1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

1962 August Coleman 501A (August 1962)

Discussion in 'Coleman No:501' started by presscall, Dec 17, 2014.

  1. presscall

    presscall United Kingdom Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    5,982
    Location:
    UK
    I'm really just revisiting the points Jeff (Knight84) picked out regarded the Coleman 501A, HERE


    Jeff's right, it's pretty much got rid of the potentially dangerous characteristics of its predecessor, the 501, and firing it up (or more relevantly running it for a few minutes) didn't present any drama, by which I mean thermal runaway as the 501 would

    1418843619-1.JPG


    Just confirming the production date here, Coleman not bothering to stamp in the 'A' suffix

    1418843626-1a.JPG


    Before I fired it I dismantled it completely and inspected parts, replacing a seal in the tank filler cap ...

    1418843637-2.JPG


    ... and installing a leather pump cup washer instead of the plastic one it had

    1418843647-3.JPG


    I appreciate a well-engineered mechanism and the pricker arrangement with a fast-threaded left-hand-thread ticks a box in that respect for me

    1418843654-4.JPG

    1418843664-5.JPG

    1418843672-6.JPG

    1418843682-7.JPG


    Partly re-assembled

    1418843692-8.JPG


    Evolution, for safety's sake. The 501 on the right had the fuel cock on the vapouriser outlet, so the control knob got very hot (and got hotter and hotter in use to the point of emitting smoke) and were a leak to spring between fuel/air valve and fuel inlet on the left of the tank top and the control valve there would be no way of shutting off the fuel. The 501A on the left has the fuel cock on the correct end of the vapouriser and although the pricker control on the right gets pretty hot in use, there's no thermal runaway and a way of shutting off the fuel at the inlet is incorporated

    1418843702-9.JPG


    The generators are of a slightly different pattern, with less of the generator in the direct flame of the burner in the 501A (on the left)

    1418843759-13.JPG


    That and a small upward curve towards the inlet and outlet connectors in the 501A generator (on the right here) contributes to less heat being conducted to the pricker control 'downstream' I'd say

    1418843738-12.JPG


    I suppose it was the case that such tweaking didn't restore confidence in the type and Coleman came out with a different design in the 502 - well, not all that different, with a strong family resemblance to the phenomenally successful grandpa, the 500 Speedmaster. Whatever, it put the Coleman 502 out in front, as it is in this photo of course

    1418849203-14.JPG


    Running now for quarter-of-an-hour and the control valve is just warm to the touch - not so the pricker valve, but at least the valve knob didn't smoulder as the 501 control knob would have this far into firing

    1418843795-15.JPG

    1418843811-16.JPG


    My thanks to Norman (Techguy) for his generosity in sending me the Coleman as a gift.

    John
     
    Last edited by a moderator: Jul 1, 2015
  2. OMC

    OMC United States Subscriber

    Offline
    Joined:
    Sep 13, 2013
    Messages:
    1,565
    Location:
    Illinois, the Land of lincoln
    John,
    Thank you, that is yet another great post. There "may" be a case to be made one might almost consider a 501A as a user. The hot valve like the 123 also like a 550 can be overcome.
    I liked the point re 502 resemblance to "older" 500. The 502 is out front but not with "newer" changes. They replaced the generator with one that is straight, cheaper to produce and easier to maintain like their "older" ones, ie on the 500.
    They replaced the burner with the band-a-blue a proven winner from their "older" suit cases. Older was better. thx again omc
     
  3. presscall

    presscall United Kingdom Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    5,982
    Location:
    UK
    Thank you OMC, always good to hear from you.

    The point you make about the 501A being almost worthy of consideration as a user stove is well-made. Certainly I've been putting it through its paces and with growing confidence that the faults of the 501 were eradicated with this variation.

    I spoke earlier about the temperature gradient in the generator being in a favourable direction in respect of inlet/control valve (cool end) and jet/pricker (hotter end) such that I gave the control valve the thumb test without raising a blister.

    The photo evidence is here, the circular generator reaching red heat over on the pricker mechanism side of the circle (right) but not on the inlet/control valve side (left)

    1418861586-17.JPG


    Jet/pricker end of the generator

    1418861614-18.JPG


    Control valve end

    1418861625-19.JPG


    Cooled down, there's the obvious contrast of heat tarnish over to the right (hotter) end of the generator and towards the jet/pricker and the untarnished generator on the left hand end in proximity to the inlet/control valve

    1418861636-20.JPG


    Reassuring evidence and yes, a user stove I reckon.

    Incidentally, looking at those photos again as I uploaded them I can see that the flame lifts off the burner at the valve side. I'm pretty sure that's something that will respond to adjustment, the jet pricker mechanism screwing into the burner mixing chamber and offering a measure of adjustment closer into the mixing chamber or further out. I've probably got it set too far out, resulting in a slight excess of air (from air inlet holes in the mixing chamber inlet manifold tube) over fuel in the mixture.

    John
     
    Last edited by a moderator: Jun 26, 2015
  4. Knight84 Canada

    Offline
    Joined:
    Jan 21, 2009
    Messages:
    3,236
    Very nice work and post.

    Jeff
     
  5. scouterjan

    scouterjan Canada Subscriber

    Offline
    Joined:
    Mar 24, 2010
    Messages:
    431
    Location:
    Maple Ridge, B.C. Canada
    Great detailed post, I have a 501 as well, only fired it for a few minutes, but I really like the flame pattern way better than the 502. Thanks for sharing
    Jan
     
  6. geeves

    geeves New Zealand Subscriber

    Offline
    Joined:
    Sep 29, 2009
    Messages:
    4,201
    Location:
    Wellington New Zealand
    I wonder if you can hybrid a 501 burner into a 502 control and generator? Best of both worlds
     

Share This Page