Engine Compression
Check engine compression with engine at normal operating temperature at specified cranking speed, all spark plugs removed and throttle wide open.
CAUTION:
Release fuel system pressure before checking engine compression.
COMPRESSION SPECIFICATIONS
| Application | Specification | |||
|---|---|---|---|---|
| Compression Ratio | ||||
| 4.0L Non-Supercharged | 10.0:1 | |||
| 4.0L Supercharged | 8.5:1 | |||
| 6.0L | 11.0:1 | |||
| Compression Pressure (1) | ||||
| 4.0L | 157-167 psi (11.0-11.7 kg/cm2 ) | |||
| 6.0L | 194-232 psi (13.6-16.3 kg/cm2 ) | |||
| Maximum Variation Between Cylinders | ||||
| 4.0L | 10 psi (.70 kg/cm2 ) | |||
| 6.0L | 20 psi (1.40 kg/cm2 ) | |||
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