Re: Compression ratio... (EbraketurnGTI)
Firstly a thicker headgasket lowers compression as you are adding volume to the combustion chamber by making it taller. This is comon on turbo conversions where replacing the pistons is an expense someone may not want to incure.
Secondly, a head gasket has no effect on stoke what so ever. That can only be changed by altering the crankshaft stroke therefore allowing the pistons to move further up and down in the block. Conversely the stoke could be reduced in the same manner.
Changing the lenght of the rod will also not change the stroke. It will however either raise or lower any given piston in the cylinder and it will also change the rod ratio which is the ratio between the length of the rod and the stroke of the crank.
Thirdly compession ratio is a function of the volume that the piston displaces in it's range from the top of the stroke to the bottom of the stroke(swept volume) plus the combustion chamber volume, divided by the combustion chamber volume and
expressed as a ratio. So 10:1 would mean the pistons displaced volume plus combustion chamber volume is 10 times the size of the combustion chamber when the piston is at TDC.
[Modified by A1Rocco, 11:30 PM 2-13-2002]
[Modified by A1Rocco, 11:31 PM 2-13-2002]