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Dome Vol= -25.70 (Calculated piston dome popup volume CC,
negative number indicates dished piston)
Compression Ratio, by Pouring Combustion Chamber.
This program will calculate the compression ratio of an assembled engine by pouring the cylinder
full of light oil or alcohol through the spark plug hole. It assumes that the piston is at top dead
center and the head gasket is installed.
Press ALT, ENGINE FORMULAS, then C/R Menu, then select Pour Chamber to start this
program.
Display Example:
==Pour Chamber==
Bore? 4.250 (Enter cylinder bore diameter inches)
Stroke? 3.750 (Enter crankshaft stroke inches)
Boost? 0.000 (Enter max manifold pressure PSI gage)
Deck Hgt? 0.000 (Enter 0 for this line)
Gskt Vol? 0.001 (Enter 0.001 for this line)
Pour Vol? 87.4 (Enter poured volume measured CC)
Ratio= 10.97 :1 (Calculated engine compression ratio)
Compression Ratio, Find Piston Dome Volume by Pouring.
Use this program to calculate the piston dome volume for a piston when the popup size is not
known. Install the piston, with rings, in the bore at a measured distance below the deck of the
block. Next, attach a flat clear plastic plate over the cylinder. The plate should have 1 or 2 holes
over the bore to fill the area above the piston with light oil or alcohol. Then measure the exact
volume of fluid required to fill the entire void. The program will also work with available
compression ratio tools that have an area above the piston notched for dome clearance. The tool
will have a volume number marked on it to indicate the notched area volume. Provide this
information to the computer to calculate the dome volume.
Press ALT, ENGINE FORMULAS, then C/R Menu, then select Pour Dome to start this program.
Display Example:
== Pour Dome ==
Bore? 4.250 (Enter cylinder bore diameter inches)
Deck Hgt? 0.400 (Enter measured piston flat to block deck inches)
Plate Vol? 0.000 (Enter 0 for flat plate or marked volume CC for tool)
Pour Vol? 86.700 (Enter poured volume measured CC)
Dome Vol= 6.3 (Calculated piston dome volume CC)
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