Restoring a Petromax 827 (newbie..)

Hi again!

First of all I would like to say thanks for the warm welcome I got when I joined this forum!

So, I’m restoring my first ever preassure lamp, a Petromax 827, which was dated on here to between 1937-1940. For any of you kind enough to help me along the road I’m gonna use this thread for my adventure.

Today I have dismantled it and brought the parts to my brother who’s got an ultrasonic washer to get them a proper clean up.
The parts:



Would you say I got everything out/apart? There’s still something inside the housing on the part furthest to the right on the picture, but I could not figure out how to get it out...
Any parts, you can say just by looking at my picture, that needs to be replaced?

Please bare with my English and my lack of knowledge regarding the names of the different parts...

Thanks in advance!

/Peter

 

Peter,

that doesn't look too bad. A problem could be the fuel pickup tube of the preheater. You should remove the small filter at its lower end, and carefully try to screw out the tube from the nozzle. Otherwise I'd suspect that you wouldn't get the muck out of it.

And there's still another important part missing on your picture: The pump valve should also be restored to a good working order. If you look inside the pump tube, what do you see? There are two different types of valves, and for one of them you will possibly need a long flat screwdriver to remove it, the other could only be done with a special tool. Here in the forum you will find how to make one by yourself. Just search for the words "NRV tool" or "pump valve tool".

Thirdly I'd suggest that you also give the upper part of the jet and the vaporizer (inside and outside) a good cleanup.

You will also need for sure some spare parts: Viton rubber seals for the valves, lead washers for the vaporizer, preheater and pump valve, and maybe some graphite packings for the gland nuts. Maybe also a new jet & pricker needle.

/Martin

 

@Peter

The preheater parts circled in green should be thoroughly clean. Check all the tiny holes are not blocked.
The preheater parts circled in red are Martin just said. The tube could be unscrewed from the nozzle. Its easier to ensure thorough cleaning that way.
The one furthest to the right you mentioned (circled in red) is the lower vaporizer part with the fuel pickup tube. That's soldered into a single piece and whatever still inside is either dirt/muck or sometimes, an added wire mesh by someone. Immerse it first in an alkaline degreasser to dissolve all varnished or gummed up old fuel.
You can use the ultrasonic cleaner to finish up the rest.
What about the Preston loop vaporiser upper part and jet? They're usually coked-up.
Pump parts as mentioned by Martin too.
Burner parts: j-tube mixing chamber, inner burner hood, ceramic nozzle etc.
And yes, the fount/fuel tank. Its not unusual that these are full of varnished fuel, some dirt and so on. Make sure that is really-really clean before you re-assemble your 827.

 

Could be the eccentric block that attaches to the conducting rod that is still inside the lower vaporiser

 

Ok! Thank you. I’ll try to get the pre heater pick up filter and tube apart as well. I think Phaedrus is right about what’s still inside my lower vaporizer. It’s not dirt or debris by the look of it. Is there a way to get it out?

I’ll post som pics of the jet and upper parts tonight! Looking forward to your comments on them!

Brg,
Peter

 

I'd say that should be it. Its missing from the earlier picture. It should drop right out of the lower vaporizer unless its blocked by dirt, etc.

 

I think I’ll have to make one of those NRV tools...I found the thread were @pheadrus42 (Phil is it..?) explained how he made his...so if I understood it right it’s basically a rod wit a nut (filed to fit snug into the chamber) and a slot in the nut to fit the nrv? Could anyone tell me the width of that slot?

 

The slot in the tool should be 5mm wide and 4mm deep. Here are some photos of a similar valve, as a whole and disassembled. On the last two pictures you can see the cork seal inside a small brass sleeve on top of the spring, which most likely has to be replaced.

 

Hi Peter,
Do you have a manual for this type of Petromax ?
If so you can see what parts tehre are and how they are named. Don't worrie about the english and how you call the parts, we have a wide language knowledge.

Most rare and not replaceable is the rapid pre heater. The red and green parts.
Like Martin said, there carefully to remove the filter at the end and the fuel pipe itself. DON'T TWIST THE PIPE.

The loose part is the extender block and blocke by pakking material ?

Since the Ehrich&Graetz and Graetz didn't change dimensions, new parts still fit.

Have fun !

 

Got it! Thanks!

So by now all parts should’ve been taken apart...got the preheater tube, nozzle and filter apart. The eccentric block is out. And the nrv is out. I’ll leave all the parts overnight in alcalic degreaser, rinse them off and shove them in my brothers ultrasonic washer within the next couple of days. Hope you guys approve on my plan

 

That sounds good, and you seem to have quite a bit of craftsmanship and the right tools.
As you can see the NRV's lead washer is scrap after removal, and so are those located at the vaporizer and the preheater. You also need two rubber seals for the NRV and for the fuel valve at the bottom of the vaporizer's fuel pickup tube. New parts are still to obtain and will fit without problems, as WimVe already wrote. Maybe you should also think of acquiring a new jet and needle.
As MYN said, a thorough de-coking of the upper vaporizer from the inside will save you from lots of frustration, and can be done by drilling out the straight part (note the reduction near the Preston loop), use the inner wire of a bicycle bowden cable to clean the Preston loop, and maybe try some heating & quenching (but that bears the risk of breaking/weakening the solder joints).

 

Those led washers, can they be replaced by heat resistant fabric sealers/washers?
I ordered a new needle, needle tool, flame tube and a couple of matels already...in hindsight I should’ve waited with my order to get all the parts I need at once...
Will give the upper vaporizer and loop a good brush up tomorrow!
By jet, do you mean the “U shaped tube at the top”? Does the jet commonly fail? To me it looks just like a bent tube...

 

To my knowledge these lead washers cannot be replaced by other material with good results. At some joints you could use PTFE gas tape, but the vaporizer and the preheater must point in the right direction and be sufficiently hard to move, otherwise they loosen during operation/handling. Some heat resistant silicone rubber washers might work, but I've not yet tried this.
The hex nozzle which is screwed on top of the upper part of the vaporizer (where the needle goes in) is called the jet. Its orifice is often enlarged, which will result in a rich fuel/air mixture and poor yellowish and hot burning. It is therefore also essential that the jet fits tightly in the vaporizer, so no leakage at the thread seat must occur. There's no extra seal (brass on brass), so be careful not to damage the seat rim during cleaning.
The U shaped tube is actually called J-tube .

 

As Martin says; the jet is the hex-shaped part on top of the vapouriser, sometimes also called 'nipple'.
I guess that you speak Swedish, and in that case it's the same as "munstycke".
Are you Finnish-speaking, it's called "Suuttimet", as you can see in this page from Petro-Valo that I have posted in the reference library:

 

I'm not sure what you meant by the heat-resistant fabric sealers/washers, @Peter .
Is it a fabric impregnated with silicone rubber or something else?
I wouldn't use any that's porous.
I've tried silicone rubbers and sealers. They are not suitable because they swell up after a while in contact with kerosene or gasoline. So, they are not fuel-resistant.
If lead washers are unavailable, PTFE tape on the threads(as Martin said) of the nrv would work as well. Otherwise, you can punch a similar piece from HDPE sheet. These are sufficiently soft and fuel resistant.

 

Well, I’m going with lead washers. On my way to pick up some lead now and punch out washers...

@Carlsson swedish speaking...

 

Was going to cut me some lead washers from a lead sheet I got today. But after a good few glasses of wine I decided to stay away from those precision tasks tonight and went for a good old scrub up. Came out quite nice...



Have yourself a nice weekend!

/Peter

 

Uppdate.

Finally got all the parts I needed to replace.
Questions/problems that occurred:

1. The treads where the jet goes in are unfortunately wasted. Is it possible to use thread sealant to seal it? Or anthing else?
2.Can’t for the life of me understand how one should fit the needle through the jet? It must be the smallest hole on earth in the jet...
3. Can I light the lamp without the needle?

Thanks in advance!

Brg,
Peter

 

The jet gets considerably hot, so lead and PTFE seals won't work. But you can try to seal the thread with some soft soap. Muffler putty is not recommended, because it will be very hard to remove. Anything else will not work.
Have you bought the right size(s) of needle and jet? Usually there is no problem to fit the needle. Of course you can try to use the lantern without needle, but any piece of debris that blocks the jet will prevent operation, and you will need to clean it from the outside, which is quite difficult during operation (you will have to remove the hot hood). With the needle it is possible to clean the orifice from within easily.

 

1. The short answer is no. Best to get another Petromax 250cp vaporiser or an Optimus 200P or Optimus 930 one. They are close to identical and will work perfectly.
2. The needle screws into the top of the conducting rod before you install the jet.. There is a little triangular tube tool for this, but it is not essential.
3. Yes, but better to install the needle as was intended.

Did you notice that the screw thread in the vaporiser was damaged when you removed the old jet? Does the old jet still screw in properly? Is your new jet exactly the same size as the old one?

 

@Martin K. Yes, i think i got the right needle for my jet. Ordered them both from the same place, fogas.se, a really helpful guy, Conny helped me with the parts I needed. Soft soap? I’m sorry but I think you lost me there...

@phaedrus42
1.yes. I will defineatly get a new one. Problem is I’m so exited to get it lit I’m crawling out of my skin over here...
2. Yes. I got the tool. But I couldn’t get the needle aligned with the tiny tiny tiny hole in the jet...mabye I’m doing something wrong.
3. Will absolutely do! But as I said, very eager to try it out. Got everything else sealed up and got good preassure when I pumped it up so it was very frustrating when the jet was leaking...

The old jet is clogged up with what I guess is an old needle. Can’t get it out. To be hounest I don’t know if I destroyed the threads with the new nozzle or if they were shot even before I tampered with it.

/Peter

 

@Peter Soft soap = liquid soap.
When it gets hot it first generates a kind of foam which then carbonizes when further heated. As long as the thread is not moved it will form a seal and stay tight.

The needle is basically self-aligning as long as the wire is straight. It should drop into the orifice easily when done by hand. Perhaps you haven't adjusted the length of the needle rod correctly? The needle should pop out 0.5mm - 1mm (max) when in upper position.

The needle is not meant to act as a valve when in upper position. This job is done by the vaporizer's foot valve at the lower end within the tank. When the needle rod is in upper position the spring will press the rubber seal at its seat. The valve is opened by lifting off the seal from its seat when the rod is in the lower position.

 

@Martin K. Oh! Had no idea about that! So regular hadsoap ok? Do I dip the nozzle in soap? Spray soap on it while it burns? What about the petroleum leaking out until the soap seals the leak? Won’t it create an inferno?

Thank you for all your help, Really appreciate it!

Brg,
Peter

 

The order of assembly: Put everything together finger tight for testing and tighten up fully after testing the adjustments. Use copaslip or other copper grease on threads.
-Conducting rod and eccentric block in lower vaporiser.
-Control wheel assembly fitted to lower vaporiser.
-Upper vaporiser without jet fitted to lower vaporiser. Check that conducting rod is centered in upper vaporiser and can move around laterally freely inside vaporiser. Not just up and down but it must be free sideways. If it is not, something is bent. Disassemble and straighten conducting rod and/or vaporiser. If you do not get this right you will break needles and/or wear out jets.
-Needle screwed into conducting rod from the top of the upper vaporiser.
-Jet fitted to upper vaporiser.
-Rotate control wheel to check that needle protrudes 0,5mm-1mm max through top of jet when in up position.
If not, remove upper vaporiser, remove control wheel assembly, adjust length of conducting rod where it screws into eccentric block.
-Reassemble and test again.
-Then when it is correct, tighten up everything.
-Voila!

 

...you should not use handsoap because of its composition & additives. Just put some pure liquid soap (German: Schmierseife) at the threads before screwing the jet in, and thoroughly keep the inner hole free. Then you can preheat just as normal.

As I wrote in the edited post above: When the excenter is in the upper position the spring loaded foot valve should be firmly closed, and no kerosene should come out of the jet while pressurizing the tank. That is a required prerequisite to use the torch preheater. Otherwise you would create big flames, smoke and soot while trying to light.

A simpler way would be to install a meths cup. Then you can preheat without pressurizing the tank, and start to pump when the vaporizer is hot enough and the preheater's flames are just about to extinguish.

 

Not sure about Finland but here in South Africa one can still buy blocks or bars of hard laundry soap: translucent green or white with blue speckles. We call it farmers soap. It works very well for this application.

 

@phaedrus42 That should also work well, chemically very similar, but not as easy to apply.

 

@phaedrus42 @Martin K.
Thank you for all your input guys!

I think the best way forward for me is to get a new upper vaporizer. The more I look at the one I got the more it looks a bit bent. The conducting rod is slightly out of alignment when looking down the upper vaporizer.

I did fill the tank and pressurized it and couldn’t see any leaks anywhere but where the jet screws into the vaporizer when turning the control wheel.

/Peter

 

Bent vaporizers are just normal. Simply straighten it and it will work. Don't forget to straighten the rod as well, as Phaedrus said.
A more serious problem is the ruined seat where the jet is screwed in. Maybe you can flatten it by grinding it down cautiously? In lighter cases I had success when tightening the jet while the vaporizer is hot.