Announcement

Collapse
No announcement yet.

Timing chain slack/oil pressure

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Timing chain slack/oil pressure

    At my last track day, all was working great on day one. Day two I did a session with no issues and parked it. Later I went to get some gas and there was a crazy sound.

    I shut it off and pulled the valve cover, it sounded like it was coming from there. The timing chain was scraping on the top of the valve cover. I went home and got a spare timing chain tensioner and tried to restart the engine. It doesn't start. I check the chain and the exhaust cam has skipped 2 teeth. I get that squared away and it starts but as soon as the oil gets warm, the noise starts up again.

    I called it a day and packed it up on the trailer. At home I drained the oil and the filter barely had any oil in it and was hand loose although there was no evidence of leaking oil from there and the oil level was fine. However I was filling the oil between every session but there was some in the catch can.

    The oil pickup tube/strainer looks fine. I ordered one from the S14 with the better opening just in case.

    Any thoughts or ideas?
    Chicago Region SCCA SM # 688 http://www.scca-chicago.com
    TSSCC SM # 688 http://www.tsscc.org

  • #2
    You have a pressure gauge? No weirdness?

    Comment


    • #3
      Yep - oil pressure?

      I'd maybe try a new tensioner, they're not too expensive, and recent ones are updated with a finer tooth count.
      '18 Chevrolet Volt - Electric fun hatch for DD duty!


      DefSport Koni Sleeve and Spring Perch Buy!!!
      http://www.nissanroadracing.com/showthread.php?t=5902

      Comment


      • #4
        oil pump break on you? pressure relief valve stuck open?

        I'd stick a pressure gauge on it and give it a hard look.
        Originally posted by SoSideways
        I don't care what color they are as long as they are LONG AND HARD.
        '04 G35 Sedan 6MT- The DD
        '96 240SX- The Track Toy

        Comment


        • #5
          I'm thinking pressure relief valve stuck open personally. If the oil pump gear or collar broke, I think you'd have a toasted bottom end and subsequent noise very quickly.
          '18 Chevrolet Volt - Electric fun hatch for DD duty!


          DefSport Koni Sleeve and Spring Perch Buy!!!
          http://www.nissanroadracing.com/showthread.php?t=5902

          Comment


          • #6
            I don't have a oil pressure gauge but I should be able to see it with the AEM. I didn't have my laptop at the track day to log into it. I guess it is time to pick one up and install it. The light never came on but I don't know if it still will with the AEM.

            My plan right now is to put in the new pickup tube, refill with oil and new filter. Then check everything out.
            Chicago Region SCCA SM # 688 http://www.scca-chicago.com
            TSSCC SM # 688 http://www.tsscc.org

            Comment


            • #7
              I'll check the relief valve as well. Thanks!
              Chicago Region SCCA SM # 688 http://www.scca-chicago.com
              TSSCC SM # 688 http://www.tsscc.org

              Comment


              • #8
                buy a cheap mechanical gauge at the parts store. stuff it in the gauge/dummy light port on the block and then fire up the engine.
                Originally posted by SoSideways
                I don't care what color they are as long as they are LONG AND HARD.
                '04 G35 Sedan 6MT- The DD
                '96 240SX- The Track Toy

                Comment


                • #9
                  Originally posted by Matt93SE View Post
                  buy a cheap mechanical gauge at the parts store. stuff it in the gauge/dummy light port on the block and then fire up the engine.
                  I changed the oil pickup tube even though the one in there looked fine. Put new oil & filter on and tried to start it. The chain had jumped again. I had to remove the sprocket off the intake cam to get it back. Re installed the tensioner and valve cover. Starts up fine.

                  The oil pressure starts out at 85 and eventually gets down to 45. It doesn't go lower than that so it seems oil pressure is good. No more noise.

                  It seems to have resolved itself? Could the oil filter rattling loose have effected pressure? It was hand loose when i went to remove it.

                  On another find. All of a sudden I have more vacuum and the idle AFRs are too high like 16 & 17. Maybe I inadvertently found a boost leak? Time to go back to the tuner I guess. If I give it gas, it goes back into a safe zone but it still concerns me.
                  Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                  TSSCC SM # 688 http://www.tsscc.org

                  Comment


                  • #10
                    Did you ever replace the tensioner? doesn't it work off oil pressure? wonder if it was leaking behind the tensioner causing free-flow of oil and drop in pressure.

                    could also be hairline cracks in the pickup tube that you didn't see. you might seal off the ends and try to pull a vacuum (or pressurize) it and see if you can find a crack. then again they're cheap enough and are wear items. toss it and don't look back.
                    Originally posted by SoSideways
                    I don't care what color they are as long as they are LONG AND HARD.
                    '04 G35 Sedan 6MT- The DD
                    '96 240SX- The Track Toy

                    Comment


                    • #11
                      My first troubleshooting step was to try the timing chain tensioner from my old engine. It didn't fix the issue but lead me to think the oil pressure was low.

                      The new pickup is the improved one from the S14 engine. It was a PITA to install due to the brace secures to a different spot that is partially covered by a windage tray. It looks like a big improvement with a bigger opening.

                      Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                      TSSCC SM # 688 http://www.tsscc.org

                      Comment


                      • #12
                        I have my mechanical oil pressure gauge installed. After warm up the oil pressure is down to about 30psi now. It starts pretty high. As I rev it, it does come right up and then slowly back down. From what I can tell this seems normal.

                        My question is if the oil breaking down caused this, do I need to be concerned about bearing wear? This is a fresh rebuild. I didn't sense any rod knock or anything. It is idling a little higher than it was at about 1100 rpms.
                        Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                        TSSCC SM # 688 http://www.tsscc.org

                        Comment


                        • #13
                          You should make roughly 20-30 psi around 1000 RPM, then by the time you get to 3000 RPM you should be over 60-70 psi. The pressure increase is roughly linear until the bypass valve opens up. It'll run upwards of 90+ psi at cold idle, but should regulate about 80-90 psi when warm at higher RPM (>4k RPM).

                          Substantially less than this is a major problem, and you should maintain constant pressure at a given RPM.
                          '18 Chevrolet Volt - Electric fun hatch for DD duty!


                          DefSport Koni Sleeve and Spring Perch Buy!!!
                          http://www.nissanroadracing.com/showthread.php?t=5902

                          Comment


                          • #14
                            Pressure seems fine then, mainly concerned with worn bearings but if that were the case, it would show in the oil pressure correct?

                            Sent from my SGH-M919 using Tapatalk
                            Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                            TSSCC SM # 688 http://www.tsscc.org

                            Comment


                            • #15
                              Sounds like oil could be a little old. Change it and see if there is any difference. I had a car that was very sensitive to oil after an event

                              Comment

                              Working...
                              X