This which has less effect on the parent casting and aids success by eliminating to great degree particularly the otherwise resultant "heat effected zone" that is most often the cause of further cracking post the welding operation in the cooling down period. 

    Scott.   

[shelbydoug]

It does also depend on exactly what you are welding.

A 351w right side exhaust manifold, cracked between #1 and #2 cracks because the casting is too thin. That one is difficult to do because of that.

By the same token, welding a crack through a main web casting in a block is much easier but what caused those cracks also twisted the block and the heat of the weld will just emphasize that, so squaring the block as well as line boring it are going to be necessary and although I have seen 427 Ford blocks repaired in this way and run hard, you need to consider it to be on "borrowed time".

Saving a block worthy of just a boat anchor instead of replacing it with a new $5,000 block is the encouragement but it is going to cost you that is time to "save it" with little or no guaranty.

[kram350]

Probably to far from you but these guys saved a 289 hipo head with severe damage when a valve hit a piston. They went thru the whole routine... clean, heat, weld, wrapped in an asbestos blanket, heat reduced. Still on the car and this was done in 1974. Maybe they can help?     
Excelsweld USA,
1231 16th Ave, Oakland, CA 94606.
Phone Number: (510) 534-3303

 

[Coralsnake]

Very much appreciate the lead

[TA Coupe]

Great article about welding cast iron:How to Weld Cast Iron: A Comprehensive Guide https://share.google/ljvE6Z4zTdfex1YXy

      Roy

[JohnSlack]

Very much appreciate the lead

Pete these guy have a classic division as well as over the road Diesel work;

https://www.dieselcastwelding.com/

We had a guy 30 minutes from us here in Puyallup that was a Vietnam veteran. When he got home from the war he went to work at Caterpillar and was certified for Cast Iron welding. I had to take a part to him for repair. We talked about cast iron welding and he gave me a really great overview of the process. He had everything from a matching number 440 block to a Duesenberg block.in his shop. -e was leaving the business due to cancer. However he said if I ever needed another welder for cast iron make sure they were certified by Caterpillar. They had the world's best program.. article link here;
https://www.cat.com/en_US/blog/manufacturing-welding.html#:~:text=Since%20quality%20welds%20are%20at,top%20talent%20is%20a%20priority.

[Coralsnake]

Very helpful

[KR Convertible]

I weld cast iron at my shop regularly.  I always pre heat and use nickel ferrite rods and if possible slow the cooling process.  I'm not usually concerned with appearance, so I lay it on heavy.