Both the car and m/c guys have tools that will measure the bore on center plug
heads. This is a finger type of deal that you put into the bore in collapsed
position. Then the fingers are spread to touch the cylinder walls, a stop is
set and the fingers are collapsed. After removal the fingers are spread to the
stop and measured. This method has proven to be very accurate in the hands of
someone like J D Tone. The stroke is measured by taking the piston to the
bottom of the stroke, setting a stop the running the piston to the top and
setting a second stop. You then measure between the stops to find the stroke.
This tool has shown to be ineffective in engines with multi valve heads such
as the Ford 5.0. The valve overlap causes interference with any tools that are
in the cylinder when moving the piston.
We still have the air pumps. These pumps are re-certified each year and are
very good when used correctly. The valves must remain closed on the cylinder
being measured. If you can do that we are able to get within a couple of cubic
inches of the actual displacement.
Harbor Freight, need I say more? A set of digital calipers, measure both
inches and metric. The calipers come in a case with an extra battery - $20.
I should have written this on the landracing website, has to be good for 50
points,
DW
"Certainly, there is great wisdom behind the rulebook's recommendation..." ron
07/14/05
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