8BA Crack in Block - Repairable?

4

49r

Senior Member
I looked at an 8BA block for sale today and wonder if its particular crack is repairable. I didn't have my camera so I'm sorry I can't post any photos.

The crack is in the number 6 exhaust port. The crack extends about 3/4 inch directly below the inside of the seat insert down the inside of the port. The exhaust seat insert itself is not cracked.There is evidence of pitting inside the port, suggesting water from the jacket has been getting in when the motor was operational. All other ports are smooth and rust free, as is the rest of the block. The block came from a running motor that when pulled was smothered in grease to preserve it. I understand that this owner had no reason to believe the block was faulty.

The first 8BA I owned lost an exhaust valve seat due to a crack from the outside edge of the valve to the cylinder which I understand is repairable - I've not seen a crack extending from the inside edge into the port. Any advice appreciated!
 
I've had similar cracks repaired. Depends on whether the length of the crack can be reached for drilling and pinning. I'd say it's easier/better than one going to the cylinder wall.
 
I've stitch quite a few down the port. As long as the crack don't go down the port so far you cain't drill and tap a hole to screw the plug in. You usually have to have a longer drill bit than a std. one. Walt
 
Yes it can be fixed. The crack is most likely under the seat as well. You must pull it out and check. As long as a drill can reach it, it can be fixed.
 
i have heard that many cracks can be filled with jb weld and it holds up very well. would like walt's and ford flatheads opinion on jb weld repairs. i have used it on aluminum heads before with excellent results---so far anyway. a machinist/mechanic friend says he has repaired many diesel blocks with jb weld with good results too. any opinions on this?
 
I think there is two schools of thought.
Is it repairable /Is it cost effective.

Its one thing if you already own the block it is entirely another if you are going to buy a block with a known problem.

So with out seeing Pictures of the crack ( I know I have problems posting Pic's also )
The only question that is being answered is if a crack can be fixed.
The answer is yes Cracks can be fixed can the one in Question be we are all guessing.

Unless it is cheap do as Charlie said "JUST WALK ON BY"There are good blocks out there.
 
Well, we've more or less determined that crack can be fixed - good. Now, was this block mag'd to find out if there are any others? With one known crack and if it has yet to be mag'd, I would not give more than $50 for it or just walk on by as Charlie says .... there are plenty more blocks out there, even in your neck of the woods, I'm sure ...
 
f1builder said:
i have heard that many cracks can be filled with jb weld and it holds up very well. would like walt's and ford flatheads opinion on jb weld repairs. i have used it on aluminum heads before with excellent results---so far anyway. a machinist/mechanic friend says he has repaired many diesel blocks with jb weld with good results too. any opinions on this?
Click to expand...
We're talking repairs in combustion chambers and exhaust ports so in my opinion an epoxy like JB Weld is not an option.
 
49 er,
Check elwoods latest post down the line a ways.
I know goodies a scarce in your hemisphere. I would look up Grahame
Raper in Victoria ( I think ), he is Mr. Flathead down under and might have a good
block. Grahame is a credit to the hobby !
Charlie ny
 
I had the block was magnafluxed. It appears clean apart from the crack mentioned and three stud to water-jacket hole cracks which, I understand from previous posts, aren't worth worrying about. The three threads which these cracks run from look good so I assume they will take head bolt torque - or are there other issues and should they be repaired?
Thanks Charlie NY - yes, usable 8BA blocks are hard to come by down this way.
 
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