Compression test on the se2

[GreyDJ]

I'd be spinning the engine with all the plugs out.

Given that it is measuring the pressure in the cylinder with the valves closed not in the inlet tract, why would the throttle position make any difference?

Were the tests run dry or with oil in the cylinders?

[Callyman]

The throttle being open (only reason i can think of) is so when the piston drops and inlet valve is open the chamber will get the max amount of air possible (therefore better compression the more air you get) if the throttle is open.

Just a thought.

[GreyDJ]

OK.

I have always run the test with it closed but as the conditions are the same for all cylinders a comparative test between them should be valid.

[GreyDJ]

Yes, I suppose with everything cold the air going in is much denser than in a running engine with hot inlet tract.

[Fraz]

I'd be spinning the engine with all the plugs out.

Given that it is measuring the pressure in the cylinder with the valves closed not in the inlet tract, why would the throttle position make any difference?

Were the tests run dry or with oil in the cylinders?

you would do a wet test after getting a low reading

[GreyDJ]

Out of curiosity I do both tests if I get more than about 5% difference, it doesn't take very long and I use Redex not oil on a cat'd engine. I would certainly do both with those figures, you would normally expect one to be low, not high.