Cracked Block

[Flathead]

Model A blocks are often cracked in that exact spot. I have several but they are not in service. I plan to have one brazed, seems like that should work and being out of the car it can be done upside down for better access and prep. In your case give it the best epoxy job you can and see what happens.

[BRENT in 10-uh-C]

Originally Posted by CT Jack

Cast iron cannot be welded so the best option of all would be to use the mechanical stitching technique. This method works well for most block cracks within the water jacket areas. We have used this method on many antique engines with good success. The final test of success is to pressurized the block for leaks. The stitching technique involves installing a series of small metal plugs along the crack line. The plugs are closely positioned to one another and individually threaded into the block which mechanically seals and locks the crack. This mechanical seal can withstand the thermal changes encountered during engine operation.

Throwing this out there. To begin with, there is a product called Muggy Weld that does allow cast iron to be welded. Second thought in this, ...if the casting has become thin due to rust (-or ???), it it has been my experiences that stitching plugs is not going to work well because there is not anything to stabilize the plug is the surrounding area is thin.



If the vehicle were in my shop, the first thing I would suggest is to remove the radiator. Next clean the area to bare metal and then do a sonic test to know what you are dealing with. At that time, you should also be able to isolate the hole. Pressurize the cooling system if need be by capping the inlet port with your hand, and use compressed air on the outlet port of the water pump. As silly as it may seem, maybe just thread a sheetmetal screw into the pinhole and then grind the head almost smooth with the block. Use some JB Weld or other epoxy to stabilize the entire area in front. Repaint the bare area and reassemble. Lenny, there are likely several ways to repair this, so don't panic.

[Lenny Bruce]

Phew I’m overwhelmed but going to weigh out all my options with all your input at hand!
Pulling the motor to try and fix it in my book would be more sensible to replace the block and know it’s not going to creat future issues. That being said it’s going to have to be a in the car
Attempt

[old ugly]

i did one similar to that with JB weld, cleaned it the best i could inner and out. i ground it out to give it tooth, washed it with gunwash (to make sure no oil or grease in the area) and dried it. i mushed it rite through the holes into the water jacket. two applications because it wanted to slump out. it has no leakage so far.
i think id try epoxy of whatever kind is recommended for that application. i used JB weld just because i have had good luck with it.

[nkaminar]

Brent, Look at the pictures Lenny shows. There are multiple holes and a crack. In my opinion, the best course is to weld it up using the Muggy rod you told me about, see post #9. There is a link there for the rod.

Lenny, I am really happy with my Burtz block. It may be cheaper and for sure better to go that route than weld it. Or you can go the epoxy route but you will have to address the issue again a few years down the road.

[Bob Bidonde]

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Lenny, keep the fix simple so the risk is low. Use J B Weld and follow the manufacturer's directions for its application. Make sure you push the J B Weld so it protrudes out of the backside of the holes. Do an extra thorough job of cleaning & de-greasing the sites. Keep a fresh tube of J B Weld with the spare parts in your car.

Many years ago I used J B Weld to repair a cracked rear main bearing cap and it is still working! I have also seen J B Weld water jacket cracks last for many years.

[Lenny Bruce]

I will go the JB weld route today. Hopeful it works for a while. If not a Burtz Block may be something to think about in the future especially if the JB doesn’t hold up. I don’t suspect it will be a long term fix but I’m willing to take the chance. I can’t afford a rebuild at this point so fingers crossed!

[jerrytocci]

I protected the radiator with cardboard, leaned a mirror against it and used a Dremel tool to prep the block. I used 2" clear tape to hold JB in place.

[Bob Bidonde]

Jerry, good suggestions, especially the tape.

[Fullraceflathead]

I think if done correctly you'll find the JB weld will last for years the cooling system is not pressurized on a model A.

[jeepguy1948]

I agree with Phil, nothing to lose. Worst case, you may have to re do it at some point although I don’t think so. If it doesn’t last you can look into other options. I would not in a million years dig into an otherwise good motor for what you have going on.

[Lenny Bruce]

Thanks fellas! I got it all cleaned up down to the bare metal. Cleaned the daylights out of it.
Got it all JB welded. Looks good! Fingers crossed!

[john charlton]

I have a JB Weld patch on the side of my Chandler AZ pickup block . I built this truck from parts 12 years ago and bought the engine complete with patch ( cheap) Not pretty but no leaks so go JB Weld !

John in continual wet weather (drat) Suffolk County England .

[Tim Ayers]

Originally Posted by stevests

Take a look into Belzona epoxy - expensive but supposedly endorsed by Caterpillar.

Edit: I didn't read the thread long enough to see you already fixed it.

This. For what you are doing, get Belzona 1212. It is designed to be used in environments that can't get surgically clean like your block installed in a the car.

I used it for a rot hole in the outside of the water jacket of a V8. It has worked great for 2 years now.

Nice thing about the 1212 is you can get it in a smaller size. Downside is, they don't sell direct so you many need to call them and get the name of the sales rep in your area. He then sells it to you.

[Dr Foot]

Cast iron can indeed be welded. I have been driving an epoxy repaired block for years with no leaks.

[old ugly]

i don't know if you did this but the cured JB weld can be sanded smooth to make it match the block. if you have a low spot ad some more and sand again once it has cured.

it will last a long time.

ou