# AW 4-gears poor performance



## tasman (Feb 17, 2007)

I have several of the new AW 4 gear funny cars. I have seen posts here and on other boards where many are saying these are really fast. Mine do not run that well. 

When I remove the idler gear and let the arm rev, all of these sound as if they should be really fast. With the idler gear out I have checked the movement of the rear axle and rear gear assembly and it seems to be free moving with no noticeable friction.

When I place the idler gear back in the car sounds like it reaches not even 1/2 of the rpms that it does without the idler in.

I have tried "lapping" the gears. I use rubbing compound and have run the car for about 1/2 hour or so at about 1/4 speed rear wheels raised. I really can't tell much of a difference. Which leads to my questions....

1. How long does it usually take to lap gears?

2. Can some gear sets be so out of tolerance that no matter how much "lapping" is done the car will never really "free up"?

3. Anything else I can try pertaining to the gears that may help?


----------



## Grandcheapskate (Jan 5, 2006)

This may or may not help.

I have a lot of used runner Aurora AFX cars which I bought over the past couple years. Recently I went through them making sure they had the correct parts installed - magnet colors, armatures, etc.

One car had a metal idler when it should have had a plastic one. I swapped the idler gear with another car. Now one car started running poorly and the other was unaffected. I put the idler gears back in the original cars and they both ran well.

So yeah, the idler can make a difference.

JOe


----------



## slotcarman12078 (Oct 3, 2008)

You do have to be really gentle with the 4 gear gears!! The idler gear is brittle, and it doesn't take much to lose a tooth. I would recommend checking the back most gear for slop. The rivet may need to be snugged a bit. Keep in mind, there is a difference between turning the gearing via the wheels vs. turning them with the armature. You have the gear ratio in your favor turning the wheels.


----------



## tasman (Feb 17, 2007)

Grandcheapskate said:


> This may or may not help.
> 
> I have a lot of used runner Aurora AFX cars which I bought over the past couple years. Recently I went through them making sure they had the correct parts installed - magnet colors, armatures, etc.
> 
> ...


Thanks,
I have replaced some of my AW X-Tractions and T-Jets with old metal idler gears and it helped most of them. However, I never owned any original 4 Gears so unfortunately I have no old gears (plastic or metal) to try in them.


----------



## Bill Hall (Jan 6, 2007)

Four gears can be troublesome all right. If the arm ohms out good, I usually dump the idlers out and start from scratch.

If there's no rear wheel or axle binding move on. It's important to check the gear teeth carefully...all of them. After inspection I like to add the gears one at a time and roll them through carefully....just listen and feel! If ya find something suspicious, change it out. 

As for lapping, you'll get all kinds of variations on the technique. I use toothpaste for plastic gears; but coarse to medium compound should be OK. I slather the gear rack and include the crown. It's important to hand roll it across yer fingers so the arm doesnt have to start a gear set dead cold slathered with grit. 

I start at half throttle to start er whatever it takes; and listen and watch so you dont dry up or bind the gear set, over heat the arm, or both. It'll sling compound and naturally dry up whatever your using for compound. So ya stop and lubricate the gears. I like oil cuz it's clingy. After lubricating, I like to reverse polarity and lap the other direction.

Due to the sling factor, you must re-distribute or re-load the gears; which is where I suspect things diverged for you 

You should be able to hear a change in pitch as you throttle back up again. As things loosen up and the compound slings off you'll have to reload the grit and lubricate as necessary. As I work back and forth directionally, I increase the power from 1/2 to 3/4 to full with each reload.

Eventually you should hear the gear set clean out and the entire drive train should pipe up. At that point, break it all down, scrub it up, re-assemble and lubricate.

Other guys spin the whole deal by chucking the axle up and driving the lapping process from the backside using a dremel or drill. This does eliminate stresses on the armature....but you never hear if your making progress. Providing your patient, err to the side of caution, and keep everything properly lubricated; the proverbial stresses are not a factor. 

Remember that a little toe up on the pickup shoes often really helps get four gears down the track.

Good luck! :thumbsup:


----------



## Joe65SkylarkGS (Feb 15, 2010)

Just my opinion on the dremel turning the rotation oppoesed to the arm doing the turning, you have to be very careful with the dremel cause it will spin the axle up so fast if your not careful, you could melt the axle holes.

Ask how I know lol.

Use the motor to do your work. just my .02


----------



## Ralphthe3rd (Feb 24, 2011)

*Slow her down...*



Joe65SkylarkGS said:


> Just my opinion on the *dremel *turning the rotation oppoesed to the arm doing the turning, you have to be very careful with the *dremel *cause it will *spin the axle up so fast *if your not careful, you could melt the axle holes.
> 
> Ask how I know lol.
> 
> Use the motor to do your work. just my .02


 It's kinda funny, that know one seems to even think about using a simple _Variable_ Speed DRILL to do things like this any more....


----------



## plymouth71 (Dec 14, 2009)

I think Joe is using a variable speed dremel Ralph... Still gotta watch the RPMs


----------



## Joe65SkylarkGS (Feb 15, 2010)

plymouth71 said:


> I think Joe is using a variable speed dremel Ralph... Still gotta watch the RPMs



Your correct sir. I did this when i wad a kid. Back then your tools were limited and there wasn't any variable speed dremels. Just on and off. But I always remembered the once it happened, and never did it again lol. And now the chassis in under a shelf queen. I did fix it too.


----------



## Grandcheapskate (Jan 5, 2006)

plymouth71 said:


> I think Joe is using a variable speed dremel Ralph... Still gotta watch the RPMs


And if you don't have a variable speed tool, this is where that Router Speed Control from Harbor Freight comes in real handy. It turns a regular drill (or dremel) into a variable speed tool which can go as slow as you want.

Joe


----------



## plymouth71 (Dec 14, 2009)

or..., you can wire a dimmer switch to an electrical outlet/box. Thats what I use...


----------



## Bill Hall (Jan 6, 2007)

So!

For all-o-you dont use the armature chuck the axle up guys, how do you know when your done lapping? :devil:

Is there a special setting on the dremel that sez this gear train is as free as I can get it and the armature is reaching the ceiling of it's performance potential with an unloaded drive train?

Mine didnt come with one...

Short of using a tachometer and laborious time consuming repetitive retesting how do you know when you've hit paydirt?


----------



## dlw (Aug 17, 1999)

*A little late but....*

Sometimes the problem is in the pick-up springs. Yours may be compressed. Give them a gentle stretching, but not too much.


----------



## alpink (Aug 22, 2010)

*sgrig by ear*



Bill Hall said:


> So!
> 
> For all-o-you dont use the armature chuck the axle up guys, how do you know when your done lapping? :devil:
> 
> ...


LOL Bill. I have loaned Sgrig dynos and he doesn't like them. he doesn't lap with a moto tool either. 
he listens to the pitch and tests on his drag track for ultimate prime output.
I think his success is inbred. he was able to tune cars with just a power supply and listening to it long before he even started rewinding and got the drag track, or any other track for that matter, to time and test on. 
he just has a natural feel for the rhythm of each car.

.


----------



## cwbam (Feb 8, 2010)

*slot car whisperer*



alpink said:


> lol bill. I have loaned sgrig dynos and he doesn't like them. He doesn't lap with a moto tool either.
> He listens to the pitch and tests on his drag track for ultimate prime output.
> I think his success is inbred. He was able to tune cars with just a power supply and listening to it long before he even started rewinding and got the drag track, or any other track for that matter, to time and test on.
> He just has a natural feel for the rhythm of each car.
> ...


the slot car whisperer ?


----------



## Bill Hall (Jan 6, 2007)

*Dyno-saurs*



alpink said:


> LOL Bill. I have loaned Sgrig dynos and he doesn't like them. he doesn't lap with a moto tool either.
> he listens to the pitch and tests on his drag track for ultimate prime output.
> I think his success is inbred. he was able to tune cars with just a power supply and listening to it long before he even started rewinding and got the drag track, or any other track for that matter, to time and test on.
> he just has a natural feel for the rhythm of each car.
> ...


That Jim guy is a wiley devil and a conjuoror of ancient mojo! 

Al, I tossed that out there hoping for a nibble....a month ago. I prefer the "oldskoolvoodoo" too. 

I was hoping to open some dialogue regarding the sweet spot, finding it, and then recognizing that there is no more. The entire point being that you might as well have earplugs inserted if your trying to find the sweet spot from the outside in; instead of from the inside out. 

In addition to your comment about "pitch", I'd like to add "feel". When moto-lapping, the auditory and tactile indicators of success dont exist....uh....because the motor isnt running! :tongue: I believe Carlos Mencia spells that Dit Da Deeeee.:devil: 

The ole' "You'll stress out yer armature jive" doesnt hold here either. If yer build doesnt have enough grunt to grind up some lubricated compound then there other mechanical issues at hand that the builder failed to address; or your doing it wrong and flat out not paying proper attention. Sum-ting-wong :freak: With hands on, you'll feel any excessive heat build well before the smoke comes out of the.....

armature. 

The technique is painfully simple albeit a hair messy. Load the gears and axle up. Then sit down, shut up, and turn yer tunes down. Apply power and listen to what the chassis sez. Repeat as necessary. With hands on and ears open, (OMG...what a concept) you'll actually hear and feel the sweet spot pop up because it's an immediate thing when it happens....yer there....yer done....like night and day.....then go wash up. Hell if it wasnt for breaking the chassis down and washing out the compound you can do it blinfolded. Certainly this is a nut shell view and there are some nuances....but it aint rocket science. 

At this point Jag doesnt make a tool for it, but I believe RTHO might be working on some kind of puller that removes chassis from dynos and also pries open your hands and ears. Arguably one could moto-lap and dyno and moto-lap and dyno moto-lap lap-n-dyno until they eventually find the nut.....

..... instead of actually learning how to do it first time everytime with a few pennies of grit, oil, and soap, plus a few scant minutes of your time.

Tongue in cheek as always


----------



## alpink (Aug 22, 2010)

as always ....


----------



## Boosted-Z71 (Nov 26, 2007)

My problem is I tweak to find the "spot", hit it and then not realize its the point of no return and continue to tweak until it again slows down, all while getting really pissed at everything in the world for effecting my fire breathing T-jet, then repeat the process several times, and finally settle that it will surpass the last car I built but am OK with the fact that last months slow car that I just pulled from the case has it by 2/3 rds of a car length and not looking back down the long straight.

I too like to put them on the transformer under a solo overhead light with complete silence, to listen, feel and let the fun begin.

A friend ask me why I have to do the tweak to get all you can from them, why not just race them as they are. I thought about it and my answer to him was "because I can" Nothing more satisfying than a self-built car that just hauls the mail.

Boosted


----------

