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WRP World Champ 2015/2016
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Discussion Starter · #1 ·
My prized SCX Fiat 131 rally car let me down badly this weekend at the Oxford round of Slot Rally GB.

I tried loads of mechanical fixes as we went through the day but nothing got me out of schtuck.
Decided to google it today and everything seemed to be pointing me at a water bath to clean it out. I had recently rescued one motor and delayed the death of another motor by flushing the oil out of the com and brushes with contact cleaner.
That did nothing for the 131.

I ended up running the motor at 3volts in water with a few drops of Fairy Liquid in it, then popping in the over for five minutes (the kids had just cooked a pizza and the oven was cooling down). I finally dunked it in some white spirit to make sure it wouldn't rust up too badly.

I got the daughter to watch me doing it, as the experiment was useful as she is off to unisoon and will be doing a fair bit of lab work. I thought this would be a good bit of prac for her.

This is what I used to spin the motor



and this is a close up of the glass and all the gunge that came out of the motor (that's a big lump of oily fluff, up at mid top right). I was quite surprised.



We were both quite impressed, as I had run the motor up to 15 v before hand, and it was stuttering, farting and running like a dog. After the first few seconds of shaking out the water, it picked up to it's former glory and ran beautifully. Fingers crossed, eh?
 

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I tried the water treatment for my 131 a few weeks ago and it didn't work, it did for a while then it started sticking again, in the end I flushed it with about 1/2 a can of electrical contact cleaner and now it seems to work ok, although I decided against running it at Oxford as I didn't think it would be reliable


It hasn't let me down since but it's wondering when it will with the temperamental SCX motors, this is the third I've had problems with
 

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Matt Tucker
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The SCX brushes I have found to be quite soft and if they get oil on them they can deteriorate very quickly. When this happens the comm gets clogged up and the motor dies. Cleaning will resolve it but only temporarily. I suggest remove the brushes, heat up a soldering iron and place the brushes on the hot iron. They will smoke as the impregnated oil burns off. Once smoking stopped, cool down and reinsert. They must be put back in exactly the same way as they came out so you need to devise a way of knowing.

Matt
 

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I take them apart and give them a good clean when they start running slow, as Matt says if the brushes get contaminated with oil then they will run slow, I hadn't thought of heating them up to clean them, I sanded them down a bit with a dremel and then ran them in for ages to get the brushes back to the right profile (and then took the motor apart to clean all the old brush material out).
 

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WRP World Champ 2015/2016
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Discussion Starter · #5 ·
I had tried a bloody good flush out with Maplins contact cleaner. Didn't shift the crud. However, spinning in the liquid with a few drops of Fairy certainly opened my eyes, you could see the gunk flying out. It was typical oily fluff, just like you see when cleaning most household leccy motors. The second photo doesnt show the amount of crud very well, it was enough to line the bowl of a teaspoon. Quite a volume for such a little cavity inside the motor. No wonder it ran so badly.

I'd heard about the soldering iron tip before Matt - will certainly try in future. What sort of Wattage we on about hear? And a gentle dab, or a good few seconds?
With the two SCRX Proxy rally motors that were dying, I whacked some comm cleaner through them and ran them for a while. Smoked a lot of oil out, though one was beyond redemption in the end, so I swapped it for a spare I had in the box. Will be very interested to see how you get on with those two cars. Marking them to ensure correct refit will be a laugh.

I'm far too heavy handed to try your method Julian - just come and watch my trim my garden hedge - just never know when to stop.

I think I'll have to get a spare motor just in case, but the 131 will get a good run out next week at club, I think it's stages night next.
 

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Prof I T
Ting Tong
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hi
flushing motors with water was a common way of bedding in brushes some 20 years ago in the rc cars.

So some of the black deposits will be brush matarial that has been removed and some will be muck.
 

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Tore
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QUOTE (snurfen @ 10 Jul 2012, 11:56) <{POST_SNAPBACK}>...I'd heard about the soldering iron tip before Matt - will certainly try in future. What sort of Wattage we on about hear? And a gentle dab, or a good few seconds?...

I use a 30 Watt iron with removable tip. I take the tip off the iron and put the brush just inside the opening, they usually they stop smoking after 5 - 15 seconds. Just remember to let the brush cool off before picking it up with your fingers, or you'll throw it around the room
 

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you guys are using way too much oil! SCX motors do benefit from water run-in more than other motors.
New motor:
1 drop of lube at either end of the motor( I use Super Lube, an oil w/ teflon in it), a glass of distilled water w/ 1-2 drops of dish liquid in it; run the motor for equal time in each direction; I've done it for as few as 15 minutes & as long as 2 hours; usually about 8-10 volts, I wouldn't go as low as 3v, maybe 5-6. I then blast it w/ compressed air, give it a bath in 91% rubbing alcohol, blast w/ air again & re-lube.
This works wonders!
By using teflon lubricants I lube my cars much less often & suffer no oily messes.
 

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you,ve just put oil back on the comm by dunking it in white spirit. take it apart and get rid of the tabs that hold the endbell on and drill and tap the enbell and can for retaing screws. take the arm out and dunk it in acetone for 30 secs. run the arm in a drill and use a rubber on the com till its shiney. clean out the com slots with a wooden tooth pick, then run a ball point pen up and down the slots to remove sharp edges. use either hawk6-7 or proslot mini brushes, and proslot euromotors have 3 different spring winds to try.space your arm carefully to centre it in the magnetic field. if youve enough play in the arm it will centre itself automatically,put washers on the arm side till thre,s no movement backward. then washer on the comm side with an oil slinger washer first, then your brass? washers till youv,e got about 3 thou of movement your motor will be better than new and you,ve made it rebuildable with the screws holding the endbell on. forgot! oil inside the bearings before final assembly/ john
 

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WRP World Champ 2015/2016
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Discussion Starter · #11 ·
Wow, some top class tips flooding in here! Learning all the time, thanks folks.

I don't think I can actually take this particular one apart stoner, as I think the SRGB rules are non-tampered with motors, else they go in the modified class. I'll check at the club which cars I can tamper with, but I've got stacks just for home use to practice on.

Another question to throw into the fray - what mods make are very low risk and which are likely to make a motor considerably less reliable?
 

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Nobby Berkshire
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Talk about a hammer used to crack a nut!

Firstly NEVER put a motor in water, especially with Fairy Liquid. This contains salts to aid the washing process. Salt + water + metal = RUST!

There seem to be so many people with fouled up RX motors on this website, but what are people doing to get their motors in such a filthy mucked up condition?

The golden rules with SCX RX motors are:

1. Never oil or lubricate the carbon 'brushes' as you will soften them and shorten motor life.

2. If there is muck around the copper plates under the 'brushes' then take out the carbon contacts and clean them with lighter fuel. Then squirt some into the 'brush' housing and clean between the copper comm plates with a long pin. Wash with more fuel.

3. If there's muck at the non-pinion end inside the motor then it's there because somebody has pointlessly fouled it with oil. Get the motor open, wipe with lighter fuel on a cotton bud. Refit without oil.

End of problems for years and years apart from sometimes having to repeat (2) every few tens of thousands of laps.

Oh, and defo don't use acetone on any plastic parts as it rapidly degrades them and reduces motor life, along with many other materials and finishes, so ignore this tip from stoner as it's probably come from someone who ruins motors regularly. It's really bad advice.
 

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thanks screwneck for the vote of confidence. i perhaps credit people with a little to much common sense. as i did say dunk the ARM in acetone for 30 secs, nothing about plastic or endbells[which are made from entirely different sorts of plastic or alluminium], long pin? to clean out the com slots, i said use a wooden coctail stick so you dont scratch the com face if you slip. he runs in a standard motor class so he cant open the motor.! so most of your advice is redundant. its a bit presumptous of you to imply i probably ruin motors regularly. if you read my post it might give you a clue as to i know what i,m talking about, inc rewinding arms, in fact if you read any of the posts, maybe you wouldnt be parroting what other people have allready said. you can even get over the problem of washing up liquid, by running it under the cold water tap and useing a hair drier to dry it. i dont run my motors in. in any kind of liquid, i might! if it was in a class with sealed motors. to get the brushes to bed in quicker and i never reuse an oiled brush, i bin them and recut new brushes. i,ll be kind and just say i wouldn,t let you touch any of my motors instead of the one word answer you deserve. john
 

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Hi All,

There's a lot of personal opinions on which is the best way to run in a motor, I recently asked several of our club members
about how many ways you could do it and in there opinion what was the best way.

I had recently came across a product using Slave power to run in motors particularly new motor brushes without any problems,
there's this product that uses a slave motor attached to an alloy bracket using nylon gears to drive the motor you want to bed
in attached to another alloy bracket - it is or does not appear to be a run of the mill Slot car item - are there any downsides
to doing this or is this something very few people have thought of doing, is THIS the best way to run in a motor.

I am currently bedding in a new motor connected to a power drill using a small G clamp to keep the motor casing from rotating.

Love to hear your comments.

Robert.
 

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You can connect the motor wires to ordinary low voltage batteries and just submerge the motor in whatever liquid you use. john
 

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That's a way of reviving a motor that is sick because it needs a good clean out.
There have been some other sound suggestions for fixing that problem

Unfortunately there are lots of other reasons why motors go sick - windings failed, brushes or bearings worn out, comm slipped, brush springs gone soft to name but a few - and that method won't help with those sort of problems.
 

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WRP World Champ 2015/2016
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Discussion Starter · #17 ·
Quite so. I'm certainly a bit wiser as to HOW I gunged the motor up in the first place, so once one or two of my earlier cars are cleaned, I don't envisage this happening very often in future.

I thought using the White Spirit would negate the salty effects of the fairy liquid, particularly as I dried them in a cooling oven after their WS dip.
Would IPA be a better solution perhaps, as I find it very difficult to source lighter fuel in my town. No idea why, but I can find the Zippo fluid at about a tenner for 150ml or so - ridiculously expensive for base naptha.

Very interested that you cut your own brushes John - how on earth do you cut the material? I've always thought of it as rather difficult to work with as it "crumbles" easily.
 

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I use a brush cutting tool,Basically a 2mm double ended spindle with a 3/8 long com size, round cutter on it,You can get diamond coated cutters But there way more expensive, I think ABslotsport stock both kinds, But you have to open the motor to do it. john
 

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provider of comestables
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Slightly to one side but I resently purchased some Johnson 111 motors. I stripped each one to clean it up before running back in.
However inside one of the cans I found a complete Formula Juniour pick up braid. Could see why that one was running badly.
 

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Tony Condon
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Hi Guys
i certainly wouldn,t use IPA (indian pale ale? ) for cleaning a motor ,you're better off drinking it
I also would not use acetone as it is a very powerful solvent and even though it wont harm metal ceramics etc i would worry that it could attack the the insulation on the windings ,in 50 years of cleaning slotcar motors ,some full of goop,i have only ever used lighter fuel,its fine and evaporates off leaving little trace unlike white spirit whih will leave an oily film
also you need to understand why folk run motors in under water
the reason is that new brushes aren,t bedded in and if you run them in in air they arc .when they arc ablation takes place on the brush reducing its contact area ,and worse than that it burns the commutator slot edges making it less conductive
Running gently under water eliminates the arcing ,but leaves you with the problem of drying the motor out afterwards
If your brushes are impregnated with oil you are putting too much on ,however the trick with the soldering iron does work
I hope that clears certain queries

cheers tony
 
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