Epoxy For Blocks

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Epoxy For Blocks

Post by ProPower engines »

hey guys
I have a Mopar block that has a crack that opened up after on the dyno. Its on the very bottom of the water jacket.
Closer to the outer side of the block under the pan rail. This is a numbers block and has way too much time in it to
scrap.
I am looking for real life experiences with a 2 part type epoxy to seal the leak that can be poured into a clean block
then pressurize to force it into the leak area.

It needs to have about a 15 minute working time so I can get a head torqued on again before adding pressure to the
cooling system side that's affected.
It also needs to be fluid enough to flow freely into the small crack.
I am going to put stitch pins in it as well to stop it from getting longer but feel a fluid epoxy will help seal in.

Any and all suggestions welcome :D

Thanks for your thought

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Re: Epoxy For Blocks

Post by PackardV8 »

ProPower engines wrote: Sun Oct 18, 2020 5:13 pmI am going to put stitch pins in it as well to stop it from getting longer but feel a fluid epoxy will help seal in. Any and all suggestions welcome. Thanks for your thoughts. Dave
Hi, Dave, no experience with epoxy, but we stitch up diesel blocks with success and without epoxy. After stitching, let water stand in it for a couple of days and even seepage will seal itself. BTDT
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Re: Epoxy For Blocks

Post by fordified »

ProPower engines wrote: Sun Oct 18, 2020 5:13 pm hey guys
I have a Mopar block that has a crack that opened up after on the dyno. Its on the very bottom of the water jacket.
Closer to the outer side of the block under the pan rail. This is a numbers block and has way too much time in it to
scrap.
I am looking for real life experiences with a 2 part type epoxy to seal the leak that can be poured into a clean block
then pressurize to force it into the leak area.

It needs to have about a 15 minute working time so I can get a head torqued on again before adding pressure to the
cooling system side that's affected.
It also needs to be fluid enough to flow freely into the small crack.
I am going to put stitch pins in it as well to stop it from getting longer but feel a fluid epoxy will help seal in.

Any and all suggestions welcome :D

Thanks for your thought

Dave
A lot of superstock guys have thin cylinder heads that seep water. A friend of mine uses those sealing tablets from goodson every time he empties the water. I've used the moroso sealer in the past.

If you drill the crack and stitch or weld the block to keep the crack from growing you can epoxy the outside for good measure. If you can remove a freeze plug and get in the jacket then you can press some of it into the crack on the inside.

If it still leaks then use the stop leak.
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Re: Epoxy For Blocks

Post by BOOT »

What if you pulled a vacuum on it, flipped it on it's side and then used green loctite? Could still epoxy inside after. Wire-wheel the crack off good n maybe grind a very slight ditch along the crack for the loctite to sit in?
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Re: Epoxy For Blocks

Post by af2 »

PackardV8 wrote: Sun Oct 18, 2020 5:54 pm
ProPower engines wrote: Sun Oct 18, 2020 5:13 pmI am going to put stitch pins in it as well to stop it from getting longer but feel a fluid epoxy will help seal in. Any and all suggestions welcome. Thanks for your thoughts. Dave
Hi, Dave, no experience with epoxy, but we stitch up diesel blocks with success and without epoxy. After stitching, let water stand in it for a couple of days and even seepage will seal itself. BTDT
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Re: Epoxy For Blocks

Post by 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!.
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Re: Epoxy For Blocks

Post by 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.
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Re: Epoxy For Blocks

Post by af2 »

1980RS wrote: Sun Oct 18, 2020 9:39 pm 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.
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Re: Epoxy For Blocks

Post by af2 »

BILL-C wrote: Sun Oct 18, 2020 8:27 pm 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!.
I think that Jack was talking about and also what I and others have done with 100% success
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Re: Epoxy For Blocks

Post by rebelrouser »

My experience with 440 mopar blocks that develop cracks after running them hard is, they are just about ready to blow the side out of the cylinder. been there seen that. If you have it apart trying to seal it up, take a close look at the block between the cam journal and the no. 2 main as well.
BUT if you want to try, you can take JB weld, mix it together, add a little acetone to thin it, then pour it in the block and it will flow like syrup and harden as usual.
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Re: Epoxy For Blocks

Post by ProPower engines »

BILL-C wrote: Sun Oct 18, 2020 8:27 pm 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 [-o<

Thanks again guys for your input
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Re: Epoxy For Blocks

Post by mag2555 »

I would like to ask the OP of this how much peak HP the motor was making on the dyno and what was the rpm the motor is needed to spin to?

If it's a deep skirt block like a 440 or 383 which are quit strong then a crack taking place where it has is to me is screaming for the need of full 8 counter weight Crank to ease those bulk head and main web loads or atleast a real good balance job done at 1.5" from the Crank center line and not the grocery store type 3" balance job!
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Re: Epoxy For Blocks

Post by BILL-C »

Ice usually breaks blocks at corners where the block casting tries to contain the expansion of the ice and fails. Panel bond is slightly runnier than JB weld.
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Re: Epoxy For Blocks

Post by rebelrouser »

ProPower engines wrote: Sun Oct 18, 2020 11:33 pm
BILL-C wrote: Sun Oct 18, 2020 8:27 pm 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 [-o<

Thanks again guys for your input
Try a test patch before you use it. But the JB weld and acetone sounds like it would work well to do what you want. Last year I had an aluminum block repaired and I poured some thinned JB weld on the inside of the water jacket just as assurance there would be no seeps from the welded areas. It takes a little longer to dry, but it hardens just like regular JB weld.
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Re: Epoxy For Blocks

Post by 1972ho »

What if you just hard bloc the water jacket a couple of inches would that just cover the whole crack and no water will get to it.
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