Product Details

9CL-40281 - Gasoline Cylinder Compression Tester (9 pcs)

  • Model:9CL-40281

    Product Introduction

    •  Test compression pressure on gasoline engines.
    •  Includes 5 spark plug adapters.
    •  Angled aluminum test bar for V-shape engines.
    •  Gauge reading: 0-300 psi.
    •  M16 spark plug adapter for Ford F-150 and Triton.
    •  Stock Ref. No. 9CL-41028-22


    1.  Start engine for approximately 10 minutes or until engine reaches normal working temperature.
    2.  Turn off the engine. Disconnect first cylinder spark plug wire and mark cylinder number on the wire.
    3.  Remove spark plug and place it into a clean surface. Check spark plug conditions. Change a new one if necessary. Clean spark plug hole.
       Note: spark plug conditions may also serve as an indication to the cylinder condition and compression pressure.
    4.  Disconnect the central high tension (HT) lead on the distributor and connect it to ground. On electronic ignition system, remove electronic ignition device or ignition coil. On GM high energy ignition (HEI) system, disconnect the main wire on distributor cap.


    Method A

    1.  Choose a suitable adapter and connect the adapter to a rubber test hose.
    2.  Screw the adapter and rubber test hose onto the spark plug hole.

    Method B

    1.  Choose a suitable aluminum test tube.
    2.  Install the aluminum test tube on the spark plug hole.
       Note: when using the aluminum test tube (angled or straight), one hand must hold and press against the test tube on the spark plug hole at all time.
    3.  Connect the gauge onto the rubber test hose or aluminum tube.
    4.  Start the engine to run at least 4 compression strokes or until the pressure gauge reading remains at a fixed level.
    5.  Record the pressure reading.
    6.  Press pressure release button before disconnecting from the cylinder.
    7.  Install the spark plug and wire back to the cylinder.
    8.  Test other cylinders one by one, and compare the test results.


    1.  The pressure should become higher after each compression stroke then up to maximum under normal conditions. The pressure of each cylinder in the same engine should follow the standards set by   the auto manufacturer.
    2.  If the pressure does not become higher after several compression strokes, then the valves could be clogged.
    3.  The highest pressure and the lowest pressure should not be more than 20 psi or 15%.
    4.  If the pressure is much higher than the standard set by the manufacturer, then there could be carbon deposits.
    5.  If the pressure in one cylinder is significantly lower than other cylinders, put a teaspoon of SAE30 engine oil into the cylinder.
      •  If the pressure increases much, piston rings could be worn out the cylinder head is not appropriately installed.
      •  If the pressure remains the same, the valves could be worn out or out of adjustment.
    30 x 20.6 x 6.7cm/set
    42 x 36 x 31cm/carton