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 1725 Compression test
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pruyter

Netherlands
199 Posts

Posted - 25 Aug 2017 :  09:41:54  Show Profile  Reply with Quote
With a completely new engine the compression pressure should be 175/185 lbs which translates in 12.3 to 13 kg/square cm.
The difference between the highest pressure and the lowest should be no more than about 10%. In your case the difference between cylinder 2 and 3 is 20 lbs which calculates for about 15% when we take 140 lbs as a basis to calculate from.
If you experience no specific problem I should do nothing with it.
If you are interested to know what could be the cause of your observations than the following procedure gives you more information:

Run the engine to operating temperature;
Take out all spark plugs;
Put a tea spoon of oil in a spark plug hole and measure again;
Proceed with a tea spoon of oil until you have measured all 4 cylinders.

When the compression pressure is higher than the measurement without the tea spoon of oil then the problem can be related to pistons and/or piston rings.
If the compression pressure remains the same then most problably the valves are the culprit.

Regards,

Peter
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Stella

France
127 Posts

Posted - 25 Aug 2017 :  09:23:04  Show Profile  Reply with Quote
Does anyone know the original compression for the cylinders. I did a compression test yesterday and found the following results:
cylinder 1: 152
cylinder 2: 140
cylinder 3: 160
cylinder 4: 150
I feel that this would be within the norm but am curious as to what they were originally.
Any help appreciated
Clive

Edited by - Stella on 25 Aug 2017 09:26:12
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