# Tjet question about magnets and gears



## bmt216a (Mar 28, 2008)

Hi
I have been disassembling and cleaning some of my Tjets in batches. Most of the cars have magnets with no markings or paint on them to help identify each. I know how to find and put opposite poles together ( north or south ),but how do you tell which goes in front. If I do it wrong, car runs in reverse and I have to take it apart, swap magnet position and then car will run in the right direction. Is there a way of checking to see which magnet goes into the front slot? I know I should just mark them first before taking car apart but there are a lot of things I should do and don't. Also is there a top or bottom to magnets or doesn't it matter?
I have two top gear plates, one with bad pinion drive gear and the other with bad armature. Which would be better to swap without having the proper gear puller or installer, the armature pinion or the crown drive pinion?
Thanks


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## slotking (May 27, 2008)

for me, swapping the arm is easier

on the magnets

simply take 1 car that is working right

pull the front magnet out, and test the other mags VS it.
if the mag repels then mark it 1 color, if attracts mark it another color.
That is the simple way.

If you have an I phone, you can download a gaussmeter app and check them for north of south.

no top or bottom on the mags, but I use the gauss meter to determine the strong side and place that down


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## Rich Dumas (Sep 3, 2008)

Pancake magnets are often stronger on one end or the other, so it can make a difference if you take one out and turn it upside down. I have a magnetometer and when I check magnets I first look for the highest reading at the inside center of the magnet, but I also take readings at the ends and mark the stronger end. When I put the magnets back in the chassis I arrange them so that the armature will be rotating towards the stronger end of each one. Doing that can shave a tenth of a second off of your lap times. It would not hurt to try the magnets the other way around as well.


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## bmt216a (Mar 28, 2008)

Thanks guys for your answers. They help me out a lot. I am not a competition racer but more of a countryside driver who likes to clean out the tailpipe on the highway. Thanks again :thumbsup:


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## roddster (Jan 17, 2010)

Buy a couple of paint sticks. I suggest red and blue, Mark the magnets before you take them out of the chassis.


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