Honing leaves a cross-hatch pattern on the cylinder walls, which
ensure proper compression for the pistons that will eventually pass
through.Because the tolerance or space between the piston and cylinder wall
must remain at the factory specification, larger (or oversize) pistons
were employed to fill the space gained by boring out the cylinders.
Fortunately, pistons for this engine come in a standard bore, .020 and
.030 over, so Herman was able to match the new cylinder size with the
proper .030 pistons.
Before boring each cylinder wall, Herman measured the diameter of
the new pistons’ skirts to determine their diameter. He then compared
the width of each piston skirt to the size he calculated the cylinder wall
would be after boring and honing to ensure the factory tolerance of .002
inches between the piston and cylinder wall would remain.
To bore each the cylinder wall, a floor-mounted boring bar was placed
through the exact center of each cylinder and locked in position with
three locating pins while the engine rested in a boring machine. A
cutting tool with a carbide insert was then run through the cylinder wall,
removing .010 inches of cylinder wall with each pass, stopping just short