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Building the S960 โ Tips & Tricks โ Part 2 (22/09/2005)
- By:
- Glenn M. Cauley
- Linked to:
- Serpent 960 1/8 scale 4WD
This article follows Part 1 (http://www.mytsn.com/publ/publ.asp?pid=11388) where I focused on building the front end of the S960.
Part 2 focuses on building the rear end of the S960. I describe some of the building tips and tricks that I have developed and/or picked up over the years which have made for very well-built, smoothly-operating cars. For those who have shared their knowledge with me, I thank you!
Again, as an overall suggestion, remember to take your time and carefully prepare all parts for assembly. The car will go together better and operate more smoothly. PATIENCE is the key here. Sure you can "slap it together" quickly and the result will most likely be very good, or you can take your time and the result will be exceptional!
Here are some items to have on hand, or have access to (note that many of these are already listed from Part 1 of the article):
Metal polish paste (I use Mothers Mag & Aluminum Polish)
Dry graphite powder lubricant
WD-40
Thin CA glue
Motor spray
Bearing oil
Graphite spray lubricant
Scotch-Brite scour pad (brown or green)
Shop towels (paper towels)
Cotton swabs
Ziplock plastic sandwich bags
Hairdryer (or heat gun - use caution)
Drill press
Mototool (Dremel or other)
Hobby knife with sharp blade (e.g., #11 blade)
3.0mm & 3.5mm reamers and handle (Starrettฎ brand is very good)
Small jewellers files (round and flat)
Pliers (needle-nose Visegripsฎ preferred)
Black marker with wide chisel tip
Safety glasses & gloves
Following the Previous Tips
Follow the various tips and procedures in Part 1 when assembling the rear end parts.
POLISH ALL METAL SUSPENSION PARTS
Follow the procedures in Part 1 to polish all metal suspension parts until they have a smooth mirror finish. This will help to ensure that the rear suspension operates smoothly with reduced chance of binding due to friction.
The following rear-end parts will benefit from polishing:
Rear pivot balls (for suspension and swaybar linkages)
Pivot pins
Anti-roll bar ends
Rear bodymount upper pins
Rear bodymount screw collars
Rear bodymount centering post
To polish the rear bodymount screw collars, put an M3x16 screw through the collar and then press firmly into the collet of a mototool while tightening the collet. This should lock the collar to the mototool and prevent it from slipping.
DRY GRAPHITE POWDER LUBRICANT
Use graphite powder lubricant on the rear hub pivotballs.
TURNBUCKLE TUNING
Assemble the rear anti-roll bar linkages carefully, and make sure all pivotballs are installed on the proper sides of the plastic ball joints and that they rotate freely.
DRIVE BELT PREPARATION
Prepare the rear drive belt by soaking it in WD40 for several days to loosen it up.
CLEAN AND LUBRICATE BALL-BEARINGS
Clean and lubricate the small ball-bearings:
Brake cam shaft
Rear anti-roll bar
GRAPHITE PART PREPARATION
Prepare and seal the edges of the following graphite parts:
Rear shock tower
Rear bulkhead upper brace plate
Brake pad support plate
Chassis stiffeners
Radioplate
THREADLOCK
Where indicated in the instruction manual, be sure to apply an appropriate amount of the threadlock; small amounts are usually better.
Use only removable strength threadlock such as Loctite 242ฎ blue-grade. DO NOT use permanent threadlock such as Loctite 262ฎ red-grade.
Unbinding the Suspension - More Tricks
If after following the "unbinding" tips in Part 1 you still find a suspension arm binding, here are other tricks you can try.
REAMING THE HOLES
Use a reamer to ream the suspension pin holes. This will ensure that there is no debris in the holes, and that the holes are the proper sizes
The pins are the following sizes:
Rear upper pins: 3.0mm dia.
Rear lower pins: 3.5mm dia.
EXPANDING SUSPENSION PIN HOLES
Sometimes it is necessary to expand a suspension pin hole slightly so that it does not grip a suspension pin excessively tightly.
Insert the end of a suspension pin into the hole (in bulkhead or press-in insert), and push it off to one side to expand the hole slightly. Then rotate the pin in orbital movements to expand the hole in all directions.
The idea is to expand the hole so that the pin rotates freely when pushed through all holes but does not have excessive slop. Test the fit of the pin frequently to make sure you do not expand the holes too much.
Drivecup Deburring & Dogbone Therapy
DRIVECUP DEBURRING
Use the dogbones to deburr the slots in new drivecups (ends of rear axle, and rear wheelaxles). It is easier to do this BEFORE assembling the parts.
Place the dogbone in the slots, and vigorously move the dogbone in and out of the drivecup while pressing the pins down against the edges of the slots (first on one side of the slot, then the other). The initial movement may feel rough, but as the pins smooth out the burrs in the slots, the movement will smoothen out.
If you notice any small burrs still remaining in the slots after this, use a small flat jewellers file or emery board to remove them.
Flush out the parts with motor spray to remove any excess metal filings.
DOGBONE/CVD THERAPY
Before installing the dogbones (or front CVDs) in the drivecups or outdrives, spray the ends with graphite spray lubricant. This gives a thin coating of lubrication on the pins and does not attract dirt like grease does.
Trimming the Rear Lower Arms
The rear lower suspension arms can be used on left and right sides of the car. As such, there are mounting tabs (for rear shock and anti-roll bar links) on BOTH sides of the arms.
Use a mototool and cutoff disk (and/or sanding drum) to remove the excess material on the bottoms of the arms after the parts are installed. Be careful not to cut into the arms.
IMPORTANT! Only do this when the arms are installed, otherwise you risk the chance of removing material from the wrong side of the arm and making both arms identical.
Sealing the Pulleys
The side pulleys (main layshaft, middle block) are made from two separate parts: a toothed pulley and a plain side plate. After the pulleys are assembled, you can seal the pieces together with thin CA glue to:
prevent pulley separation
prevent debris from getting between the parts
prevent premature drive belt fraying and failure
Put a small drop of thin CA glue where the side plate meets the toothed pulley. Capillary action should draw in the CA and seal most of the way around the pulley. Use a tissue paper to wick away any excess CA that settles between the pulley teeth.
Rounding Edges on Rear QC Levers
Use a small jewelers file (round) to round the edges of the rear quick-change levers as shown. This will make it easier to slide wheels over the levers and wheelaxles.
You only need to round the edges on the outside of the QC levers; you do not need to round the inside edges, since those never contact the insides of the wheels.
Freeing up the Rear Bodymount
There were a few tricks I did with the rear bodymount to ensure smooth, free operation.
POLISH ALL PARTS
Polish the following parts for the rear bodymount:
Center guide post
Screw collars
Upper pivot pins
SIDEPLATES
1) If the sideplates grip the rear upper arms too tightly, the friction will prevent smooth, free operation. Use a pair of pliers to gently bend the sideplate arms outwards.
2) Use a sharp, pointed hobby knife (#11 blade) to bevel the edges of the holes where the screw collars go into the sideplate arms.
3) When attaching the sideplates to the rear upper arms, tighten the screws and then loosen each screw by at least 1/2 turn. There should be a small gap between the screwhead and the collar.
CENTER GUIDE
When the suspension is fully relaxed, the center guide comes very close to touching the rear belt.
I used a sanding drum to shave a small amount of material from the bottom inside edge of the guide, closest to the rear belt.
Do this BEFORE you install the center guide.
Modifying the Rear Carbon Brace
The rear drive belt comes very close to touching the rear upper carbon fibre brace (which connects the two rear bulkheads).
Use a small flat jewelers file to file a shallow, beveled 'channel' at the rear underside of the brace to give more clearance for the rear drive belt. The channel should be slightly wider than the rear drive belt.
Be careful not to make the channel too deep or you will weaken the brace.
After I finished sanding the channel, I sealed the channel with thin CA applied with a cotton swab.
Installing Optional Parts
Before you begin your build, and especially before you start an assembly step, collect all the parts that you plan to install. Get everything ready before assembly, so you can avoid having to disassemble parts to install optional parts.
During the assembly of the rear of my S960, here are some of the things that I had planned to install:
Ventilated brake disks (9606)
Wheelaxles rear QC/fixed set (902370)
Radioplate alu bracket (902156)
Engine monoblock M21 (902341)
Alloy steel flathead M4 screws with Allen sockets (replacing the stock Philips head screws)
When installing optional parts, make sure that all parts fit together properly and operate properly.
Completed Rear End
By taking your time in assembly, and following the tips and tricks described here, the rear suspension should be VERY smooth and operate very freely.
In Part 3 of this article I will write about assembling the radioplate and center components of the car, including more tips and tricks or anything noteworthy about the assembly.
Stay tuned!
IMPORTANT NOTE!
When you are using hand tools and power tools (drill press or mototool), you MUST exercise extreme caution, and use proper protective eyewear and gloves. NO loose clothing around power tools, either! It only takes a momentary lapse in concentration to receive an injury or damage a part.
Expanding a pivot pin hole
Drivecup deburring
Remove excess tabs from bottom of rear lower arms
Seal pulleys with CA
Round edges of rear QC levers
Bend sideplate arms outwards
Remove material from center guide
Channel in rear carbon brace (underside shown)
Completed rear end
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