The Ford Barn - View Single Post - Piston and cylinder clearance / measurement???

Jim Brierley · 01-24-2021, 01:22 PM

Johnneilson has explained it correctly. I bore the block to .003" oversize and hone another .0005". (.0035" total) Always have the new pistons in hand before boring the block, to be certain of the clearances. If you are going to run the engine hard, give them .004". Not necessary to allow for more clearance at the rear of the block, however it is a good idea to clean the water jackets to get rid of 90 years worth of rust. You can turn the block upside-down on an engine stand and use a piece of speedometer cable or wire rope to mechanically loosen all the crud and let gravity remove it from the block.

01-24-2021, 01:22 PM	#10
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,089	Re: Piston and cylinder clearance / measurement??? Johnneilson has explained it correctly. I bore the block to .003" oversize and hone another .0005". (.0035" total) Always have the new pistons in hand before boring the block, to be certain of the clearances. If you are going to run the engine hard, give them .004". Not necessary to allow for more clearance at the rear of the block, however it is a good idea to clean the water jackets to get rid of 90 years worth of rust. You can turn the block upside-down on an engine stand and use a piece of speedometer cable or wire rope to mechanically loosen all the crud and let gravity remove it from the block.