Aligning smoke unit with stack

Do you know whether the unit has ever been replaced?  There have been several different units installed in MTH RK Challengers since they debuted about 1992.

I think its original. It was aligned before I took the shell off

I'd remove shell and see what got messed up.

Make sure the chassis is flush to the base of the boiler. I usually shine a light down the stack and peer down to see if things are lined up. Removing your eye correction and looking close with one eyeball will help.

I've also found some steamers like the front of the boiler to lower down slightly first then the cab or vice versa.

ok thanks!! I'll try that!

I just put an old PS1 smoke unit into a PW rebuild that I did.  I took advantage of some existing holes and a few brackets I had laying around, and the smoke unit aligns about halfway back the stack in the shell.  There' enough exposed area for me to fill the unit using a syringe, and there's enough smoke coming out that it's satisfying.  

But it's just enough interference that when I'm under full power, the smoke does start to escape down around the steam chest at the drive rod level, which I actually really like!  Seems like there's a bot more realism there. 

I thought about leaving it, but the smoke coming out the stack isn't forced and just seeps out. not the best look

I've tried and tried,  Nothing I do seems to align it properly. Smoke still comes out the bottom and softly out the top. I guess I'll step away from it. Also broke a small wire to the marker lights. Dang it!! Very Frustrating. Guess I'm not holding my mouth right or something.

HEY  Rest,

I've worked on the smoke on Railkings.

Only four things I can think of.............                                            1) WICK....... the wick sometimes is partially blocking the funnel opening or the blower fan opening.

  2) GASKETS....... when replacing the smoke stack if you have removed and replaced the inner funnel......make sure the gasket  (I think red ) did  not get squished over some of the opening  Make sure the larger gasket between the smoke unit and smoke unit cover is bolted down well.

  3) WIRES......hopefully there is not one of the electrical wires for the marker lights caught between the metal boiler stack pipe and smoke unit funnel  openings.  If so, reposition it before a short 😨 develops. 

 4) ALIGNMENT.......make sure the alignment is good between the smoke unit and the boiler opening like Rick O mentioned above. 🙄

Good luck , have fun and be observant 🤓

@RWillSr posted:

I thought about leaving it, but the smoke coming out the stack isn't forced and just seeps out. not the best look

Now you've said something that resonates.  I think the smoke unit needs a little maintenance!  Sounds like either the smoke motor isn't work, or the impeller is loose on the shaft.  If you hear the motor pulsing for chuffs, and you don't see a nice plume of smoke coming out as some velocity, it's very likely you need a new impeller.  You can try a little CA adhesive on the shaft of the old one, but that's not a permanent fix in my experience.

When I take the shell off and run the smoke unit full on, it’s pours out smoke and chuffs properly. As it’s smoking, I put my finger over the chimney from the unit and I don’t see smoke leaking. The problem seems to only occur when I put the shell back on.

Did you sight down the stack and see if it's aligned?

I lined it up as best as I could.  It looks like it is right. Maybe a little forward? I don’t know.  There’s a groove and a gasket on the inside of the boiler at the smoke stack where to smoke unit funnel meets the boiler shell.  My hunch is that there’s a gap somewhere in that area and it’s leaking the smoke.  

thanks for talking me thru this. 
 Maybe a need a new gasket?

On some locomotives I find that I have to iinsert a small screwdriver down the stack and "pull" the smoke unit into alignment with the shell stack opening.

HEY RW,

my suggestion #4 would be a tough one on the dual stack Challenger if you try to align everything by looking  down the boiler openings.

It sounds like you are doing the best by observing the situation from the inside.   I'm not sure what kind of material you might safely use for sealing.

If I remember right the Challenger smoke unit has a bolted down funnel so it wouldn't be something that would have been bumped down by accident.

Is the top of the smoke unit funnel smooth with no chips or dents ?       If the alignment looks " a little forward " is it possible the smoke unit screws are loose or is the smoke unit support bent ?

Actually, the funnel on the Challenger is pretty easy to spot if it's not centered, it's like most dual-stack locomotives.

It looks centered.  Maybe it’s just not seated all the way?!  I was looking for my of my bent picks to feel inside for any gaps.  Haven’t found it yet 

My confusion stems from the fact that you said it works great with the shell off.  Yet, with the shell on, and clearly seeing the funnel under the open stacks, it doesn't work.  That  suggests to me something is affecting the smoke unit operation, not that there is some leakage.  If the funnel is right under the stack and the smoke unit is working normally, most of the smoke will still come out the stack.

RW,

got a video of this issue ?

I’ll record it tomorrow and post

thanks everyone!!  

thanks everyone! 

RW,

The way the smoke is just drifting out around the front of the boiler area makes me wonder if there is a leak at the gasket where the funnel is bolted to the smoke unit .........or is there the presence of fluid residue on the outside of the smoke unit and sourounding area.

In your video was this as a maximum smoke setting fully warmed up ?

RW,

Outside of the fact that a not to good oily residue building up  in the internal area of the engine , the video of the drifting smoke made me think of the real Challenger.  🤓

However, the smoke in your video makes me think of what GRJ mentioned in a different post about filing the smoke stack area to even out both stacks  performing equally....................there isn't any obstruction in the stack is there ? 😨

..

There’s no obstruction other than where the smoke unit funnel gets divided between the two stack openings.  

Video, without boiler shell, for reference

Well, the video doesn't really match the previous description, I see definite evidence that the fan is running, so we're back to some obstruction, a really poor alignment, or some serious leak around the shell seal.

The unit has always ran without problems. I just can't seem to align it properly so all the smoke comes out the smoke stack. The smoke coming out the front whole seems to have more force than the smoke coming out the rear hole even though it's coming from one smoke unit. 

well let me amend this statement....

The unit would smoke some, the reason I took the shell off to start was to check the smoke unit wick. It was on the dry side so I added a good little bit to re-prime it. The smoke really started coming out. The the alignment problem come about putting it back together. 

So I was able to move the smoke unit a little with the shell on.  Underneath is a flattened o-ring/gasket.  I’m think it’s not sealed allow smoke to escape. 

GEE  GOLLY  RW,

Seeing your great videos and photo I'm sure you are on your way to resolving this issue of the shifting smoke signals.  👍

I hope so!!  I have a message to MTH for a call back. Hoping I can just order the correct part and be done with it!

Again, thank you all for your help!!