Hobbyist Forums banner
1 - 10 of 10 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter · #1 ·
Has anyone changed crown gears on a/w 4 gear ? different tooth count to change ratio. Looking to speed up a couple of my 4 gears, that just won't go like like my others.
Any help appreciated.
If so what make and tooth count can i use. thanks:wave:
 

·
Model Murdering
Joined
·
7,331 Posts
I prefer the standard AFX crown conversion for the four gear chassis. Dont see why one couldnt proceed in the same manner on an AW. You can either bevel the back side of the gear or nibble a bit off of the the gear plate at the outside edge the pinion window. Check your rules if it matters.

Never gave the gear ratio change a second thought until I was pleasantly surprised afterwards. My primary focus was eliminating the slipping and skeezen' on four gear final drives.









 

·
Registered
Joined
·
2,209 Posts
Back.To.HO

Maybe you should ohm your arm to see if it (they) aren't faulty. Also check your electricals:

Are your comm brush holders hanging out of the bottom of the chassis?
Are your springs too compressed?
Loose rivets?

Sometimes fixing these problems, which can happen just by sitting around for long times, can wake up a dog chassis.

Also, a little magnet zapping can give a speed boost. If you don't have a zapper, don't worry......Just grab a pair of Xtraction magnets and attach them to your car's magnets to restore their strength. If you don't have any handy, just stick your car to your bathroom's medicine cabinet magnets. A bit old school, but it works.
 

·
Registered
Joined
·
51 Posts
Discussion Starter · #4 ·
dlw

dlw, i changed the top plate, all new, gear train is now very free turning. the original, had a bad cluster assembly, rivet was junk. tried a screw , didn't work - thus new top plate assembly.
will check other rivets , i think brush contacts are properly tweaked, is it possible that magnets are just weak ? it now has new arm, and speed is same.
medicine cbainet magnets ? do mean the one that holds door closed ? would some strong noe magnets work also?

please excuse my lack of knowledge, but i am fairly new to all of this, and playing catch up rather quickly. thanks :wave:
 

·
Registered
Joined
·
51 Posts
Discussion Starter · #5 ·
Bill Hall

great video's , you usestandard AFX crown, what is tooth count, and is from AFX , magnatraction or what chassis ? need to know so i can order a few.

Also, what tires are those in video, i need a slightly taller than stock a/w uses, due to chassis sitting too low ....

terrific info, thanks A.:wave:
 

·
Registered
Joined
·
2,209 Posts
Back.To.HO

Yep, those magnets. Take your magnets out of the car and attach them to the medicine cabinet. You could place the car itself onto the magnet, just be careful to warn folks about closing that cabinet door.........

And as I mentioned, check the pickup springs to see if they are compressed. A little gentle stretching should fix that. You'd be surprised how much speed you can get. A good pair of springs should be strong enough to almost cause wheel hop.

And for the rivet on the gearplate, a hammer and puch will fix the excess slack problem there, just tap gently.
 

·
Model Murdering
Joined
·
7,331 Posts
Well...yeah, my disclaimer is that Daves probably right. Four gears are very tuning sensitive and should always be properly sorted out before you resort to extreme measures.

I guess the question I should have asked is, "Do your four gears seem anemic when compared to other four gears; or do the seem anemic to other chassis of different configuration?" I read your post as implying the latter.

The high tooth count crown worked good with the tall drag tires and the gajillion pounds of extra weight that the dragsters carried. However the specialty cars always seemed to need something extra as they spooled up quick on the more squirrely table top set tracks of the era; but hit their ceiling early on the long stretches. Additionally, they did not withstand the test of time IMHO. Not only are their teeth weak and thin, there are often issues with excessive lateral clearance regardless of the condition of the cluster gear/rivet. It's the weakest link in the design. To date I havent had one failure with the conversion. Addmittedly they are not high zoop drag cars, but I do run 6 ohm arms and poly mags with complete reliability.

So if your comparing apples to apples, then its a good idea to follow conventional wisdom and back track to sort out the whats really wrong. Even without the freeway gear modification they should move out sharply and skitter on down the road in stock form.

Yes, tuffones, A/FX, or Magnatraction will work. The tires are PVT "Specialty" now available through Tom Heister, he's a memeber here.
 

·
Registered
Joined
·
2,209 Posts
Forgot to mention, Bill.... That Model A you got there flies. It's really satisfying when you can get Afx or AW cars to run that well.

The only complaint is that we can't see the car run the whole track :tongue:.
 

·
Model Murdering
Joined
·
7,331 Posts
Forgot to mention, Bill.... That Model A you got there flies. It's really satisfying when you can get Afx or AW cars to run that well.

The only complaint is that we can't see the car run the whole track :tongue:.
Thanx, even with the leggier gear mod they'll still get right up on the pipe with the Specialty rear wheel and tire set up. I would not recommend the mod for chassis with dragster diameter tires.

Like any other slot chassis, it takes time and effort to work out the bugs on four gears. Removing excess frictions if you have them, and proper gear lapping are absolutely critical to to the motor and drive-train response. A balanced arm sure doesnt hurt. Naturally balanced or otherwise.

Track manners mean a lot too. The four-gear pick up settings are also critical. Subtleties can make the difference between average and beast. To start with I always minimize the spring pressure by adjusting the shoe hook where it goes into the hanger plate slot. I also adjust the toe of the shoe upwards so it doesnt plow the rail and then level the contact patch as it goes rearward. The reality is that ya gotta bend some shoe and re-check contact patches. I do this to every pancake I tune. The chassis combination must prove to me that it requires more pressure first....then I add it back if required at all. IMHO, clean electricals, and the friction created from forward motion on a properly adjusted foot print and the rail are more than adequate to transfer current to your average slotcar. Pounding up the spring pressure creates more issues than it solves.

It's noteworthy to consider that there are a several front and rear wheel and tire combos available as well as assorted shoes to choose from. There's no one right setting! Depending on what combination of parts a four gear has; one may have to alter the angle of the dangle considerably to get them to skim along properly because the rake of the chassis can vary substantially.

A good Peace Tank or Roaring Rolls setting would be excessively heeled for a Model A or Grand Am; where as a proper setting for the Model A or Grand Am would be overly toed on the Peace Tank or Roaring Rolls. :thumbsup:

Edit: Yeah Mark, "Funkifying" with the Tower.... "Rock-a-billy" with the solo Setzer....a lil Doors....I just load up the changer and push play.
 
1 - 10 of 10 Posts
Top