BR49A pre heat blockage

Discussion in 'Fettling Forum' started by BigStevie, Oct 8, 2019.

  1. BigStevie

    BigStevie United Kingdom Subscriber

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    image.jpg
    There’s a block in the control cock body of my BR49A, I was perhaps wondering if the end of the pre heat control stem was damaged or broken (inside the body, would explain the block?).
    If anyone has a similar control stem they could check the length of against the above photo, it’d be much appreciated.

    Thanks folks, Stevie
     
  2. Anthony

    Anthony Australia Subscriber

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  3. BigStevie

    BigStevie United Kingdom Subscriber

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    Thanks Anthony, I can see my valve isn’t broken. Time for plan b.....
     
  4. BigStevie

    BigStevie United Kingdom Subscriber

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    After more faffing than fettling, I’ve eventually managed to clear the blockage in the valve body....
    ....which has now highlighted a new problem. Even with the pre heat valve fully closed, fuel is continuing to flow.....Perhaps the previous user blocked the pre heat feed for this very reason? As is now, the lamp can’t be used (constant trickle of fuel to pre heater)...
    Ah well, time for plan c....

    Stevie
     
  5. JonD

    JonD Subscriber

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    Isn't there 1mm difference in length there? Might be enough to explain it.

    I might think to add a solder blob on the end if it will take it. If that improves the situation then think about using silver solder or braze to make permanent.

    Looks like brass - is it?
     
  6. BigStevie

    BigStevie United Kingdom Subscriber

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    @JonD Hi Jon, the end of the spindle is slightly concave plus there is some light scoring on the non threaded end. I’ll do a bit more research before I start making any mods to the spindle.
    There’s no stop on the threaded section, so I don’t believe that the length is an issue. I can’t make out how the stem stops the flow, is it the end of the spindle making a seal or the threads? I don’t want to bugger anything up, so will go slowly! Yes, it’s brass.
    Thanks for the input!

    Stevie
     
  7. JonD

    JonD Subscriber

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    Yes good luck - you will figure it out.
     
  8. BigStevie

    BigStevie United Kingdom Subscriber

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    @JonD aye, its mildly irritating me now, so will have to beat it!
     
  9. BigStevie

    BigStevie United Kingdom Subscriber

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    @Anthony Hi Anthony, is the tip of your pre heat control stem concave, flat or other(!)?

    Stevie
     
  10. JonD

    JonD Subscriber

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    @BigStevie I think mystery solved thanks to @Stuart Taylor
    In the reference section is this.

    You probably have the ball version and that explains the concave dimple. Could be it's been displaced as described or lost.

    BR49.jpg
     
    Last edited: Oct 8, 2019
  11. Tony Press

    Tony Press Australia Subscriber

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    @BigStevie

    If the ball bearing is stuck, give it a blast with carburettor cleaner.

    Tony
     
  12. Anthony

    Anthony Australia Subscriber

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    This picture makes the concave dimple look bigger than it is.

    IMG_2564.JPG IMG_2566.JPG

    I'll take mine out to the shed today to see if I still have the ball.
    Well found @JonD and thanks for the info @Stuart Taylor .
     
  13. JonD

    JonD Subscriber

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    Hope this leads to a cure.
    Those typed Tilley instructions have a typo anyway. Talks about undoing the valve spindle 234 more than 2-3 turns.
    234 is the seal washer while 247 is the spindle itself.

    Today we have delete and backspace keys, search and replace etc. Back then they had a gritty rubber eraser and they could only type over the remaining mess.
     
  14. Anthony

    Anthony Australia Subscriber

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    They sure were accurate on the 2mm though

    IMG_2572.JPG IMG_2570.JPG
     
  15. BigStevie

    BigStevie United Kingdom Subscriber

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    Thanks guys for all the input. Today’s idiot award goes to me. My brother is staying at the moment, while fiddling with the lamp this morning I said to him that I thought a small ball bearing would probably fix the problem...... I had no idea that it did indeed need this small but vital component as I hadn’t been able to find any reference to it in the Tilley parts lists (and it was missing from the cock).

    So folks, all your time helping me was due to my ignorance. I suspect this won’t be my last visit to the realm of the blindingly obvious.

    Somewhat ashamed, Stevie
     
  16. Tony Press

    Tony Press Australia Subscriber

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    @BigStevie

    Don’t be hard on yourself. I’m sure there are only a very few people here that knew of that mechanism. I certainly had no idea. I checked my BR49 after seeing Jon’s post and it has the tapered end, not the ball bearing.

    Cheers

    Tony
     
  17. Anthony

    Anthony Australia Subscriber

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    I did not know about the ball baring either.
    Without your post I still wouldn’t.
    JonD is the man of the hour on this one.
     
  18. BigStevie

    BigStevie United Kingdom Subscriber

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    @JonD You'll be mentioned in dispatches.

    Many thanks mate, Stevie
     
  19. AussiePete

    AussiePete Australia Subscriber

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    Same here mate. Had no idea of the ball bearing variant.
    So thanks to you Stevie, we all know.
    Cheers
    Pete
     
  20. JonD

    JonD Subscriber

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    Credit belongs to @Stuart Taylor since without his upload we would be none the wiser.
    Just need to find a BR49 of my own now ;).
     
  21. BigStevie

    BigStevie United Kingdom Subscriber

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    Again, thanks folks and especially @Stuart Taylor. Interesting as @Tony Press mentioned, his BR has a tapered valve rather than the ball bearing type. I wonder which was the original design and which was the modified?

    Stevie
     
  22. AussiePete

    AussiePete Australia Subscriber

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    Yes, a big shout out for @Stuart Taylor for solving the mystery.
    Cheers
    Pete
     
  23. JonD

    JonD Subscriber

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    The typed doc is pretty clear that the ball design replaced the needle version, that said, there is nothing to say they didn't revert back later.
     
  24. BigStevie

    BigStevie United Kingdom Subscriber

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    You’re quite right, and I suppose that my lamp being a 1960s BR it would have the later design. It’s a shame the Tilley document is undated.
    Looking more closely at my pre heat valve spindle I can see that the dark tarnished area (that exposed to the air) is screwing into the collar about 2mm further than it should! I should have noticed this earlier....

    Stevie
     
    Last edited by a moderator: Oct 9, 2019
  25. JonD

    JonD Subscriber

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  26. BigStevie

    BigStevie United Kingdom Subscriber

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    Just to report, new 2mm ball bearing fitted and the valve is working a treat!
     
  27. george

    george United States Subscriber

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    WOW, I didn't jinx it after all!:mrgreen:
    Really glad you got it fixed![-o<
     
  28. BigStevie

    BigStevie United Kingdom Subscriber

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    @george sleep safe in knowledge that the jinx is off!
     
  29. JEFF JOHNSON

    JEFF JOHNSON United Kingdom Subscriber

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    That's good news!:thumbup:
     
  30. ColinG

    ColinG United Kingdom Subscriber

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    Glad you got it fixed - now we need some action shots!
     

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