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Good compression,bad leak test. Sitting, cold, dry motor.

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Old Sep 25, 2012 | 07:42 AM
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Default Good compression,bad leak test. Sitting, cold, dry motor.

215psi x 4 compression. Correct for a h23a VTEC blue top. Altough some say it should be higher...

Leak % :

#1 : 10%
#2 : 65%
#3 : 8%
#4 : 50%

TDC was spot on and the t belt hasn't jumped.

Leak is from exhaust valves. Air comes out of the exhaust port.

There is no detectable leak from oil cap or dipstick.

Should I remove the head and have it cheked...? Or should I just drop the motor in, start it and clean it...the fact that it's cold, dry and been sitting, and that there is carbon deposit could make the test read that way ?

Your opinions would be appreciated.
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Old Sep 25, 2012 | 07:49 AM
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Default Re: Good compression,bad leak test. Sitting, cold, dry motor.

set the valve lash and check again its rare that lash clearances tighten up but I have seen it and if it gets tight it will hold the valves slightly open. Also when performing this test you rotated the engine to TDC of each cylinder before/on (depending on how you look at it) its powerstroke right? otherwise the test is void.
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Old Sep 25, 2012 | 07:53 AM
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Default Re: Good compression,bad leak test. Sitting, cold, dry motor.

I will measure/adjust valve lash right now.

I am unsure which stroke is the powerstroke, but i'll check the leak at TDC, then do 360 degree spin to check it again !

Brb.
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Old Sep 25, 2012 | 08:06 AM
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Default Re: Good compression,bad leak test. Sitting, cold, dry motor.

To properly do a leak down test you need to test each cylinder at its TDC point at the top of the compression/beginning of the power stroke. In other words the way you set valve lash and you have to rotate the engine to each cylinder and adjust at those points are where you leakdown test from does that make sense?
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Old Sep 25, 2012 | 08:38 AM
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Default Re: Good compression,bad leak test. Sitting, cold, dry motor.

Yes. The test was made correctly, at each TDC for each cylinder.

Valve lash is in spec.
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Old Sep 25, 2012 | 09:11 AM
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Default Re: Good compression,bad leak test. Sitting, cold, dry motor.

Well in that case if it was my engine I would pull the engine and inspect the head. Sucks but Id rather be sure that everything is functioning correctly before install.
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