the dreaded crack

[marty in Ohio]

Well, guys, we need your advise. In rebuilding a '29 engine everything was going along well until we stripped off the putrid yellow paint and found the dreaded crack in the block. There are actually two cracks, about five inches long on each side on the water inlet pipe. They're up high in the water jacket.
What's the best thing to do? Weld the cracks? Use J B Weld? Look for another block?
Marty

[jhowes]

Save the block. I had a similar problem and ground a V in the crack (be careful, you can go right through a block. How do I know?) Then I filled the V crack with marine grade epoxy. You can find it on line. Jack

[BRENT in 10-uh-C]

Originally Posted by marty in Ohio

Well, guys, we need your advise. In rebuilding a '29 engine everything was going along well until we stripped off the putrid yellow paint and found the dreaded crack in the block. There are actually two cracks, about five inches long on each side on the water inlet pipe. They're up high in the water jacket.
What's the best thing to do? Weld the cracks? Use J B Weld? Look for another block?
Marty

The best thing to do is to stitch the crack closed with cast tapered pins. Most quality engine machine shops will have this capability. The second best option for you would be to have the block welded using a low temp product such as Muggy Weld. Both of these are considered a permanent repair. The third best thing IMO would to consider using an epoxy as suggested above. The reason I do not suggest the epoxy being the best is due to the dissimilar rates of expansion between the metal and the epoxy. Given enough time, the two will no longer be bonded together, and then Murphey's Law will take over.

[100IH]

Have it inspected and repaired by someone familiar with Model A blocks. You found 2 cracks, suppose that all of the work is dine and then they tell you they found another? Not easy to fix cracks in the ports, they are thin walled. In the end, the best scenario is to find someone who has a pressure testing bench setup. The best final inspection.

[CWPASADENA]

As Brent has suggested, I have used tapered pins with very good success.


Chris W.

[Pete]

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There are 2 possibilities for a good fix.

1- Stitching.
2- Tig welding with ER70 rod.

Either will have to be done by someone familiar with the process.
TIG welding is better but very hard to find someone familiar with the process.
Get a pressure test guarantee.

[marty in Ohio]

Thanks for your responses, guys. We have decided to go with the weld. Seems more permanent and after some research on-line we feel we have the ability to do the job right. Thanks again.
Marty

[BRENT in 10-uh-C]

Originally Posted by marty in Ohio

Thanks for your responses, guys. We have decided to go with the weld. Seems more permanent and after some research on-line we feel we have the ability to do the job right. Thanks again.
Marty

What rod are you going to use?


A little trick to help on the welding process is to be able to find a way (oven, old BBQ pit, old barrel etc.) that you can preheat it with charcoal briquettes. Once up to temps, do your welding and then return it to the preheat area and cover it up and let the briquettes burn out. Cooling this way allows the temps to decrease slowly. Just as a safety, check the oil drain tubes from the valve chamber to the main webs to make sure they are not compromised due to the heat. If so, use an old horn rod to repair the damaged one.

[J and M Machine]

Originally Posted by marty in Ohio

Thanks for your responses, guys. We have decided to go with the weld. Seems more permanent and after some research on-line we feel we have the ability to do the job right. Thanks again.
Marty

I hope the welder has experience in welding old cast iron or else you'll have to search for another block. The metal is thin in those areas and we've seen many experts blow through them.
We do the crack repairs using metal stitching leaving a seamless permanent crack repair.
The radius area is a common crack prone location for Model A engines which we see all the time.
http://www.jandm-machine.com/metalStitching.html

[BillCNC]

The area of this break is the one reason I'm not so convinced that the engine stand mounting adapter for the "A" is the best nor safest way to hold a populated block.

Regards
Bill

[Purdy Swoft]

Whether a person chooses welding or epoxy to repair the cracks it is important to drill a small hole in the ends of the crack to keep the crack from running farther .

[Mikeinnj]

Originally Posted by BillCNC

The area of this break is the one reason I'm not so convinced that the engine stand mounting adapter for the "A" is the best nor safest way to hold a populated block.

Regards
Bill

Good point. I have the same concerns.

[Ed in Maine]

I had a crack similar to the one shown here. I was in high school and didn't know any better and was on a paper route budget. I ground a small "V-notch" in the crack. I didn't drill any holes in the end of the crack. Nobody told me to do that! I cleaned the V-notch with a wire wheel and then metal prep, and cleaned with solvent. Then I used a mixture of finely cut fiber glass mixed with the resin-expoxy & pressed it into the crack with a putty knife. Then, I sanded it back with fine sand paper and painted the block. I drove that Model A over 10,000 miles and never gave it another thought. If it becomes and problem in a few years, just repeat the above and move on! Good luck, Ed