59AB sonic test. Good or bad?
 

Hello. I just ran a sonic test on a 59AB block.
Here are the numbers. I don't know if they are good or bad.
If anyone with experience in these matters could cast an eye over the numbers that would be great. I have listed the theoretical numbers if the bore were taken .125" over. Do these look ok? Thinnest sections are marked in orange.

Thanks in advance. Mart.

https://www.fordbarn.com/forum/attac...3&d=1639943164

Re: 59AB sonic test. Good or bad?
 

Check this thread-----


https://www.fordbarn.com/forum/showt...7043&showall=1

Re: 59AB sonic test. Good or bad?
 

Depends on how much it needs to be bored. My machinist insists on a minimum of .100 wall thickness left after boring. Others may have different values. Also what are you doing with the motor. If you were putting a blower on it, you would probably want a little more meat there. These values have worked well for me as I have 5 early Fords with engines bored by this man that are all drivers, the oldest (my avatar) has been on the road since 2000.

Re: 59AB sonic test. Good or bad?
 

Mart not much to worry about the block bored .125 over will handle at least 8 pounds of boost with out any trouble.
Ronnieroadster

Re: 59AB sonic test. Good or bad?
 

Mart, I'd done a few blocks in the past with less meat remaining than you are looking at. I'd never had an issue.

Re: 59AB sonic test. Good or bad?
 

I also agree that .100 walls are ok and you will safe at .120.

Although sonic testing was not available in the 50's & '60's I think a lot of guy's got away with ~.090. I know the most common over bore was 3.375 back then. I had a '48 Merc bored 3/16 and most of the hot FH's were 3/8 x 3/8 (3.375 x 4.125).

As a hot rodder and a mechanic, in those days, I don't remember split cylinder walls.

Re: 59AB sonic test. Good or bad?
 

I agree it looks fine. If you want to, you can shift the boring bar a bit to the thicker side...the offset won't hurt a thing.

Re: 59AB sonic test. Good or bad?
 

The only risk is if there are pebbled spots of corrosion that might break through. This is the stuff that is hard to see. Keep your fingers crossed. A of folks get lucky on these old Fords.

Re: 59AB sonic test. Good or bad?
 

You should be just fine - I've tested quite a few blocks and if you have .120 you're more than good to go. Back in the full-on race days, there were guys that went all the way down to .080 or so. That is way too low for me in that the cylinder walls tend to want to do "the hullah dance" - making it hard for rings to seat and stay seated. Also, when you get under .100, there is much more of a chance of splitting a cylinder wall.

As noted by RotorWrench, the problems you can't see is if there is a rust pocket/pit or a casting flaw - so being a bit conservative is not a bad thing.

Re: 59AB sonic test. Good or bad?
 

Gents: If one were considering "moving" bores about, what are the "rules"?
Do you move odd ones as necessary, or move them all in the same direction?

Max offset up and down? .010? .020?
Max offset side to side? .010? .020?

Any guidance gratefully received.
I'm just scoping out a .1875" overbore instead of a .125".

Mart.

Re: 59AB sonic test. Good or bad?
 

If you're going to be moving cylinders around a bit, also think about the THRUST sides of the cylinder - which is opposite on the Driver's side versus the passenger's side. On the Driver's side the major thrust side is the inner cylinder wall (intake side), while on the Passenger's side it is the outer cylinder wall (exhaust side). If one is moving the bore of the cylinder around, usually you want the most thickness on the major thrust side.

Just some more mumbo-jumbo to ponder! Best of luck.

Re: 59AB sonic test. Good or bad?
 

Yes,,,,,like B&S said ,
Major thrust direction,,and minor thrust direction,,,,,matters .
Either way,,,,,I believe you should be fine,,,,unless you encounter porosity .

Tommy

Re: 59AB sonic test. Good or bad?
 

Mart, when we bore blocks we move the bores as-needed...no set pattern. Usual maximum is .020" offset, .010" and less being more common.