compression test v8

J

Joop

Member
Hello,
These measurements i made. The car is a rover 3500S with 10,5 :1 motor

2 cyl 10 bar 1 almost 11 bar
4 ,, 10,5 3 ,, 9 bar
6 ,, 9 5 10 bar
8 ,, 9 7 8,5 bar


Secund measurement with 20W-50 oil for cylinder 3 results 9,7 bar and cylinder 7 results 8,5 bar

Conditoins: engine not cold, outside temperature 20 degree Celsius, throttle down.

Is there too much blow by gas ? Or maybe piston?
 
Here is the correction. Is here a problem with pistonrings? Or is this acceptable?

2 cyl 10 bar 1 cylinder almost 11 bar
4 ,, 10,5 bar 3 ,, 9 bar
6 ,, 9 bar 5 ,, 10 bar
8 ,, 9 7 ,, 8,5 bar
 
Bars don't mean anything to me other than 1 bar is about 14psi IIRC and if that's the case you have a large difference between the highest and lowest readings (about 35psi) which is not a good thing. Do the test again with some oil down the bores to see if the readings improve, if so it is ring related. Convert all the readings to psi and I can be more specific.
 
If I recall from my days on the bench, the aim is to have less than 5% split between highest and lowest.
The actual pressures are not that important, because ambient conditions, state of your battery and the
technique in doing the test will have an effect on the recorded pressure per cylinder.
 
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