Potential Cam Failiure?

Small Block Mopar Engine

  1. Alex.Sciortino

    Alex.Sciortino Active Member

    Messages:
    26
    Likes Received:
    3
    Joined:
    Jan 8, 2017
    Location:
    Peoria, AZ
    Local Time:
    10:06 PM
    I've got a 360 that when built, the machine shop had the exhaust valve guides too tight. During cam break in, it hung an exhaust valve, and bent a few push rods on the exhaust. I put a different set of heads on the motor, and ran it, because the lifters looked OK at that time. The car was then driven about 150 miles. At this point, there was a bit of valvetrain noise. I have 273 rockers, figured they loosened up a bit, and readjusted them. I was also fighting an issue where the engine was breaking up pretty bad over 3000RPM. Put another 100 or so miles on it. At this point, the voltage regulator went out, and I parked the car until last week. This week, I have put maybe 10 miles on the car, and it developed a pretty bad clunk in the top end. I have the rocker as tight as it will go, and there is still play. It also happens to be the exhaust on the cylinder that had the valve hang. Car runs like garbage, and there is glitter in the oil. I'm fairly confident that I have a flat cam lobe, but I won't be able to pull the intake and get a good look until I am home from school over Thanksgiving. Any good ways to tell for sure? If it is a flat cam lobe, I'd like to start looking for a 5.9 Magnum to drop in the car over break, so I can drive it until I have the time and money to build something a little hotter.
     
    • Like Like x 1
    • furrystump

      furrystump Well-Known Member

      Messages:
      1,005
      Likes Received:
      624
      Joined:
      Nov 13, 2004
      Local Time:
      6:06 AM
      Pull a valve cover turn it over and see if one valve moves much less than the others. If you have one of the cheap harbor freight bore cameras you might be able to fish down through the oil drains in the head to peek at the cam
       
      • Like Like x 1
      • pittsburghracer

        pittsburghracer Well-Known Member

        Messages:
        2,695
        Likes Received:
        4942
        Joined:
        Apr 20, 2016
        Location:
        Freeport, PA.
        Local Time:
        1:06 AM
        Dial indicator on that rocker would tell you for sure if you can’t see it by eye.
         
        • Agree Agree x 3
        • Alex.Sciortino

          Alex.Sciortino Active Member

          Messages:
          26
          Likes Received:
          3
          Joined:
          Jan 8, 2017
          Location:
          Peoria, AZ
          Local Time:
          10:06 PM
          Not that I can see, but it is hard to tell.
           
        • Alex.Sciortino

          Alex.Sciortino Active Member

          Messages:
          26
          Likes Received:
          3
          Joined:
          Jan 8, 2017
          Location:
          Peoria, AZ
          Local Time:
          10:06 PM
          Unfortunately, my dial indicator is at home, so I won't have it until I am home for Thanksgiving.
           
        • 4spdragtop

          4spdragtop Well-Known Member

          Messages:
          28,344
          Likes Received:
          8174
          Joined:
          Aug 28, 2009
          Location:
          Wasting time here
          Local Time:
          12:06 AM
          No matter what the issue is, a teardown is involved to diagnose the "glitter"?
           
          • Agree Agree x 2
          • yellow rose

            yellow rose Doctor of Thinkology.

            Messages:
            20,408
            Likes Received:
            16489
            Joined:
            Jun 19, 2015
            Location:
            Living on the razors edge
            Local Time:
            10:06 PM
            I'm going to say this not to be demeaning, but because I've seen this so many times its second nature.

            An machinist is getting called out because he set the guide clearance too tight. While this is possible, that machinist would have to be stupid, lazy or both. It's not that hard to do.

            What most likely happens is guys *THINK* it's better to use very late (slow, retarded...whatever you want to call it) timing on intial start up because it's "safer"

            Well, it ain't safer, it's more likely to cause an exhaust valve to stick that anything else and it needs to be corrected.

            When starting any fresh engine, you want MORE timing than you would normally run, or at least the same amount of timing you would normally run.

            For example, if you normally time the engine at 35 total and it's all in by 3000, and you fire this new engine with only 10 degrees on it, and you set break in engine speed at 2000, depending on the timing curve you may only have 15-18 degrees on it.

            And that, makes a huge amount of heat. And that heat goes right into the exhaust valves and IDK if you set the with .005 clearance that will stick. Every single time.

            What happens is you are delaying combustion so late (and there for you complete combustion late) that combustion is still happening, the exhaust valve opens into all that heat and it gets over heated. And it's happening so fast that the valve can't possibly dump all that heat through the seat. Next thing is the valve gets hotter and hotter, the stem gets bigger and bigger and boom, it grabs the guide.

            I'm not saying this is your issue. I'm saying I've seen this happen so many times its criminal. If a machinist sets guide up too tight he should quit the business, because as I said, he is either stupid or lazy.

            Just a FYI.
             
            • Like Like x 2
            • Thanks! Thanks! x 1
            • Agree Agree x 1
            • Garrett Ellison

              Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

              Messages:
              2,344
              Likes Received:
              1823
              Joined:
              Jan 1, 2018
              Location:
              Southwest VA
              Local Time:
              1:06 AM
              Yeesh, I'm already cringing... I can guarantee with 100% certainty that it wiped out all the lobes that had bent push rods. There is absolutely zero tolerance for that type of error during a camshaft break in...
               
              Last edited: Nov 9, 2019
              • Agree Agree x 2
              • MoparMike1974

                MoparMike1974 FABO Gold Member FABO Gold Member

                Messages:
                1,917
                Likes Received:
                1257
                Joined:
                Jun 16, 2017
                Location:
                Maryland
                Local Time:
                1:06 AM
                I would pull the cam to be sure. Its worth it for peace of mind to know for sure. Some metallic flaking can be normal during break in so dont be too alarmed with that. You still need to investigate it for sure.
                 
              • yellow rose

                yellow rose Doctor of Thinkology.

                Messages:
                20,408
                Likes Received:
                16489
                Joined:
                Jun 19, 2015
                Location:
                Living on the razors edge
                Local Time:
                10:06 PM

                Not on my stuff. It better be damn little. And it should look like it came off the springs and retainers and nothing else.
                 
                • Agree Agree x 2
                • PRH

                  PRH Well-Known Member

                  Messages:
                  1,597
                  Likes Received:
                  2365
                  Joined:
                  Dec 14, 2018
                  Location:
                  So. Burlington, Vt
                  Local Time:
                  1:06 AM
                  About the only two things it can really be are the cam is going flat(most likely), or the adjuster screw/pushrod is wearing out.
                  Compare the length of the adjuster screw to one of the others.
                  If it’s the same, the cam is done.
                   
                  • Agree Agree x 2
                  • pittsburghracer

                    pittsburghracer Well-Known Member

                    Messages:
                    2,695
                    Likes Received:
                    4942
                    Joined:
                    Apr 20, 2016
                    Location:
                    Freeport, PA.
                    Local Time:
                    1:06 AM
                    Cut the filter apart
                     
                    • Agree Agree x 2
                    • 4spdragtop

                      4spdragtop Well-Known Member

                      Messages:
                      28,344
                      Likes Received:
                      8174
                      Joined:
                      Aug 28, 2009
                      Location:
                      Wasting time here
                      Local Time:
                      12:06 AM
                      Drain your oil and filter it to see how much glitter?
                       
                      • Agree Agree x 2
                      • RustyRatRod

                        RustyRatRod Weenie idiot loser. FABO Gold Member

                        Messages:
                        58,502
                        Likes Received:
                        28913
                        Joined:
                        Jun 7, 2010
                        Location:
                        Georgia
                        Local Time:
                        1:06 AM
                        Why? He already sees glitter.
                         
                        • Like Like x 1
                        • oldkimmer

                          oldkimmer FABO Gold Member FABO Gold Member

                          Messages:
                          14,010
                          Likes Received:
                          3447
                          Joined:
                          Nov 11, 2006
                          Location:
                          Kindersley, Saskatchewan,
                          Local Time:
                          12:06 AM
                          And all that glitter is not gold. Kim
                           
                          • Like Like x 4
                          • Thanks! Thanks! x 1
                          • pittsburghracer

                            pittsburghracer Well-Known Member

                            Messages:
                            2,695
                            Likes Received:
                            4942
                            Joined:
                            Apr 20, 2016
                            Location:
                            Freeport, PA.
                            Local Time:
                            1:06 AM

                            It’s tells the true story. I cut all my performance filters apart. Some kinds of oil including brad penn that I use has some crazy coloring at times and under different lighting. I’ve gone to friends houses to cut their filters apart when they thought they saw things. Not a big deal
                             
                          • RustyRatRod

                            RustyRatRod Weenie idiot loser. FABO Gold Member

                            Messages:
                            58,502
                            Likes Received:
                            28913
                            Joined:
                            Jun 7, 2010
                            Location:
                            Georgia
                            Local Time:
                            1:06 AM
                            I agree 100%, but he already has evidence. You know, the stuff they slap ignored in the OJ case? lol
                             
                            • Like Like x 1
                            • pittsburghracer

                              pittsburghracer Well-Known Member

                              Messages:
                              2,695
                              Likes Received:
                              4942
                              Joined:
                              Apr 20, 2016
                              Location:
                              Freeport, PA.
                              Local Time:
                              1:06 AM


                              I try to diagnose my issues even if I am planning on a rebuild. Example: before I pull my small block that I’ve races for four years I will do a compression test, leak down test, filter will be cut apart, and I will even check and redegree my cam. 45 minutes of testing gives me a lot of future data.
                               
                              • Like Like x 1
                              • RustyRatRod

                                RustyRatRod Weenie idiot loser. FABO Gold Member

                                Messages:
                                58,502
                                Likes Received:
                                28913
                                Joined:
                                Jun 7, 2010
                                Location:
                                Georgia
                                Local Time:
                                1:06 AM
                                I cannot agree more. But a tear down is a tear down. And that's what he's lookin at. lol

                                When was your last race?
                                 
                                • Like Like x 1
                                • Agree Agree x 1
                                • pittsburghracer

                                  pittsburghracer Well-Known Member

                                  Messages:
                                  2,695
                                  Likes Received:
                                  4942
                                  Joined:
                                  Apr 20, 2016
                                  Location:
                                  Freeport, PA.
                                  Local Time:
                                  1:06 AM

                                  3rd week of October. Finally in the shop and ready to freshen. And yes it truly sounds like he has some work ahead of him.
                                   
                                  • Like Like x 1
                                  • Agree Agree x 1
                                  • yellow rose

                                    yellow rose Doctor of Thinkology.

                                    Messages:
                                    20,408
                                    Likes Received:
                                    16489
                                    Joined:
                                    Jun 19, 2015
                                    Location:
                                    Living on the razors edge
                                    Local Time:
                                    10:06 PM
                                    And she's buying a stair way to heaven...
                                     
                                    • Like Like x 2
                                    • Garrett Ellison

                                      Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

                                      Messages:
                                      2,344
                                      Likes Received:
                                      1823
                                      Joined:
                                      Jan 1, 2018
                                      Location:
                                      Southwest VA
                                      Local Time:
                                      1:06 AM
                                      More than likely, the cam and lifters already there...
                                       
                                      • Like Like x 2
                                      • stixx

                                        stixx Well-Known Member

                                        Messages:
                                        760
                                        Likes Received:
                                        518
                                        Joined:
                                        May 30, 2006
                                        Location:
                                        Southern Germany
                                        Local Time:
                                        6:06 AM
                                        Does a worn cam go to heaven? :lol:
                                         
                                        • Like Like x 2
                                        • pittsburghracer

                                          pittsburghracer Well-Known Member

                                          Messages:
                                          2,695
                                          Likes Received:
                                          4942
                                          Joined:
                                          Apr 20, 2016
                                          Location:
                                          Freeport, PA.
                                          Local Time:
                                          1:06 AM

                                          Full religious cams do, or was it full race cams.
                                           
                                          • Like Like x 1
                                          • Thanks! Thanks! x 1
                                          • yellow rose

                                            yellow rose Doctor of Thinkology.

                                            Messages:
                                            20,408
                                            Likes Received:
                                            16489
                                            Joined:
                                            Jun 19, 2015
                                            Location:
                                            Living on the razors edge
                                            Local Time:
                                            10:06 PM

                                            Gotta be 3/4 race or bigger for a worn cam to get into cam heaven.

                                            Those 1/2 race and lesser cams have a long term in cam purgatory before they get there.
                                             
                                            • Like Like x 3
                                            1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                                              By continuing to use this site, you are consenting to our use of cookies.