HO P2K 0-8-0 Mechanism

If you don't have the exploded view parts diagram that came with the loco, check their (Walthers, that is) website or call them for help.

Dante

I haven't contacted Walthers yet

I bought the model used, and it didn't come with the exploded diagram.  I've searched on line, including HOseeker.com and I can't find anything definite.  I found one photo of a model with the shell off, though I can't get much in the way of dimensions from it, and I'm pretty sure it's an N scale model, not HO.

I may have to just bite the bullet and take the model apart.  I just hate to open up a model that runs so beautifully.

...

I doubt you will get a smaller boiler over it.  The shell fits like a glove.

Have you had one open?

I expect it does, but how much of that is motor and gears, and how much is weight?  I can cut metal, but If I have to redesign the mechanism I might as well start from scratch in the first place.

Well, that was fun...

I decided to bite the bullet and see what I could learn on my own.  Screwdriver in hand, I took my portable workbench and sat down in front of the TV and went to work.  Here's what I learned:

The shell came off easily enough, though it did take a little fiddling around the smokebox.  Right off the bat, I can see that the photo I posted earlier was defnintely not of an HO scale model.  Next, that motor is big and up high.  It's probably not going to work, even if I replaced it with a smaller model.  But might as well keep going.

Interesting.  I am impressed with the quality here.  Split frame, sprung drivers, bronze bearings,and (unlike most Spectrum engines I've opened) correct wiring colors.  Lets finish taking it apart..

Like I said, this thing is remarkably well engineered, with lots of parts that fit together like a puzzle.  time to put it all back together...

As I feared (expected, really), there were a few little pins that broke during disassembly and will require repair.  I've only "lost" one part, a little cover plate over a frame screw between drivers #2 & #3.  I still have the part, but I would have to glue it in place.  You have to look REALLY hard to see it, so I'm not worried about it.  The power reverse, on the other hand, will have to be glued back in place, probably with a new brass pin inserted into the plastic.  Given that the bell and whistle were already off from the previous owner, and I've got a little detail repair work to do one of these days.

So, will it work?  I doubt it.  I haven't compared it to my drawings in detail yet, but it doesn't look promising.  What I might be able to do is to modify the main drive gear by turning off the larger side and driving the smaller sgear directly, moving the motor down.  That and possibly a smaller motor might just fit.  I'm not sure if it's worth the effort, but it's at least worth considering.

If nothing else, hopefully this will help the next guy who comes along and wants to know what's inside this model.

An idea - Am I crazy?

I have an idea on how I might be able to use the P2K mechanism in my model, but I'd like some advice from my fellow modelers.  I believe that the gears and worm will fit within the smaller 2-8-0 boiler.  The two boilers do not look to be that different in size, so it's just the height of the motor which is a problem.  Would it be practical to mount the worm on its own shaft and to move the motor down, driving the worm shaft via a 1:1 gear, belt, or friction drive.  Even if I have to use a smaller can motor, it might still be easier than building a completely new frame and gear drive.

Opinions, please?

A possible source for help

Ken:

I would suggest getting in touch with Loco Doc at http://www.locodoc.com. He can also be found at http://www.roundbell.com.  Same place. He has an email link on his web page.

He has a variety of motor and drive line solutions for many brass models and might be able to help you. He is a source for Faulhaber coreless motors.  Slap a gearhead on one of those and you will have a superb combination.  Be advised superb does not come cheap.

I am not affiliated with Loco Doc in any way.  I have simply seen some of his work and solutions posted on the Yahoo HOn3 forum.

Jerry

The issue would be with the low speed operation

I think the wheels are geared down from the motor.  If you move the gear ratio to 1:1 then the motor will have to turn significantly slower for the low speed you will likely desire.  The motor may not want to run that slow.  I think I would look for a smaller motor.  The RPM difference is still going to be an issue.  Hopefully you can get the specs on the two motors to be sure  the power and RPM trades still give you a desirable result.

Larry  

This is probably a bad idea

I was thinking of leaving the gears in the model.  The worm would not move at all.  The 1:1 ratio would be between the motor and worm jackshaft - I'd remove the worm from the motor and mount it on its own shaft, so that the motor could be moved down.

You're not kidding!  That's the main reason I'm giving any thought to modifying a commercial product.  I could buy a complete P2K 0-8-0 which runs like a Swiss watch for about the same price as just a motor and gearbox from most quality sources.  I think that if I was going to replace the motor and gears, I'd be better off starting from scratch anyway, because of the extreme frame and axle modifications needed.