The compression gauge is used to check the ability of each cylinder to compress the air/fuel mixture for burning. It is an important tool for troubleshooting .it can tell the mechanic about a number of important internal engine parts and how they are working.
Using the gauge: to use a compression gauge to check engine cylinder compression, remove all the spark plugs insert the tip of the compression gauge into the spark plug hole.
Crank the engine over for a period of time to complete revolutions of the engine. Most good compression gauges equipped with a device that traps the air inside the gauge so that the highest reading obtained will stay on the face of the indicator ( by the use of a dual pointer) until you release it. Note the reading on the indicator (write it down), then go to another cylinder and repeat until you have checked all the cylinders.
CHECKING THE RESULTS: Because all engine are note identical, it is best to refer to the shop manual for the engine you are working on for correct readings. The gauge readings should be 10 pounds above or below the reading specified by the manufacturer .
Reading below the listed specifications indicate that the rings, valves or pistons require maintenance. you can further check this by squirting some medium-weight oil into each spark plug opening. Work the oil down into the rings by cranking the engine over for a few seconds, then repeat the checks with the compression gauge. If the reading come up normal, the problem is the rings, pistons or cylinder.
BLOWN HEAD GASKETS: A serious drop in pressure in one or more cylinders can mean several things, from broken rings to a hole burned in a piston, but the most likely cause is a blown head gasket. Another strong sign of a blown head gasket is tow side-by-side cylinders that show approximately the same low compression reading while other cylinders check as good. This indicates that the head gasket is blown (torn or broken) between the cylinders.
Caution: BE SURE TO DISCONNECT THE COIL HIGH-TENSION LEAD BEFORE CRANKING THE ENGINE.
Using the gauge: to use a compression gauge to check engine cylinder compression, remove all the spark plugs insert the tip of the compression gauge into the spark plug hole.
Crank the engine over for a period of time to complete revolutions of the engine. Most good compression gauges equipped with a device that traps the air inside the gauge so that the highest reading obtained will stay on the face of the indicator ( by the use of a dual pointer) until you release it. Note the reading on the indicator (write it down), then go to another cylinder and repeat until you have checked all the cylinders.
CHECKING THE RESULTS: Because all engine are note identical, it is best to refer to the shop manual for the engine you are working on for correct readings. The gauge readings should be 10 pounds above or below the reading specified by the manufacturer .
Reading below the listed specifications indicate that the rings, valves or pistons require maintenance. you can further check this by squirting some medium-weight oil into each spark plug opening. Work the oil down into the rings by cranking the engine over for a few seconds, then repeat the checks with the compression gauge. If the reading come up normal, the problem is the rings, pistons or cylinder.
BLOWN HEAD GASKETS: A serious drop in pressure in one or more cylinders can mean several things, from broken rings to a hole burned in a piston, but the most likely cause is a blown head gasket. Another strong sign of a blown head gasket is tow side-by-side cylinders that show approximately the same low compression reading while other cylinders check as good. This indicates that the head gasket is blown (torn or broken) between the cylinders.
Caution: BE SURE TO DISCONNECT THE COIL HIGH-TENSION LEAD BEFORE CRANKING THE ENGINE.
