I found a couple of 8ba blocks and had them both thermo cleaned and checked for cracks. 1 has a crack from the valve to a cylinder which has been sleeved. Junk ? The other is okay but will probably need new valve seats and probably 2 sleeves because 2 cylinders have pitted. Should I fix this one, or look for a good one. Kinda getting tired of looking, and taking things apart and hauling things around. What would you expect to pay for a good clean crack free block?
If the cracked one is a exhaust valve ,scrap as that would be a $$$ fix. How deep are the pits ,will a .120 over bore clean them up. Pistons for that size are readly available and you get a usuable displacement increase. Good block $300-400 UPPPPP!
Considering they can be bored 120 + over the pits probably arent an issue. Save the cracked one it will be worth fixing someday.
A lot of them will go 3/16" (.1875) over. Make sure you have it sonic checked. As I mentioned in a post a couple of weeks ago, Speedway seems to be liquidating their flathead pistons. They listed a set of 3 3/8 stock stroke pistons for less than $200. That's a lot of pit removal room. Back in the day, some guys were able to overbore a 3 3/8 engine .010 to re-ring it. I don't know if I would stand behind that.
A friend rebuilt one without having it sonic checked turns out it was core shifted. Blew out the side of the cylinder wall where it was only about 1/16 thick. Jim (55willys)
Sounds like mine: it's an 8BA that had been bored to 3 3/8 long ago. Broken rings dictated a cleanup-the machinist found +.030 pistons for 3 3/8 so bored the block .030 over. Two cylinders "found water" which meant I'd been running with approximately .015 of wall thickness. The holes were down low in the bore so probably never exposed to cylinder pressure. We sleeved the entire block (it already had 2 due to previous problems.). Never scrap a Flathead block unless the center main web is ready to fall out of it. Most things that can be seen on the top side can be repaired. Pinning, sleeving, and, as a last resort, welding, can save about anything.
Picked up the blocks the one with the pitted cylinders is pretty bad. I think it would be a better idea to sleeve them. Don't want to bore them, to risky. The other is cracked at least at 2 exhaust valve and a couple of intakes, but the cylinders are nice. They said it could be fixed, but would have to be shipped to the states and get welded there and pressure test. Costly!
Well my machinist is away this weekend racing. So I won't be able to get the block to him till next weekend. I'll keep you guys posted.
I had one that was 3 7/16 + .020 with .090 wall left. Since 1952 I have built or machined 10 flatheads with 3 7/16 bore. Of those 10 engines it took over 100 blocks to find 10 that would end up with .090 walls.
Good luck finding one that isn't cracked a bit somewhere. Can't remember the last one which was perfect. jack vines
Well took the block to the machinist. He's going to measure the bores and bore and sleeve most likely three cylinders, to the minium. New valve seats and the block should be good to go. Have another question. I have a mercury 4" crank, but not from this block. He said it might be a problem to use the crank, because the longer strock will hit the block, so he would have some grinding on the block to make it work. He suggested using a regular crank. The block I got the crank out of was a C 8BA block #and the block we're working on is also a C 8BA block#. Has anybody run across this problem before?
The crank will fit just fine with no machining, the mercury block is the same as the ford. Go with the mercury crank, ford and mercury use the same connecting rods.
I think you need another machinist. I have never heard of anyone having a problem putting a stock 4" Merc crank in an 8BA. If thsi guy is telling you this, run as fast as you can and find somebody else. Everything this guy has told you is now suspect.
Nah, I don't think so, the guys bin building engines for years. He's built for me to, very compitent builder with a list of references a mile long. Maybe its been awhile since he's done a flathead. Mostly builds engines for drag racing. Good guy.
Did your machinist want you to leave your 4 inch crank with him so he could dispose of it safely for you?? He may know a lot but you haven't led us to believe that.
No I have to get the crank magged and ground yet. I don't know maybe I got it wrong. Anyway glad it will work. Thanks for the input.
The Jalopy Journal
