of attaining the desired cylinder diameter.
Before finally boring each of the eight cylinder walls to the desired
diameter, Herman stopped short to allow for the material that will be
removed in the next step of honing the cylinder walls. Honing leaves a
desirable cross-hatch pattern to the cylinder walls, and although it’s not
as abrasive as the boring process, honing still removes iron from the
cylinder walls (about .002-.003 inches). While honing the cylinder walls,
a constant stream of oil is poured through the cylinders to cool and
lubricate the honing tool as it scuffs the cylinder walls.
Removing too much material from the cylinder walls would result in
the need for even larger pistons, and only so much material can be
removed from the cylinder walls before their strength is compromised,
so Herman constantly checks the dimensions of the cylinder walls with a
dial bore gauge throughout the boring and honing process. In addition to
size, the gauge also measures taper (a variation in diameter from the top
to bottom of the cylinder wall) and roundness (an egg-shape to cylinders
with a larger diameter at the center of the cylinder compared to the top
and bottom). Neither taper or roundness should exist at the end of the
boring and honing process.
After the boring and honing process has left the cylinder walls at the
desired diameter and with a cross-hatch pattern, the engine is cleaned in
a caustic bath to rinse away any of the metal particles removed in the
process. If particles remain, they will damage the engine as they enter
the oil. This step also removes the oil used in lubricating the honing tool.
Before the engine is ready for the next step, Herman prefers to tap out
threads throughout the engine, then clean the engine with soap and
water. The engine block is then bagged in plastic in preparation for the
next step involving the block: assembly.
singke
(singke)
#1