Technical Flat Head Ford Crack

Found another Flat Head for a build as my block is toast! Will this crack be a problem? Should it be taken care of or can I run it as is?

 

You will need to do a pressure test on the block to see if it is in the water jackets. From the looks of it, it is. If that's the only crack, I 'm sure it can be pinned and fixed.

 

Take it to a good machinist and have it checked out. It would probably be cheaper to fix than replace, if possible. My 2 cents, not enough to buy a stick of gum these days.

Joe

 

You need to check that crack very carefully. That is a freeze crack and a bad freeze can distort the block .
You need to clean the block well and magnaflux it. These cracks can also extend into the center main bearing web and into the front. Personally, I would pass on this one. The pan rail is not very strong on these and being part of the water jacket it is usually the first place to crack if it freezes. Not the worst case I've seen. It could be repaired by a pro if it doesn't extend any farther. Also clean and and check for cracks around the valve seats. These engines cost a lot of money to build. Too much to have to do it over.

 

That sucks. Seems very common for them to crack there. People think they have drained the block of water, only to leave water in the bottom. My last project caused me pain, due to searching out and looking at six blocks, only to find five that were cracked at the pan rail like this, the sixth block was cracked at the deck. By this time, I was so disenchanted, I wasn't willing to take a chance with any of them and went with an altogether different engine.
Your block may be fixable but, for me, peace of mind wasn't going to happen knowing I had an inherently weak block that had been weld repaired.
Good luck!

 

I'll pass on it.

 

Had an early Merc motor with cracks in both pan rails. Thought about saving it for at least a half-a-second, ended up selling the crank and rods for more than I had in the motor.

 

Well Mart on here has weld a similar crack I believe, others have used JBweld, and Auliz has used cement to fill the bottom for a crack like that. The key is to make sure it doesn't extend into the inner part of the block and make sure you drill at both ends of the crack to stop it from progressing.
On the other hand ignore all this. However, for me this is a interesting problem as I have a good block with a short crack similar to yours and finding another block around here is not the easiest thing to do.