Working on the MDC Climax

Discussion in 'HO Scale Model Trains' started by Glen Haasdyk, Aug 16, 2006.

  1. Glen Haasdyk

    Glen Haasdyk Active Member

    I've been puttering around my workshop, trying to find a decent (and cheap!) stardard guage engine for my Caribou lumber company to work the switchback. In my collection I've aquired 3 of these MDC clmaxes. For those of you unfamiliar with these little beasties they were designed in the mid-sixies and the design has never changed. They are powered by a 5-pole open frame motor screwed directly to the zirmac cast frame. Coupled to it are a plastic motor gear, followed by a brass idler gear and a large 'bull' gear that turns two very short universals under the frame to to trucks which are then driven by jack shafts with brass work gears and a gear on each axle. The design is simular to MDC's shay.


    While the design to strong, and the engine will pull like a mack truck, the noise that comes from it is considerable probably due to a few things:
    1) the bull gear sits quite lose in the gearbox, allowing it to move back and forth and 'rattle' in the box.
    2) the open frame motor is mounted (screwed) directly onto the frame, trasmiting all the motor noise to it.
    3) the fact that the motor has to turn at high speeds for the engine to get up to speed. Granted climaxes aren't meant to be speed record holders, But the massive gear reduction contributes to the noise as well.

    My first modification was to open the gearbox, clean the gears and inspect for any flash. seeing none, I then tried shimming the bull gear so it wouldn't move side-to-side in the box. I tried to find a thin washer at a couple fastener dealers but I couldn't find one thin enough. Finally I made one out of .015" styrene. It's inside diameter was 21/64" and I just made the outside diameter small enough not to interfere with the gearing. I'm not sure if using an even smaller washer on both sides of the bull gear will help. Keep in mind that this is an experiment. When I reassembled the gearbox back into the engine I discouvered that the motor wouldn't turn due to four lugs that hold it in alignment in the frame. The spacer that I had made squeezed the bullgear in the gearbox so you can do either one of two things, 1) make your gear spacer out of thiner material, or 2) file two of the lugs. I chose the later and now the gearbox spins freely. Upon reassembly of the engine I used my demel tool with a brass wire brush to clean both the wheels and the brass pickup wipers. Speaking of those I'me thinking of eliminating them and hard-wireing the trucks to the motor.
    When I ran the engine with the spacer in the noise had diminished a little but I still think more can be done.
    My next step it to try to isolate the motor from the frame, this will involve cutting off the two large shoulders on the cast frame and milling down the motor area, hopefully adding a rubber motor mount and seeing what will happen. I may keep my eyes open for a small can motor as well, as long as I can get one cheap.

    I'll attach photos as I get them and try to keep my progress updated. As I said this is mostly experimenting, seeing what if anything will work to make the little fellow's noise level more mangable. If anyone has any suggestions I'm all ears (so to speak!)
  2. pgandw

    pgandw Active Member


    I agree with your summary - very slow speeds, pulls like a mule, incredibly noisy.

    For what's it's worth, my version had a short piece of rubber tubing leading to the gearbox, and on the back side of the gearbox, the shaft continued into a die-cast flywheel. The flywheel "bearings" were vertical slabs of plastic. The flywheel was/is not well balanced - it vibrates and hums at any RPM. The motor has significant cogging.

    Changes I have in mind:

    - changing the motor mount to align the motor vertically with the gearshaft. Replace the rubber tubing connection with model aircraft fuel tubing.

    - remotor?

    - replace flywheel and install real bearings. Original is quite small diameter and out of balance. The bigger the diameter, the more effective the mass of the flywheel at adding inertia.

    - ensure proper gear mesh in gear box, and no flash on gears, like you said

    See what happens from there.
  3. Glen Haasdyk

    Glen Haasdyk Active Member

    oh, the flywheel was the first thing I tossed, it doesn't really do all that much anyway. Besides, I already lowered the front boiler so the flywheel mounts don't fit anymore.
    The pic in my thread is of my original climax, bought in 1987. I'm using it as a baseline for the other opne that I'm modifying.
  4. 60103

    60103 Pooh Bah

    The description of the mechanism sounds like MDC's boxcab diesel. I've long suspected that their geared locos were just bodies on that mechanism.
    Maybe I'll try that fix with my boxcab.
  5. Glen Haasdyk

    Glen Haasdyk Active Member

    That's true, the boxcab was issued first and then MDC simply made the climax body to fit over the mechanism.
  6. Glen Haasdyk

    Glen Haasdyk Active Member

    Okay, a couple days wiser and I've discouvered that the motor can't be isolated easily or at all without seriously messing with the chassis and the gear alignment between the motor pinion gear and the idler gear.
    First Here's a picture of the gearbox spacer I added:
    Behind it is the stock chassis.

    Next I took another chassis and cut the cast shoulders off the top, following the blue lines:

    I used an ordinary hacksaw to do the job, finishing with an orbital sander to smooth the motor mount area. I tried to shave the motor mounting area down so I could add a thin piece of foam to try to isolate the motor from the frame but unfortunetly to get the gear meshing right I had to compress the foam down to the point where it was useless, the end result was the motor noise was as bad as it was before. My next attempt will be to find an inexpensive can motor to install since I don't believe that the stock open frame motor can ever be made to run quietly and I suspect thats where most of the noise is coming from. and now that the chassis has been shaved a can motor will fit better (as soon as i find one)

    Anyhow, since my seach continues for the drivetrain, here's quick look at what can be done to inprove the body shell when you shave those shoulders down:
    Sorry for the shadows
    On the left is a stock climax, and on the right is a modified one. The modified one has a lowered boiler (the shoulders would interfere with this mod) and I also cut out the doors on the cab. The chassis under the modified climax isn't totaly shaved, just the front, that's why you can still see the chassis through the doors.
  7. Glen Haasdyk

    Glen Haasdyk Active Member

    Oh yeah, the boiler lowering is discused in a dec 1981 MR (I think)
  8. MilesWestern

    MilesWestern Active Member

    Question: Is there a prototype for this most unusual of climaxes? I've seen the "regular" climaxes with the lil' drivewheel, and the eccentricly(?) mounted piston. Yet to see an old photo of this 'um though...hmm... :confused:
  9. RailRon

    RailRon Active Member

    The Climax 'A type' had a vertical cylinder steam engine inside the cab - only the later B and C types had their cylinders outside which acted on the characteristic drive wheel.

    The first A types had a round water tank at the rear end, but you also could order engines with a rectangular water tank. And this comes nearest to the H0 engine which is (was?) produced by MDC Roundhouse.

    I found a pic on the very interesting Climax website:


    You see that the MDC engine's boiler sits way too high, but that is because MDC really used the same mechanism for the Climax and the boxcab diesel. :oops:

  10. Ray Marinaccio

    Ray Marinaccio Active Member

    I've been tinkering with one of the Climaxes recently and came up with a quiet alternative primary drive. It is a rather radical change.
    I just bought a box cab kit at the show Saturday and my son got another Climax so I plan to do some more experimenting.
  11. jetrock

    jetrock Member

    Definitely interested in these repowering examples. How is the performance of the motor out of the CD-ROM drive? I have a few junked ones lying around I could adapt to nefarious purposes.

    I have a couple of those Climax/boxcab kits too, one of each in fact. I plan on using one to create a boxcab electric freight motor for my prototype, a heavy homebuilt job originally designed as a combo freight motor/express motor, Sacramento Northern 410:
    Suydam does a model of SN 410's original configuration, which was longer, but the locomotive was cut down to 38 feet in 1930, and nobody makes an HO scale model of the shortened version. I figure the boxcab frame is just about perfect, although I'll have to fabricate another body out of brass or styrene. Considering the prototype had a maximum speed of 35 MPH flat-out and was nearly legendary for its monstrous pulling power, it seems like a good match--I just dislike the big open-frame motor that comes with the kit, and that cheap-looking flywheel. A good motor and a brass flywheel seems like it would help.
  12. Glen Haasdyk

    Glen Haasdyk Active Member

    Looks like you've got a good solution there. I had considered a belt drive but couldn't figure out how to modify the gearbox for it, and here you didn't even have that! My hats off to you.
    Where do you get all those VCR parts? You aren't a repairman are you?
  13. jetrock

    jetrock Member

    Scrapped VCRs are pretty abundant these days: take a look at garage sales or thrift stores (the low-rent kind) and look for the most beat-up old piece of junk you can find for $5 or less. Or you can always dumpster 'em...
  14. Ray Marinaccio

    Ray Marinaccio Active Member

    The CD-ROM motors work best with a little more gear reduction as in the Climax example.
    They are smooth and quiet running. They fit nicely into the cabs of HO steam locomotives too.This is an old Tyco 2-8-0 I remotored with the same type motor.
    As for VCR parts, I tell everyone I know not to throw out their old VCRs, that I can use them for parts.
    If you need to stretch the wheelbase for the freight motor aframe would be easily built to adapt the MDC trucks to.
    I had concidered mounting a can motor on top of one of the trucks with a belt drive to a pulley mounted directly on the worm shaft of one of the trucks, then run a driveshaft to the other truck. Like the old Varney F3s.
  15. RailRon

    RailRon Active Member

    Awesome work, Ray! :thumb::thumb::thumb:

    A question concerning these CR-ROM motors: Am I right that they run on maximum 5.9 Volts DC? (I conclude this from the Note 'D / V 5.9' on the sticker attached to the motor.)
    If they do - how do you adapt to our normal model RR 12 Volt, so that you won't burn up the motor? Do you add a resistor in series, or did you add a DCC decoder and fix its maximum output voltage to 6 Volt?

  16. Ray Marinaccio

    Ray Marinaccio Active Member

    Thanks Ron,
    Some of the CD-ROM motors are 12V.
    You can put a resister in series to drop the voltage. These motors draw very little current.
    I am working on a voltage following circuit to reduce the voltage but for now I watch how much throttle I give this loco.
    All Electronics has a few small motors that would make good replacements. They are rather inexpensive too.,_MABUCHI_FK-280_.html
  17. Glen Haasdyk

    Glen Haasdyk Active Member

    Thanks for the tip on the CD-rom motors Ray, I took anold one of mine apart and foud two in there! One was being used as a belt drive so it has a small pulley on it, maybe I'll start looking at a belt drive system for my own. now I just have to find a pulley the right size to fit the gearbox.....
  18. Glen Haasdyk

    Glen Haasdyk Active Member

    As a short update of what I've been doing. a couple weeks the CD changer died in my car so after I replaced it I took it apart to find three can motors and two of the short round motors (like the cd drives) I mounted one of the small can motors on the MDC chassis using an alluminum spacer and silicon as an adhesive. I can say that the noise is a little less, but it certianly can't beat ray's belt drive system. I was wondering if the original bull gear could be turned down and grooved in a lathe to make a pully that would fit in the existing gearbox?
  19. Ray Marinaccio

    Ray Marinaccio Active Member

    That might be a possible solution Glen.
  20. Glen Haasdyk

    Glen Haasdyk Active Member

    Okay Ray, since you're the one with the lathe, you first!
    Actually I'm having trouble with the climax on my switchback as well. It doesn't seem to like my track with the sharp curves and steep incline. My P2K sw1200 runs it just great though, must be the 30 year diffence in engineering.

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