Welding Tips and Tricks

New to the forum. Been a subscriber to Jody's YouTube channel for a couple of years now.

I'm looking for some tips on welding a cast iron cylinder head. I've been porting the cylinder head for a Chevy 250 inline 6 engine I have in a project vehicle. I've found 3 cracks near the #4 combustion chamber. I'm going to finish porting the head mainly just to finish the video series for my YouTube channel.

But, I'd like to try and repair the cracks in this head myself. Though it will need to make a trip to the machine shop if I do get the cracks repaired.

This is what I have to work with. 110V Miller 140 Mig with 75/25 argon/co2. Two MAPP gas torches.

I've heard stainless wire will work. True? I currently have a 2lb. spool of 309 wire. Can I get the head hot enough with the MAPP torches?

Any tips would be appreciated! I've found a couple of heads on my local craigslist and a machine shop that will sell me a stock head that has been magna fluxed for $125. If I fail, it's not too big of a deal… other than the time I spent porting it. $125 is not that expensive of a lesson.

Thank you,
Joe

i dont think a mapp gas torch will do the trick.

need somethin that will REALLY heat the entire piece and keep it hot while doing the repair.
it should be made to cool down gradually..
got a wood burning stove? set it on top and build a fire.
hopefully some other guys put their two cents in, as im also new here and new to welding, but this is what ive heard from several sources.

good luck


WW

Welcome to the forum Joe.

Joe,
First off having been around cars and trucks most of my life, I'm here to tell you that you are going to end up buying one of the other heads if you don't want a head gasket leak.

Now as to your trying to repair the cracked head, like Winston said you'll need to heat the entire head. With a straight 6 inline head being in the neighborhood of three feet long and 8 inches wide, it will take a pretty large furnace to heat it up. Then you'll have to cool it at a very slow pace down to room temp. or it will crack after you weld it, and that's if you are a very good welder. If you do everything perfectly and you get it repaired and remachined flat, it will crack down the road sometime right next to your repair.

If your goal is to learn how to do cast iron repairs, I would try on something that doesn't take a half of a day to replace when it fails and possibly puts antifreeze in your oil. Your next project will be learning to do a weld build up on a 250 crankshaft when you spin a rod or main bearing. Now if this was the only 250 head that you could find, I'd say by all means give it a go.

Len

Getting the head hot enough (preheat) is my biggest worry. Aside from the MAPP torches, the only other thing I have is the BBQ grill. The head is too long to fit in there. I don't have an oxy/fuel torch. I have a plasma cutter for cutting, and rarely have to preheat material to ultra-high temps.

I'll have to think about this some more. The dollar value loss is low but I've got nearly 30 hours of port work into this head. I'm one of those guys that would rather buy a tool and learn how to do it myself, than pay someone to do it for me. In this case, I may have to throw that out the window. I think I'll be making a trip to the machine shop before I strike an arc… if I strike one at all on this head.

Thanks for the input!

-Joe

Joe,

I understand that you have a lot of time into porting the cylinder head (believe me, I know how that can go), but welding a cast iron cylinder head is a PITA, and especially so without a large enough oven. Have you looked into drilling and pinning the crack? It's much more common, although, to look at it, you would never think that it would work. I would definitely buy the head from the machine shop, to get the car up and running if that is the concern at hand, and then explore other possibilities for repair of the cylinder head if still want to do that.

Sam

I have some experience with these heads. Do you have the straight head or the integral manifold type? I would suggest the you have the head magnafluxed. There may be more cracks, especially if it is the integral type. 1 of the problems with weldind a cast head is that they get so hard that you really can't do much to machine them afterword. And if you do weld, mig is not the process to use. To properly weld a cast head may be cost prohibitive. The cracks need to be cut out and then filled. There is a lot of preheat and post cooling involved. There are some shops that can spray weld. This can work ok, but again a lot of work. A better solution may be pinning. Also called stitching. We used to pin a lot of these back in the day, but rarely ever see them anymore.

Well I guess I should have read all the posts before I posted. Pinning has a pretty steep learning curve. And the taps can be a bit spendy. The tooling is a bit specialized. Its a whole system. Pins, taps, drill bits etc. If you want to try this yourself try Lock-n-stitch products. But get the head magged before you begin. I'll bet there are more than 4 cracks.

Thank you for all the responses!

I think I'm going to forget about repairing this myself. I just don't have the equipment to get it done.

The head the non-integrated. I'll be taking it to the machine shop to at least get an estimate. It may be more cost effective for me to just buy a good (maged; no cracks) head from the machine shop and re-port that one.

I looked into pinning, which is likely what the machine shop will do, but that's not something I'm going to tackle either. I RARELY do engine work. I'm a weldor… that's why I'm here. It's not worth investing the money in the tooling for pinning.

Again, thank you for all the responses! This is an excelent resource!

-Joe