Dang nab it there was a thread a couple days ago that you posted on and now I cannot find it. I have a couple noisey athern sw-7 that run smooth and quiet but I put the shell back on and it growls like an angr cat. What did you say you did to help quiet it down? Thanks for the help.
Mike
someone mentioned, maybe not brakie, about inserting something somewhere to quiet the engine. Where would I insert and what would I insert?
Sometimes a plastic body shell can amplify the sound of grinding of gears and couplings in a locomotive drive train. But if it’s not that, then something must be rubbing against the shell. If the loco has the older tapered flywheels, one of them might be lightly rubbing against the shell. If a flywheel is rubbing, then it means that the motor is not sitting properly in the frame. I’ve encountered that problem before.
Mike,The SW7s and S12s can be rather tricky…
Remove the shell and see if it returns to running smooth if so,replace the shell till you hear a slight “snap” as the shell snaps into place…Sounds funny but,if the shell isn’t seated properly it will vibrate.
The motor mounts has a tenancy to vibrate lose as well.Check to ensure these mounts are snug.
Also try adding 2 pieces of stick on weight to the inside(top) of the shell.The added weight will cut down on vibration.I use the cab area.
Interesting. I’ve got a Bach Geep that does this. Have to give the weight thing a try.
Thank you Brakie. I have sighted down the loco with the shell off and everything falls within the marks of where the shell sits. It runs real smooth and quiet with shell off. I will make sure the motor is seated well as I have taken it out to do the athern overhall to make it run better. The shell snaps into place well so I will try your method of adding a weight in the cab to cut the vibration. Did you also say something about adding foam or something to it as well?
Thanks again
Mike
Mike I tried the foam, but was not crazy about trapping the heat in the shell. One trick I use on my BLI sound steam engines tenders is one a strip of electrical tape on the lip of the tender chassis. It make the shell fit tighter and help cut down on the rattle when I sound the whistle.
Cuda Ken
Before you go to all that trouble there might be an easier solution. The shell itself could be loose on the chassis and vibrating. Put a couple of wedges between the shell and chassis on the same side and see if the noise goes away. If it does you just need to glue a styrene spacer on the inside edge of the shell to stop the vibration.
Mike,I never use foam…I am sure that would trap the heat in fact I carefully remove the side window glass so the motor can get air and run cooler.This is not a easy job and its very time consuming.
As far as wedges…Use only as a last resort.
I had the same problem with two Athearn locomotives. After a lot of trial and error I found out that the noise was caused by a very minute wobble in the spline from the motor to the gear assembly. This caused the spline-coupling unit to rub against the contactclip from the truck. Bending the clip back only so slightly solved the noise problem. I don’t pretend that your problem has the same cause but it is worth investigating.
Thanks everyone for the help with this. I am finishing a rebuild on an old AHM Plymoth diesel swithcer. I remotered it with a cv backshop heisler motor. Runs smooth and slow and is very quiet. It also pulls(so far) about 12 boxcars on lever track. When I finish with the details on this engine I will get into the sw’s and let everyone know what I found out.
Thanks again
Havent had that problem with my SW-7 but I did have a similar problem with SD-40T where the motor mount broke. The motor would torque over against the side of the shell. Hopefully its just loose and you can tighten it up.