Part 4: Building the Drivetrain
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| parts of the drivetrain |
Bearings
‘Look what I found in the Tamiya Box! A bag of bushings! – Honestly, come on Tamiya, are you serious?’
Because I knew what to expect from this entry level kit I also ordered a bag of Ball bearings right with it. The Tamico online store recommends this set from Carson (#500904026) with the GF-01 Chassis, and it won’t burn a hole in your purse. Containing 24 bearings, size 5x10x4mm, for under 18€, it’s a cheap 0.75cents per bearing. Right, this car uses the same bearings size throughout, an aspect I really like! Only missing are two bearings 5x8x2.5mm that go into the steering lever (D3) witch I luckily had in spare.
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| welcome to the Tamiya-World... |
Out of the factory the bearings are filled with a thick grease. If you’re not too worried about a totally freed up drivetrain, simply use them as they come. But since I am very pedantic about my models I rinsed them out with brake cleaner and re-lubed them with a light oil from 1up Racing. It lets them spin like forever, but on the other hand I assume the original grease could extend their lifespan.
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doing it properly
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Healthy Teeth Insurance
I did a dry fit of the differentials and realized that they were running a bit hacky. Unfortunately, this was exactly what I expected after seeing that all the gears had small burrs and sprues. I suspect the gears are aluminum die cast. Thus not steel, which indicates that this model was not designed for really hot motors.
So I got my Proxxon out (Mini Rotary Tool = green Dremel) and spend hours grinding all the burrs and sprues and polishing each and every tooth flank. The surface of the tooth flanks feels quite ok, just lightly rough, but polishing makes them perfectly smooth.
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| kept me busy for hours |
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| still more grinding and polishing to do |
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| suffering from a Boreout |
When inserting the larger outdrive gears (MA 8) into the housing halves (#10555092), they jammed slightly. So I carefully reamed the holes with sandpaper and broke the edges by hand with a countersink. The washers which are used with the outdrive gears (MA 6) also had one sharp and one rounded edge from being punched out. So I ran them over sandpaper and polished them as well.
‘Kill it, while you’re at it…’
Some hours later, after all the sticky remains of the polishing paste where finally removed, the gears had a shiny finish. Just good enough for my liking. Moreover I broke the edges along the slots of the diff-joints and wheel axles (MB 7, 8 and 9). From my experience this protects the pins in the dogbones.
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| breaking edge technology |
I tried an M3 Screw in the diff housing but decided that the plastic is too soft. So I used my Helicoil Set again because I didn’t want to install the self-taping Tamiya screws or risk stripping a thread. Another dry test-fittig proved that the drivetrain now felt silky smooth, so I filled the differentials with 300000 cst silicone syrup from Core Rc. Now it takes some effort to twist the outlets against each other with your fingers. I’m curious to find out if the diff will stay locked after some runs.
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| I love Böllhoff Helicoil |
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| another dry fitting |
Tamiya provides you with a tube of ceramic grease to put on the gears, and I used it in abundance. Only to find out after I assembled the chassis that it might have been a bit too much and I wiped some off again.
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hopefully the diffs will stay locked
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| ceramic grease in abundance |
Normally Tamiya always puts a tube of Anti-Wear-Grease in their Kits, at least so I thought. I searched the entire box for their ‘stickiest stuff on earth’ but could not find any. But since I always have AW-Grease in my trolley, I used it to fix the axles in the chassis while putting the intermediate gears in. Some of it also went on the edge of one chassis half to seal the connection between the D-Parts 1 and 2.
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| the drivetrain is finally assembled |
Highgrip - Always getting high on 𝝁
