block crack

Bill Pursel

Bill Pursel

Member
Well guys I got this engine for free to go in my pickup as a temp.engine till I get some funds for an insert engine. Well it is .020 overbore and no ridge and a great bottom end but a crack in the deck. Model A Medic say its junk I thought about heli coil the stud hole and run it. What you others think?
 

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In my opinion the block isn't junk. There are ways to repair block cracks. The two cracks don't look bad from what I can see in the picture you posted. There is a metal stitching method I think would work for you. A search on the internet will show you haw it is done. There are also liquid products that will seal small cracks like Irontite.

Rusty Nelson
 
Bill Pursel said:
Well guys I got this engine for free to go in my pickup as a temp.engine till I get some funds for an insert engine. Well it is .020 overbore and no ridge and a great bottom end but a crack in the deck. Model A Medic say its junk I thought about heli coil the stud hole and run it. What you others think?
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My shop would repair that crack using the stitching method followed by a sloshing it with a ceramic sealer, installing a Heli-coil in that one hole, and resurfacing the deck.


Since this is a temporary engine, you might want to try using it as-is and use some sodium silicate or high-powered crack sealer that parts stores sell for band-aiding cracked heads. The key to making this sealer work in your situation is to make sure the water jacket area is clean before introducing the sealer. Then plug the overflow tube where the system can build a slight amount of pressure to force the sealer into the crack once the engine is up to temps. This can be risky if you totally "cap" the system as it can build too much pressure, but being prudent in your method and leaving the cap slightly loose, you can be pretty effective. If it does not work, then you have not lost a lot other than time. To do the job correctly, it will need to be dismantled enough that the block can be stitched and then mounted & leveled in a surfacer.
 
Those cracks will not affect your engine. If the deck is flat, spray your new head gasket with a "copper coat" sealant, put your head on and go have fun in your Model A. I have run engines with more cracks than that. Just make sure you have no cracks in the valve seats.
 
I would put it together with the new head gasket and Healy coil lead stood fill it full of water glass and run the snot out of it but if you're that afraid of it I will pay for shipping


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if the deck surface is flat across the crack put it together, don't touch the stud, torque it last, if it is raised up it needs repair first
 
If you do this Brent's way, you can run this a long long time without looking back. This will save you the cost and time for an insert engine. I don't agree on the insert idea for an A but there are plenty of threads on that subject already. Jack
 
That crack goes all the way into the stud threads. I disagree with not fixing it. Yes the crack will not leak water in to the cylinders. But your stud will pull out some time. It will not hold the torque for long. But it is up to you.
 
I find when I rebuild engines and someone needs a core block, no one wants a repaired or sleeved block. This being my experience, the value of the block now and after repairing is not great when trying to sell it to someone else.

If this block was the only one I had to work with and it was for myself, I would not hesitate to repair it and run it. The repairs necessary to correctly cure the ills of this block are as Brent and George indicate. This block could give lots of years of service if properly repaired and then treated right...avoid overheating.

Since the value of the block is low to someone else, I think the block could give you enough life, until you can obtain the inserted engine you have your sights on, without doing anything. Put it together, install the head stud in the hole with the crack with Permatex Right-Stuff around the threads. Place a bit more Right-Stuff around the stud before you install the head gasket...just enough to seal the space between the stud, block and head gasket. Any excess sealant will climb up the stud hole in the head and further seal the area. This process, done properly, will stop the coolant from rising out around the head nut. I have successfully completed this seal for many customers not wanting to spend the money to stitch the area.

At this point, try it. You have next to nothing to lose.
Good Day!

www.durableperformance.net
 
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George Miller said:
That crack goes all the way into the stud threads. I disagree with not fixing it. Yes the crack will not leak water in to the cylinders. But your stud will pull out some time. It will not hold the torque for long. But it is up to you.
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What about the untold thousands of flathead V8's running around with similar cracks? They seem to hold up OK. They're so common some have said that Ford assigned them a part number!
 
40 Deluxe said:
What about the untold thousands of flathead V8's running around with similar cracks? They seem to hold up OK. They're so common some have said that Ford assigned them a part number!
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If that is what you think go for it. But with a cracked thread it will not hold long. But like I said do your own thing good luck
 
Mike V. Florida said:
So how many said fix it and how many said junk it?
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Don't think anyone said to "junk it", except for the "medic". Devalue it, yes, but never junk it.

I'm just not sure sealer would do much good, given it's totally internal to the engine. Where those cracks are, they may not go any further. I think I'd heli-coil that stud, install the head with copper coat and call it a day. After all, he is not planning to run it forever anyway.

Just what I'd do, and we all know if it's a forum reply, 90% of responders will disagree with anything one posts.
 
Again thanks all for the info. I am going to Helicoil the stud and seal it with Permotex and leave the cracks alone as they and the deck are flat. It had a Brumfield head on it which will not go back on, will use a stock head. We will see what happens.
 
Bill Pursel said:
Again thanks all for the info. I am going to Helicoil the stud and seal it with Permotex and leave the cracks alone as they and the deck are flat. It had a Brumfield head on it which will not go back on, will use a stock head. We will see what happens.
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Why get rid of the Brumfield head?? Seems like a giant step backward!
 
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