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Worn PW3 cam

Discussion in 'Norton Commando Motorcycles (Classic)' started by Fullauto, Apr 20, 2018.

  1. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Why not R??

    R needs to be warm enough to work properly, below that it’s like treacle and ain’t working.

    If it gets too hot, it breaks down and is ruined.

    Between those parameters it’s brilliant stuff.

    But after the race, it will gum up engines if left in for too long, and it absorbs moisture.

    Bottom line: R is great but is very high maintenance. Good modern synthetics are also great, without the diva high maintenance.
     
  2. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    I live in a village where during the war Merlin engines were salvaged for usable bits.. At a commemoration do a merlin camshaft was handed round.. The lobes on it were massive and more radical than anything I have seen on bike engines.. True the revs were fairly low but on full boost presumably higher .the time allowed in a dog fight was around 10 or 15 mins .. Then it was likly to blow up.. there was a wired gate and if broke then the engine was changed as a matter of course. They were pretty near the edge of materials - sodium filled valves and technology . And worse they would get hammered virtually from cold in the event of a so called scramble. And the valves were big andnheavy so would have needed a fair amount of spring pressure . And this was what set me thinking.

    I do not have a source but came across the info through a google search the string being something like cam failure in ww2 aircraft. Not a mention but the astonishing thing is in the 21st Century some one has filed a patent in the US i think with a proffered solution to the problem This for contempory piston engined aircraft operating under ideal conditions




    Just a speculation on my part as you say but it made me wonder about oil. I do not claim any expertise but if my assertions are correct then in a cooling engine the two types of oil would behave differently and possibly this is a contributory factor . Years ago when i was a graduate student I was told by ba research fellow that little was understood about how oils actually lubricate in the case of boundary conditions. Whether that is still the case I do not know.

    But it seems in the case of Steve A monograde was implicated and Baz has suffered Combat Cam failure with R40 .
     
    Last edited: Jul 15, 2018
  3. Onder

    Onder

    Joined:
    May 11, 2010
    It has been a long while but I remember Lycoming had cam follower issues with, I think, the IO 360. They tried additives but I think the problem
    was really that the cam wasnt getting much lubrication due to location (Norton not blameless here either). Now even more iffy memory-wise they changed the followers to roller type. You aircraft guys can sort me on this Im sure.
    But my point is actually nailing down the failure is some times a bit difficult and the cure may well work but you still dont know what the actual
    cause was.
    ...and I quit running straight weight in any of my brit bikes back in the early 80s.
     
  4. Madnorton

    Madnorton VIP MEMBER

    Joined:
    Jun 9, 2008
    what i need is the video of the cam lobe / follower. As many will know in the automotive world there is not a cam like a Norton cam, it is brutal even in the basic guise. Here in lies the issue, and many have indicated this envelope is proven - it is how we take it from here. The cam I have fitted will surprise many when they see it it, Yes, I can provide an example but it is not the whole story, so far I have managed to produce HC 850 forged full skirt pistons lighter than standard originals, rods forged from alloy 30% stronger than original but I still have a problem, the crank and the push rods, with these resolved, and it will happen, I can then think about providing a system that can deliver fuel quick enough to spin the whole lot faster.

    As for oils, do the homework, in the UK the synthetic oil was developed in the 80's & 90'S, it was the best there was but it still contained ZDDP, mobil still list it, but this day and age it has been nigh on eliminated and thus the new synthetic oils are crap even compared to old mineral oils with additives. The order of improvement is environmental, engine design, oil formulation. There are still some full synthetic oils out there that contain at least 1000ppm ZDDP. R40 is very good but breaks down very quickly, multigrades - depends on which you chose to use, mineral, synthetic there are both good and bad examples out there. I got lucky.

    As for coatings, some are very good in what they do, I have said that before, again do your homework - why were automotive companies interested in using them, it was to compensate for the crap oil quality derived by environmental requirements, yes it suited racing - short lived = max gain, but the reliability factor is poor. Ask yourself why do most race teams now use very clean modern steels without coatings. At 40 x times the price differential the latest steels blow the coating process away.

    Make no mistake, I keep my ear to the ground, I know what is out there, and yes even if USA made I have been the first to try it. I still have a problem where no company in Europe or the USA knows how to process a material - I have sussed the the first stage, and they are still under my bench waiting for the next process. There is now steel out there, just come out from under the US patent, that makes 6 speed boxes inadequate, 7 and 8 speed would be the norm with it.

    Come to the open day, see the material and have a chat - you are most welcome, I may even make you a cup of tea.
     
  5. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    Finally ! You offer me what I wanted from the start. A cup of tea.
     
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  6. Dances with Shrapnel

    Dances with Shrapnel VIP MEMBER

    Joined:
    Jul 8, 2011
    He said "may".
     
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  7. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015

    That is profoundly true.. I do not bear a torch for mongrades as such but the Commando engine in particular has a very high piston velocity and that wreaked havoc with the additives package in many earlier multis. Porche in particular objected to their usein air cooled engines. Doubtless the breed has improved immensely since then. But its all snakes and ladders . For cold starts in cold climates then with a plain bearing crank MGs will be superior ,but it could be monos have superior film strenght on certain bearing surfaces. Have stuck with them partly out of habbit and partly because wet sumping is less of an issue. My other Brits have roller bearing big ends and here I think Monos probably are still the best bet.

    I was on the point of changing out of kindness to my Alton starter ,but its been an exceptionally hot summer here and that SAE50 runs free.. And then this thread has made me wonder .
     
    Last edited: Jul 15, 2018
  8. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Ash, there are several high quality synthetic oils available today with high ZDDP content.

    My own preference is Redline at 2250ppm.

    Contrary to popular belief, all weights are available from super thin 0-40 to 20-60, or even a straight 60 (I use the 20-60).

    But they’re only availble from specialist suppliers, I have to buy a few gallons at a time.

    Which makes me think... if oil is such a crucial thing in the longevity of Norton cams (and other components) that you sell, how about AN stocking and selling a suitable oil?

    All Norton owners could then buy in confidence.
     
    Last edited: Jul 15, 2018
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  9. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015

    And especially gearbox oil.. The original castrol ep 90 is hard to get and synthetics come in so many blends for specific apps its diificult to know whats for best
     
  10. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    Whilst R remains a good lubricant I wouldn't choose to use it in anything other than a pre-mix 2 stroke, where there is little residue to worry about.

    (Even then noting that synthetics have been used in 2 stroke race bikes since the '70s Bel Ray. I have a Suzuki T500 project I plan to use fully synthetic Castrol A747 like most current 2 stroke racers)

    R, or bean oil is old technology, which reflects more on managing it than if it provides lubrication. If you want the hassle, fine. Most don't.

    And OBTW, I used it in my race bike for a whole season in 1976. Changed it every 2nd race meeting. At the end of the year rebuild I had to have the crank ground!

    And had a whole lot of fun removing the residues. True the cam didn't show any wear, but nor did it for the following few years on GTX mineral 20W50!
     
  11. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    No, or at least that is not what is intended.

    The choice of which holes to close or open in the crankcase/timing chest wall depends a lot on your choice of breather, if you are looking to limit the amount of oil in the timing chest, and the orientation of your motor (Vertical as per the Atlas in my Rickman).

    The 1/4 hole I think you are referring to is designed to drain oil out of the timing chest. And in the case of my motor, which has a reed valve breather at the lower rear of the crankcase and the original larger holes blanked, the negative pressure in the crankcase would surely ensure one way travel of any oil towards the breather!

    Assuming a more standard configuration with open holes to the timing chest, when the motor is running and any wet sumping has been cleared the only thing likely to travel through the open holes, crankcase to timing chest is oil/air vapour mix on it's way to a breather on the back of the timing chest!

    If there was liquid oil pooled up to above the centreline of the crank you would be losing several horsepower to oil drag. (and most likely your scavenge pump circuit would not be working!)
     
  12. Dommie Nator

    Dommie Nator VIP MEMBER

    Joined:
    Apr 2, 2013
    [QUOTE="Fast Eddie
    My own preference is Redline 20-60 (ZZDP content 2250ppm).
    But they’re only availble from specialist suppliers, I have to buy a few gallons at a time.
    .[/QUOTE]

    https://www.oldhallperformance.com/

    Old Hall Performance will sell it to you by the quart (US quart)
    Handy for me as it's only a couple of miles away. Take no notice if you see they only sell wholesale on Google as that's out of date.
     
    Last edited: Jul 16, 2018
  13. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    Thanks for sharing that... but now am wondering what the cam was?
     
  14. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011

    The cam I ran in the 1970s was stamped TX!

    I got it from a development engineer who had just been made redundant by Norton in late '75!

    He described it as 'a 4S with a bit more mid range' and 'one of Peter's!'

    It worked well in an 850 with an ex space frame short stroke head and Omega pistons running about 10.25:1 and 36mm Amals and works dimensioned separate exhausts. Not many dynos around at the time, and certainly I was never able to use one, but by the way it performed it was putting out high 70s at the crank, and would have compared favourably with the 76 that Norman White records as the best for a works 750.

    As a works cam I beleive it was ground from a blank of the period, and not chilled cast. It even survived the loss of a stellite foot from a follower with no damage!

    I would be happy to have one again, but I suspect what I have works as well.
     
  15. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    Interesting lineage... What made me ask in part was that Factory supplied 4s cams had begun to dry up by this time . I picked up a 4s from Joe Francis Motors in 78 I think.. But have never been happy about the provenace . Did have a word about it with Kuhn's - brilliant people - and they said they hadnt seen one in as many years. Suppose best thing to do would be to get it hardness tested. Its def not chilled cast and then got on the blower to Steve before he goes and see about regrinding some followers.
     
  16. gtiller

    gtiller VIP MEMBER

    Joined:
    Nov 5, 2012
    TX as in Thruxton I wonder?

    I think the rare Thruxton Club Racer with the short stroke engine was called the TX750 wasn’t it?
     
  17. NKN

    NKN

    Joined:
    Mar 28, 2016
     
  18. NKN

    NKN

    Joined:
    Mar 28, 2016
    Thank you for taking some of your precious time to explain to beginners ;)
     
  19. Snotzo

    Snotzo

    Joined:
    Mar 12, 2013
    Madnorton, re post [HASHTAG]#365[/HASHTAG]

    I cannot remember any previous post on any topic that contained so much rubbish, but this one hits the jackpot !

    I may have to get to the open day to see for myself just what kind of person it is that can come out with this stuff.

    Four paragraphs of mostly off topic ramblings, but the last one is just impossible to believe.

    I had to look at the calender after I first read this to satisfy myself that it was not April 1st
     
  20. SteveA

    SteveA VIP MEMBER

    Joined:
    Dec 20, 2011
    Thought it was pretty clear where it came from in my post! But I doubt it had much to do with club racers other than having been under the same roof at some point!

    I was told it had been used briefly in a race engine before I got it.
     

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