Flathead block welding? is it possible?or not for me? AV8?

The recent posts that we have had about cracked flatheads and then AV8's post on welding in the exhaust spitter got me a thinking...
So here is the scenario; one of my 8BA blocks (merc) has a vavle to piston crack (hairline) that extends down the cylinder about a 1/4-3/8ths of a inch.
What I want to do:
Grind out the crack about a 1/16th or so,( in the cylinder a little deeper for boring) and drill a small hole in the cylinder end of the crack( to stop the crack from expanding). Heat the area with the torch for about 10/15 minutes. weld with the mig and let cool. then grind it down and bore it out .010 to .020 over depending on what I need to cleen up the cylinders.
Am I just plain loco? I know I can get it profesionally welded or pinned. But I one of those do it myself kinda guys. Plus as usual I'm broke as hell.

 

If it was easy to weld blocks, or any cast iron parts. there would be, hundred of examples out on the webb.

As far as i understand yes it can be done if you know what you are doing.But there is no warranties.

Metal stitching and a sleeve is the way to go in my mind.

But do a search on Welding cat iron on Google and make up your own mind.

 

you might be better off using threaded plugs.welding cast iron is a bitch.if you're determined to weld it anyway go toi your welding supply and ask the folks there about it.i don't think MIG wire has enough nickel content to do it right-george

 

I got a buddy here in Seattle that all he does is repair aluminum and cast iron enginge parts give him a call he can explain all about this subject. His name is dave.
Aluminum head welding
(253)931-1148

 

I've had fair success welding non-stressed cast iron parts with a TIG. I take the sheilded Ni-rod, pound the flux off and use them for filler. The weld flows well but it's difficult to not have any porosity. I've seen lots of cast iron welded with a MIG but again, non-stressed.

Chris

 

Actually cast iron welding is fairly common and not hard to do. It is just not something you see on a daily basis with engines.

Ive repaired several flatheads, here is the process.

Drilling as you said to relieve stress.

V groove. Sometimes gets tricky and I have a variety of straight and angle air die grinders.

Area to be repaired has to be absolutely clean. No grease, oil or grinding and drilling residue.

Preheat to about 350F; this is crucial for mig, tig or gas. I use an oldelectric oven for small items, a charcoal barbecue pit with iron grate for blocks. Just trying to heat with a gas torch is OK for small areas but the work cools fast and often at different rates.

I prefer gas and use a Henrob as it minimizes oxidation as well as gives deep penetration in just the area you want.
Use special made for cast rod, has high nickel content but is easy to machine, not expensive in small amounts. Some use Mig nickel wire but see below.

Mig is a real pain as you have to change gas and wire; neither is cheap and if only used very seldom not cost justified. I dont own a tig; too much money for too little use. The Henrob can do it easier and faster anyway. Boiler repairs are often done with a regular gas torch to heat and a stick welder. I know a guy who makes a very good living doing heavy machinery repairs on site with a Henrob and portable tanks. He has a van full of everything needed. Charges a bundle but saves the customer many thousands usually. Being this is New England some stuff is a century old and parts are unobtanium.

Mig wire is very hard, gas is softer and more approximates the cast so it is simple to machine and not present different wear rates in a cylinder. If just doing an area that wont see that type of use anything works OK. I used Mig myself before getting the Henrob.

Practice on some scrap, an old head or bare block of any kind is usually free at the dump or boneyard.

And expect to get singed a few times, gloves are too bulky for down in the bores and I dont like the restriction anyway, especially with the Henrob pistol grip. I did buy the extension just for cylinder work.

 

It sounds like Carl has it sussed. I don't have the skills or knowledge to weld cast iron. but I'd certainly like to learn enough to repair non-stressed componets or non-stressed areas of large pieces, such as a block. It would relieve some of the "stress" in my life when I'm doing some serious port work. I've heard lots of good words about the Henrob in situations such as this and would like to learn more.

BTW, the welding of the exhaust baffles is easily done with either MIG or TIG because it's done in a not-stressed area where the casting is very thick.

 

286... Thanks for your input. I may just sleeve the cylinder and mig the rest if the crack. I am going to keep this motor pretty stock with as little cash input as possible, as this is going to be a cash generator for my 'hot' flattie. With prices as they are curently it makes sense.
FS