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T-Maxx - 26 Apr 2004 14:21 GMT

I have just purchased and broken in my T-maxx. I have some questions
that I hope someone will be able to answer for me. If it seems like too
many questions just answer one of them so that I can R.I.P knowing that
I haven't done anything stoopid (or should I say "too stupid").

1) The spinning black gear (the slipper clutch), should it be spinning
when the car is idling, and should it revolve freely by hand when the
car is off and stationery. What is a factory setting since I tightened
it on the advice of someone.

2) Has anyone had any problems with Blu Thunder and high engine
temperatures (10%). I used my truck on this at the weekend , which as
we know was quite hot in some areas, and I managed to melt the rubber
covered plug that goes on the glo plug. The engine must have been
running very hot. I decided to call it a day and the next day cleaned
the engine and put in a new plug. Was running a bit hot but not like
before so I ran the engine more rich by using the hi speed needle.
Plenty of blu smoke and nitrous pouring out of the exhaust. What's the
best setting at the moment for a t-maxx in the south east of england?

3) Does the engine need much revving to actually make it pick up, or is
now the time to adjust the lo-speed needle ? I need to give half
throttle for it to pull away , or something like that, but once its
moving i can rev it less.

4) Now that I've changed fuel should I do the engine run-in again ?
I'm now using some 16% stuff that contains more castor oil and should
therefore keep the engine running cooler ?

5) When I first tried the truck the car didn't go ANYWHERE either in
forward or reverse although the engine was revving. After a bit of
"coercing" i.e. pushing it forwards with my foot.. it worked and stayed
working. It's done this a couple of times since , is this bad?!
Seems like the transmission is not engaged or something.

Sorry for so many questions, im sure some of these are probably obvious
to you veterans but smoke coming out of the top of my engine on tank 5
certainly gave me a heart attack since i dont have £400 spare at the
moment.

Hopefully someone will be able to put me at ease or at give me some
pointers so that I dont cause any further trauma to my engine.

Cheers!

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kbeaudet - 26 Apr 2004 17:05 GMT

Here are some ideas for your questions... I have a T-Maxx and have been
messing with it for a couple years!!!

1) The black gear (spur gear) will sometimes spin at idle. Usually it's
because the truck is idling a little too fast causing the clutch to engage.
It won't hurt anything though. Good starting point for the setting is:
tighten all the way and back off about 1/2 turn.
2) I would say that the engine got too hot (running too lean). I would
recommend getting a temp gun and monitoring temps (anything over 300F (about
150C)) is too hot. You can pick one up for about $30 US (here anyway). I
haven't personally run the blue thunder (or 10%) for that matter. I (and
most of the people I race with) use 20% Trinity Monster Horsepower. Check
your LSN too. Different fuels require different settings on both needles!
3) Sounds like your running too rich... the engine will rev some to engage
the clutch in the transmission, but 1/2 throttle sounds a little excessive.
4) You should take it easy for a couple of tanks with the new fuel. Also,
set both needles back to factory and re-tune the engine. More oil will keep
the engine cooler, but may also affect performance.
5) Sound to me like the shift servo isn't fully engaging when you shift
between gears. I had the same problem... I just removed the servo and shift
fork (forward only!). If you want to keep the reverse... try adjusting the
linkage for the shift servo.

Hope this will help you out...
Ken B.

> I have just purchased and broken in my T-maxx. I have some questions
> that I hope someone will be able to answer for me. If it seems like too
[quoted text clipped - 40 lines]
>
> Cheers!

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Zardos - 26 Apr 2004 23:12 GMT

>1) The black gear (spur gear) will sometimes spin at idle. Usually it's
>because the truck is idling a little too fast causing the clutch to engage.
>It won't hurt anything though. Good starting point for the setting is:
>tighten all the way and back off about 1/2 turn.

What is the idea of the "slipper" clutch ? why is it necessary ?
i mean why isn't the bell clutch enough ?

Fill the gaps in me knowledge guys ;-)

Zardos
--

The all singing all dancing
Crap of the world !

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frater mus - 27 Apr 2004 14:57 GMT

> What is the idea of the "slipper" clutch ? why is it necessary ?
> i mean why isn't the bell clutch enough ?
>
> Fill the gaps in me knowledge guys ;-)

You could read p.38 of your owner's manual for that info. :-P

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Zardos - 29 Apr 2004 18:02 GMT

>You could read p.38 of your owner's manual for that info. :-P

Couldn't you explain it to me ?

Zardos
--

The all singing all dancing
Crap of the world !

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Bert Olton - 26 Apr 2004 20:58 GMT

Hey T-Maxx -

Ken B already gave you some great answers, I only want to add a couple
notes to two of them.

Your question #1. Yup, the big black gear on the engine side of the
tranny, the spur gear, will spin with engine fluctuations. And yes, it
should spin freely with the engine off. The slipper clutch assembly is
mounted on the spur gear (the little spring, steel washers, friction
plugs, etc.) Traxxas recommends adjusting it by:

First tighten down the lock nut on the spring until the spring stack
binds up tight, then back off the nut one quarter turn. It's not easy
to do with everything assembled - you have to reach a finger or
something in and push the slipper clutch in towards the tranny to lock
it up so you can turn the nut without turning the threaded shaft it's
mounted on (essentially a tranny input shaft.)

Your question #2. Ken gave you lots of info here too, but I'll just add
a question for you - did you cut away any of the body to allow better
air flow over the cylinder head? It's a good idea to cut out the
passenger side of the windshield and rear window of the cab, and also to
trim the front edge of the body up to allow more wind to get through things.

Another point is that a new, unbroken-in engine will almost always run
hotter than it does once it's broken in.

A third point is, according to Traxxas, it's not a good idea to change
fuels after break in. I *do not* know from experience however, how
critical that is. Traxxas says if you break an engine in with 10%
nitro, continue to run it with that. This is probably a topic for
debate, so I'm not pushing any particular side - but as you mention
regarding your heart attack on seeing smoke <g>, I've followed Traxxas
recommendations just for the sake of maintaining my warranty - the
company is very thorough about lab testing engines sent in for warranty
claims.

All in all you're probably doing just fine. These tiny engines are
really touchy, but if you use good sense and pay attention to them, they
work great. My TMaxx is just under a year old and we're working on our
fourth gallon of fuel through it - still running like a champ. Read
that manual over and over again!!

Best regards and have fun,
Bert

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frater mus - 27 Apr 2004 14:55 GMT

> 1) The spinning black gear (the slipper clutch), should it be spinning

spur gear

> when the car is idling, and should it revolve freely by hand when the
> car is off and stationery.

The spur does is not driven at idle since neither the forward or
reverse gears are engaged at that point. You can spin it freely.

>What is a factory setting since I tightened
> it on the advice of someone.

all the way tight, then back off 1/4 turn.

> 2) Has anyone had any problems with Blu Thunder and high engine
> temperatures (10%). I used my truck on this at the weekend , which as

I have heard no reports of BT causing high temps.

> covered plug that goes on the glo plug. The engine must have been
> running very hot. I decided to call it a day and the next day cleaned
> the engine and put in a new plug. Was running a bit hot but not like

IMO if the engine was running hot enough to melt the plug, it would just
stop running and not restart until it had cooled.

> before so I ran the engine more rich by using the hi speed needle.
> Plenty of blu smoke and nitrous pouring out of the exhaust. What's the
> best setting at the moment for a t-maxx in the south east of england?

There is no meaningful answer to that question.
"Mu", as the Japanese might say.

> 3) Does the engine need much revving to actually make it pick up, or is
> now the time to adjust the lo-speed needle ? I need to give half
> throttle for it to pull away , or something like that, but once its
> moving i can rev it less.

Feel free to lean out the LSN to clean up off-idle accelleration.

> 4) Now that I've changed fuel should I do the engine run-in again ?
> I'm now using some 16% stuff that contains more castor oil and should
> therefore keep the engine running cooler ?

No new break-in is required, but you'll have to retune.

> 5) When I first tried the truck the car didn't go ANYWHERE either in
> forward or reverse although the engine was revving. After a bit of
> "coercing" i.e. pushing it forwards with my foot.. it worked and stayed
> working. It's done this a couple of times since , is this bad?!
> Seems like the transmission is not engaged or something.

Idle is likely too high, if you're seeing this behaviour after a f/r
shift.

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Model Forum / Radio Controlled / Land Models / April 2004

[T-maxx 2.5]