Got yet another one for my friends on the forums: I recently got components to power my 3 dummy GP20s. (As I have mentioned in previous posts, they are Tythearns: Tyco GP20 shells mounted on Athearn BB GP35s with modified frames.) Anyway, when I installed the same power components on each engine, I get three different results (Power pack is a Tech II 2500 on level Atlas track. The drives use the gold side motor, gear drive, and connector clip [and yes, I get the clips to work just fine on all my Athearn locomotives]):
The first powered up and ran perfectly normally at all power ranges just like the rest of GP20 power units.
The second unit runs slow both directions (taking at least 60% power to move and resulting with a very warm motor) and slants slightly to the left when moving forward, which on the test track is going to the left.
The issue with the third unit is both trucks won’t sit level. The inside wheels on each truck are jacked up such that they don’t make contact with the track. (This problem makes the unit not able to be powered.)
As usual, any ideas anyone has would be most welcomed.
Second unit, sounds like motor mounts are bad or not seated correctly or being brittle…should flex…motor running warm indicates a bind…Lube motor armature shaft bearings/bushings fore and aft, with a suitable oil, like LaBelle #107 or equivelant.
Third could have a warped frame and or trucks, not seated on bolsters correctly…should float, up/down, fore/aft…also flash on trucks or bolsters…drive line could also prevent that movement. Put engine on piece of glass/mirror, try to slide a sheet of paper under all wheels, should not be able to…if You can…see above.
Just to reiterate what Frank told you, maybe check the drive shafts, are they too tight? weather they are the dog-bone style or the spline type (one shaft slides into the other), makes sure there is the correct amount of play. Also check the worm gear, and make sure the thrust washers are in correctly. I’ve had this problem, and with a missing or misplaced thrust washer, the worm gear wants to jump back and forth, causing it to bind.
Also check what Mike suggested for the drive lines…I forgot to mention that…with worm gear removed from top of truck gear tower, the rest of gears in trucks should roll freely…as a matter of fact…do that first and while it’s off lube the motor bearings/bushings…then you can turn the motor easier when lubing and even let it run.
I disassembled the two misbehaving engines as suggested. In the process of checking the roll of the trucks, I discovered that three of the four trucks had binds in the gears. (I could put my test track at quite an angle and the trucks wouldn’t roll at all. Appears the next step will be cleaning up/swaping out gears.
It may be that the problem is nothing more than old hardened grease in the gear towers of the trucks. The trucks come apart for merely popping off a clip on the bottom of the truck. Clean everything well with solvent, wipe each tooth of each gear with a pipecleaner to get invisible bits of black plastic flash off, remove any flash you may find, and reassemble. Lube lightly with grease, the gears and gearbox are all made from a slippery engineering plastic that doesn’t really need much lube.
Over the years I have disassembled many of this type of truck. (Athearn F7s also use this same type of truck. Most of my locomotive fleet is Athearn so I am very familar with the construction of Athearn trucks.) These trucks are new enough (except for a couple which were from my parts pile) that they shouldn’t have been and weren’t gunked up with grease. I have had to play around with gears before to fix truck issues. I just had never had this many problems with Athearn units before.
I’m getting closer to solving the problems. The unit with the jacked up trucks was solved by shortening the spline by a hair and adjusting the flywheel (It was a little too far away from the motor). The other engine probably won’t get completely fixed until Sunday. When I had the units on the layout at the ranch where I grew up (the layout and I are about 5 miles about and I don’t drive) to test conductivity, I accidentally used a set of switcher wheels from the parts pile instead of road unit wheels when I was checking the rolling qualities.
If you suspect hardened grease, you can always add some oil to the gear boxes. Oil and grease do mix and the oil will soften up hardened grease and make it easier to clean out later.
I solved the wheel issue on the 3rd engine but I found yet another problem that I have no idea how to solve: One of the flywheels won’t stay “attached” to the shaft on the motor. As a result, when I try to power up the engine, the end that has that flywheel freezes. The only idea I have to solve that problem would be super glue the shaft to the flywheel. Any other ideas/thoughts would be most welcomed.
Wow, go figure, as you ususally have to really work to get them off. Some guys have made wheel pullers to do this.
Did you take it off originally ? or was it always loose?
Anyway, I have heard of super glue working, but, it might not withstand the torque. If it doesn’t work, “A Line” / ProtoPower West sells a flywheel cement for about $5. It’s their product number 20010
As a follow-up, I finally got that 3rd engine to work properly. It took a little bit more doing. I used the loctite and glued the flywheel. Unfortunately I must have gotten a little bit of the stuff in the motor shaft as it was frozen when I tried to get the engine to move the first time. After taking the motor apart (and prying the glued flywheel loose), I managed to get the area cleaned and got the motor put back together. Unfortunely, I managed to lose a motor brush spring in the process. Thankfully, I had a spare switcher motor that I raided a replacement spring from. Once I got everything cleaned up and the flywheel reloctited and let it dry, the engine came up with a minor whine. That was solved by switching a worm gear out with one that has an aftermarket end that is a little shorter than a stock Athearn one and doing a little bit of filing on the spline as I had gotten the end out of square.
These locomotives took a lot of patience to build. Given that each one of the 8(!) required 26 custom bent stanchions and the GP35 frames had to be cut with a Dremel tool and a hacksaw in places where the Dremel wouldn’t fit. As one might guess, each one of these locomotives was an operation in itself.