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Cam and follower tests.

Discussion in 'Norton Commando Motorcycles (Classic)' started by comnoz, Aug 12, 2018.

  1. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    I have been experimenting with alternative cam followers for my engine.



    Here is some cuts from the spintron testing. Over the past 2 days the hardweld followers have ~ 16 hours of runtime.

     
  2. Brooking 850

    Brooking 850 VIP MEMBER

    Joined:
    Oct 3, 2011
    Great stuff Jim, that will put the cat amongst the woodpile!!!!
    Regards Mike
     
  3. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    So, Jim, why have you had to go down this path? Surely your genuine Andover Norton followers would have ably done the job? Were they somehow not made to spec perhaps? What does it all mean?
     
    CanukNortonNut likes this.
  4. Onder

    Onder

    Joined:
    May 11, 2010
    If you dont know you have to try to find out. Testing might provide some knowns and unknowns.
     
  5. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    You're not right up there with the current trends in sarcasm, are you?
     
    CanukNortonNut likes this.
  6. Matchless

    Matchless

    Joined:
    Dec 23, 2010
    Jim,
    What Rockwell hardness are standard followers? Also, would the definative test be a cold start every two or three hours for a week; if you had nothing better to do that is.
    It's a pity there isn't enough room for a follower which can rotate like a BMW air head or a modern bucket & shim arranement. Or is there?

    Martyn.
     
  7. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Jim, I have been studying the design virtues of the unified twin (UT) engine lately (reprinted in the last 3 issues of "Jampot", the AJS/M club magazine). Maybe you have read it. If not, I would be happy to send you the articles. They are a contraction of articles first appearing in Real Classics [HASHTAG]#134[/HASHTAG] / 135, and [HASHTAG]#144[/HASHTAG] / 145 / 146. This UT engine has several design virtues of what the Dominator engine should have evolved into. One of the virtues is improved camshaft oiling: The camshaft sits in a trough of oil. I know this has been tried on Commandos as well. My question is, to which extent does lack of lubrication, or insufficient lubrication, or lubrication using super-hot oil, affect camshaft and follower wear? And why doesn't the trough design work in the Commando engine - or does it?

    Both Norton and Matchless have obvious design problems when using solid followers (Matchless on their performance singles), where followers tend to dig into the ramp of aggressive cam lobes. I think the problem is similar with the Dominator engine - contact forces become huge and the lubricating oil film is penetrated.
    My second question is therefore, what are the design challenges in constructing a lightweight roller follower?
    https://shop.brutespeed.com/Comp-850-16-Hydraulic-Roller-Lifters-GM-SBC-LT1-LS1-Comp-850-16.htm
    The rolling friction factor Crr is much, much lower than the gliding friction factor Crg and to me, a development in this direction is the obvious answer to abnormal camshaft and follower wear. Roller tappets also makes it possible to extract more power using a dedicated camshaft.
    http://www.lunatipower.com/Tech/Cams/FlatTappetOrRoller.aspx

    However, I admire your systematic research of the faults found with the stock design!

    B.R.
    Knut
     
    Last edited: Aug 13, 2018
  8. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    Whilst other things may be of interest, I think we are going for a basic enquiry here. And a workable solution at reasonable cost.

    Norton cam and followers, within certain limits, were fairly successful for 40 years. Now some failures are occuring that don't seem to follow the trend of that period. What has changed?

    1. Design? No.
    2. Manufacturing processes? Possibly, certainly we know manufacturers have changed.
    3. Materials and hardness (hardening processes?), could be!

    I think Jim is investigating 3 to address a workable, and sort of immediate, solution at reasonable cost based on refurb of existing components.

    A good answer here gives those of us who might need it an available solution, and provides information to others on a way forward.

    Even if a roller follower solution were viable, how many would opt to modify their motors to use it?

    After one more race meeting this month I shall be opening my own motor with some trepidation!
     
    marinatlas likes this.
  9. o0norton0o

    o0norton0o

    Joined:
    Apr 27, 2015
    The stock followers have their stellite pads attached by oven brazing. Sadly, some of these pads will eventually delaminate from the body of the follower and can do some serious damage to the bottom end. I had a follower lose it's pad while my bike was idling in the driveway last year. I heard the noise start, shut the bike off then went through the long process of pulling the top end apart to find the follower's pad detached, sitting on top of it's cam lobe. No damage! I got lucky as hell.

    A norton friend of mine, just this previous weekend had one of his intake valves drop it's captured pushrod. All of a sudden he has a great amount of play in that valve train linkage. (I suspect he lost the stellite pad on his follower...) It happens often enough to be a flaw. He rode his bike home on one cylinder. I'd hate to see what his cam looks like now... (probably like Jim's cam looked)
     
  10. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    All interesting stuff, but in this case, totally irrelevant.
     
  11. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    The original spec for the cam follower called for RHc 58-60

    Of the ~ 100 cam followers I have checked, about 10% did not meet the spec, some by a large margin.

    I suspect this has had a lot to do with cam failures over the years.
     
    Fullauto likes this.
  12. Deets55

    Deets55 VIP MEMBER

    Joined:
    Oct 3, 2013

    Might explain the one badly worn lobe and three good lobes phenomenon.
     
  13. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008

    I had two cam failures in quick succession back in the early 80's and designed a tube with a cutout in the top to clear the followers that created a large trough to hold the oil after the first failure.

    A short time later the new Weber cam that was in the trough failed also and I removed the trough and rifle drilled the repaired Weber cam cam for lubrication.
    At the same time I also went back to a straight weight oil with a GM additive called EOS.

    I had not had any more cam issues again -until this summer.

    I chalked my two cam failures up to oil that was not up to the task. I had been using 10-40 Penzoil right out of the hose in the lube bay at the auto dealership where I worked.

    I have since had a camera inside a running Norton motor and seen the blizzard of oil that convinced me that lack of oil was not likely. The camera was though a 3/4 "hole in the front of the case -pointed at the cam. The lens was coated with oil the instant the engine started.
    Removing the camera and starting the motor made an immediate mess -with oil everywhere.

    A roller follower could be built to fit in the Norton. I have seen some pictures of a set that was built by a fellow up in Canada several years back. They were quite limited in width and roller diameter. I have never heard anything more about how they worked out.

    The biggest problem would be designing a cam that would work with the roller follower.
    A hardweld cam or an iron cam are not a good match for a roller follower.
    A case hardened gear steel cam would need to be built using a lobe design for a small diameter roller follower. This would be an expensive endeavor.

    Then roller cams also have there own set of problems that would need to be worked through. These problems would likely be made worse by the small roller that could be used
    -unless you wanted to re-design the barrel also.
     
  14. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    This is relevant, as I will not use the early design follower in my motor.
    I do not want to chance loosing a stellite pad when I am 2000 miles from home. I don't usually have a chase truck handy like I did this summer.
     
    CanukNortonNut likes this.
  15. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    When did the cam follower design change and how did it change?
    Sorry for my ignorance on this. I tried a search on Cam followers, read thru it but couldn' find anything on the change.

    Glen
     
  16. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    The followers went from design where the pad was simply brazed to the bottom of a flat steel body to a spiggoted design where the pad fits into a depression in the bottom of the steel body. This solved the problem of spitting the pads.

    The change was made in the mid 80's as I recall.
     
  17. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    So all original equipment followers are of the early , failure prone design?
    Also, from reading thru the search material it appears you were using BSA followers a few years ago. I take it that is no longer the case?

    Glen
     
  18. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    Yes all the OEM followers were non-spiggoted.

    I tried the BSA followers in my street bike for a short time.
    I used them in my roadracer for several years,

    They also loose the pads occasionally, that was the only time I have lost a pad in my streetbike engine, luckily I was at home when it happened and damage was minimal. Of course it wiped out the cam -not the 312a grind which will not work with the BSA follower..

    I went back to the same Webcam and Norton followers I was using before.
     
    Last edited: Aug 13, 2018
    worntorn likes this.
  19. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Extract from an article "What's In a Camshaft". Autor Kris Wieber. The Shop Magazine, Dec. 2, 2009 :

    Another factor that contributes to camshaft performance [life, added by KS] is oil. The lubricity of oil has been a recent issue for nearly all manufacturers of internal engine components.
    "Motor oil has changed over the years, mainly with the removal of zinc-phosphates (ZDDP). The reason for the removal is because today’s new cars have roller tappet camshafts. Roller tappet cams do not require these additives that flat tappet (hydraulic or mechanical) camshafts need. Flat tappet camshafts require this extra protection because the lifter slides across the cam lobe. This metal-to-metal contact between the cam and lifter will not last long without this additive, especially during ‘break-in,’" says John Steely, sales manager for Howards Cams.
    There are specialty oil manufactures, such as Brad Penn, that have this additive, he notes. But most of the common name brands (including Shell Rotella) no longer have zinc-phosphates at all.
    ---

    Is this common knowledge?

    -Knut
     
  20. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    Judging by the lengthy oil threads with much discussion of ZDDP numbers and effect, on this forum and many other forums, I would say yes.


    Glen
     
    Last edited: Aug 13, 2018