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compression test results

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Old Feb 28, 2012 | 06:31 PM
  #1  
rotermotor's Avatar
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From: dallas
Arrow compression test results

87 rx7 with 200k on it

just got it as a gift so..... i checked the compression today and it bumped even 3 times on both housings 60 psi, 95 over all. Is it time for a new motor? I see ppl saying that it has to be over 85, is that the bumps or over all?


thanks
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Old Feb 29, 2012 | 10:29 PM
  #2  
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From: Smiths Falls.(near Ottawa!.Mapquest IT!)
tell "us" how you are performing this Compression test.
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Old Mar 1, 2012 | 02:23 AM
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From: GMR
hmm not bad for a motor with 200k.

i say 95 psi is average for a motor with 130-150k well atleast the owns that ive owned.
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Old Mar 1, 2012 | 01:00 PM
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From: dallas
i used the top plugs with the motor hot. the 60 psi was with the valve out. 95psi was with it in.jumped to 60psi even each time the motor was cranked.
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Old Mar 1, 2012 | 11:56 PM
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removing the schrader valve when using a piston engine compression tester is how it's done. it's the only way to get a true reading for each rotor face. 60psi is too low. it MIGHT start cold but hot starts will be impossible.
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Old Mar 2, 2012 | 10:29 PM
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"Total compression" is a meaningless number. You really just need to remove the schraeder valve, and watch the pulses. Spec is > 85 psi, but ideally you want to at least be in the 90s.

This is the best compression test writeup I've found. I think I put it in the FAQ too.
http://www.banzai-racing.com/compression_test.htm
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Old Mar 2, 2012 | 11:20 PM
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From: Spokane
So what do you do if you have bad compression in a rotary?
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Old Mar 2, 2012 | 11:27 PM
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From: GMR
wait for it to blow then rebuild
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