Engine Compression
During compression test, engine must be at normal operating temperature, all spark plugs removed, and throttle valve must be in WOT position. See COMPRESSION SPECIFICATIONS table. Crank engine through 4 or more compression strokes.
COMPRESSION SPECIFICATIONS
| Application | Compression Ratio | |
|---|---|---|
| 4.5L | 9.0:1 | |
| 5.0L (VIN E) TBI | 9.3:1 | |
| 5.0L (VIN F) TPI | 9.0:1 | |
| 5.0L (VIN Y) 4-Bbl. | 8.0:1 | |
| 5.7L (VIN 7) TBI (Police) | 8.2:1 | |
| 5.7L (VIN 8) TPI F Body | 9.3:1 | |
| 5.7L (VIN 8) TPI Y Body | 9.5:1 | |
| Compression Pressure | ||
| 4.5L | 140-165 (9.8-11.6 kg/cm2 ) | |
| All Others (Min.) | 100 psi (7.0 kg/cm2 ) | |
| Maximum Variation Between Cylinders | 30% | |