Mechanical Inspection: Compression

Check engine compression at normal operating temperature at specified cranking speed. Release fuel pressure. See FUEL SYSTEM . Disconnect coil wire at distributor. Remove all spark plugs. Depress accelerator pedal fully to hold throttle valve wide open. See the COMPRESSION SPECIFICATIONS table.

NOTE: If cylinder compression in one or more cylinders is low, repeat inspection using a small amount of oil poured into each cylinder. If compression pressure increases, piston rings may be worn or damaged. If compression pressure does not increase, a valve may be sticking or seating improperly. If compression in any 2 adjacent cylinders is low and does not change after oil is added, there is a leak past head gasket. Make repairs as needed and reinspect.

COMPRESSION SPECIFICATIONS ⁽¹⁾

Application

psi (kg/cm² )

Standard

178 (12.5)

Minimum

149 (10.5)

Maximum Variation Between Cylinders

14 (1.0)

⁽¹⁾	Readings taken at cranking speed (300 RPM).