Primus 981 madness

Discussion in 'Fettling Forum' started by Alex74, Jul 5, 2020.

  1. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    Hi Ian

    That looks to be a nice clean example of a 981. It should clean up well. Once again, I can only stress to be careful when cleaning the nickel on the hood. I don't know what went wrong for Primus with these tops (and sometimes the globe cage as well). I suspect they outsourced production of them and the nickel quality is not what you would expect from Primus.

    I would not remove the vapouriser block from the tank. They are fitted and soldered in at the factory and are not meant to come out again. The fuel pickup is just a straight tube that is in line with the opening at the top. If there is a blockage it is just a matter of pushing a sharp screwdriver or similar all the way through.

    Jets and needles from the 991 can be used on these, so spares are available.

    I have seen examples of these where the top is just held on with the screw put in from the top and a plain nut on the inside. Maybe they ran out of top nuts at one point and just wanted to complete the order.
     
  2. CaptainFantastic

    Offline
    Joined:
    Jun 26, 2015
    Messages:
    8
    Thanks Nils.
    How do I get the pricker rod out!? It seems 'sprung' somehow but for the life of me I don't know what to push or pull to free it up :-)
    Ian
     
  3. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    There is a fitting on the side of the vapouriser block containing a spring and follower that pushes on the side of the cleaning rod. That has to come out first, then the rod should be loose enough to come past the valve shaft with the pinion gear. The shaft on these is a combined valve and pinion gear for the cleaning rod. When the valve is closed, the rod is up with the needle through the jet (or it is supposed to be).
     
  4. CaptainFantastic

    Offline
    Joined:
    Jun 26, 2015
    Messages:
    8
    Hi Nils,
    I guess you mean nut '1' in my photo?
    Also I got the stuff out of the flame thrower at '2', but what do the screws at '3' do? Do I need to take these out as well to really clean that jet?
    Thanks!

    20200712_142456.jpg
     
  5. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    It's always good with a picture. :)

    Yes it is no.1 that I meant with the cleaning rod.

    The two screws, no.3, are for access to the fuel and air side of the channels in the quick starter. I expect it was to blank holes after machining that they were put in. It does aid in cleaning if there is a blockage. Most times blockages are at the feed end of the pick up tube though.
     
  6. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Thanks Nils,

    success at last. The lever is off safely thanks to your instructions and to an old post (2012) by Carlsson which had an exploded view of the torch lighter. Isn’t it amazing what you can do on this forum?! There is a ton of information which remains accessible to members for years and years. So many thanks to Carlsson too, for writing such useful info 8 years ago. I will send a few photos tomorrow after work.

    I’m still waiting for the broken/ spares 1080 from Romania. Can I not use the pricked rod from that?

    I also managed to remove excess solder from the tank with careful application of a soft Dremel rotary tool. I don’t mind solder repairs, but they have to be even and neat, even if they’re invisible. Solder purist at heart!

    captainFantastic, I suggest your nice 981 is beyond repair and so you should send it to me for spares! :lol::mrgreen:
     
  7. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    The cleaning rod from the 1080 will be too long. If someone is handy with a lathe then could be shortened.
     
  8. Carlsson

    Carlsson Sweden Admin/Founder Member

    Offline
    Joined:
    Sep 6, 2010
    Messages:
    3,567
    The picture with the dis-assembled preheater for the 1081 in this post?
    Yes, sometimes it's true as they say; a Picture says more than a thousand Words.:lol:
    The graphite for the gland is of course too long (red Arrow below). I just placed it there to show where it should be, and roughly what it should look like. Just imagine it much shorter. Or use any other suitable packing material, like the old trick with a length of twisted plumbers tape rolled around the spindle.
    Also the lever for the torch is on a straight shaft on that version, not the tapered one.

    Skärmklipp.JPG
     
  9. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Carlsson,

    yes - thanks again. It was indeed that post (2014) but also another reply of yours posted on 5 August 2012 (8 years ago!..) In which you said....

    That's the main jet. It has nothing to do with the quicklighter you are having problems with.
    The jet is only needed if it's worn, and I'm not sure you have run your lantern enough to judge that yet?
    That nut you have gotten round aren't the one you shall tighten to tighten up the gland.
    It's the smaller hex closest to the lever. It compresses the grafite against the spindle.
    The larger hex is just seated against a metal rim inside the torch and makes a seal that way.

    Take a look at this cross section from the patent:

    View attachment 24432


    Nils, thanks for the advice. If the rod from the 1081 doesn’t fit I’ll have a little problem. I don’t know anybody with a lathe unfortunately. Unless I take it to a local workshop I guess...
     
  10. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    And here’s some photos of progress (?) as promised. The chrome plating on the tank did not even stand washing with a soft yellow sponge scourer and hot soapy water. It turned to a horrid oxidised green colour in many places. Contrary to my original thought, it had gone under that grime. So we’re going to have a whole-brass version...note the solder repair now.
    3DDBC81B-ABF3-4EE4-BAAC-0BF655FD150B.jpeg 57261B61-0CAC-4BB2-8FDE-BA16CD1AE773.jpeg DAD5BD5A-748F-4E8D-9B7C-B2CE80578777.jpeg

    the gear teeth of the pinion wheel still look sharp and decent, despite the bodged pricker wire:


    0B66FC77-FDCA-419C-A60C-5469055308D1.jpeg

    and here’s the lighter disassembled. The graphite nut looks very worn, almost crumbly. And the jet is clearly blocked. Also the internal surface of the tank appears to be covered in verdigris, some of which is flaking off. But I’m having fun!.... AD2301AD-8E98-4C76-B965-242D2454F548.jpeg AD6DD24C-A376-4D24-9B63-6FE0F184AAB5.jpeg

    7D66458D-54B3-42B8-9841-742F61287D2B.jpeg
     
  11. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    That's certainly progress. You're almost finished. ;)

    I'm surprised at the quality of the nickel on the tank. The tanks are usually very well nickeled so maybe this lamp has had a hard life.

    Have you been able to get the valve/pinion shaft out? It should just screw out but the compressed graphite is most likely stopping it. This is similar to regulating stove burner.

    The pick up tube should unscrew from the quick starter housing. The filter on the end should also unscrew. There should also be a rolled up piece of brass mesh around the tube pushed up into the opening in the housing. Here using an old drill chuck is a good way of holding things.
     
  12. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Hi Nils,

    Ah! I didn’t know that the pinion shaft unscrewed out. Now done. I can’t see a graphite packing in there. There’s a small brass cylinder and a rubber seal in good condition (still flexible and rubbery). Please see photos below.

    I’ve also unscrewed the pick up tube and end filter. The pick up tube appears to have a bend when it’s out. This was not evident before I unscrewed it. The end filter appears to be clean and the pick up tube is also free of crud as I can easily blow air through it. What’s the purpose of the brass mesh roll? It’ll be a job to push it back in now! The poor lamp is now truly and well ‘in pieces’ !!:shock::cry: And you’re right. This thing clearly had a very hard life and it must have been loved by its owners. They even went to the extent of fashioning an improvised rack pricker for it.

    The nickel/chrome literally ‘washed away’ down the sink. I have never seen anything like it and I wonder if in the early 1938 lamps destined for the UK market (as per glass globe, assuming that’s original to the lamp) the company used a too thin and poor Electroplating (?) coating. After washing, the remnants were removed easily by mere brief contact with the buffing wheel (no polishing compound required either!)

    Question. Presumably during operation the pinion chamber gets flooded with paraffin all the way up to the jet orifice? With fuel acting as a lubricant?

    I’ve now ordered a service kit and the pumpventil key tool from Fogas. :lol:

    375D0324-648C-487C-B8A2-0C60B6BF08C6.jpeg 2C833B1C-11A2-4DF5-BF8E-BF9439885986.jpeg B131380C-BC03-405A-A181-87797FA3AF22.jpeg 76475E12-1A21-4B84-9EEA-AED4CEAB151A.jpeg FFD4AE2B-3C6E-4395-8F0B-089F30326FF6.jpeg
     
  13. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    We'll start with the valve. The rubber o-ring is not original. It would normally have been a graphite cylinder. The brass ring should have one side that is flat and the other is slightly concave. I would expect the graphite to be innermost, then the brass ring with the concave side towards the graphite, then the gland nut. I will try and find one of mine that I can pull apart tomorrow evening and see if I'm right. Instead of the original graphite cylinder, you can use graphite strips or string. It all gets compressed into the right shape when tightened. The stuff from Trojandog works well.

    Now to the quick starter. The tube is meant to have that bend in it. The hole it screws into is not centered to the housing, so with the bend it ends up straight when screwed in. The hole for the air from the tank is beside the threaded hole for the feed tube. The brass mesh is to act as a filter for this. I'd say all you need to do now is make sure the jet at the top of the housing is clear then put it all together. From memory the jet is the same size as a 300cp jet, so a 300cp cleaning needle could be used to clear it.

    Looking good so far. I'm looking forward to see what happens next. :)
     
  14. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Hi Nils,

    that’s very kind of you and thanks for all your explanations. If you happen to have an original pricker rod lying around, I’d be interested to see that too at some stage, but without rushing. ](*,):-({|=

    While waiting for the key and the washers, I’ll attempt to repair the mid collar using brass sheet and solder. And the old 1081 should arrive this weekend. I might be able to scavenge a few bits.
     
  15. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    Well I pulled the shaft out of the 981 I was thinking of and it doesn't have the brass ring at all. It has had a very hard life so who knows what has been done to it in the past. I have had a look at a couple of catalogues and they actually contradict each other. One from 1939 shows the brass ring innermost, then the graphite packing, then the gland nut. One from 1945 shows the packing innermost, then the brass ring, then the gland nut. I'll see if I can dig out another one to have a look, but that could take a couple of days.
     
  16. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Greetings,

    so the 1081 has arrived yesterday. Along with the old Petromax that also came in the sale. They’re good fettling projects in their own right, especially the old Petro! As expected there a decent control wheel and the original pricker rod is there the Primus. But, it doesn’t fit in the vap of the 981, as Nils said. Also the mid collar does not fit. Ah well, I’ll have be ingenious and find fettling solutions which is where the fun and final satisfaction lies... so I’m thinking of cutting and shortening the 1081 pricker rod in the middle Of the shaft and shunt it back with a makeshift brass plate fixed with micro-screws. Solder would eventually fail I think? And the pinion shaft of the 1081 shows the brass ring and graphite packing in this order....

    A9523418-B0D6-4F58-86DD-94568227A6E4.jpeg 16CD0D3D-F69E-45D2-B6EC-3E3C40CB1ECB.jpeg 763E98D8-9F03-4130-970D-2E297192EC1F.jpeg 07D40F79-84E3-43EC-9F10-125EA3207F35.jpeg 52351352-A92E-4541-9FE6-D1FE9AFF6350.jpeg F03C7809-43F7-4864-BA8D-045314CC1965.jpeg BF00E449-BCFF-4A8C-93D8-1801AC3CBF95.jpeg DBE15C0A-9A56-439C-9872-A3AED77A8873.jpeg A129B526-E3CA-4102-9A3E-0527E5393360.jpeg 0807F157-320D-4047-BDC5-F776BF716758.jpeg
     

    Attached Files:

  17. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    Just to provide another challenge. The thread for the cleaning needle is not the same for the 981 and the 1081 (typical Primus). The cleaning needle for the 1081 uses the same thread as a 1020 which is 2.1mm diameter with a 64tpi Whitworth thread. The cleaning needle for the 981 uses the same thread as a 991 which is 2.6mm diameter with a 60tpi Whitworth thread. I have found that for a 1020 thread you can use a #2 UNF tap and die and for the 991 thread a M2.6x0.45 tap and die will work. I'll try and measure the length of a 981 cleaning rod during the weekend.

    It's a pity the 1081 is missing the inner and outer top parts as the rest looks reasonable. The chance of finding them as spare parts is pretty slim though. I would be tempted to say the 1081 is not as common as the 981.
     
  18. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Thanks Nils,

    Life is never simple, is it? What fun would that be? :shock: :rage:As I said this is my first venture out of ‘Tilley comfort land’ and I’ve already learnt loads about these lamps thanks to the advice I had here. So thanks again. Do you think I could just tap the new thread over the old one in that rod? Or would that be recipe to disaster? And yes, it would be great to restore the 1081 as well, but without the top parts is not really worth it I think. I’ll just keep it as spares/ repairs for a future project, should I come across a complete example....
     
  19. CaptainFantastic

    Offline
    Joined:
    Jun 26, 2015
    Messages:
    8
    I'm following this with interest. Thanks for all the excellent info and photos.

    So far I did not progress much on mine (got distracted by a Coleman 236). It is down to the fount but with the preheater and valve still solidly on the fount! Also, I could not get that side nut off the valve, I dare not force it too much as I'll bend the fount I just know it!

    However the good news is the pricker came out with a slight twist against the spring. And the preheater is now unblocked at the top jet hole.

    Based on "if it ain't broke, don't fix it!" I'll now soak the fount and get it all clean and see how it runs...
     
  20. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    @Alex74
    I have finally pulled one of mine apart and had a look at the parts. It is from 1948, though that shouldn't make any difference.

    The cleaning rod overall length (not including cleaning needle) is 154.5mm. There was probably some tolerance on that, so I don't know how exact it has to be. I would guess at +/- 0.5mm.

    The valve shaft on mine had brass disc, graphite then gland nut. See below.
    Primus_981_1948_valve_shaft.jpg

    @CaptainFantastic
    When there is a tight nut etc. I always try to get a solid point where I can use the clenching force of my hand. That way you avoid bending tank tops etc. For the side nut you are talking about, I would screw the vapouriser back on and use it as the fix point. See photo.
    Primus_981_1948_loosen_technique.jpg
     
  21. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Hi Nils,

    apologies for the long silence. Life took over for a couple of weeks. Back to the Primus 981. I did in fact find an old 981 manual online quoting the total length of the Cleaning rod as 155 mm, so I shortened the 1081 rod With the Dremel and threaded the new middle ends (M3 x 0.5 mm) to make a ‘fine tuning’ length rod which can be adjusted as the needle slowly wears away in time. A 3 mm copper tube has been tapped to be the coupler... it works well. I have also re-threaded the top with a M4.5 x 0.75 and the new needle fits like a glove... D39BFD89-E624-40D4-9DE4-233CD0F53DD0.jpeg FE1F09CF-6869-4748-8015-3977C0D0ABD4.jpeg 6249DC2E-AA07-4F7C-8047-CBA6FC63FE9D.jpeg 2CF6A25E-F03A-4ADA-A68C-74387B9A122C.jpeg D1D42235-F505-4212-ACD7-6CD8B87DB0B8.jpeg 895DDD61-F6C9-4216-967B-3E8A51FB50B2.jpeg 4E16388A-1F58-43DC-8D78-47DEF396FD92.jpeg

    D39BFD89-E624-40D4-9DE4-233CD0F53DD0.jpeg D39BFD89-E624-40D4-9DE4-233CD0F53DD0.jpeg FE1F09CF-6869-4748-8015-3977C0D0ABD4.jpeg
     
  22. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    But thanks for confirming the length of that rod! A couple of questions: in the NRV service kit from Fogas I found two rubber pips, one of which is rather mysterious. Where does it go?
    There is also a lead washer which I suspect goes down the pump barrel ? (I can’t see an old one stuck down there...)

    Question 2. What is there to stop the nut that pushes against the rack of the cleaning rod from leaking? Should there be a washer there too?
    2DE69F6F-FA7E-4C76-9778-5CA97D7CC924.jpeg 790BAA10-1F65-4F0B-B13A-B7DB2E40BF7D.jpeg
     
  23. Henry Plews

    Henry Plews Subscriber

    Offline
    Joined:
    Jun 23, 2014
    Messages:
    1,194
    Location:
    North Yorkshire
    If it's the one next to the spring, it fits in the end of the spring - these are the internals of the new style NRV.

    I'm guessing the non mysterious rubber pip is rather plain and looks as if it would fit in a small brass cup, this is for the old style NRV.
     
  24. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Henry,

    bang on. Thanks. Question is, shall I put the mysterious one in or not? There isn’t an old one at the end of the spring....the lamp dates from 1938 so quite an early one.
     
  25. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    We now have pressure....and the gauge still works but I had to take it apart and clean out all the dust around the coil. It holds pressure fine. Should be able to fire it up tomorrow.

    BB0BCCE2-0762-4866-8FAE-E552FFF7F905.jpeg
     
  26. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    Sounds like you got the NRV sorted. Good to see the manometer working. I have one on a 1381 which doesn't.

    Also as it's holding pressure you must have answered question 2 as well. There is not washer there. It is just a brass to brass fitting.

    How did you get on with the collar?
     
  27. isfuzzy

    isfuzzy Subscriber

    Offline
    Joined:
    Feb 13, 2014
    Messages:
    124
    Location:
    Singapore
    @Alex74 You might want to have this set handy in your shop.
    Pic just for illustration, they come in hex, round or straight knurls.
    M2 M3 M4 Male Female Hex Brass Spacer Standoff Scr.jpg
    Typical electronics standoffs, most of the time made of brass. There are sizes like M2.5, M4.5 just slightly harder to find.
    Imperial sizes not that easy either.
    If there is space at the bottom part or the top part of the rod, you can just pop in the nearest size or trim off to suitable lengths.
    I'm planning to do it to some of my lanterns. The cheaper reproduction needles are a tiny bit shorter than the originals. At the bottom part of the rod, the block only engages 2 to 3 threads, which is bad to me.
     
  28. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Hi Nils,

    yes, it’s coming along with thanks, but I haven’t had time to try assembling and lighting on Sunday. So definitely this weekend. The collar.... I decided to head your advise and ‘repair with some ingenuity...’ so I bought some fluxed brass brazing rods and a 0.5 mm thick brass sheet. I’m planning to braze the broken/ split collar with a new section of brass sheet cut to size and shape. Again the plan is to do this on Saturday. Wish me luck! Could you recommend a good mantle for this lantern?
     
  29. Alex74

    Alex74 United Kingdom Subscriber

    Offline
    Joined:
    Oct 13, 2019
    Messages:
    309
    Location:
    Faringdon, Oxon
    Thank you for the brilliant advice on small parts. I’ll definitely consider buying more consumables and small parts as I get more involved with the hobby.
     
  30. Nils Stephenson

    Nils Stephenson Founder Member

    Offline
    Joined:
    Sep 9, 2010
    Messages:
    2,586
    Location:
    Copenhagen, Denmark
    I use Optimus 250cp mantles on mine, but that is because I have quite a few of them. Any 200 to 300cp bulb shaped mantle should work well.
     

Share This Page