Petromax 821E conversion to petrol/Benzin?

Discussion in 'Fettling Forum' started by Harder Sorensen, Mar 24, 2019.

  1. Harder Sorensen

    Harder Sorensen Subscriber

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    I could use a bit of advice - I have a well serviced PX 821E, and I was wondering, what it would take to convert it properly to petrol/benzin?
    As I can see - I’ll be needing a 250HK benzin-/universalvergaser, but are there other issues I should be aware of? (My washers and pips are Viton).

    Thank you in advance
     
  2. MYN

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    To be honest, its not very easy to convert it to safely run on 'Benzin'/petrol/gasoline.
    At the minimum, you'll need to install a positive shut off valve(like those found on Coleman white gas-fueled lanterns).
    The pump nrv end should have an outlet tube extending to the upper air space in the fount. Besides, there should also be a positive lock down valve on the pump itself to ensure no leakage in case the ntv fails.
    In addition, although not absolutely critical, the air inlet should be extended lower down by means of a tube(s) to avoid exposure to intense heat under the hood. That's to prevent hot fuel from spraying outwards in case the jet somehow got clogged partially and the fuel stream is skewed.
     
  3. phaedrus42

    phaedrus42 Subscriber

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    Harder, as @MYN said, it cannot easily be done safely. Best advice is to get a classic Coleman like e.g. the 242B or 200A. They are really good little lanterns, and designed to safely use white gasoline/Coleman Fuel. The fun part is the instant lighting with no pre-heat required.
    For ordinary unleaded petrol, either a 249 or 237 which will run on paraffin too but will need pre-heating or you could look at the Coleman Premium or Powerhouse Dual Fuel / Unleaded lanterns, but you may be disappointed with the materials quality.
    Unleaded petrol is smelly stuff that goes bad quite quickly in a lantern and tends to clog up generators much sooner.
     
  4. WimVe

    WimVe Subscriber

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    You can't shut off a petromax when it starts leaking badly by the pumpvalve.
    Or somewhere else for my part.
     
  5. george

    george United States Subscriber

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    Agree with Vim, not a good idea to convert the 821E to burn gasoline. Stay with kerosene and be safe![-X Hair and eyebrows take too long to grow back!:roll:
     
  6. ColinG

    ColinG United Kingdom Subscriber

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    The easiest answer is simple - don't do it.

    Others will have pointed out the safety reasons why you shouldn't - trust them, it's absolutely critical.

    A year or so ago, a guy in the US was using a Coleman petrol/gasoline/naptha fuelled item (no-one knows if it was a stove or a lantern) and it malfunctioned. His burns were so severe he died. Converting a kero based lantern to run on petrol/benzin makes the chances of a catastrophic failure much more likely, with potentially devastating consequences.
     
  7. Harder Sorensen

    Harder Sorensen Subscriber

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    Thank you all for good and sound advice (have sacrified several times x eyebrows and hair, incl. 3 x Eye surgery in my younger years ](*,))

    - but I wonder, how come we have been using the same NRV design in our Optimus 111B for ages - and still do. Eventhough the fuel is much closer to the flame compared to a lantern mantel behind a globe?

    Several armies have used the smaller PX with petrol for a decade or two?
    The accidents which now and then took place - how many were caused by pure stupidity or neglient maintenance and how many were actually due to malfunctioning NRV’s?

    Looking at a beauty like this made on specific NATO specs (Petrol and 10 hours continous burntime) - they can’t be that bad? Or are even this one a disaster waiting to happen?

    7CE8AA72-30A4-46F2-9B32-0E413F57CAB5.jpeg

    (Picture borrowed from Finn Hjelmerud)

    That said - I will definately reconsider my project.
     
    Last edited: Mar 25, 2019
  8. ColinG

    ColinG United Kingdom Subscriber

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    Maybe the military spec ones had built in safety features as part of their design? The matt chrome finish looks pretty badass actually!
     
  9. JonD

    JonD Subscriber

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    Isn't safety in a military environment something which is "relative" and even then quite a new idea? (Compared to the lamp designs under discussion at least).
     
  10. MYN

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    There are no additional safety features in the military Petromax(Bundeswehr) as compared to the civilian ones.
    The only differences are having a straight vaporiser instead of a Preston loop, supposedly meant to burn 'Benzin' and has a matt finish.
    Provided there are no defects on the lantern, you can still burn petrol in any such Petromax, including civilian ones and light up fine.(I've done that).
    Only thing is, you can't do it safely. And you do at own risk. For instance, should the NRV fail when the lantern's in operation, it'll flood the pump and surroundings with petrol and that'll burst into flames almost instantly, well before you could do anything to stop it.
     
  11. Harder Sorensen

    Harder Sorensen Subscriber

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    @MYN
    Thats true - but yet a lot of us use the Optimus 111B with the same lack of safety?
     
  12. MYN

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    I'm afraid so. But then, the Optimus 111B has a rack-pinion type of cleaning needle/shut off at the burner. The gearing mechanism is strong enough to allow you to seat the cone snugly on the jet to cut off the fuel. You could still turn off the flames on the roarer burner with that.
    The guys over at CCS would have a better idea to advise on that.
     
  13. Mackburner

    Mackburner United Kingdom Founder Member Subscriber

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    It's all about risk assessment ie what can go wrong and what are the possible consequences? A Petromax has a pump check sitting in the fuel and a shut off in the fuel feed both of which have spring loaded rubber seats. So can they fail and what then happens. Yes they can, not often maybe but it happens, and then you can get a full tank of fuel vented if the pump nrv fails. With kero that makes a mess, with gasoline it makes a fire and a pint of gasoline can certainly kill.
    Have a look at this article https://classicpressurelamps.com/threads/exploding-petromax.238/ which looks at the design of Petromax in particular with regard to safety. ::Neil::
     
  14. phaedrus42

    phaedrus42 Subscriber

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    @Harder Sorensen , I once tried to ease the tank pressure on an Optimus 111B while it was burning. The fumes made a whoosh! and scorched my arm hair. :shock::rage:
    Granted, the 111B runs at lower pressure and the total volume of fuel is smaller than in a lantern but they were also not originally designed for gasoline and I use mine with some trepidation and respect. I feel much more comfortable using a 111 with paraffin.
    I do not shy away from using gasoline in stoves and lanterns that were designed for it though. I love using my Speedmaster 500 and Primus 1060 as well as the Coleman suitcase stoves.
     
  15. WimVe

    WimVe Subscriber

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    Leaking kerosene gives also a mess but it ignites not that quick.
    As fas as I know only the Swiss army used petrol in their modified petromax lanterns for a long period of time.
    The risk analyses should also include the toxic fumes when burning gasoline inside small structures like tents and bunkers.
     
  16. Harder Sorensen

    Harder Sorensen Subscriber

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    @Mackburner
    I most definately tip my hat to that very thorough description/dissection you kindly linked to!
    You’ve got some persuasive points, to which it is hard to argue against.

    I wonder how many in here still use their Army PX -Benzine versions with Benzine?

    @phaedrus42
    A Primus 1060 is sooo high on my wishing list - sadly they rarely surface!
     
  17. Mackburner

    Mackburner United Kingdom Founder Member Subscriber

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    Use of lamps and stoves in confined spaces is indeed a risk and not just for gasoline. The fuels may be different but the products of combustion are the same and the dangers are CO and CO2. One poisons and the other asphyxiates but the end result is still death. In a tent with a fitted groundsheet there is also the risk that if you have a leak and a fire there may be no escape.

    These risks also have to be considered in houses. Older properties with open fires were draughty because an open fire demands an air feed and they had to be draughty or a fire would not draw so good air flow though badly fitted doors and windows was actually essential. Using gas or kero lamps in such properties was never a problem because there was always good ventilation. Modern houses tend to be much more leak tight and therefore with double glazed openings and no chimneys there is the risk of a dangerous reduction in oxygen and build up of toxic gasses. That is one reason that people die from badly maintained gas and oil boilers. A well fitted boiler has its own vent but lamps in a house do not and require separate ventilation. ::Neil::
     

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