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Compression Test Results. Are These Acceptable ?
https://www.ausmini.com/forums/viewtopic.php?f=2&t=18649
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Author:  Maxi23 [ Sun Apr 30, 2006 3:20 pm ]
Post subject:  Compression Test Results. Are These Acceptable ?

Ran a compression test this arvo on the engine in the green machine.

Hadnt done one yet cause i didnt want to see anything nasty...

3 & 4 both got 125-130 (Cylinders furthest from thermostat)
1 & 2 both got 100-110 (Cylinders closest to thermostat)

[Engine was tested while cold, will test hot once it has rego]

Would it be safe to assume that the head gasket may be weak in between cylinder 1 & 2 ? Or are those numbers fairly reasonable for an engine which has 60,000k on it ?



If I have the cash left over after rego I may get a mechanic to whip the head off and replace the gasket and generally tell me what condition its in. [Yeah, I could do it myself but Im slightly over taking minis apart at the moment]

Author:  poeee [ Sun Apr 30, 2006 3:36 pm ]
Post subject: 

The difference bettwen the 4 cyls isn't abnormal. The readings are a bit low though. Was this a dry or wet test, meaning did you squirt some oil down the plug hole?

Author:  Maxi23 [ Sun Apr 30, 2006 3:45 pm ]
Post subject: 

Test was dry.

Is it ideal to squirt oil in ?

Author:  poeee [ Sun Apr 30, 2006 4:26 pm ]
Post subject: 

Yep, squirt some oil down there and do another test. 8)

Author:  clubmn [ Sun Apr 30, 2006 4:58 pm ]
Post subject:  mini

Squirting oil down the bore, will not give the required outcome, unless your desired outcome is to make yourself fooled that the motor is a good one.

If you have low comp, on a particular cylinder, and you put oil in the plug hole, then the comp rises, it tells you that your rings are worn (the oil helps to seal the worn rings)

If the comp still doesn?t rise, or rose by just a fraction, then you can do another test where you put oil in the inlet ports, if the comp rises then you can blame the poorly seated valves, getting your head built will fix this problem.

Remember when doing a comp test, all the plugs should be removed, and the accelerator should be open. If you are running twin su's it may be best to take the su's off to get the best reading.

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