Operation CHARM: Car repair manuals for everyone.

Compression Check: Testing and Inspection

Compression pressure, checking

- engine oil temperature minimum 30°C (86°F)
- throttle plate completely open
- ignition coil lead removed from ignition distributor and connected to ground
- check compression pressure using pressure recorder US 1120
- follow operating instructions for recorder
- operate starter until recorder unit indicates no further pressure increase

Compression pressure values bar (psi)
New Wear limit
8-12 (116-174) 6 (87)

- permissible difference between all four cylinders: 3 bar (43.5 psi)