TB evo3:- oneway gear stripping - cured?

[WillyChang]

Took the newly acquired TB evo3SL out today for its maiden run

in its new home state, after a week of complete rebuilding. []

This car has (as its only discernable optionpart) the

Tech Racing 3-piece driveshaft.

Rest of car had been rebuilt to all-Tamiya parts only.

Front oneway was shimmed nice & tight, the 1280 bearings were made

snug fit in its housing with masking tape and the gearcase's cover

was held on by 12mm (longer than stock) machine screws.

Had an idea that the gear stripping is due to the 1-piece shaft

stabbing into the front gearbox on hard impact. The 3-piece is

joined by dogbones & cup and I further added some padding at

the front cup so that the shaft could never be jammed tight.

Ran about 10 packs thru it without resting, after only minor

adjustments the red devil handles so well it was full throttle

all the way (Novak SS). Managed to clip the boards a few times

too, some of them bumps hard enough to (1) chomp a large chunk

out of the bumper support and (2) rip a front bodypost out. [|)]

When finally ran out of batteries, the motor was stinking hot

at 95degC and the ESC was 125degC!! (257degF)

Smacking the std EvoIII like that (hard front impact @ full throttle)

would inenvitably strip a few teeth off the oneway gear, but

when I opened up the e3SL's front gearbox at home tonite...

wow - every gear tooth still alive & present!!

Looking good that the stripping problem might be cured..!?!!

[DJTheo]

Are you using a "gun" infrared thermometer to measure the temperatures? Find those devices very cool![8D]

[WillyChang]

Yep, using the old finger to test engine temp proved a bit painful

after a while so I got a Raytek MT4 about 2+ yrs ago.

Since then I've used it on everything except nitro... [|)]

(tune by ear is still the best, actual temp isn't important)

MT4 also useful for

-cooking in the kitchen

-1:1 engine tuning... check temp of exhaust at header or at plugs

-checking 1:1 brakes... compare temp of each drum after use

-high resistance points of wiring, etc

-keeping eye on Tamiya connectors when pumping 30A thru them []

[DJTheo]

How much do they cost, we use at work some professional ones which are $$$$ [V]

[WillyChang]

Last time I looked, Rayteks appear often on eBay.. about US$80ish?

The common ones are the MT2 (IR temp only) and MT4 (with laser pointer),

only a slight price difference between the two.

I wasn't originally planning to buy one and would not have bothered

getting one off eBay, but I found a one-off at a local disposal shop

and talked them down to an irresistable price, so why not.

These days there are much smaller "keyfob" units for nitro, about

$30-40 but they run on watch cells. Raytek uses a 9V (provided)

and mine's still running on the factory battery after so long.

There are more-expensive units available, either with better

accuracy or higher temp range (up to 5000? furnaces?!).

Raytek makes a wide range, MiniTemps are bottom of food chain.

The MT4 does +/-0.5deg I think, that's the minimum step it takes.

[rc-martin]

Where can i find this 3 piece shaft Willy? Sounds like the answer to one of my evo3 troubles. []

[WillyChang]

Good question BB... but afraid I don't know.

I was looking everywhere for the part too, and opinion is divided

as to either they've stopped making the thing, or everybody's just

constantly out of stock. [8)]

Was also contemplating to buy all the bits-n-bobs to upgrade the ol'

#58299 but in the end, had an offer of another whole car (red!)

with the all-important option shaft tht I wanted to try.

On the other car, I've also:

1) added extra 1260 bearing in front, inserted from rear

2) shimmed both 1280 bearings with masking tape to sit firmly

3) put in a front diff... [|)]

Dunno, seems to be running smoothly still.

Me thinking... maybe its all to do with stopping the shaft from

spearing into the front gearbox on impact by finding a way to

fix it laterally to bear against that 1260 bearing.

Like a 6mm ID collar, gotta go find one.

The 3-piece shaft has a 1280 bearing running in there to hold the

front drivecup, that's where I got the idea from.

[loopy]

Hi

I dredged up this topic as i run a surikahn evo3 and still havent managed to fix this stripping problem.

Can someone provide a link to the tech racing site??

Cheers

loopy

[WillyChang]

From all accounts I'm told, Tech have stopped making it.

[WillyChang]

Forgot to add:-

If you've got a Surikarn that's running the red stock shaft,

try the Tamiya optionpart "lightweight" drive shaft.

Its 2mm longer at the front tip and helps the stripping a bit.

Judicious shimming of the front diff's gear mesh also helps.

All my EvoIIIs haven't stripped a gear for years.