Cracked block repair failure

Skeezixx

Skeezixx

Senior Member
I bought a 31 Coupe abandoned project expressly for the rebuilt (in 1986) engine sitting on the stand with zero miles which I installed in my roadster.

I managed to put 511 miles on it when, on a recent tour, an old JB Weld crack repair failed revealing a 4" long crack in the outside water jacket.

I took it to a local industrial machine shop where they welded the crack but the weld wound up with tiny hairline cracks in it. I spread some J B Weld over the length of the weld but don't have a lot of faith in this. Should I also use some sort of engine block sealer.

Or am I looking for another block?

Any suggections?
 

Attachments

  • IMG_1839.jpg
    IMG_1839.jpg
    51.3 KB · Views: 510
Since you know, or think you know, that you have good internals...I'd try the liquid glass treatment. If it doesnt work you arent any worse off than you are right now.Good Luck:)
 
I agree with Rex in post #2 . At this point you've got nothing to lose. I've used water glass with good success, the used car dealers have secretly used it for years. The important thing with any type block sealer is to first flush the cooling system with a good cleaner and follow label instructions to the letter. I have also used ceramic block sealer . Snyders lists a ceramic sealer on page A-215 part # M-6006 price $11.65 . I would first use their Thoro-flush part #8006 . I haven't used Snyders ceramic sealer but used Moroso ceramic sealer in one of my model A engines over 20 years ago and its still working .
 
Skeezixx, I'm very sorry to hear about your troubles. I hope that anyone else who may be reading about your misadventures will consider metalstitching for repair of a cracked iron casting. I hope one of the above repairs will get you through. Good Luck!
 
Last edited:
Herm is right about trying to weld a cold block. Many years ago I tried to weld a 2 cylinder John Deere head, and it only spread the crack.

To weld the block it would have to be very hot from a large oven and cooled slowly. I saw one done at Steven's Point, WI. and you couldn't even tell it had been welded.
 
Like Purdy says...nothing to lose.

I have used the Irontite products from Snyder's and they work well.

At this point, I would thoroughly clean the cracked area of paint and oil for the following two step seal...
1) Use the Irontite cleaner and sealant...follow the directions. The leak should seep coolant at first and then as the Irontite works its magic, it will stop seeping. You will need to run the engine to heat activate the sealant.
2) Re-clean the cracked area beyond the repair area and apply a coating of slow set JB Weld over and beyond the repair area. Let it set up overnight and then file and sand the repaired area to blend the repair edges to the cast iron. Apply paint and the repair should blend in and not be noticeable. Slow set holds much better than JB-Kwik.
I agree with the comments about Metal Stitching...but to make the best of where you are the fore-mentioned is a solution.
Good Luck!

Good Day!
 
Tom Wesenberg said:
Herm is right about trying to weld a cold block. Many years ago I tried to weld a 2 cylinder John Deere head, and it only spread the crack.

To weld the block it would have to be very hot from a large oven and cooled slowly. I saw one done at Steven's Point, WI. and you couldn't even tell it had been welded.
Click to expand...

Hey Tom,
If it 'can't be done on a cast A/B block, does that also apply to a cast iron head :confused:. I few months ago, I took a cast 5:1 Snyder head over to a 'head repair shop'. They welded up TWO cracks in water jacket on head face, recut head and it looked fine. After reading Herms/your remarks, not so sure it will remain fine now ?
 
hardtimes said:
Hey Tom,
If it 'can't be done on a cast A/B block, does that also apply to a cast iron head :confused:. I few months ago, I took a cast 5:1 Snyder head over to a 'head repair shop'. They welded up TWO cracks in water jacket on head face, recut head and it looked fine. After reading Herms/your remarks, not so sure it will remain fine now ?
Click to expand...

I don't know, but about 25 years ago I overhauled an older large Case diesel with 2 cracked heads. The owner said he will find the heads to install, and he came with two heads welded in the rocker arm area. I told him I wouldn't use those heads and didn't trust the welds. He told me to use them, so I did. A week later I had to do the whole job over because the cracked heads leaked antifreeze and took out the bearings.
 
I don't know what welding techniques you are all using. But 50 years ago when I was working on the bench repairing large electric motors, most of which had cast iron endplates, we used gas torches and bronze welding rods to repair cracks. I think borax was used as a flux.

The theory was that the lower heat reduced the risk of further cracking. Also it took a lot less skill than using real welding.
 
ian Simpson said:
I don't know what welding techniques you are all using. But 50 years ago when I was working on the bench repairing large electric motors, most of which had cast iron endplates, we used gas torches and bronze welding rods to repair cracks. I think borax was used as a flux.

The theory was that the lower heat reduced the risk of further cracking. Also it took a lot less skill than using real welding.
Click to expand...

Otherwise known as brazing or "spelter-welding." A process which is a lot more forgiving both in its application - and in the possibilities for problems afterwards.

Brass is inherently more ductle than cast iron. Not to say that it is any less strong. A good cast iron has yield strength in the 32KSI range, and a good brazing rod is similar, if not a little stronger (you can braze a much more homogenous weld than the virgin cast structure it might be done upon.)

As to welding a head cold, I have attempted that with totally unsuccessful results. Even using nuclear qualified Eutectic brand cast iron weld rod at $125 a pound. Had I given it more thought, and a lot of MAPP gas, I might have done better with braze.

That head was replaced with a standard head in good condition bought at Amherst, NH Antique Auto Flea Market for $10 (OK $25 including $5 parking and $10 gas to get there and back.)

Sometimes you just have to go the easy route...

Joe K
 
ian Simpson said:
I don't know what welding techniques you are all using. But 50 years ago when I was working on the bench repairing large electric motors, most of which had cast iron endplates, we used gas torches and bronze welding rods to repair cracks. I think borax was used as a flux.

The theory was that the lower heat reduced the risk of further cracking. Also it took a lot less skill than using real welding.
Click to expand...

I know exactly what you are talking about. We call it brazing when done with an acetylene torch . Years ago you could buy flux in a can for brazing, still can. If you ran out of flux, borax worked just as well. we would heat the end of the brass rod and stick it in the flux or borax and braze. brass rods were later available that were already coated with white flux at a higher price. Flux is only needed when brazing dirty or rusted cast iron or steel. when I found this out I would grind and V out the spot clean that I needed to braze and used no flux. Brazing is only a bond, you heat the desired area red hot and puddle the brass in the area that you need to bond together. There is no penetration of the metals but you can get a strong bond that is as strong or stronger than ever with cast iron. The main problem with brazing engine water jackets is that both sides need to be clean. Oil or grease residue will rise up through the crack in water jacket repairs that will cause fish eye like spots that the brass won't fill even when flux is used. When flux is used it will cause spots that will continue to rise around the brazed spots that will cause JB weld or other such filler material to fail and turn loose, same with paint, even after the brass and flux is ground smooth. There is a method used with arc welders where a ni rod or nickle rod is used and this usually cracks or never seems to hold up on water jacket repairs. I have successfully brazed chunks broken off around the wdges of model A heads where they had been broken off by prising with a screwdriver in attempts to remove a stuck head . If both sides are clean I have veed the edges of the crack, heated only the desired area red and brazed the broken piece back in place using no flux. This type repair has worked good for me . For small water jacket cracks in model A blocks, I have never had a problem using JB weld or other two part epoxy on properly cleaned areas.

Just to add... When ever I brazed broken cast pieces back together I would place the brazed part in a box of sand and cover it well so that it didn't cool too quickly, this is important for a sucessful repair.
 
Last edited:
Here in Indiana they use material that bowling balls are made of, to seal the crackes. It is used on High Performance engines and seal they crakes.
 
Tom Wesenberg said:
Herm is right about trying to weld a cold block. Many years ago I tried to weld a 2 cylinder John Deere head, and it only spread the crack.

To weld the block it would have to be very hot from a large oven and cooled slowly. I saw one done at Steven's Point, WI. and you couldn't even tell it had been welded.
Click to expand...

They now sale mig wire that you can use without heating the block [but it cost ]
 
welding cast iron is a fool's errand,
unless you are one of the very few specialized shops that can heat the entire block up to a very high temp and cool verrry slowly
 
Where I work, they weld cast iron everyday. I ask the one welder what they use and he said they use nickel mig wire and crank the amps way up (high heat). They also don't pre-heat.
 
Dave in MN said:
Like Purdy says...nothing to lose.

I have used the Irontite products from Snyder's and they work well.

At this point, I would thoroughly clean the cracked area of paint and oil for the following two step seal...
1) Use the Irontite cleaner and sealant...follow the directions. The leak should seep coolant at first and then as the Irontite works its magic, it will stop seeping. You will need to run the engine to heat activate the sealant.
2) Re-clean the cracked area beyond the repair area and apply a coating of slow set JB Weld over and beyond the repair area. Let it set up overnight and then file and sand the repaired area to blend the repair edges to the cast iron. Apply paint and the repair should blend in and not be noticeable. Slow set holds much better than JB-Kwik.
I agree with the comments about Metal Stitching...but to make the best of where you are the fore-mentioned is a solution.
Good Luck!

Good Day!
Click to expand...

So far this sounds like a good plan.
 
The Kwikset JB weld is good, its less likely to sag but does not have the "stick" and is not as hard as the regular JB weld. They both have their place.
 
I have a friend who welded a Catepillar head by heating it to 1400 deg. F in an oven for a while. Then he welded it with 6010 wire. It Held! 6010 wire has a very violent arc and will clean a lot of carbon out of the weld. Any welding of a head/manifold has to contend with massive carbon build up from running at a high temp in a carbon rich atmosphere. This carbon prevents the weld from getting a good grip on the parent metal and they almost invariably fail.
Terry
 
You must log in or register to reply here.
Back
Top