Inside a rigid plastic case is an eight-piece kit to let you test the compression on almost any kind of gasoline engine you can think of. The 2.5-inch gauge is marked with three scales—0 to 300 ...

If there are longitudinal and transverse gauges on the same side (front, say), then they should be at R1, R4 to sense compression. 4 gauge example: See the crude diagram below: With reference to the ...