# Thunder Plus Chassis



## T-Jet Racer (Nov 16, 2006)

Ok heres the deal, I have a few of these thunder plus chassis. I had one run around the track for about 10 min and as usual the armature went kaput. So I swap in the old who knows how many ohm just lying around aurora armature and Wa La! I'm running again. So I lap the gears car runs sweet so I figure lets throw some magnets in so I grab a pair of white and blue Johnny lightnings and Damm they dont fit. Now I know sombody fit them in at some point how did you do it, grind the chassis, or sand the magnets ? The chassis don't look to meaty and cutting the magnets kind of kills the point so I need some ideas.....


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## SwamperGene (Dec 1, 2003)

We sand JL mags all the time for Fray T-jets, at least when they don't fit well.


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## T-Jet Racer (Nov 16, 2006)

SwamperGene said:


> We sand JL mags all the time for Fray T-jets, at least when they don't fit well.


yea for the aurora they are snug, sand them slightly, no problem. In the thunder plus they are real tight, how do you sand them super fine paper and oil?


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## tjettim (Nov 29, 2005)

Make sure you sand them unevenly to advance the timing like
the fray guys do too.


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## T-Jet Racer (Nov 16, 2006)

tjettim said:


> Make sure you sand them unevenly to advance the timing like
> the fray guys do too.


So sand the side that faces the rotation of the armature? On these I think I will need to sand the chassis, it is very tight and the chassis is visibly distorted when you stuff it in


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## SwamperGene (Dec 1, 2003)

tjettim said:


> Make sure you sand them unevenly to advance the timing like
> the fray guys do too.


I've heard this before and still don't buy it. Without sanding the chassis the radial position of the mags doesn't change in relation to the armature poles. Maybe you could gain the effect of a degree or two according to where the sweet spot on the mag is, but you gotta be able to find that first....on both mags, precisely. Could be too that this timing trick is an assumed effect due to air gap manipulation. :freak:


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## martybauer31 (Jan 27, 2004)

I use a diamond hone to sand mine, they work great, I picked up a 3 pack of them at Harbor Freight one day and they do the job quickly.

As for which side to sand, I will hope that Tim will come in and correct me if I am wrong here, but if you have a lower ohm fray arm (i.e. 16.0, 16.1) then you sand the side with the end points. If you have a higher ohming motor (18.0 for example) you want to sand down the back, or curved side of the magnet. Again, I may have this reversed, someone will be along to correct me soon if I have gotten them mixed up.

I haven't ever heard or sanding them unevenly, maybe that's a secret of the fray gurus not released to us commoners.


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## T-Jet Racer (Nov 16, 2006)

Personaly I don't see how it would make any difference if you got 1 to 2 degrees it would be a lot. I thought the only timing had to do with when the brush hits the comm vs the arm pole position. I saw on the quadralams that the wires were soldered on in a "different" location with a comm trace running twords the usual spot. I assume this means it has been advanced.


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## SwamperGene (Dec 1, 2003)

Marty's right, hones work great. :thumbsup:

Short of that, fine sandpaper on a flat solid surface works, too. To cut the front faces I've also used a dremel cutoff wheel in a drill dress with the mag in the vise...almost like milling the end, you get a nice square cut. You can get a little tricky with this setup and shave measured thousandths off at a time.

I think Marty's right on the air gap tip, a weaker arm might fare better with the strong JL mags back a hair.

T-Jet Racer the quadralam's were advance timed. You can spot the difference easily by looking at how the commutator spaces line up with the poles.

Also, if you were able to advance the timing by moving the mags, you'd want to move them in the direction of rotation.


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## tjettim (Nov 29, 2005)

Make sure you put the strongest side down,the reason these mags
were prefered over the super2s is that they have more downforce.
Even on a t-jet it is noticeable.Buff them with a dremel buffing
wheel until a mirror finish.Use the wizzard 80% copper brushes
and buff your comm also.Cnc'd gears are a must also.Run a Titanium
rear axle and the smallest tires you can.Get the lowest lightest body
you can find.


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## waltgpierce (Jul 9, 2005)

*Sanding - How to*

Near the bottom of the page:

http://frhoracing.com/hop-up-hints/Slot-Car-Magnet-Sanding-Better-Fit.asp


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## tjettim (Nov 29, 2005)

Check your rule book for legality first.
Most EX. Tjet racers;
'I cannot believe I used to spend so much time and money to go so slow.'


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## dlw (Aug 17, 1999)

Your T+ chassis had one of those faulty 50 ohm arms, that pretty much destroyed that company. MM did mike some better arms to fix that problem.

Also, some Aurora bodies don't work well with T+ chassis. Its wheelbase is slightly longer than Aurora chassis and will sometimes be hindered by the rear screwpost on an Aurora body.


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## T-Jet Racer (Nov 16, 2006)

dlw said:


> Your T+ chassis had one of those faulty 50 ohm arms, that pretty much destroyed that company. MM did mike some better arms to fix that problem.
> 
> Also, some Aurora bodies don't work well with T+ chassis. Its wheelbase is slightly longer than Aurora chassis and will sometimes be hindered by the rear screwpost on an Aurora body.


Yea swaped in an Aurora arm, just put johnny lightning mags in runs good except the crown gear skips I need to get some spacers to tighten it up a few .000. Runs very well now with the upgraded arm and magnets.


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## dhamby123 (Jan 6, 2007)

i dont think timing would be the big thing by sanding the magnets i think the air gap would be the ticket on this if your running a long track a big airgap so it will turn up would be good if your running a small track a small air gap would work good more tor. this is how it works with any othere motor so i would think it would be the same with these


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