Engine Compression

Check engine compression under the following conditions: engine at normal operating temperature and specified cranking speed, all spark plugs removed, and throttle wide open.

COMPRESSION SPECIFICATIONS

Application

Specification

Compression Ratio

4.9L (VIN B)

9.5:1

5.0L (VIN E & F)

9.3:1

5.7L (VIN 7)

9.8:1

5.7L (VIN 8)

10.25:1

Normal Compression Pressure

4.9L (VIN B)

140-165 psi (10-12 kg/cm² )

All Others

⁽¹⁾

Minimum Compression Pressure

⁽¹⁾

⁽¹⁾	The lowest compression reading should not be less than 70 percent of the highest compression reading. No cylinder compression reading should be less than 100 psi (7 kg/cm² ).