How long should a cylinder stay compressed?

At TDC maximum compression with the engine off, how long should the air stay pressurized in a good running engine before escaping? I can hear the air coming out in about a second or so.

3 Answers

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  • Dan
    Lv 4
    5 months ago

    At TDC the compressed volume is very small and it won't hold pressure very long at all. The valves should seal almost perfectly - listen in the intake and exhaust to check, but it's impossible for the rings to seal completely. The time will depend on engine size and it's compression ratio, a second or so may be perfectly normal. Like a compression test I would think it's more important to worry about uniformity across all cylinders if you're using this as some kind of test.

  • Gabe
    Lv 6
    5 months ago

    A cylinder should stay compressed for approximately 1 minute 37 seconds

    • Dan
      Lv 4
      5 months agoReport

      Absolutely there is, and you're absolutely full of it.

  • 5 months ago

    about 20 minutes okay okay

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