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JSeery · 04-30-2017, 05:40 PM

I don't know the specs off the top of my head, but there are several things to consider. Taper, how egg shaped/out of round the bore is, ridge at top of the cylinder, etc. Ridge must be removed or there is a good chance of breaking the top ring.

Per Repair Manual, Ford, Mercury & Truck, V8 Engines, 1937 to 1947, Ford Motor Company, July 7, 1947:

Ware limits

Bore out of round - .003 max
Bore taper - .006 max
Bore ware - .006 max
Piston to bore - .005 thickness gauge 1/2 wide 6 to 10 lbs pull

04-30-2017, 05:40 PM	#2
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: 239 bore. I don't know the specs off the top of my head, but there are several things to consider. Taper, how egg shaped/out of round the bore is, ridge at top of the cylinder, etc. Ridge must be removed or there is a good chance of breaking the top ring. Per Repair Manual, Ford, Mercury & Truck, V8 Engines, 1937 to 1947, Ford Motor Company, July 7, 1947: Ware limits Bore out of round - .003 max Bore taper - .006 max Bore ware - .006 max Piston to bore - .005 thickness gauge 1/2 wide 6 to 10 lbs pull Last edited by JSeery; 04-30-2017 at 07:04 PM.