Conference vmszoo::rc

    If you're willing to spend another $30 or so, a genuine Kyosho belt
    drive upgrade kit is available for the Turbo.  It includes a belt,
    new differentials, and front and rear gearbox housings.  All the
    hobby shops here have them in stock.
    
    The benefits are greater reliability, higher efficiency, and quieter
    operation.
    
    Ed.
    

    
    Rather than start a new note, I thought I pick up here...
    
    I wanted to warn any present or potential Optima/Optima Mid/Turbo
    Optima builders to be to be absolutely certain that the belt drive
    system is totally sealed.  For the second time in a few months,
    I've managed to munge up the spur gear in the rear gearbox with
    particles of sand.  The first time, the contaminants breached the
    lower belt cover, which had lifted off of the chassis plate.  My fault.
    
    Recently, it happened again.  The symptoms were motor overheating,
    and difficulty in rotating the large drive gear (the one that the
    motor pinion mates with).  Apparently, the sand or dust or pollen
    will lodge itself in the root between two gear teeth, building up
    to a layer of crud that eventually prevents the gears from meshing
    properly.  The mating tooth will actually begin to pound itself
    out of shape.  The only fix is to rebuild the gearbox with a new
    spur gear and differental.  I don't mind the few bucks for parts,
    but the labor involved is a real bitch.
                              
    I had thought that the contamination was also making it's way in
    through the large 15 mm differential bearings, so I had smeared a
    little grease on outward facing shields on these bearings to
    act as a dirt barrier.  Apparently, this hasn't worked.   I'm not sure
    just how the crud got in this time. 
    
    I also plan to avoid lubricating the gears this time.  It seems
    that any grease on these gears acts as a dirt magnet.  I'll take
    my chances on tooth wear, heat, and noise.
    
    Has anyone else had similar problems?  
                                               
    Ed.

    
    Wow, that graphite is pretty slick stuff.  I picked some up last
    night and tried it out.  It takes a little work to pulverize it
    and get the particles to cling to the gear teeth, but I found that
    a stiff paint brush does the job nicely.
    
    The belt/gear train is now amazingly friction free, without the
    viscous resistance of grease.  I'll seal it up again tonight with
    RTV and see what happens.
    
    Thanks for the graphite suggestion.  I guess I'll try some on the
    suspension pivots and kingpins etc, too.
    
    Ed.

    
    Bad coice of words... I, too bought a small tube of powdered graphite,
    but the stuff has a flaky texture.  If you rub a little in between
    your thumb and finger it crumbles into a very fine film.
    
    The flakes won't stick to the plastic gears.  You have to sort of
    'smear' it onto the parts.  I found a stiff brush works well for
    this.
    
    Ed.

    
    
    	Try Paragon Racing products graphite lubricant.  I'ts very good
    at lubricating gear teeth and dogbone ends.  It comes in a small
    bottle with a needle aplicator.  It's a liquid graphite solution
    that you apply and dries out in a couple of seconds leaving a
    graphite lasting graphite coating on the surface.  It will definitely
    NOT attract dirt.
    
    						Orlando.
    

    I think most of your problem is the grease.  I have had a belt drive
    in my Turbo-Optima for a long time and have had ZERO problems. 
    I did nothing special to seal the drive train although extra
    precautions can't hurt.  When I used the chain drive I did use grease
    and like you say, the grease was a dirt magnet.  I had LOTS of problems
    with the chain and dirt.
    
    Todd
    

    I finally settled on a product made by Paragon that is teflon particles
    suspended in a volatile solution.  The liquid evaporates in a few
    minutes leaving a fine white dry film.
    
    I degreased the entire car and applied the teflon.  The car glides
    so easily that my battery is lasting 6-8 minutes, even with a hot
    motor.  The car is so quiet that you can't hear it from 20 feet
    away.  All in all, it looks like I'm all set now.
    
    Ed.
    

    I got the Paragon lubricant at Bill's Hobby Barn in Sudbury, MA.
    A 2 oz bottle was $3.95.  It only takes a few drops to lube the
    entire car.
    
    For de-greasing, I disassemble the entire car and run it through
    the dishwasher!  It works great.
    
    Ed.

    Well, I did it. I went and bought a Turbo Ultima. It looks like
    a real nice car. I finished putting the suspension together last
    night, and here are some impressions:
    
    The transmission is nearly friction free. It has a full compliment
    of bearings with a ball differential. The ball differential requires
    some adjustment to set the compression on the balls. This is done
    via an axial hex screw, and is pretty delicate. There is some friction
    when you rotate the rear wheels in opposite directions, but forward
    power offers little friction. There are two ball races, one between
    the halves, and the other behind the compression screw. There are
    fourteen bearings in all, two for each wheel, and two for each gear
    axle, of which there are three, including the differential.
    
    The suspension consists primarily of an A strut ( no toe alignment
    on the rear ), and a ball joint for adjustable camber. The ball
    joints are not the turnbuckle type, they are adjustable, but have
    to be removed first ( there is a right hand thread on both ends).
    This makes it harder to adjust the camber. The connecting rods also
    have the same type ball joint. It looks like nylon around polished
    metal, probably steel. The shocks look really nice, they're the
    sealed oil piston variety, and have an adjustable damper. The spring
    is also adjustable via a collar.
    
    Both front and rear suspensions have anti sway bars, connected through
    ball joints. The whole suspension feels really smooth. I can push
    down on the chassis, and the whole thing returns to normal without
    sticking. I can drop the chassis, and it doesn't bounce at all.
    
    Overall, I'm pretty happy so far. More to come.
    
    							John.

    Well, I made a couple of refinements. I decided to junk the three
    speed resistor throttle control in favor of a fatuba 112B throttle
    controller. It's the size of a servo and mounts in the same place.
    I replaced all the tie rods with turnbuckle types. I have this fear
    of stripping the plastic threads on the knuckles while removing
    the tie rods several times to adjust camber and toe in. I got the
    whole thing together (except the body, which I painted last night),
    and took it for a test drive. Does this baby scream!
    
    I ran it out on the street outside my house, trimmed th steering,
    and proceeded to give it full throttle. I didn't clock it, but it
    must of hit 30+. It has a nice low center of gravity, and proved
    impossible to tip. The receiver has a built in BEC that operates
    as low as 4 volts, so runaway was never a problem. I ran down the
    battery on purpose to see what would happen, and the throttle never
    locked.
    
    I'm going to install the body tonight, and I'm looking forward to
    some good fast runs.
    
    						John.

    Ed,

    The January '89 issue of RC Car Action has an article on "Chemical
    Warfare" which lists two products from Paragon, Ultralon and Liquid
    Bearings.  Which of these two are you refering to in .12?
    
    Brad