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    #1

    Mystery knock

    So guys, my m42 as developed a weird knock.

    It only happens with the engine fully warmed up after it idles for a very long time or if i shut it off. After driving around it goes completely away.
    It comes from the head directly above the exhaust valves for the 4th cyl

    I already changed the oil and filter (castrol gtx 10w40) and there were no metal particulate in the filter.

    Here's two videos. The first is after i drove it around and got it warmed up (normal m42 noise with a bit of chain slop me thinks). The second one was taken after i let it sit turned off for 5 mins.



    https://www.youtube.com/watch?v=upvzde1bPSU




    https://www.youtube.com/watch?v=Mmb6h7j4NAk



    So, rod kock or lazy lifter guys?
    Originally posted by kendogg
    Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
    OG RACECAR
    Tags: None
    #2
    The constant noise is deffinately timing chain. Maybe guides or tensioner. Check you can hear teeth.

    The only other noise I hear is right when you hit the throttle and goes away when you let go. Is that it?
    DENY IGNORANCE!
    Schwarz 325-totaled
    brilliantrot 318i-daily

    Originally posted by mkcman17
    don't think your hamster wheels are fast now. you will still have to give up when trying to pass that V6 odyssey to make your offramp.

    Comment

      #3
      That's the one i'm talking about. The sharp knock
      Originally posted by kendogg
      Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
      OG RACECAR

      Comment

        #4
        I don't hear a knock at all....
        My 325iX DIY Threads:

        Front Wheel Bearing Replacement

        325iX Rear Subframe Bushings and MUCH more w/pics!

        325iX Steering Rack Replacement, Suspension, & Oil Pan job w/pics!


        Comment

          #5
          Originally posted by EyExR View Post
          I don't hear a knock at all....
          It's on the second video, every time i accelerate
          Originally posted by kendogg
          Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
          OG RACECAR

          Comment

            #6
            timing case brah

            Turbo M42 Build Thread :Here
            Ig:ryno_pzk
            I like the tuna here.
            Originally posted by lambo
            Buttchug. The official poster child of r3v.

            Comment

              #7
              Yup, sounds like timing case. Start thinking about getting in there to take a look.

              Transaction Feedback: LINK

              Comment

                #8
                Originally posted by bmwman91 View Post
                Yup, sounds like timing case. Start thinking about getting in there to take a look.
                Well, better than a rod knock. Gonna order a tensioner just in case.

                Btw, just to enlighten me, how does trouble in the timing case relates to knocking towards the back of the engine?
                Originally posted by kendogg
                Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
                OG RACECAR

                Comment

                  #9
                  Maybe I was missing the knocking sound (watched both videos). It sounds a lot like timing case noise to me. Is it that apparent that it is specifically coming form the rear of the engine when you listen in-person, or did you hold a screwdriver and listen to that to try to pinpoint it?

                  Transaction Feedback: LINK

                  Comment

                    #10
                    Originally posted by bmwman91 View Post
                    Maybe I was missing the knocking sound (watched both videos). It sounds a lot like timing case noise to me. Is it that apparent that it is specifically coming form the rear of the engine when you listen in-person, or did you hold a screwdriver and listen to that to try to pinpoint it?
                    Just listening to it it seems pretty obvious it comes from the back of the engine. More specifically above the exaust valves for the 4th cylinder.

                    Its the sharp knock whenever i accelerate that goes away when i let go of the throttle. (on the second video)

                    Could it be the valves hitting the piston from something loose in the timing chain?
                    Originally posted by kendogg
                    Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
                    OG RACECAR

                    Comment

                      #11
                      No more feedback?

                      I wanted to know if can keep driving the car or not
                      Originally posted by kendogg
                      Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
                      OG RACECAR

                      Comment

                        #12
                        the other noise he was talking about besides the timing noise was right when he hits the throttle. at the moment when its about to accelerate its a slight piston slapping sound and it goes away when the engine revs. you havn't overheated your engine anytime have you? thats the only time ive ever heard that noise or the engine is really beat or hasnt been maintained. Definitely have to get on that timing case though.

                        Originally posted by M42Power View Post
                        Could it be the valves hitting the piston from something loose in the timing chain?
                        piston to valve noise would be constant and a heck of a lot louder than that.

                        have you checked your spark plugs?
                        Last edited by kwill22; 05-16-2014, 05:23 AM.
                        DENY IGNORANCE!
                        Schwarz 325-totaled
                        brilliantrot 318i-daily

                        Originally posted by mkcman17
                        don't think your hamster wheels are fast now. you will still have to give up when trying to pass that V6 odyssey to make your offramp.

                        Comment

                          #13
                          Originally posted by kwill22 View Post
                          the other noise he was talking about besides the timing noise was right when he hits the throttle. at the moment when its about to accelerate its a slight piston slapping sound and it goes away when the engine revs. you havn't overheated your engine anytime have you? thats the only time ive ever heard that noise or the engine is really beat or hasnt been maintained. Definitely have to get on that timing case though.



                          piston to valve noise would be constant and a heck of a lot louder than that.

                          have you checked your spark plugs?

                          It only happens when i full throttle. I'm mabye thinkining it can be pre-detonation.

                          The plugs seem good. The wires i'm not so sure

                          The engine was slightly overheated for a very short period of time, and that was nearly 6 years ago. The engine has been well mantained so far. Has like 130k miles
                          Originally posted by kendogg
                          Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
                          OG RACECAR

                          Comment

                            #14
                            Only at WOT, sounds like TPS or o2. The TPS takes over for wot and the o2 is ignored right. Something like the TPS reads WOT and the DME switches to a different map?
                            DENY IGNORANCE!
                            Schwarz 325-totaled
                            brilliantrot 318i-daily

                            Originally posted by mkcman17
                            don't think your hamster wheels are fast now. you will still have to give up when trying to pass that V6 odyssey to make your offramp.

                            Comment

                              #15
                              Originally posted by kwill22 View Post
                              Only at WOT, sounds like TPS or o2. The TPS takes over for wot and the o2 is ignored right. Something like the TPS reads WOT and the DME switches to a different map?
                              My car doesnt have an o2 sensor, so it could be a bad tps. But i'm going to sort out the iginition system first. I think i might order a cop kit.
                              Originally posted by kendogg
                              Don't know, but the E90 wasn't designed from the ground-up intending to be a racecar like the E30 was.
                              OG RACECAR

                              Comment

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