Hello everyone.

I have been working on a Weaver diecast  2-8-0 that runs jerky and surges. There is no binding to be found anywhere in the drive rods, or smoke piston. Turning the flywheel by hand, it feels smooth all the way. I put in a Cruise Commander and the loco jerks and surges, especially when unloaded, and particularly at low speed.

It did this even before putting the Cruise Commander in it.

My conclusion/suspicion is that the motor is bad. The motor has excessive end play and I am wondering if one of more of the commutator segments are bad or have broken windings.

It's the standard can motor that is in our China drive diesels and some of our smaller steam engines.

The only unique thing about it is the worm gear has a different pitch than all the MTH, Atlas, and Williams motors I have in my parts stash. I do not have any pitch gauges for worm gears, so cannot tell the actual pitch. Comparing it to my other motors shows that the pitch is different.

It's possible that the shaft is longer, but I cannot determine that, either.

So... where do I find a replacement motor with the correct worm gear? Can someone pull that Weaver-unique worm gear and put it on another motor for me?

This is just the kind of loco for a slow freight drag, so I want to be able to run it slowly.

 

RoyBoy

Original Post

Going all the way back to when they were released, I've always read that these locos weren't good runners.  The motor itself is nothing special.  However, removing and reinstalling a worm gear isn't trivial.  (There was a recent thread on this very subject.)  The key is finding a worm gear that has the correct pitch and tooth depth to match the worm wheel on the axle.  Replacing the worm wheel is a whole other project!!

Could it be that some of your driving wheels are not quartered properly?  Maybe the quartering jig used by the factory had an error, which is responsible for the sub-optimal performance?  Again, checking and changing the quartering won't be easy.  Maybe you'll be the first to solve the mystery of poor performance with these locos.

Creep, coast, and pull.  We're not talking about cold fusion here.

I am going to take another shot at the quartering and rods to see if something is amiss there. It sure feels smooth when rotating the flywheel by hand, but we will see what we see.

The drive rod screw on the second from the front right side driver has worked loose twice, so there may be something going on with it.

My first thought was Timko for a new motor, but he gets pretty busy this time of the year. I should have worked on the loco in the spring,

RoyBoy

I'd go one step farther than Rod specified.  With the motor unhooked, run it with a DC power supply and monitor the current draw.  I've found a number of the no-name motors in Williams and Weaver locomotives draw amps when they should draw milliamps!  With no load at 10 VDC, a good Mabuchi 3xx sized motor should draw no more than 200-250ma with no load.  The Mabuchi 555 pair I have both draw right at 250ma no load at 10VDC.  Typically, the bad motors I find draw a lot more current. 

Three segment commutator motors frequently have issues with ERR cruise.

FWIW, usually I find that motors with excessive end play have been abused, likely by people trying to pull the flywheel or gear, or putting one back on.  If you put ANY pressure on the shaft holding the body of the motor, it's quite easy to slide the commutator on the shaft and ruin the motor.  The most often observed symptom of this is excessive end play.

RoyBoy posted:

I am going to take another shot at the quartering and rods to see if something is amiss there. It sure feels smooth when rotating the flywheel by hand, but we will see what we see.

The drive rod screw on the second from the front right side driver has worked loose twice, so there may be something going on with it.

My first thought was Timko for a new motor, but he gets pretty busy this time of the year. I should have worked on the loco in the spring,

Take the motor out and see how the locomotive rolls in your hands...that’ll tell you right away if your on foot or horseback as far as the quartering goes, Roy. If you roll it in your hands and it binds up, you’ll know at least then it’s something with the wheels and or rods.......Pat

The Water Level Route.......You Can Sleep

harmonyards posted:

If you roll it in your hands and it binds up, you’ll know at least then it’s something with the wheels and or rods.......Pat

Might even show up rolling it on a piece of track.

gunrunnerjohn posted:
harmonyards posted:

If you roll it in your hands and it binds up, you’ll know at least then it’s something with the wheels and or rods.......Pat

Might even show up rolling it on a piece of track.

Or on a piece of track in your hands!.....touché sir!.........🤪........Pat

The Water Level Route.......You Can Sleep

Worked on it for a few hours today.

All of the running gear seems to roll smoothly without the motor, but... stay tuned.

The worm gear and the worm wheel are clean and free from burrs and in alignment and newly greased.

I do not have a precision power supply. Was going to buy one, but then the bad reviews on the Chinese one some months ago stopped me. Using a Lionel HO power pack that does not like to hit 10 volts. 9.5 yes, and 11.5 yes.

When free running, removed from the chassis, the RS-385PH motors read out as follows with no load:

Weaver motor 190ma - 210 ma at close to 10 volts

Lionel 160ma at close to 10 volts

MTH 160 ma at close to 10 volts

All three motors have similar torque values while being stalled by my admittedly uncalibrated hand. The Weaver motor has more end play than the others by a factor of 2.

Too bad the Weaver worm has a coarser thread than MTH or Lionel, but has a finer thread than K-Line.

On rollers, the loco will run slowly at around 2.5 vols and around 600 ma, with smoke unit off, but still clacks and bucks.

Thought the smoke piston was problematic. Relieved the push rod with a grinder where it looked like it was touching the smoke unit and also removed the O-ring around the piston.  Made a slight improvement, but did not solve the problem.

The third set of drivers is connected to the gear box. Upon close visual inspection, it appears that this third set of drivers might be slightly out of quarter by only a few degrees on the right side of the loco. When running with the motor, the loco clacks on the rollers as the sound is coupled to the bench and the fiberglass lunch tray on which the loco, track, and rollers sit. Rotating the flywheel by hand, there is slightly more physical resistance at one point in the driver's rotation and at that point, the side rods between the second, third, and fourth set of drivers get tighter on the right side of the loco.

So it looks like I will have to send it to someone who can re-quarter the third set of drivers.

Thanks for all the help and ideas so far.

RoyBoy

If you feel ANY change in resistance, the first step it to remove the smoke piston linkage.  Then, any resistance is usually an issue with the rods.  The key you mention is the rods getting tight at one place in the wheel rotation, that's almost surely your problem.

I had already checked and modified the smoke piston and its drive rod.

So I sent the loco and tender off to harmonyards (Pat).

It didn't dawn on me until after I spent $$$ to ship across the country, that I could have just removed the drivers and axles and shipped them to him and saved a bunch of shipping.

But this way, he can check out the whole assembly  and make sure everything is right, which is what I would prefer if I were doing the work.

Gotta drag freight on the layout, just waiting for an old Consolidation to drag it.

RoyBoy

RoyBoy posted:

I had already checked and modified the smoke piston and its drive rod.

So I sent the loco and tender off to harmonyards (Pat).

It didn't dawn on me until after I spent $$$ to ship across the country, that I could have just removed the drivers and axles and shipped them to him and saved a bunch of shipping.

But this way, he can check out the whole assembly  and make sure everything is right, which is what I would prefer if I were doing the work.

If anyone can make it right, it'll be Pat. 

Will look forward to hearing how it all turns out...

Mark in Oregon

I just talked to a friend. He knew that the problem with these Weaver diecast 2-8-0 locos was a driver out of quarter. Too bad he didn't tell me that a week ago.

I'm sure Pat will fix it. You should see how he modified/repaired the CCII Niagara. Amazing!

RoyBoy

It’s a good thing you sent the whole locomotive and tender Roy, the very first thing to do is to identify and confirm the very reason you sent it clear across the country in the first place. Job 1 is verify customer complaint. Then we’ll diagnose the actual issue and make the needed repairs. No point in doing dart board diagnostics.......🧐😁...Pat

The Water Level Route.......You Can Sleep

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