- Checks cylinder compression from 0 to 300 psi (0 to 21 kg/cm2).
- Adapters fit 14 and 18mm spark plug holes and a special air-hold valve is included to easily reset gauge. Has a 12" rubber hose.
- Run engine long enough to bring crankcase oil to normal operating temperature.
- Stop engine and remove all spark plugs and their gaskets.
- Block choke and throttle valve in "open" position.
- On standard ignition, remove high tension cable from distributor cap and ground it. On HEI, remove three terminal connectors and battery connector.
- Select the correct size threaded adapter.
- Screw adapter into the spark plug hole.
- Crank the engine four compressions to obtain maximum reading. Make a note of the pressure in each cylinder.
- To remove the gauge from spark plug hole, depress the valve below the dial, releasing the pressure. If compression readings vary more than 10% between cylinders further tests should be performed. See Manufacturer's Service Manual.