Epoxy For Blocks

[BILL-C]

For repairs like what you have described, i use lock-n-stitch crack repair pins. No extra epoxy or sealer should be required. On extremely difficult repairs where there are small areas that can't be stitched, i pack problem area with 3M panel bond on both interior and exterior surfaces. Panel bond is designed to glue automotive body panels together instead of welding. Awesome stuff!.

This crack is a very unusual place.It is right where the outside of the block meets the inside of the casting.
If you imagine when the block is casted the junction where the bottom of the inside of the water jacket meets the lower part of the bore but right at the outside of the casting area.

Its far enough to the outboard side of the water jacket that stitching it would be possible but the potential for drilling
through to the outside of the block.

The use of hard block or something similar was my 1st thought but the issue with distorting the bore even with a part fill makes me nervous as there is a ton of time into the block and the fact that I am on my 2nd set of custom pistons to try and save this block just sickens me to have to start over.
While the block sonic tests very good ( .285 on both thrusts ) so I am convinced its worth trying to save before I invest all the time in redoing lifter bores again as well as all the rest of the effort to copy what was a screwed up previous attempt from an other shop in a past life now that the bore is at 4.105" so no shelf pistons can be used without reducing the bore size and still needing a custom piston anyway.
And while they are very hard to find a numbers block for this car its going in I find myself trying to find a way to save it.
The good part is its not a daily driver but it will get beat up good when its taken out of the barn for a run.

But you mentioned panel bond. Is that thin to apply?? I have never used it before and since this is close to a frost plug if I could pump in a pile of it in the area of concern it could be spread over the spot in question.
The only concern is whether it can deal with the water temp and I am guessing it will flex some since its used to bond body panels together.

The sale of speciality body shop materials is regulated to a degree that if you want to use the stuff the shops use the acquisition of these kind of materials must be accompanied by using the correct " BODY GUY LINGO" or they just won't sell it to you and I would be forced to deal with the dipshits at the local auto parts store which leads to the issue of the counter guy reading a brochure not knowing what its properties are and then sell you the wrong stuff.

That said if you had a brand name and specific purpose you have used I would be willing to try it

Thanks again guys for your input

The adhesive is 3M 08116 and application gun (looks like a double barrel caulking gun) is # 08571. you will still need to buy some applicator mixing tips, but store clerc should be able to handle that. This stuff is expensive, but much better than JB weld.

[ProPower engines]

Here is what i used on a 409 block with cracked water jackets. I welded it with muggy weld and put AB epoxy over it. Let it set up and pressure tested the block on both sides for over 30 minutes at 40psi. No leaks, so I am happy with the repair.

What AB epoxy did you use??

[turbo camino]

WTH is Muggy?

If it's good enough to be a big hit with the Youtube clickbait-for-money crowd, it's good enough for me!

[n2omike]

I repaired a cast iron 289 head that cracked in the intake port. I drilled a hole between the intake and exhaust valve spring seats, repaired the crack through the hole with JB Weld, tapped the hole and inserted a pipe plug. Clearanced the plug for the valve springs, and ran the head for at least a decade afterward with zero issue.

If you can repair the crack from the water jacket side, it stands a VERY good chance of being successful, as the water pressure will be forcing the repair into the crack, not out of it. Just be sure to get the surface clean, clean, clean... and it should work just fine.

Good Luck!

[lc-gtr-1969]

First, I have no first hand experience with sealing a cracked block, I have tried other parts like heads etc and epoxy has not been a long term solution- crack theory indicates that the crack will continue to split and spread unless holes are drilled and intercepted at both crack ends.

I would be pin and stitching it, in my mind this is the only way to repair it for anything vaguely long term. Perhaps hard block it as well for general safe keeping as well. Just my thoughts of course. With heat and expansion, the crack will likely open up and spread or risk further compromising with the block, epoxy may not stop it in my opinion.

[Krooser]

Here is what i used on a 409 block with cracked water jackets. I welded it with muggy weld and put AB epoxy over it. Let it set up and pressure tested the block on both sides for over 30 minutes at 40psi. No leaks, so I am happy with the repair.

WTH is Muggy?

A brand of cast iron welding rods.

[racear2865]

I was installing hardened seats in a 1967 Corvette 435 HP tri power head and broke thru to water. Drilled a hole right below header port and installed 2 part epoxy for instally new style composite bumpers. Attach vacuum pump with 20 inches vacuum and left over night. It pulled sealant into water hole and hasnt leaked a drop. Came back and installed pipe plug in the hole and ground down and dresses with JB Weld and primered and could never tell I touched the head

reed

[1980RS]

Here is what i used on a 409 block with cracked water jackets. I welded it with muggy weld and put AB epoxy over it. Let it set up and pressure tested the block on both sides for over 30 minutes at 40psi. No leaks, so I am happy with the repair.

What AB epoxy did you use??

Not the Moroso stuff as it bad out of the package. I use the AB epoxy from Amazon works great.

[1980RS]

Here is what i used on a 409 block with cracked water jackets. I welded it with muggy weld and put AB epoxy over it. Let it set up and pressure tested the block on both sides for over 30 minutes at 40psi. No leaks, so I am happy with the repair.

WTH is Muggy?

It's a arc welding rod that is for cast iron welding. I have had very good luck with it. Look it up on line, plenty of videos on their site.

[motormonkey]

I have done cast welding with my tig. I buy the arc rod and remove the flux. It isn't cheap but it's cheaper than a loss sometimes. It's a process but not voodoo as its been made out to be.

[gn69z28]

I had a diesel mechanic tell me about something called Belzona this morning. He says Caterpillar uses it to fill in pitts on older blocks they rebuild. I don't know if that's true and I don't know if that would work in this situation. I've never used it but reading the website info it sounds like something I will try in the future.

[Krooser]

Belzona has some fans here on ST...