Engine knock... Does this sound familiar?

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  • 01001010
    Low Range
    • May 2007
    • 59

    Engine knock... Does this sound familiar?

    Ok, needing some help here guys...

    I'm working on a 2.25 petrol engine with an interesting knock. I'm going to try to record a sound clip so you guys can hear. In the meantime, an explanation will have to do...

    There is a knock that doesn't follow any pattern. With the valve cover off, I can hear that it's definitely coming from the valve-train...maybe the first 2 or 3 valves from front to back. I'll check clearances as soon as I can find my feeler blades.

    EDIT: Nvm...file wasn't the correct type for YouTube
    Last edited by 01001010; 03-11-2011, 09:09 PM.
  • 01001010
    Low Range
    • May 2007
    • 59

    #2
    Ok, here's the vid...

    Comment

    • SafeAirOne
      Overdrive
      • Apr 2008
      • 3435

      #3
      If the engine wasn't running so smoothly, I'd almost say it sounds like the "snap" of a leaky spark plug wire arcing to ground.

      It seems like it's a one-click-per-two-revs noise, so that should narrow it down.
      --Mark

      1973 SIII 109 RHD 2.5NA Diesel

      0-54mph in just under 11.5 minutes
      (9.7 minutes now that she's a 3-door).

      Comment

      • bkreutz
        4th Gear
        • Apr 2010
        • 408

        #4
        Sounds like a valve sticking and then snapping closed, and I think I see a matching hesitation in the lowest rocker arm in that film clip. Just a guess on my part. (without being there myself, you can usually tell a sticking valve by looking for a fluctuating needle on a vacuum gauge.)
        Gale Breitkreutz
        '03 Disco
        '74 Series III 88 (sold, 4/13)
        '47 CJ2A

        Comment

        • 01001010
          Low Range
          • May 2007
          • 59

          #5
          Wow...thanks for the quick response guys.

          AirOne... I know exactly what you are talking about but this definitely sounds like metal slapping metal.

          bkreutz... That's the first thing I thought but it seems to sound louder on side opposite to the valves. This still remains high on the "Culprit List" though.

          Comment

          • 01001010
            Low Range
            • May 2007
            • 59

            #6
            Could there be a faulty tappet?

            Comment

            • 01001010
              Low Range
              • May 2007
              • 59

              #7
              Bump

              Comment

              • SalemRover
                3rd Gear
                • Aug 2007
                • 310

                #8
                When you rev the engine around 7 seconds it seems to stop for a moment. Is the sound consistent at all rpms? Sounds like something valve train related. Does the exhaust have any clues through smoke, smell or backdraft (if an exhaust valve is sticking).

                On an unrelated topic, is your name 01001010 the binary equivalent of the ascii number for the letter J? Just curious.

                -Jason

                Comment

                • I Leak Oil
                  Overdrive
                  • Nov 2006
                  • 1796

                  #9
                  Could be a sticking valve. Could be a weak valve spring. Could be a worn rocker shaft bushing. Try turning the motor with a crank handle and have someone watch the suspect valves to see if you can pinpoint it.

                  My wife just asked me if I was watching a video of a steam engine. Told her it was a rover engine. She said "Oh, not much difference".....they just don't understand....
                  Jason
                  "Clubs are for Chumps" Club president

                  Comment

                  • SafeAirOne
                    Overdrive
                    • Apr 2008
                    • 3435

                    #10
                    Can you pinpoint the location of the noise using a short length of hose like a stethoscope? An even better alternative is to get a $10 mechanic's stethoscope, which has a metal probe that you can place on different parts of the engine to pinpoint the source of an engine noise. Extremely effective! Watch out for the radiator fan when and if you do this.

                    Pinpointing the exact location that the noise is coming from is essential in diagnosis, Otherwise, "the engine is the problem" is probably the best anyone can do with any accuracy.
                    --Mark

                    1973 SIII 109 RHD 2.5NA Diesel

                    0-54mph in just under 11.5 minutes
                    (9.7 minutes now that she's a 3-door).

                    Comment

                    • martindktm
                      2nd Gear
                      • Jun 2008
                      • 218

                      #11
                      Could it be from the timing chain?

                      Comment

                      • Terrys
                        Overdrive
                        • May 2007
                        • 1382

                        #12
                        Sounds like a sticking valve to me.

                        Comment

                        • 01001010
                          Low Range
                          • May 2007
                          • 59

                          #13
                          Terry!!! Good to see you're still on here man! I'm BACK!

                          Guys, I made some time to get dirty with Sasquatch today so I got started by taking the oil pan off and inspecting things from underneath. Everything looked fine until I found what looked like part of a shim on the oil pumps mesh screen.

                          With the Oil Pan off, I was removing the last little bit of oil when I started to come across tiny golden nuggets. I immediately knew...

                          Two hours later:

                          Comment

                          • albersj51
                            5th Gear
                            • May 2010
                            • 687

                            #14
                            Pardon my ignorance, but what is it?

                            Comment

                            • badvibes
                              3rd Gear
                              • Mar 2007
                              • 364

                              #15
                              Originally posted by albersj51
                              Pardon my ignorance, but what is it?
                              When you click on the pic and enlarge it look at the pic title in the lower left corner.....

                              Jeff
                              1964 Series 2A SW, LHD mostly stock, often runs!

                              1991 Range Rover Hunter

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