I have a 59AB block where the largest cylinder diameter measured 3.273" using an inside mic. I would like to bore it to 3.3125". I figure thats about a .017" depth of cut in order to leave enough to hone and deglaze to the final bore. In your experiences is there enough stock to achieve an accurate bore? Hopefully I don't have to look for another block, Thanks! Joe
59AB blocks can take a 3/8" overbore, lots of old rodders did it. Some heating issues, not recommended for street use, but the iron is there. Yours should be safe at the bore you want.
Have it decked first. You maybe looking for a different block after that anyway. I have been through a whole mess of blocks trying to find one I can bore. have a bunch that will work for sleeving but nothing I can bore for my 3.375 pistons.
I was thinking the 3.3125" bore just to leave some room if it ever needs to be freshened up again.... and then there is that caveat that is in the back of my mind from McNicholls How to Build a Ford Flathead book where he warns about thin walls, core shift and sonic testing a block thats been treated to a 3.375 bore" . The reason I asked about the depth of cut or lack there of is because I was unsure what the machines are like that bore these blocks out (i.e. accuracy in setup, rigidity, cutting tool type, concentricity, taper). My thought was that with so little wall to spare compounded by the length, the existing bore might be tough to tackle. I'm not afraid of the cylinder wall to coolant jacket thickness that remains but rather can an engine boring rig handle such a light depth of cut. At work our mill/turns can take .001 to .002 D.O.C finish p*** with no tool deflection or chatter and leave perfect surface finish, .017 is a roughing cut LOL! Irondoctor, Any other details about problems you encountered? Thanks everyone, hope this makes sense, Joe
Friend of mine rebuilds motors.I asked him about that one time.He told me block sits on main bearing bores and boring head has some kinda probes that center it up on existing bore.That was on the machine they have I would talk to whos doing it and ask them how they do it.I would also tell them to start with that cyl so if it dont clean up they dont waste there time/your money on the rest of the cyls.Then you will have to decide if you wanna go 3.375.I think you will be fine at 3.312.
If you brought me your block I would measure your pistons and bore the block .003 smaller than the desired running clearence. I then would hone the cylinders to size with three progressively finer grits of stones. You stated that you would like to bore from 3.273 out to 3.3125. That would be .0395 which would be .003 smaller for honing then .0365 would be the material cut. A very easy task>>>>.
Re: "59AB blocks can take a 3/8" overbore" I'm confused. A 3/8" overbore is 3-9/16" (3.5625"). I can't find any reference to being done at all, let along successfully. Did you mean "overbore to 3/8"?
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