Roundhouse Jack Lighting and Running problems

dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
13,680
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St.Neots Cambridgeshire UK
#1
My long suffering Jack dated 1992 is having some serious issues. It has been fitted with a Chuffer Pipe and a SloMo. In truth it has had issues before but these manifested themselves last Xmas and it has been lain moribund till I tried to Steam it up the other day. I did get Steam Up, but that took in excess of 11 Minutes with Water and the Loco both at House Temparature which is far too long. Getting the fire Jack to Pop back into the Tube was a long drawn out process. Also the Gas Jet is not screeming as if there is a Lack of Fire or Burning of the Gas. I did wonder if I was Gassing up the Tank fully so have swopped out both the Gas Input Ronson Valve and the Gas Control (having one in stick) as well. This has made no difference. Adjusting how the Poker was in the Tube by pulling in and out a little to change the supply of Air to be greatervor lesser has also had no effect.

So poor Jack is in bits on the workbench.
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Next thoughts are still to the input of Air and having removed the Poker it appears that there is a severe bend where the Poker attaches to the Boiler, I suspect that this may be allowing Too much air into the Fire Tube.
112462_073e7dc76fd983a10a8493732b5fe469.jpeg

Also where the Steam Pipe passes into the Fire Tube, the Tube has been bent possibly allowing even more air into the mix.
112461_7449f52ae512d59be58640b8434c6628.jpeg

Any thoughts would be welcome.

Finally to get the Chuffer in Place I had to cut the Exhaust Pipes some when fitting the Chuffer Pipe, I overdid this and made up the two part piece over of the said Exhaust Pipes. Can be seen balancing on one of them. I should add thatbthis is a Push Fit rather that a Silver Soldered one due to the difficulty if putting Jack back together when in place. This I believe also has the issue of chucking Exhaust Steam into the Fire Tube thus putting out the Fire, something that has on ocasion been occuring. But that is once I get the Fire going!
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G-force1

G-force1

Prevarication Rules!
4 Aug 2015
3,136
1,160
North Middle Earth
#2
I would change the gas jet as a matter of course, it could be worn, and at least that should eliminate one major source of problems.

The 'ding' in the flue pipe should be possible to mostly correct by inserting the correct size of bar inside and CAREFUL dressing with perhaps a flat punch and 'tapper' (NOT hammer). 'Tis copper should be soft enough.
 
Rhos Helyg Loco Works

Rhos Helyg Loco Works

Registered
#3
Where do you put the flame when lighting it? Under the front of the loco, where the gas has fallen (heavier than air)? Or at the top of the chimney, where the gas might be if you wait long enough?

The chuffer pipe always makes them harder to light at the chimney top, but then why would anybody do that anyway...?

One modification you might consider with the loco in this disassembled state is making the smoke box removable without having to remove the boiler and most of the loco's front end. A bit of cutting and drilling and tapping two holes will do it, and it will end up as per current Roundhouse locos. You can then light it up with the smokebox removed and see what is going on.

As for the burner, make sure you have some PTFE tape around the gas jet threads before screwing it back in to its housing. You should be able to see through the gas jet, and pumping some water through it with a syringe will tell you how accurate the hole is ... should get a small but solid jet coming out square to the end. Any dribbles or misalignment could cause the problems you describe. If it doesn't look right, using the same syringe suck some water through the jet, which should clear any debris.

You'll probably need to replace the superheater tee O-rings before you put it back together. They have a tough life.
 
Last edited:
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
13,680
3,201
70
St.Neots Cambridgeshire UK
#4
I would change the gas jet as a matter of course, it could be worn, and at least that should eliminate one major source of problems.

The 'ding' in the flue pipe should be possible to mostly correct by inserting the correct size of bar inside and CAREFUL dressing with perhaps a flat punch and 'tapper' (NOT hammer). 'Tis copper should be soft enough.
Thanks will do both of those suggestions to see if they work. Have a few spare Gas Jets, never thought to change that as it is passing gas OK.

Where do you put the flame when lighting it? Under the front of the loco, where the gas has fallen (heavier than air)? Or at the top of the chimney, where the gas might be if you wait long enough?

The chuffer pipe always makes them harder to light at the chimney top, but then why would anybody do that anyway...?

One modification you might consider with the loco in this disassembled state is making the smoke box removable without having to remove the boiler and most of the loco's front end. A bit of cutting and drilling and tapping two holes will do it, and it will end up as per current Roundhouse locos. You can then light it up with the smokebox removed and see what is going on.

As for the burner, make sure you have some PTFE tape around the gas jet threads before screwing it back in to its housing. You should be able to see through the gas jet, and pumping some water through it with a syringe will tell you how accurate the hole is ... should get a small but solid jet coming out square to the end. Any dribbles or misalignment could cause the problems you describe. If it doesn't look right, using the same syringe suck some water through the jet, which should clear any debris.

You'll probably need to replace the superheater tee O-rings before you put it back together. They have a tough life.
Lighting up tried at both ends though normally through the Top of the Chimney and yes that has been a bit trickier since the Chuffer Pipe added, but Stanley not changed - wierd!

Looked at the Pop Rivet joints in the Smokebox and wondered if a Nut n Bolt Options would be workable, all 3 of my Roundhouse Locomotives are quite old now so I think all 3 are Pop Riveted. Jack certainly is.

Tried out the flame test on all the screws the other day and no leaking Gas Found, but PTFE certainly a good belt and braces thing to do. In the past when I was messing with puffers more than now I would have done that, just like a Politician lessons have been forgotten!

RE THe superheater T Rings, good suggestion as there is a lot of Steam from the bottom end when running, though it does look good! They Neoprene?
 
Rhos Helyg Loco Works

Rhos Helyg Loco Works

Registered
#5
The pop-rivets can stay. It is the smokebox mounting plate and the frame spacer that need to be drilled, allowing smokebox and plate to be removed as one item. The smokebox just needs the hole in its base turning in to a mouse hole, i.e. not a hole at all, open at the back.

O-rings are nitrile.
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
13,680
3,201
70
St.Neots Cambridgeshire UK
#6
I would change the gas jet as a matter of course, it could be worn, and at least that should eliminate one major source of problems.

The 'ding' in the flue pipe should be possible to mostly correct by inserting the correct size of bar inside and CAREFUL dressing with perhaps a flat punch and 'tapper' (NOT hammer). 'Tis copper should be soft enough.
So I have been at Jack again, Gas Jet appears to have been the issue though I have flattened the Holding Sort of Washer for the Poker which I also suspected to be letting in too much Air. Pleased to report all is well with a typical nice Roundhouse Roar to the Burner. Fired up and running just fine. Thanks for the suggestion Tony. All I need to do now is refit the Chuffer Pipe.
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
13,680
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70
St.Neots Cambridgeshire UK
#7
Happy to report that all of the issues have been resolved.
-New Gas Jet (thanks to G-force1)
-New RH Gas Valve tgat was in Stock though I think the old one is actually OK

The Loco was pulled apart and put back together umpteen times during the work. One thing that has helped was to cut a grove so that the Smokebox is removable without taking off said Steampipe. Rhos suggestion was unfortunately not practical as I have added a new Buffer Beam and the 2 screws that hold it on and a nut n bolt at the rear of the Smokebox make it easy enough to remove, particularly since my mod just mentioned. Most of the faffing was to get things boiling and working, to this end taking off just the Boiler was the easiest operation. Once a satisfactory Steaming Rate was obtained then it was the Chuffer, this is a much faffed about item with the Pipes of the Exhaust having been cut too Short meaning that it was too low in the Chimney to work. A bit of Silver Soldering to make what I believe could be called ‘Petticote Pipe’ using 3.0 and 3.5 KS Tubing has resolved fitting. Wire on the Chuffer now holds it down on the Exhause Pipes. Vid below showing him working with possibly nit the loudest Chuff, but good enough. Next task to see if that Roundhouse Howl can be tamed.


Note even though this is a Test Run Signals must be obeyed and returned to Danger after being passed! Wagons are my French ones with my recently competed French Van having it’s first Steam and Video run.

Thanks again for all the help and suggestions, been a while since I was pulling a Dragon apart and much of the tech forgotten!
 
TLR

TLR

anything to do with model L/S loco's boats etc
24 Oct 2009
455
38
62
Clacton on sea Essex
#8
Happy to report that all of the issues have been resolved.
-New Gas Jet (thanks to G-force1)
-New RH Gas Valve tgat was in Stock though I think the old one is actually OK

The Loco was pulled apart and put back together umpteen times during the work. One thing that has helped was to cut a grove so that the Smokebox is removable without taking off said Steampipe. Rhos suggestion was unfortunately not practical as I have added a new Buffer Beam and the 2 screws that hold it on and a nut n bolt at the rear of the Smokebox make it easy enough to remove, particularly since my mod just mentioned. Most of the faffing was to get things boiling and working, to this end taking off just the Boiler was the easiest operation. Once a satisfactory Steaming Rate was obtained then it was the Chuffer, this is a much faffed about item with the Pipes of the Exhaust having been cut too Short meaning that it was too low in the Chimney to work. A bit of Silver Soldering to make what I believe could be called ‘Petticote Pipe’ using 3.0 and 3.5 KS Tubing has resolved fitting. Wire on the Chuffer now holds it down on the Exhause Pipes. Vid below showing him working with possibly nit the loudest Chuff, but good enough. Next task to see if that Roundhouse Howl can be tamed.


Note even though this is a Test Run Signals must be obeyed and returned to Danger after being passed! Wagons are my French ones with my recently competed French Van having it’s first Steam and Video run.

Thanks again for all the help and suggestions, been a while since I was pulling a Dragon apart and much of the tech forgotten!

Perhaps you should turn down the gas burner , you are wasting a lot of steam through the safety valve. The loco should be capable of hauling a load without blowing off all the time.

Shaun
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
13,680
3,201
70
St.Neots Cambridgeshire UK
#9
Perhaps you should turn down the gas burner , you are wasting a lot of steam through the safety valve. The loco should be capable of hauling a load without blowing off all the time.

Shaun
Was turned down just before the vid and it soon gets loud / blowy off again. RH Gas Valves are not renown for their subtelty of control. There is a guy in the US that makes RH Gas replacement needles that are a lot finer. Not heard of anyone that has one as yet but it may be a possibility.
 
M

My45G

Registered
9 Nov 2016
31
26
Henley
#10
The later Roundhouse gas valves are better than the earlier ones. They used to creep back up caused by tension in the rubber O ring. Roundhouse later fitted a spring behind the knob to try and stop this happening with some limited success. I run at exhibitions in noisy halls and the trick is to be able to turn the gas down as low as it will go without turning it out, difficult when you can't see the flame. I drilled a 1/16th hole in the knob and fitted a short length of brass wire to act as a pointer and fixed another piece to the cab rear and when the two are in alignment, the burner is about as low as I can get it.