RC12L3 Resto: '87 Buick GNX Build: Finished

[Phin]

There are wide one piece spacers available.

[Coelacanth]

There are wide one piece spacers available.

Part number? I had other washers I tried with bigger O.D. and caused the bearing to bind up when I screwed on the left hub. I'm going to the LHS after work and I don't know the O.D. of the correct shims; just that they're 1/4" I.D. Thanks!

[Phin]

ASC8213B but again you can find them from other pan car companies too like CRC or IRS.

Are you making sure that the tires are equal distance from the center of the car? If you add shims to the left side you may also need to add shims between the diff and motor plate. Also you may want to check if the new wheels you are using are the same offset as the white Jaco's you were using.

[Phin]

Here's a 1/8" spacer from hyperdrive:
http://www.lefthander-rc.com/catalog/product_info.php?products_id=990

...and a set of different lengths from KSG:
http://www.lefthander-rc.com/catalog/product_info.php?products_id=676

[Coelacanth]

The stock white wheel set, although being the same width, have the inner ring of the wheel rims pretty much flush with the hub mounting surface, while the black wheels I swapped in have about a 1/4" of rim offset (negative) from the hub surface. Good point about matching the shims on both sides.

EDIT: Thanks for the links, I'll write those down and look for those or something similar at the LHS tonight.

[Coelacanth]

Some earlier pics of my chassis repair job. It probably wasn't necessary, the corner damage wasn't all that bad to begin with, but I didn't like seeing the fibers hanging out of the carbon.

Before

After

I first built up a couple layers of CA glue, colored after drying with a Sharpie. When you put on a subsequent layer of glue, it seems to dissolve the Sharpie ink and it gets into the glue.

I then filed the excess CA away, applied one more layer, filed again, inked it again with Sharpie, and the final result is certainly better than the chink with exposed fibers hanging out.

[Coelacanth]

I pretty much finished restoring the chassis, but I have about $25 of goodies coming from AsiaTees.com that I'll be swapping in for the stock parts (most of it was on clearance or heavily discounted prices, and I had a $15 credit to use there, so what the hey!).

I got the tire rubbing issue resolved with about six 1/4" shims on the left side and 4 on the diff side. The tires look to be pretty centered when measured with a caliper from the center of the chassis. I've only got about 1/16" of space between the motor pod plate and the left tire; not much, but enough not to rub. I have the diff adjusted and played with the tweak adjustment, but I'm not sure how to adjust the dampener. What's the technique for dialing that in, and having the rear pod adjusted properly?

[Coelacanth]

RC12 experts, I have a few questions, as I'm not familiar with pan car builds.

1. What modern LiPo battery packs would work on this chassis, and how would you mount them? I'm guessing either a 2S saddle-pack or maybe a single shorty LiPo, but what kind of hold down could be used?

2. What motor would be suitable? Something in the 17.5T range, perhaps? I've seen some of these with 13.5T motors, that seems overkill for a chassis this small.

3. How do you adjust the dampener? I've spun the dampener washers both ways and can't see any change. Is there supposed to be lube between the plastic washers and the dampener plate? The installation instructions don't mention anything about this but the "dampener plate maintenance" section at the end of the manual says to keep them lubricated with diff lube.

Thanks for the setup tips.

[Phin]

Lipo's and t-bars on a 1/12 pan car don't play well together that's why almost all modern cars are link. I don't believe anyone currenty makes a 1s saddle pack (meaning a 3.7v battery split in half not two 3.7v to make a 7.4v)...Speedzone did but they've been discontinued. You can mount a 1S shorty battery on one side of the t-bar and all the electronics on the other but balance is an issue, as is weight transfer.

Brushless motors can be a problem too because they're a bit bigger than brushed motors. Modern pan cars have wider rear pods that shift the motor plate a few mm to the right to get a better balance with a BL motor.

[GoMachV]

A 2S pack (2 1S in a saddle) should be fine for outdoors tho right?! We always ran 6 cell outdoor bitd
Wasn't there someone running a 380 size brushless motor around here? That might be a good setup to get the size needed and kill a little power if using the 2S?

[Phin]

Yeah I like the idea of 380 motors in 1/12 cars myself. Tamiya, Kyosho and I think Yokomo have put out cars that can use them but I don't think they're cars aimed at the de facto 1/12 class.

From what I've read, during the transition to brushless/lipo one of the arguments against 380 with 2S in 1/12 was that the cars would have to be redesigned to deal with the smaller motors and different weights. Thing is though that even with the class sticking to 540 cans and 1 cell batteries the cars got redesigned anyway. T-Bars got replaced by links, pods got wider, diff hubs got offset, chassis got stiffer, etc.


I'm a firm believer that eventually 1/12 t-bar cars will make a come back when the next battery technology replaces lipos and there are batteries about the same size as a ESC available.

[Coelacanth]

I was doing some browsing and found this 1600 mAh 2S battery, for an Airsoft gun, but looks like it has decent specs...and at 66.1 x 43.6 x 14.5mm, should fit one side of the car pretty well...I'm not sure about how to secure it, though. What do you guys think?

http://www.gensaceusa.com/98p-20c-1600-2s1p-2222.html

[RC10th]

Battery strapping tape is the most common, If your going to put the battery on one side put it opposite the servo and make sure the weight is equal right to left. If one side of the car is heavier it will drive like it's tweaked.

[Coelacanth]

Battery strapping tape is the most common, If your going to put the battery on one side put it opposite the servo and make sure the weight is equal right to left. If one side of the car is heavier it will drive like it's tweaked.

Thanks, RJ...I was going to put it on the left side, as the servo is off-centered on the right...and I'd put the electrics on the right. A battery with the specs above should be able to mount quite close to the center-line, and I could mount the electrics more outboard to hopefully balance the chassis left/right. Are those battery specs okay for a 1:12 car (1600 mAh, 2S 7.4V, 20C)? If I mounted something like a 17.5T motor in there, that should give a pretty decent run-time, and not be ridiculously fast, I'm hoping?

[RC10th]

That battery should be ok although a little on the light duty side, it can safely supply 32 amps continuous which with a mild motor should be ok. Anything more though and I'd be looking at a slightly bigger battery. Run time should be ok, if my calculations are correct if you pulled a constant 32 amps you'll get 3 minutes of run time. In reality I'd say your average would be a lot less and about 8 - 10 mins would be close.