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.

Contents:
1. Run engine long enough to bring crankcase oil to normal
operating temperature.

2. Stop engine and remove all spark plugs and their gaskets.

3. Block choke and throttle valve in "open" position.

4. On standard ignition; remove high tension cable from distributor cap and ground it. On HEI; remove three terminal connectors and battery connector.

5. Select the correct size threaded adapter.

6. Screw adapter into the spark plug hole.

7. Crank the engine four compressions to obtain maximum reading. Make a note of the pressure in each cylinder.

8. 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.