Reliant compression readings ?

[kapri]

What sort of readings should I expect from a compression test on an 850cc?

[Olds]

Can't find a figure quoted but I would hope for 160-170 with less than 10 per cent difference between cylinders.
Might be worthwhile asking Fifer.

[terry t]

flying pasty, in misfire thread had 10.5/10.8 app 150psi on he's. so any thing from 130 up should be ok. it will still run

[kapri]

i thought it would be about 150-160 based on compression ratio ...only 110 on 3 with the best of 125 on the remaining cylinder

[terry t]

i thought it would be about 150-160 based on compression ratio ...only 110 on 3 with the best of 125 on the remaining cylinder

Kev these readings may get better after  it been run for a while.

[kapri]

It's running Ok but intermittent blue smoke, sometimes a cloud sometimes nothing , on hard acceleration?

[fifer]

Stick a spoonful of oil in each cylinder .
If the compression goes up it is the rings at fault if not it is valve seat related .

If it is an old engine which has been unused for a good few years and was last used with leaded fuel and the head has not been lifted , then there is a good chance of carbon build up and sticky valves .

Many years ago I had an engine with 220,000 miles on it .
I had never lifted the head and it used to pink like mad and often kept on running after I switched the ignition off .  
Sold the car and the new owner ran it for a further 2 years . #
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If it is running ok I would leave well alone .
These engines are very forgiving .
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