Spectrum 2-8-0 Drive Slipping?

[belairguy427]

I have a Spectrum 2-8-0 w/DCC and Sound. I love it with the exception of 1 issue that has develeoped. The problem that it appears to have is that the drive belt is slipping. It occurs after running for a minute or so even with a light consist load of 8 cars.
I suspect it is belt slippage as the syncronizing of the sound does not match the loco speed which is empahsised when going up grade (loco slows down but sound sync stays the same and also at "full throttle" there is excess motor noise with lower top speed than normal.
It is fairly new and has no more that 6 hours total running time.
The loco is still under warranty so I plan to return for repair but I was wondering if anyone else has experienced this and if this maybe a weakness in the design.

Jim

[lmackattack]

I have a smilar issue with my bachman 4-8-2. I found that its not the belt thats slipping its the motor. Its to weak to pull a heavy train and maintain its speed. I installed a Soundtraxx decoder and it chuffs faster than its moving when pulling any grade or tight turn with more than 5 freight cars. Its Kinda sad as the detail on the spectrums are great the weight that it can pull is awsome but that motor is just to weak to maintain its speed. I even tried double heading it with another engine but it will not pull its share of the train, The motor RPMS drop on the 4-8 -2 and then the lead loco spins its wheels untill the grade levels out. Im a little picky but I like the sound and movement to in step

I still like the Bachmans but I need to find a diffrent motor to install soit will pull like a mountain should!!!

[Yampa Bob]

The Spectrum 2-8-0 has a typical drawbar force of 3.5 to 4 ounces, which equates to 40 easy rolling cars on level grade. When properly tuned, most cars should require a pulling force of only .08 to .1 ounce, for maximum performance.

The only way to determine locomotive drawbar force and required pulling force of cars is by using a spring force gauge.  I make my own gauges, but here is an inexpensive ready made.

http://www.delta-education.com/productdetail.aspx?Collection=Y&prodID=1973&menuID=

The 250 gram (8.75 ounces) is sufficient for HO scale.

[belairguy427]

Thanks guys.
I do have a force gauge and the 8 or so cars measure about 1 ounce total on level and 1.2 ounces on the steepest grade.
I measured the draw bar pull on a 0-6- 0 that I have and it measured almost 5 ounces at which point the drivers started to slip.
On my 2-8-0 however there is no driver slip just iwhat sound like increased motor speed and increase of the sound syncronization with no increase of driver speed.
Looking at the exploded view that came with the Loco the only place that I can see slipage would be possible is with the drive belt. I was just wondering if anyone else has had the same issue.

Jim

[r0bert]

The belt is toothed like a timing belt, and I have never seen one slip on these locos.
I have, however, had one loco that the flywheel glue broke loose, and the flywheel would slip on the motor shaft under load, a little CA fixed that.
I'm thinking that your problem has more to do with the Tsunami's load/torque compensation/bemf/ control cv's that need to be adjusted.
My J took quite a bit of monkeying around with that bank of cv's to get it to run right, new from the box it wouldn't even pull it'self up a 2% grade.
I can e-mail you the cv settings I ended up with if you like.

[belairguy427]

Robert:

I would appreciate it if you would send the CV's. May not be the final settings but at least a good point to start with.

Also if it is the flywheel that is slipping does anyone know the disassemby procedure to gain me access  without disturbing the drive mechaism and the quartreing of the drive wheels? I had another 2-8-0 years ago that I took apart and never did get the drivers set right. 

[r0bert]

There are two screws to remove to actually seperate the shell with motor from the drive, well really four screws, but the first two just allow acess.
draw bar screw and screw just foreward of it release rear section.
remove pilot wheel bar to gain access to  screw that goes thru cylnder mount.
spread the pilot steps away from the boiler and rotate up from cab end to seterate driver assembly from shell motor.
motor/chassis can now be removed from the shell, and the two halves seperated to gain access to the flywheel.
diagram here
http://www.bachmanntrains.com/home-usa/dwg/dwgs/H845x-IS001.PDF

[r0bert]

Robert:

I would appreciate it if you would send the CV's. May not be the final settings but at least a good point to start with.

 

email sent

[Jim Banner]

I recently ran into several Spectrum Consolidations that had bearing failures on the counter shaft due to faulty frame castings.  These failures allowed the worm gear to rise and rub the frame, making a lot of noise and taking up much of the power output of the motor.  One 2-8-0 was run in this condition for too long and the worm lost mesh with its pinion, destroying it in the process. 

[Yampa Bob]

If you just want to remove the shell, remove only the drawbar screw. The other screw in front of the drawbar screw, along with the screw under the front pilot, hold wheels, axles and drive mechanism to the main castings.

The two smaller screws secure the wiper assembly and bottom plate. Use TLC when removing the wiper assembly.

Best way to separate the chassis halves is by laying the loco on its right side. When you remove the screws, there are plastic "t-nuts" on the right side that will fall out.  Just above the worm gear is a small plastic square that must be replaced properly by lining up the tabs with slots in the chassis halves.  The part is a "slinger" guard to keep grease from being thrown out of the gear box.

[belairguy427]

Thanks guys.

I will take the shell off tonight and take a look.

Jim

[belairguy427]

Update.
Took the shell off (Thanks for the instructions!!)
Found almost no lub on the worm drive so I aded a small amount of grease. Also put a very small drop of oil on the axles etc.
Ran it for 1/2 hour and all seems to be back to normal.
Also reset the CV's (thanks Robert)
My 2-8-0 is now back in the roster for feight duties
I am relatively new to the forum and I am impressed by the quality of the responses. Thanks to all who replied

Jim

[r0bert]

happy to help

[djp]

Hi Jim that is exactly what happened to my 2-8-0 where the worm destroyed the plastic gear. I have asked Bachmann to send me another gear. Do you thing this problem will repeat itself?

[Jim Banner]

djp, check your frame castings in the area that holds the worm shaft bushings.  These small bushings are fine if they are properly supported, but if there is some metal missing from the frames, the bushings can tilt and then they wear away quite quickly.  As they wear away, the worm shaft rises up, pulling the worm out of mesh with the axle pinion.  Replacing the axle pinion is only a temporary fix in this case.

Check the condition of the worm shaft bushing to make sure they are perfectly round both inside and outside.  If one or both are worn on one side, making the hole egg shaped, then there is no use wasting a new gear by putting it in without fixing the basic problem.  Bachmann should be able to send you new bushings if yours are worn but if the wear is the result of missing metal in the castings, I don't expect the new bushing will last any longer than the old ones did.

What i have been experimenting with is longer bushings that cannot twist in the frames, even with a bit of metal missing.  So far, they seem to be working.  If you feel that your problem is the same and you would like to try the longer bushings, let me know and I will make you up a pair.