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Compression test!

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Old Jun 21, 2016 | 10:17 AM
  #1  
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Default Compression test!

Hey, was getting oil thru my inter cooler thought at first it might be turbo removed all looks to be ok. Was advised to do a compression Check which I done last night.
Tho not sure if the results are good or bad.

Piston 1 was 139psi
Piston 3 was 130psi
Piston 2 was 128psi
Piston 4 was 140psi

Which gives 12psi from worst to best would these results be something to worry about?

Next step is to fit a catch can but reluctant to incase it's hiding something more serious.

Any advise appreciated thanks.
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Old Jun 21, 2016 | 10:35 AM
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I'm not sure what the acceptable pressures and differences are for these engines but others I've worked on I've seen acceptable differences of up to 14psi in the workshop manuals. I'm sure the more knowledgable folk will be along soon to give you a better idea.
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Old Jun 21, 2016 | 01:38 PM
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Its normal to have a small amount of oil in the intercooler if you dont have a catch can fitted.

The breathers feed back into the intake and contain oil vapour.
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Old Jun 21, 2016 | 05:27 PM
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Originally Posted by piehole1983
I'm not sure what the acceptable pressures and differences are for these engines but others I've worked on I've seen acceptable differences of up to 14psi in the workshop manuals. I'm sure the more knowledgable folk will be along soon to give you a better idea.
Thanks i would just like to know what the tolerances are could the 128 be bad rings?

Originally Posted by Davros 1979
Its normal to have a small amount of oil in the intercooler if you dont have a catch can fitted.

The breathers feed back into the intake and contain oil vapour.
Dude it was a lot of oil that was going thru the intake so much so that it was coming out the dump valve and running down the bulk head.
Thanks
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Old Jun 22, 2016 | 07:41 AM
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I'm honestly not sure what would be acceptable at all. You seem to have very similar low readings on two cylinders. It may be something more sinister as you say. Maybe have a search through other threads about oil consumption and compression and see what they say. I had read a couple of threads recently where cracked pistons were to blame.
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Old Jun 22, 2016 | 11:37 AM
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anything below 120 is low 150 good, was the engine warm or cold when you did the test. is the oil level correct.
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Old Jun 22, 2016 | 02:39 PM
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Originally Posted by 4u2nv2
anything below 120 is low 150 good, was the engine warm or cold when you did the test. is the oil level correct.
Stone cold will do a warm test later and I think the oil might be a little low at a guess I would say not much below the second hole.

Thanks
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Old Jun 22, 2016 | 03:09 PM
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You really need to do it at operating temp mate with the throttle wide open too.
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Old Jun 22, 2016 | 03:56 PM
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Originally Posted by piehole1983
You really need to do it at operating temp mate with the throttle wide open too.
Done the throttle open looks like I'm going to have burny arms tonight
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