I’m going to refer to a law of Physics known as Pascal’s Law.
Pascal’s principle, also called Pascal’s law, in fluid (gas or liquid) mechanics, statement that, in a fluid at rest in a closed container, a pressure change in one part is transmitted without loss to every portion of the fluid and to the walls of the container. The principle was first enunciated by the French scientist Blaise Pascal.
This explains why the length of the compression tester hose makes no difference. In this case, the source of compression is the piston compressing air within the combustion chamber.The hose is not part of the source of compression, but is part of the sealed system. The sealed system will pressurize to the maximum pressure generated by the source, no more, no less.
Because air is compressible, the only effect of the longer hose, which creates a larger sealed system, is that it will require more strokes of the piston to reach maximum pressure.
By adding two head gaskets, as fleetwin mentioned, you have changed the characteristics of source of the compression by increasing the volume of compressible air within the combustion chamber. This will lower the final compression readings, but only because the source has been altered. The hose itself is the recipient of the compression built up in the combustion chamber, and is not part of the source.
Another example in this hobby is the dual line pressure tanks. The crankcase generates a fixed amount of pressure, say 5 PSI, and this is the pressure source. Both four gallon and six gallon tanks will pressurize to that pressure. The only difference being that the six gallon will take a few more pulses of the crankcase to reach that pressure.
Improvise-Adapt-Overcome
