Any of you guys have suggestions/experiences of repairing a small weeping crack in a cast iron cylinder head?
Been welded already but chasing the weld.

JB Weld Iron putty, etc,?

Intake or exhaust port???

If its external, loc-n-stich pins work great, I have used them on many a block and head.

I've had several heads and blocks cracks repair using that method, that to me is the best method out their

It’s a Hemi. Internal crack at the top of the ledge between a spark plug and a stand boss.

under the valve cover is still exterrnal to me. Into water? loc-n-stich is still the right fix. lets see it.

I was made aware of stitching over 50 years ago.

I was asking for suggestions using epoxy, etc.

Thanks.

What was it welded with?

A shop that does a fair amount of head repair did it, not really sure.

Depends on the skill of the welder doing the repair. I seldom see cast iron welding hold up unless the part is preheated and cooled down in an oven. On a cylinder head that will mean disassembly and regrinding the seats as they may move during the heating process. Cracks that have to hold water should be drilled at the end of the cracks and then welded. If you don't preheat and say, try to use just a nickel rod very poor success rate.

The 1968 to 1970 ("916" or are they "906" castings # ?) BB heads are horrible about freeze cracking under the center two exhaust ports
Stitch and lock has worked great on repairing several that I have had fixed

Since it's been welded already and leaking through the weld, I think some sort of epoxy is your only option.
I don't know what to suggest b/c I've had zero luck w/ welded cast iron holding water.

Is this a coolant passage leak ? If so, where are you trying to apply the epoxy ? internal or external of the cooling circuit ? anyway, I'd search for a 3M product, JB weld epoxy probably isn't the best. good luck though.

Have you thought about trying head gasket sealer ?
Blue Devil sealer works. I found it lasts 4-6 months of daily use.
You pour it in with engine cold, start and idle for 50 mins. Done
I kept a car going for a couple of years with it.

BlueDevil's Head Gasket Sealer is a permanent seal that can repair and seal leaks in cracked heads, warped heads, blown head gaskets, heater cores, and freeze plugs. It's compatible with diesel and gasoline engines and can bond to aluminum, cast, alloy, metal, or plastic. It's safe to use and won't clog or harm your engine because it doesn't contain any solid or particulate matter.

I have used similar products and yes they do work. If you take an engine apart after using it looks like it has been painted with varnish in the water jackets. The ones I use ALL the antifreeze must be removed that means draining the block not just the radiator. Fire it up to operating temp then drain the engine, including the block let sit a day or so empty. Last one I did had a crack in the deck next to a head bolt, I helped it out a little by pulling a vacuum on the problem cylinder while it was cooling down. That was in a mud truck it lasted the season no problem.

Thanks for the suggestions. I was planning on using a sealer after the epoxy repair. That sealer mentioned looks like a good choice.

If you would give more and better info in your post you would probably get better answers.

Sodium Silicate aka Water Glass.

GM uses a powder sealer (a small amount, like one talblespoon) in all their new motors from the factory is what I have been told
They sell it in one gallon containers also

That’s Obama’s cash for clunkers juice. I realize you’re not talking about putting it in the crankcase, but still……