Technical Cracked head

Right by the temp sending hole

Im 1/2 tempted to try J.B. weld it

 

I've seen that shit work miracle's. Grind it out and fill it in, It's not like it's gonna hurt anything now! Lol!

 

Hmmmm , somebody overtightened the sending unit ? Looks like the lightweight casting heads ?

 

I would

 

I’m sure they are lightweight castings -
I certainly didn’t over tighten it, but who knows what’s happened to it over 39 years.

 

Right!
It’s garbage now anyway

 

TIG with silicon bronze?

 

I had a Chevy marine engine that had a cracked block and the previous owner JB welded it. It lasted for years before and after I bought it. I think the stuff is great if applied properly in certain situations. What could it hurt?

 

Dry it, V it out, get it good and dry and clean. Mix the JB Weld properly apply and forget about it.

 

Hey! Those look like 5/8" socket plugs to me! Shouldn't this thread be banned? 8^) Jack E/NJ

 

Or # 12 copper house wire. I have repaired a few blocks that way.

 

Drain your motor of antifreeze then remove the t-stat housing and remove the t-stat... Bolt the housing back on then hook up a shop vac to the t-stat inlet... Apply the J-B weld in the cracked spot and turn the vac on.... That should seal it forever.....

 

The crack or the vac? LOL

 

If it was me, I'd cold weld it, providing I could get to all of the crack, you take a center punch and hammer and start about 7/16 to 1/2 in from the crack and start tapping the metal towards the crack on both sides of it, gently so you don't do anymore damage, run back and forth a couple times working your way closer to the crack, that very likely will seal it up, dump a can bars leak in it and you'd be set of I don't have much faith in jb weld, but after your done you now have plenty of divits for that to stick to.

 

Drain the coolant out, remove thermostat, fill with water, warm it up and drain again, pick up I believe it's Moroso brand ceramic seal have engine running and add all of the bottle put cap on and take it for a ride to build heat,
drain all of the water out of it, block and all, let sit for 24hrs fill coolant system back up and check to check if you see a leak chances are you won't find one
used this stuff on motors always seem to have head studs leaking good always just watch them leak and they would spit a little and stop leaking just that quick
good luck
Terry

 

I repaired a cracked straight-6 block with an industrial grade 2-part epoxy...basically bootleg JB Weld. It held together really well....and I beat the crap outta that thing!
MAde sure it was dry, 'V'd it (Prolly more than needed) and filled it up. Let it set for a few days and put it back in service.

 

I would put bars leak in it. I remember in the 70s watching Bill Jenkins fill the radiator on his pro stock car with bars leak! Those old Chevy heads cracked a lot!


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Wonder if that sensor is coming out without taking a chunk of the head with it.

 

I have done that on some late model aluminum heads and intakes to close up some pin holes. It worked ok from what I saw. No more wet spots. That crack looks like it goes to the edge of the head so it might not work as good

 

Hey Marty, care to walk us through that one? Sounds like something I need to add to my repertoire.


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I'm thinking because its crack that is Open to a threaded hole that's tapered , with a tapered brass threaded fitting ,that will expand & contract more than most any plaice else on the engine , because its between exhaust ports , that anything short of metal fusion won't last long & even then its iffy. Bars leak may be your best bet !

 

Here is a repair for crack cast iron used for heads and blocks. I had a block repaired with this method 18 years ago still good.
locknstitch.com

 

There are some variables, but a lower pressure cap can slow down or help stop a leak.

 

Bob, I use a die grinder to shallow V, out the joint, and polish around the edges. Then, using # 12 house wire, either the ground, or strip off the insulation, and Tig weld the crack, using just enough heat to flow the copper, about a 1/2" at a time. You should have extra filler wire handy, with copper being a conductor, it warms up pretty quick in your hand. This is not a high strength repair, but it works for some circumstances.

 

Upon further inspection
It’s cracked all the way thru and all the way across.

 

Well that ends that..

While we're on the subject, this broke on me yesterday. Looks like it was cracked already. I don't think JB weld is going to do, much as I like the stuff. Hoping I can TIG it tomorrow and get back to work Friday. Should be cast steel no? Going to have to put the ball in first, I guess. No special rod? Maybe add an extra strap around the outside.

 

What's the numbers on the head?

 

I’ve heard that those lite weight Sb chevy heads were prone to cracking in that area but never seen it first hand.
It should be easy enough to find another good replacement


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Funny you would say that , a number of years ago I stopped at an old friends wrecking yard only to find him pitching SBC heads off a shelf , out the door , into a loader bucket . When I asked him wtf , he said he had a request for a set of SBC heads , he'd spent 4 hours sandblasting candidates & magnafluxing them , I counted 22 PAIRS of heads in the bucket , Budd said he couldn't find 1 , let alone 2 , so he gave up . He was a hot headed SOB & a true blue Ford guy !