Measuring pistons?
 

I have sets of used pistons that look very good but would like to confirm how to measure them.

I think I should mike the piston 90 degrees to the pin and bottom of the piston? Very bottom or just below the pin?

Seems that the top the piston has always been smaller than the bottom.

Thanks for helping me learn.

Fourdy

Re: Measuring pistons?
 

Top AND bottom parallel to the pin AND ninety degrees from the pin.

Re: Measuring pistons?
 

The measurement perpendicular to the pin and about 1/2" above the bottom of the skirt is what is used to determine the bore size for proper clearance. Another very important measure is the width of the ring grooves to be sure they are not too worn.

Re: Measuring pistons?
 

Flathead Jack is right, The skirt tappered about .002 up. I used to get semmy pistons and grind them any size I needed. Walt

Re: Measuring pistons?
 

Along with measuring, clean the grooves completely with solvent and a stiff bristle brush. Look at the sides of the grooves closely with a magnifying glass or loupe. If you see a step worn in the groove it won't seat new rings.

Lonnie