Pistion / Bore Question

Douglas Walker

Registered User
I need some info for a sc motor rebuild.

"Stock style HP pistons"
I need to know what size pistons are avaliable besides the standard.
How they are measured in MM or Inches


Also how much extra bore clearance is recommended for a performance engine than a daily driver. Or would you just go with the spec that ford has.

Doug
 
I'm not sure who has the combustion chamber mock ups other than Wiseco. They make forged aluminum pistons, but they will cost you around $500.

Piston-to-wall clearance varies depending on the material of the piston used and the technology of the manufacturer. Wiseco and CP pistons use the lowest piston-to-wall clearances at around .004" as a high performance motor specification. The average piston-to-wall clearance is .007".

Other than that, Speed-Pro makes some hypereutectic pistons in sizes from .020"(50mm), .030"(75mm), or .040"(100mm) overbore.
 
the inventory of 20over pistons is no more. Ive talked to Napa and oreillys and they are discontinued and unavaliable. So thats interesting
 
Is the block already bored and honed? You can check www.rockauto.com maybe they have them.

If you haven't bored the block yet, you can use a .030" over piston with no problem.
 
#1 - have pistons in hand before doing anything with the block.

#2 - Follow the piston specs for clearance. There isn't any reason to open them up or shrink them.

#3 - check rockauto. Pistons are .50mm, .75mm and 1.00 mm oversize.

Federal Mogul still lists them in their online catalog.
 
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