V8 60 block boring amounts?

[Oakhurst]

Still trying to rebuild a V8 60 for my 1933 Summerset Hydroplane, PODH class.
Talking to several engine builders, I have gotten conflicting opinions on what is the maximum they can be bored. More than one has said they have gone to .100. My builder does not want to go over .030. What is safe?

[flatheadmurre]

Why guess on a racebuild check the cylinder wall thickness with an ultrasonic meter.

[Oakhurst]

Yes, we are going to do that as many of the blocks I am finding show a lot of rust and we can't tell how much rust is on the inside. We are using sonar, but how thin can the walls be and still be safe?

[Kurt in NJ]

Ford sold Pistons to .060 then the tin sleeves back to std

[russcc]

The Midget racers typically were allowed .040 over. I had a set of pistons I sold that size. If you need them, I may be able to get you the new owner's #.

[Ol' Ron]

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I don't thing boring the 60 for a compression or power increase is worth the problems it might cause, The Hydro revs pretty high and the old Clay smith 284 cam would put them in the 7 grand area. Light pistons are the most importan item you can put in a 60 as this will reduce rod stretch at hi revs. The 258 I had in the Hydro would turn 5500 with an L-100. Alonger cam would have been better but the family jewels were mor important.

[flatheadmurre]

Originally Posted by Oakhurst

Yes, we are going to do that as many of the blocks I am finding show a lot of rust and we can't tell how much rust is on the inside. We are using sonar, but how thin can the walls be and still be safe?

If the coolant side is badly rusted thickness is only one problem, pinholes is next pain on the list.
Ultrasonic testing can show you enough meat in the walls but you end up with something looking like a sieve from the pinholes.
Just pick the best candidate and have a go at it.

[Kurt in NJ]

Originally Posted by Ol' Ron

I don't thing boring the 60 for a compression or power increase is worth the problems it might cause, The Hydro revs pretty high and the old Clay smith 284 cam would put them in the 7 grand area. Light pistons are the most importan item you can put in a 60 as this will reduce rod stretch at hi revs. The 258 I had in the Hydro would turn 5500 with an L-100. Alonger cam would have been better but the family jewels were mor important.

Ron, when I bought a load of NOS 60 parts from a retired hydro racer he said that with stock bottom end -- 7000rpm -2seasons before rebuilding, 7500 rpm 1/2 season --- this gave me the confidence to wind out the 39 with the 60, found best fuel economy was to downshift when the incline slowed the car to 45, and to run it at 70 on the parkway--- all Pistons and rods were within 1 gram plus- minus out of the Ford boxes, and the steel Pistons weighed less than the aluminum ones

[Gary in La.]

Over the years I have disassembled 4 V8-60 engines from racing boats. Two of them were bored to .100" over. There were many other mods to the engine and internals. On one of the blocks every crank web was cracked. From what I have learned over time is most V8-60 blocks that have never been sleeved are candidates for a large overbore depending on the amount of internal corrosion.

[Oakhurst]

Could not check the thread for a few days. Thanks very much. I have 3 engines now from All Ford in San Jose, CA. Starting to disassemble them now to pick one. I was told that only the 40 had the oil filler hole cast into the block. Is that correct?

[raybee]

No. The 40 is the only year without the oil hole in block. They had the oil fill hole in the intake. The best solution might be to bore .080 and install tin can sleeves taking it back to stock bore.