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Premature cam failure

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  • Premature cam failure

    All, have/had a Kent 276 cam in my 1380 wagon. Noticed a slight knocking sound last time I started it. Started the investigation and ended up with the engine on my work bench with camshaft in my hands. Three lobes of the cam and the corresponding followers are severely worn. I believe the hardened surface of the cam has begun to fail. The engine has less than 10K miles, and have changed the oil every spring which is usually less that 1K miles. Anyone had experiences like this? Interested in opinions. Bad cam, bad luck?

  • #2
    Bad luck is a possibility as is a bad cam or bad lifters. Is there any sign of distress on the other lifters? Who made the parts? It's also possible that the bad lifters are just a bit too large in diameter and won't rotate.

    If it isn't any of the three previously mentioned conditions, it could be the initial start-up procedure or the assembly lube. Chances are that what ever went wrong happened very early in the engine's life.

    Years ago when the first reports of a lack of ZDDP causing problems, it was just the sort of failure you're seeing. It's never been proven and to the best of my knowledge it's never been seen in an A-series engine (and I've asked, a lot).

    It would be interesting to have the hardness checked on the cam lobes and the lifters.

    If you can afford the car, you can afford the manual...


    • #3
      I remember reading that a few years ago Kent was grinding their profiles onto stock cams which led to failure.
      My Mini is plastic.


      • #4
        Thanks Tom, sure would be nice if I could write this whole thing off as a simple cam failure.


        • #5
          I started adding a DZZP product at each oil change at the recommendation of the folks at Delta Camshaft who have seen premature camshaft/lifter failure in race as well as street applications. It's cheap insurance, if you ask me. Matter of fact, it's cheap insurance if you don't ask me. Although as Kelly mentioned, it would be interesting to perform a hardness check on on the cam/tappets and I never considered the over size tappet possibility. Interesting, keeps us informed.
          Last edited by Jerry; 03-05-2014, 01:24 PM. Reason: context


          • #6
            Tim, maybe the cause there is due to excessive "CLF" wear?

            CLF = Corbett Lead Foot


            • #7
              Good one Andrew, watch your mirrors!


              • #8
                Couple of thoughts here. Some people may remember the sw5 camshaft.and then the sw5-07. As i remember they had a problem with material hardness and accuracy of the grind with the first series. you say that the sw5 is not a kent grind but if you look at the marking on the end of the cam they are marked the same way. Probably a bit of outsourcing. The other thing is that a cam lobe has a small bit of taper so that the lobe turns the lifter as it rotates because it is riding on one side of the lifter. Also some lifters are ground flat but actually they are supposed to have a bit of a crown. Then there is the issue of break in where the surface is hardened by the lobe and lifter sliding across each other. Another reason that there is zddp in break in oil. Any one of these could have been the root cause of your problem. Something to remember is to buy only the recommended parts made to work with each other. No way to tell at this point. But i have to say good choice, the 276 is my favorite street cam. Aaron
                racecar spelled backwards is racecar