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  • cyl. leakdown test

    I'll start with the gauge. It wasn't possible to calibrate the gauge at less than 100 psi. The tech manual suggests 80 psi(optimum) for testing. So I had to test @ 20 psi over that setting. The gauge was about $40. I ordered it from eastwood. Next question...Is it normal to have to recalibrate the gauge before each reading? Also they say tighten the plug insert hand tight but there appears to be leakge. I didn't want to trash the o ring on the stem.
    Now the test...First dumb question...How do I know (without valve cover removed,) if I am on the compression or the exhaust stroke? I wasn't sure so I put the gauge on for both and got (uh, oh) basically the same readings. I could hear air coming from the oil fill, (valves?). When I plugged the oil fill I heard it from the carb (intake gasket?), and there was also air coming from the dipstick (rings?). This was only the number one cylinder. I didn't even bother with the rest. I assume (unless I'm doing something wrong) that I'm looking at a rebuild or crate engine? Is there a big price difference? I've never done a complete rebuild but may go that route if it will save substantial $$. I know this is a whole lot of questions. I'd appreciate any and all input.

  • #2
    First of all welcome to the board.

    Need some more info on the engine, symptoms, etc.


    • #3
      Thanks for the welcome.

      When I did the blowby test (plastic wrap over the oil fill hole) it mushroomed out instead of being sucked inward. There is also a cylinder misfiring (#4 if I remember right) which I can't trace to anything obvious. The (carter) carb is a pain in the butt and doesn't seem to hold adjustment. There is no air leaking around the mount that I can tell. The compression test (to my knowledge) was okay (125-135 across the board.) I've replaced all the vacuume hoses and can't detect a leak anywhere. Thanks for any input.


      • #4
        Do you have the PVC valve hooked up?


        • #5

          The pvc valve was in place when I did the test, however it was disconnected from the filter as the manual stated to remove the filter for testing.


          • #6
            My PVC valve connects to the carb. Without the PVC connected on my 304 the oil fill tube also blow out air instead of sucking it in!