Daro wrote: Hi Kawboy, the spec is from the same table you posted, I converted (119~171 psi) to 8,2~11,7 bar and 14psi to 0,96 bar. Its still with in the usable range but I just thought 9 bar was rather on the low side, also the difference between two cylinder which in my case is almost 0,9 bar, its nothing dramatic thou, but still a slight concern.
the ideal compression
We have to keep in mind that this is a service spec. As the engine wears cylinders will wear at the top and piston rings will wear and the ring gaps get bigger. Valves will transfer material from the valve seats to the valves and also out the exhaust so the seal on the valves will be less.At the same time as all this happens, ash and carbon deposits will build up on the piston and cylinder head which will affect compression readings. So every engine manufacturer will come up with a service limit and allow the engine to run in a certain design criteria. If the compression falls outside of this window, you should probably do something. Too high a compression, and you take the chance of detonation. Too low compression and the wear rate will exceed exponentially.
You're differential pressure between cylinders can probably be explained away with different build up of carbon between the 2 cylinders and I wouldn't get too worried about it.