How do I measure my compression ratio? --98 Cobra

 

Compression ratio or engine compression?

 

compression ratio

 

Pull a head andmeasure the volume of the combustion chamber, and then the volume of the space above the piston at TDC, then add in the (thickness of the head gasket * pi() * the diameter of the hole in the gasket squared) / 4--do this all in cc's (cubic centimeters); call this Vtcc (total volume of the combustion chamber).[/align][/align]Then divide 575.1 (90.2² * pi() * 90 /4000 = the swept volume of one cylinder, call it Vswp) plusVtcc (the number from above), by Vtcc. [/align][/align]
The answer is the compression ratio...[/align][/align]I.e. CR (compression ratio) = (Vswp + Vtcc) / Vtcc[/align][/align]
Piece of cake...[/align][/align][/align]