I have a whole bunch of brass engines that I replaced the open frame motors with can motors, and replaced the tubing with new tubing. However, the old (PFM/United) gearboxes seem to make a lot of noise, seemingly from a ton of vibration. What can I do to reduce this vibration?
Suggestions: does an arm of some sort that attaches to the gearbox and chassis frame help? I heard using those universal connectors is better than tubing. Will this help? What are the advantages of using universal couplings over tubing?
Trying to spend as little money as possible…so last resort (although most long term solution) is to get a NWSL gearbox.
PS How do I choose what NWSL gearbox is right for me? I heard 0.3 mod for light and 0.4 mod for heavy…what are the advantages of ball bearings? Right hand or left hand? Besides just the gear ratio, how do I choose one that’s right for me?
How do you know it is the gearbox doing the vibrating/making the noise, and not the new tubing? Or some other defect over alignment or other parts that have gotten out of whack, or need lube or something?
Not challenging your position, just want to understand better how you have arrived to your conclusions.
You might want to double-check the concentricity of your replacement tubing. I purchased some Du-Bro “Super Blue” silicone fuel tubing from Hobby Town for a brass boxcab I was upgrading from an open-frame motor to a can motor. The lumina on the tubing was noticeably non-concentric; causing some vibration as the motor rotated and the boxcab moved down the track.
I bought the tubing on Ebay from the link shown in a prior forum thread about silicone tubing. And after installing it into multiple brass engines I thought it was normal for it to be sort of lop-sided. I did some research and its most likely from Du-Bro. Many of the key and sunset brass engines didnt cause any additional noise(most likely due to the gearboxes having an idler(?), but it seems like its not very friendly to United gearboxes as they tend to have more play, which the vibration just makes them scream. Ive already tried sanding down the bottom to reduce the extra play but it didnt seem to help.
Anyways, is there a better source for tubing? Can someone send me a link to some concentric tubing?
Getting tubing installed just right can be tricky. I’ve used it quite a few times, and have often spent a lot of time fine-tuning it to get rid of vibration. Needle-nose pliers help a lot for gripping the end and giving it a little twist here and there to adjust the position.
When it arrives I’ll let you know if its any better.
@DSF Correct me if Im wrong, but I dont think there’s much you can adjust when the tubing hole is inherently off center, with the DuBro tubing that I was previously using.
