Mechanical Inspection: Compression
WARNING: This page is about a different car, the 1996 Jaguar XJS, 1996 Jaguar XJR, 1996 Jaguar XJ6, and 1996 Jaguar XJ12. However, it is still accessible from the selected car via links, so may be relevant.
Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions. Release fuel system pressure before checking engine compression. See FUEL SYSTEM .
COMPRESSION SPECIFICATIONS
| Application | Specification | ||||
|---|---|---|---|---|---|
| Compression Ratio | |||||
| 4.0L | |||||
| Base Engine | 10.0:1 | ||||
| Supercharged Engine | 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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