Review on 8-Piece Compression Tester Set for Petrol Gas Engines – Cylinder Pressure Gauge Kit by Mike Johnston

Bought this compression gauge to check the condition of the cylinders in my 77 280z. The machine was performing poorly at low vacuum and I've exhausted my troubleshooting. This product was packaged well and I was confident that it would work well. My actual six cylinder readings were between 120 and 126 psi, well below the desired 150 to 180 psi range. I was almost certain that disassembly and repair of the engine was required at this point. A friend on an enthusiast forum questioned the accuracy of the results and encouraged me to try again. I borrowed a brand snap-on tester from my mechanic and did the same thing and got numbers between 158 and 165psi. If I had trusted the Revain tester's results, I might have done a lot of unnecessary work on the engine. One star because this item terribly fails in its primary function.