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remotor noise possibly from silicon tubing

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  • Member since
    October 2022
  • From: Pasadena California
  • 89 posts
remotor noise possibly from silicon tubing
Posted by BradenD on Friday, July 14, 2023 6:22 PM

Hey all. Just Attempted a remotor of a PFM 4-8-4 using a Mabuchi motor. The remotor went well except for the fact that there are some odd noises . I think that the sound is from the 1/16" silicon tubing I used. It appears to not like the worm shaft . What should I do?

here's a video of the operation: 

https://i.imgur.com/DVEQ9Di.mp4

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Posted by SeeYou190 on Friday, July 14, 2023 6:30 PM

With that much length, I would have used a driveshaft with NWSL universal joints.

-Kevin

Living the dream.

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Posted by gmpullman on Friday, July 14, 2023 9:35 PM

It is possible that a 'torque arm' might help in your application. The axle gearbox wants to rotate in a counter direction to the rotation of the axle. This 'thrust' is being imposed on the motor bearings through the silicone tubing and shafting.

A torque arm will allow the thrust to be confined to the gearbox and not transmitted to the precision motor bearings.

I've seen lengths of 'intermediate shafting' applied to longer lengths of silicone drivelines. In other words use two shorter lengths of tubing with a short length of steel shafting between. It helps mitigate twisting of the tubing.

It seems there is a bit of 'run out' at the worm end of the tube. Is the wall thickness not true there? Perhaps another length of tubing can be fitted that has a better 'center' or more even wall thickness? 

As Kevin points out, universals are a much better method of transmission:

 PRR_N1_sam1 by Edmund, on Flickr

 

Good Luck, Ed

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Posted by dennis461 on Friday, July 14, 2023 9:38 PM

Is the worm gear in bearings? Looks like it is flopping around

 

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Posted by BradenD on Friday, July 14, 2023 9:42 PM

Yes it is flopping around but I'm not sure why

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Posted by BradenD on Friday, July 14, 2023 9:43 PM

Yeah I might use a universal . I was hoping to avoid them because they are much more costly than a few cents of tubing. 

The issue with the torque arm is that I don't have a gearbox. This is an open worm 

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Posted by hon30critter on Saturday, July 15, 2023 2:46 AM

Hi Braden,

I can clearly see the tubing vibrating when the locomotive first starts up. I agree that a NWSL universal shaft setup would likely solve the problem. I had a similar problem when I was scratchbuilding my rotary snow plow. The silicone tubing caused all sorts of vibration. The NWSL parts are cheap when you compare them to having a shelf queen that won't run properly.

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by snjroy on Saturday, July 15, 2023 8:24 AM

Yeah, there is a lot of tension on that tubing. Was the original power train set up like this? Part of the noise comes from the gear, but it's hard to tell whether the noise comes from the vibration of the tube or the meshing of the gear.

Simon

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Posted by Overmod on Saturday, July 15, 2023 9:22 AM

R tubing Too much torsional 'resonance' being developed -- it made me think of the disaster that was the flexible driveshaft in the early-'60s Pontiac Tempest.

The tubing winds up and tries to corkscrew out of line; I suspect that's what's moving the worm.  The out-of-axis force is causing increased resistance or momentary binding which is then relieved.

Shorter lengths of tubing either side of a metal or hard plastic intermediate driveshaft, as suggested, should fix this.  It is possible that inserting a stiff plug into the center of the tubing, perhaps by injecting or pressing epoxy into the center section while leaving the ends flexible, or putting a piece of close-fitting metal or plastic tube over the center of the flexible shaft, would stiffen up the objectionable action.

Ed, are those flexible universals like little enclosed giubos in that PRR chassis, or something like a CV joint?  They can't be pinned universals because they aren't crossed and wouldn't have any Cardan action.

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Posted by Ron High on Saturday, July 15, 2023 3:28 PM

Join the Groups.io forum "RepowerAndRegear".  There have been many discussions about use of silicon tubing and or universal joints. you cansearch or ask questions.

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Posted by BradenD on Sunday, July 16, 2023 6:15 PM

Hey everyone ended up resolving the problem with some styrene. Took the old mount out and then made a custom one out of styrene that was closer to the gear shaft. Also secured a piece of styrene to the top of the gear housing and attached it to the motor as well. This solved the problem of the gear moving back and forth. It is now a quiet and smooth runner. Thanks for the advice everyone!

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Posted by maxman on Monday, July 17, 2023 11:41 PM

BradenD

Hey everyone ended up resolving the problem with some styrene. Took the old mount out and then made a custom one out of styrene that was closer to the gear shaft. Also secured a piece of styrene to the top of the gear housing and attached it to the motor as well. This solved the problem of the gear moving back and forth. It is now a quiet and smooth runner. Thanks for the advice everyone!

 

A picture of the solution would be helpful if you have an opportunity.

Thanks

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Posted by Darth Santa Fe on Wednesday, July 19, 2023 12:50 AM

With that much tubing, I would suggest slicing it in the middle of the gap and adding some metal rod to help stabilize it.  Tubing can be tricky to get just right, so after installing the rod, turn the motor slowly by hand to see which way the tube "wobbles", then gently push the tubing to the other side until it turns smoothly with the motor.

_________________________________________________________________

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Posted by BradenD on Thursday, July 20, 2023 11:30 PM

I'm actually planning on making a video on it. I will link it here when I make it

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Posted by BradenD on Sunday, August 6, 2023 9:50 PM

Here is the video detailing my process if anyone else wants to do something similar:

video

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Posted by wrench567 on Sunday, August 6, 2023 10:44 PM

   On my remotor jobs. I've used a bed of RTV or brass motor mount. Also the torque links are brass flat strip for up and down flexibility. The .040 styrene should last awhile unless the glue fails.

    Don't discount the open frame motors. Replacing the iron magnet with super magnets will give you a high torque low draw powerhouse. I'm running two with decoders and one is sporting a micro Loksound at under 1/2 amp. The other can pull 16 HW passenger cars before it spins the drivers on the grade. I like the oil wicks in the open frame motors too. Come to think about, my Bowser 2-10-0 has a tuned DC71 motor too. That thing could pull stumps out of the ground. It has an early TCS WOW sound decoder.

      Pete.

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Posted by BradenD on Wednesday, August 9, 2023 9:01 PM

wrench567

   On my remotor jobs. I've used a bed of RTV or brass motor mount. Also the torque links are brass flat strip for up and down flexibility. The .040 styrene should last awhile unless the glue fails.

    Don't discount the open frame motors. Replacing the iron magnet with super magnets will give you a high torque low draw powerhouse. I'm running two with decoders and one is sporting a micro Loksound at under 1/2 amp. The other can pull 16 HW passenger cars before it spins the drivers on the grade. I like the oil wicks in the open frame motors too. Come to think about, my Bowser 2-10-0 has a tuned DC71 motor too. That thing could pull stumps out of the ground. It has an early TCS WOW sound decoder.

      Pete.

 

 

I've seen a lot of people rocking old pittman motors with new magnets and that seems like a viable route to go down. To me it's just much less of a hassle to just replace the motor itself. With new magnets are they still loud?

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Posted by wrench567 on Thursday, August 10, 2023 3:23 PM

  The one in my 2-6-0 has a tiny hum. The Bowser DC71 and the one in my K5s pacific are quiet as can be. They also have better WOW sound decoders. The 2-6-0 has a Loksound select micro. I could probably tune it but when the sound is on you can't hear it. It also dates back to the 1950s. It was imported in 1959 according to the label on the box. I have put so many miles on it, the plating is completely worn off the drivers and wheels. Most of my diesel fleet, all with can motors are louder.

        Pete.

 

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Posted by BradenD on Friday, August 11, 2023 7:48 PM

Ok that is very interesting. I'm actually going to try that with the next locomotive I upgrade.

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