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Discussion Starter · #1 ·
Since the HO Gang (myself included) seems to have a tendency to stray off topic, thought I'd start a thread devoted to wrenching on these tiny cars and maybe make things easier to find. They're a lot different than they were when I was first doing this shortly after electricity was invented. I'll start with a couple quick questions I have: 1) Pickup shoes. I see posts about shoe tuning or flattening shoes to get better conductivity. What are you looking for, just maximum contact patch? I assume you set the car on a piece of track and then just gently bend the shoes to maximize? After first making sure your guide pin isn't hitting the bottom of the slot of course; 2) Gear mesh. When I was breaking in motors I noticed I have a couple Mega G cars where the gears bind when the axle moves all the way out to passenger side of car. Both these cars pulled significantly more amps than the other two Mega G. I'm not sure how much axle play I should have in the rear so not sure of the best way to fix. Should I just press the spur/crown gear towards the left slightly and leave the play or should I actually shim the axle assembly so there's a little less play? Any rough measurement on how much side to side play I should have in rear axle? Thanks.
 

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Pickups. On tyco 440 cars, and perhaps others, the pickups form a straight line from the rear (hinge point) to the front. This creates a triangle of sorts, and tends to lead to the front of the pickups wearing quickly.

Over the years, I developed two quick tweaks--both on the car.

1) I place a small flat screwdriver under kind of in the middle of the shoe and pry "out" away from the chassis, creating a new bend--forming a "flat" contact patch when viewed from the side.

2) On the front of the shoes, where the slot is that travels up and down on the chassis as the car moves along, I bend the vertical piece back toward the chassis slightly. This lowers the whole deal and helps handling.
 

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You answered your own questions Cjtamu, and you're spot on.

The shoe should sit as flat as possible on the rail from toe to heel. Rich's tuning articles are a great resource for this.

I think the pinion under load keeps the crown spaced properly. It would be a problem if the axle didn't spin freely in your fingers and the gears were binding.
 

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Discussion Starter · #4 ·
You answered your own questions Cjtamu, and you're spot on.

I think the pinion under load keeps the crown spaced properly. It would be a problem if the axle didn't spin freely in your fingers and the gears were binding.
If I spin right rear they spin freely, spin left rear and you hit a point where it locks up completely because you're bumping the crown gear away from pinion. The other 2 MG cars don't have this issue. I would assume that in a left hand corner the weight transfer moves crown gear in towards the pinion but in a right hander it's moving away and that's where the issue would be. Were it to lock up the way it does by hand I'd be replacing gear(s). These 2 cars were pulling 250+ mah at 6V just sitting on a break-in stand, much more than the other two MG cars. And much noisier. I'm going to shim it in slightly, just trying to figure whether to shim axle or just move crown in. I'll look for Rich's tuning articles. I figure over the years he's probably answered, more than once, every question one could ever have about slots. I just have to find the posts LOL.
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Rich Dumas
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Modern high magnetic downforce HO cars have a considerable amount of pickup shoe spring tension and are more tolerant of shoes that do not ride flat on the track. If only a portion of the shoe is touching when it is new it will eventually get grooved, and the contact area will increase without you doing anything. Pancake type car, especially T-Jet types have much less shoe spring tension, making shoe adjustment much more critical. If a car just wants to crawl around the track a simple shoe adjustment can make it a lot faster. You can get the shoes to ride flat on the rails and also bend them at the hook end to change the spring tension without changing the springs themselves in any way.
See this article to get an idea of what I am talking about: T-Jet Tuning Article by RHD Rev 11.pdf
 

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Land of the lost.

Correct pick up shoe stamping got lost in translation. The leading edge needs to be slightly curved ... The MG+ shoe reflects a slight return to the idea. We want any aberration in rail height to be absorbed along this gentle curve rather than the a 90 degree edge bluntly scraping along.

Hard shoes are supposed to be doing what down the rail? Skiing.

So ask yourself ... do toboggans, skis or sleds have blunt or square leading edges? No they dont.

Just a touch is all it takes. Use an old shoe to practice if your shaky about it.

*

We have two ears. Use them. If a chassis at half speed goes by you and makes a nice swishing sound .... swwwwwhhhhhhhhhhhhhhhhhh ... yer pretty close.

If it goes by and around like a putty knife ... skkkkkkkkkkkkkkkkk ...
yer not close.

Learning to read the "burn" and adjusting it is what it's all about. A t-jet burn will be hour glass shaped. A 440 burn will be more of a the top half of that hour glass. This is due to the location of the guide pin not being centered in the contact patches. How the pin is situated is significant because it controls the pivot point of the available contact patch. The burn character differs from brand to brand unless the pivot relationship is identical.

Imagine just standing there and grinding the shoes onto the rails, as though you were lapping them in. It makes a unique pattern characteristic to the relationship between the guide and the contact patches of the model/brand.
This optimum pattern is the correct burn we're looking for; a lapping pattern developed by running the chassis.

To get the correct burn.

The approach angle, "the hangle", of the contact patch dictates how much of an optimum pattern appears in operation. It can reflect too much toe, to much heel, or the porridge is just right.

Alien? maybe a little. You'll get used to it pretty fast if you stay after it. Listen and watch!




Ya really need to make or buy one of these. Simply an old jewelers driver that had the philllips portion galled off. I split it with the dremel disc.
 

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Addendum to post #2:
In addition to the rest of the adjustments, turn the front of your shoes into skis.

Just did it and the car is (incrementally) quieter and smoother. Used needle nosed pliers and my fingers to get there, but will also be making that tool, which would make the process easier.

Thx, MM
 

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Addendum to post #2:
In addition to the rest of the adjustments, turn the front of your shoes into skis.

Just did it and the car is (incrementally) quieter and smoother. Used needle nosed pliers and my fingers to get there, but will also be making that tool, which would make the process easier.

Thx, MM
Well, when I delve into the minutia, I always forget important or relevant little tid bits. It should be mentioned that magnet cars make a lot more racket naturally, than a T-jet or a gravity sled. Because of the added racket, ya might have to listen more closely.

In the abstract, I liken it to boating: When you are smooth and fast, you are up on plane, rather than wallowing in yer own wake.

It always bothers me to see cleavered up shoes
 

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Discussion Starter · #10 ·
Great little tool. Gotta make one. Lord knows I have enough Dremels and small screwdrivers.
 

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Discussion Starter · #11 ·
I've searched the forum looking for a comprehensive tuning guide for HO thread, no success thus far. Bits and pieces here and there. Is there a "HO Tuning Guide for Dummies"? If not, there should be.
 

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Rich Dumas
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I have done tuning guides for the various types of HO pancake cars. There are minor differences between the T-Jet types that might be confusing, so I have done similar articles for Aurora, Johnny Lightning/Auto World and Dash cars to hopefully avoid confusion. I also have a tuning article for non-magnet 1/32nd cars. I have not published anything about modern inline HO cars.
Doing a complete tuning guide for all sorts of HO cars would be a daunting task.
 

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Discussion Starter · #14 ·
A comprehensive guide for H0 tuning .... giggle.

It would dwarf War and Peace.
Yes, but people would actually FINISH the tuning guide ha ha ha. I have a better than average understanding of vehicle dynamics. What I DON'T have is any idea what to do to get these little cars to handle the way I want them to. Don't have the variety of adjustments either mechanically or electronically that I'm used to. I'll just keep asking questions and see where we end up. Like , right now I have one MG+ cars that's just a dog compared to the other 3. These were all NIB cars. IME with tabbed can motors it's typical for some to run better than others. You can hear the RPM difference in this car with the wheels lifted. I'm going to take it out, spray, oil and put back in and see if that helps. Is there a good way to zap the magnets in this motor? Any other tweaks you can make to these?
 

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Rich Dumas
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Zapping magnets would only be helpful if they were not fully charged. Magnets can be zapped in the can, but I do not know of anyone that does those N can motors. If one car is a dog first make sure that the motor is fully seated in the frame. If that is no help it is easy enough to swap in a motor/RFI filter assembly from another car. If that fixes your problem JAG Hobbies sometimes has replacement assemblies in stock. We have found a few cars that have a poor or even open connection between the shoe hangers and the motor, fixing that would be difficult for most people, so replacing the whole works would be the way to go.
 

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Discussion Starter · #16 ·
Thanks, @ RichD. House full of people next few days and as that car sits it’s a good one for the grandkids to play with. It’s going to be my sacrifice/experimenting car so I’ll tear into it after everyone leaves. Suspected might be magnets because it feels different when rolled by hand but I’ll look at the other stuff too.
 

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The MG+ has copper metallic brushes. Now kinda lost knowledge, in the beginning it was found they can require more time on the break in. This is why listening to a motor break in is more important than assigning a time duration. In the case of your dog, remove the rear axle assem so you can turn the pinion and feel whether its the motor or the mesh. If the motor feels gritchy, it's junked.

The gear mesh should be silky smooth to have them at their best. The mini can isnt overly torquey to start with.

The motor was spec'ed with a 17 ohm wind and mediocre ceramic magnets. A can swap with poly mags was not the easiest task, yielded more heat with and no discernible performance advantage. Like putting polys on a 17 ohm T-jet, it makes a good hand warmer. As a knuckle head, I still have to reprove things that I already know. Their small size, delicate components, and precision soldering puts them well out of the range of the average bear.

Direct replacements are available as are upgraded cans, but someone has to do the soldering. While it is possible to dis-assemble the stock can without de-soldering to change an armature, it takes a brain surgeon's touch so I dont recommend it. The commutator is whimpey compared to other minicans. In the end, it becomes a question of what your time is worth.

As Rich stated above the forward current path has enough potential failure points to dictate a wholesale swap of the motor and pick up hanger module. Due to the precision soldering required, ya just change the whole enchilada.

Wheel and tire replacement involves the whole hog including axles, thanx to crudely knurled axles made of playdoh. (easily bent and ruined by you, but not easily shoved up lil Johnny's nose)

In a nutshell, some shoe voodoo, gear lapping, wheel and tire truing, and adjusting the traction magnet influence is all ya really get. As a hand wringing soccer mom approved can arrangement, they arent particularly hot rodder friendly when compared to other open fame inlines.

All by design of course, the same engineer(s) who ensured that lil Johnny couldnt eat it or it's bits, also prevents the home tuner from doing much. Still a wonderful entry level platform.

It can be both!

Edit: And there in lies the challenge... If you cant tune a piano, you cant tuna fish. When you dont verify your fundamentals, how in the heck do we know there's even a problem?

Throwing hot rod parts at something doesnt always guarantee performance. Changing a crazy donkey into a thoroughbred stocker through the application of fundamentals, is how you learn the craft: and gain what I call acquired intuition.
 

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Discussion Starter · #18 ·
LOL @model murdering. I’ve cracked a bunch of tabbed motors in my time but never anything this tiny. I have 4 that run well, then this one that handles well but has no huevos. Actually turns good lap times on a 30’ish foot track, just no top end. I think I’m going to order a complete chassis then swap an aftermarket motor into this one and see what happens. Gear mesh in this car is excellent. Super smooth, very quiet.
 

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I have done tuning guides for the various types of HO pancake cars. There are minor differences between the T-Jet types that might be confusing, so I have done similar articles for Aurora, Johnny Lightning/Auto World and Dash cars to hopefully avoid confusion. I also have a tuning article for non-magnet 1/32nd cars. I have not published anything about modern inline HO cars.
I'm only interested in pancake cars (and I admit I'm curious about the 1/32 car).
I think the high magnet HO cars just aren't fun.

Where do I find your article?

I noticed that my new Auto World 4-gear cars have wobbly wheels and are gutless. So I'd like to fix them up.
 

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Brush retraction. Ya might need this down the road. Some mini-cans have it, some dont. The AFX 17 ohm N20 does.


You can see the service channels in the brush plate


I use a paperclip-a-mabob to ease the brushes back.


Then ya dont snag the tail shim and wad the brushes/springs on the way in/out.



A rare 9 ohm N20 on a gravity sled.




An MG+ with a 2 ohm N30 neo magnet shoehorned in. Ballistic.
 
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