skootmaxx

Hi everyone and thats for having me. I have a few questions concerning my T-maxx .
I bought this t-maxx used and found that the unit had weak compression . I replaced the 2.5 with a brand new 3.3 . I put the 3.3 in and while following traxxas break in steps found a cracked bulkhead and skid plate. I decided that i would replace those parts after the break in since the unit was still holding together. ( believe those parts where broken when i hit a tree and damn near full speed)
I had also been doing head on's into parking bricks and doing back flips over speed bumps . Pretty tough little sucker id say. well on my last and finally tank of the break in i applied breaks and the truck stopped but the motor when ape Sh*t . I saw smoke coming from somewhere around the tranny . upon shutting it down i notice the brake and spur gear had been so i took to the lhs and bought a new spur gear and found another brake i had laying around. I started to take it apart but got fustrated when i couldnt get the entire thing back together. After returning from my trip i took to the local hobby shop where the guys in less than 3 hours help me get it back together( thanks guys). after getting it slightly running again i noticed that when i went full throttle the engine would get stuck in that position. Aparently the bellcrank was being over extended . We could not figure out why it was doing that and i had been advised to replace the servo's so i did . still same problem. I finally extended the ball up on the carb arm enough to keep the throttle from over extending its self. Now that part that pisses me off is this. I have replaced damn near everything on this truck that is important . When i tried to drive it yesterday it would not come out of reverse . It also sounded like it took the engine to get alot of rpms before it would propel the truck. THe engine does not seem to want to run slow enough to allow the truck to go in reverse . the lhs also suggested a new clutch. I havent put it on yet as it does not seem like it is the problem. After all that crap the truck refuses to start. Please guys help me I'm inches away from giving up. And if anyone lives near vegas i would love to pick their brain.

Macanan

So you have an older 2.5 T-Maxx converted to a T-Maxx 3.3 ?

skootmaxx

yes i do !!!!!!!!!!!!

Mspeed

Gosh, were do I start. Sounds like could be alot of things wrong with it. For stuck in reverse, umm check all linkages and the reverse servo, for not idling down, make sure your throttle rest against the stop screw when off throttle, it also could be your LSN is too lean or your idle stop screw in too far. For the higher rpm to get going, it could be running too rich, check the temp of the motor or look for alot of blue smoke on acceleration, lean it (on the high speed needle first till its right then do the LSN) if your done with break in to correct, or it could be worn clutches, or your slipper clutch is way too loose. Here is a important tip that could help your problem that I have found with alot of Traxxas vehicle clutchs, take the clutch bell off and reverse the rotation of the clutch shoes. This will help create a more postive clutch engagement and build up far less heat in the bell, giving you a lot more clutch life as well as added bearing life and more get up and go from the start. Another thing it could be as simple as a glow plug that is fouled and lowered the power output making it work harder to get up and go. Lastly, if your fly wheel is loose it will slip and cause problems moving the truck forward. Did I miss anything? Probably, get back to me after you check some of those things.

skootmaxx

thanks for the above info i will be checking the bell housing and slipper clutch tomorrow . I also recently bought a new glow plug so i will put that in and see what happens. as far as the linkage it all should be correct . It looks as if the carb closes as far as it should.but meh im not an expert . Ive put way to much time into this truck not to be having fun but im not ready to give up !

Mspeed

A good idle stop screw adjustment to start with is about .7 to 1mm opening in the throat of the carb when fully closed. Take the airfilter off and get a allen wrench that measures right about the thickness of a credit card and put it down in the throat to check it when closed.

savtraxx

take apart time

RCCanuck

sounds as though the slipper clutch is too loose and needs to be adjusted....tighten it all the way down then back off 1/4 turn.....that should set that up right...next inspect clutch look for stretched spring and or broken or cracked clutch shoes-replace if neccesary(this is what caused the smoke from around transmission)......Next set idle....I do this in 2 steps....step # 1-Take the servo horn off of the throttle servo-turn truck and transmitter on-set throttle trim on transmitter to 0-put servo horn back on so that the carb is fully closed-set brakes by adjusting linkage.
Step # 2-With truck and transmitter turned on remove air filter housing from carb-----look down carb you want about .5 to .7 mm gap between the carb body innder wall and the slide.--If it needs adjusting do so with the idle stop screw....with the truck still on but not running open the trottle a bit and adjsut the screw until you have the desired opening.....

You are done.....don't forget to put a new zip tie on that air filter housing or you will lose it and injest some dirt into the engine and fry it...
Now you can adjust the amount of idle via the throttle trim on the transmitter for warming up the engine and so forth....
Not sure why its not shifting from reverse to forward I would check the linkage/servo/tranny in that order to find your problem

ryanarthur

if it will not shift prperly.. and u have the stock radio.. there is a small adjustemnt screw on the back of the controller.. turn it a little.. and it affects the shifting capibility.. just a sugesstion

skootmaxx

This little feature a guy at the lhs didnt even know about. he's been helping me alot so i wont say he doesnt know anything. I just doesnt know everything !. So what we think it boils down to is this . she idles really high. due to the idle being so high it doesnt allow the tranny to disengage long enough to shift from reverse to forward. We we concerned that maybe the servo's werent strong enough to close the carb as far as it needed to go .I replaced those and adjusted the linkage to the point where the sero wouldnt over extend the throttle. so at this point the gentlemen thats been helping me suggest that i allow another guy who is just as good with monster trucks look at it . me not willing to give up take it home to tinker . I turn the idle screw counter clockwise and see how far the carb closes. I then turn the lsn also to allow the car to close even more.at this point she kicks over but will not stay running. So little by little i undo what ive done till she stays running and shes got a low hum. At this point it seems to shift in and out of reverse . I also have a noticeable increase in take off speed . until i forgot to replace the screw in the little part that changes throttle linkage angle.So at that point she went wide open throttle.I bought a new bellcrank(not sure if thats what they call it) and while putting that on the throttle arm seem to slip . So thats where I stand at the current time. hopefully i can get that fix tomorrow when i get a small enough allen wrench . from there its upgrade and bash time.

skootmaxx

[>:]OMG SO I HAVE TO UPDATE EVERYONE.[>:]
I'm not upset or even remotely unhappy. At this point im extremely please with the powerplan that i think is the 3.3 . I'm not sure if i got it tuned correctly but it does seem to be shifting properly but once its in forward i dont mess with it anymore. With out a temp gauge is there anyway to guestimate what kinda temps its running. A guy at the local hobby shop said at one point it smelled hot(whatever hot smells like i dont know!). Now for the big news. I managed to tear the front end off my t-maxx. SO now i know what people mean by they arent as durable out of the box as some other trucks. Now I need all new front bulkheads . And a new front skid plate. Question is should i Do alum or stick with some thick plastic. I want it to be harder to snap off this time. though i was going pretty fast.

Macanan

Go Aluminum like this, I did that before I even broke it in because I knew the plastic ones would be week. If you got the 2.5 T-Maxx then the chassis is 2.5mm thick I would go ahead and order the 3.3 chassis if it will work because there 4mm thick

skootmaxx

Ive uploaded some pictures of the damge. On your maxx did you just replace the skiplates and the bulkheads. I was thinking of doing all alum all around but i know it bends . then i was looking at some of the after market chassis and omg are they expensive. will using one of those chassis make my maxx stronger?

.

Macanan

Few of the Problems they have out the 2.5 T-Maxx is that the chassis is 2.5mm and bend and bulkheads break on both the 2.5 and 3.3, and the plastic skid plates on both break easily, I don't have the aluminum bulkheads YET, that is next on my list to get, but with the all aluminum skid plates, bulkheads and RPM arm's it would be just about indestructible Thats one of the reasons when they made the 3.3 T-Maxx they made the chassis 4mm, but I did hit a stump in the yard and knocked it out of the ground, and yes part of it was rotten but half of it wasn't you can see where it snapped from the roots, but it did NO damage to my 3.3 T-Maxx with only full aluminum skid plates and RPM arm's.

skootmaxx

sounds like a plan for me !

skootmaxx

sounds like a plan for me !

systemlord

I would recommend getting some 7075-T6 aluminum bulkheads at Great Assembly R/C and maybe some titanium skid plates. The titanium skid plates will take some serious abuse, my truck in the picture below has titanium skids that have grinded against assfault, hit brickwalls head on and still they are not even phased by all that abuse! Just don't forget that you need a breaking point somewhere in your front end and to have plastic A-arms with strong aluminum bulkheads/titanium skids is about the best you can hope for, somethings gotta give and A-arms are cheap. The only parts that are original from my T-Maxx 2.5 are the throttle servo and 1st & 2nd plastic tranny gears. [sm=lol.gif]

<link removed by Reiko>

Great Assembly R/C http://www.greatassemblyrc.com/Great..._Bulkheads.cfm

skootmaxx

im seeing this term supermaxx everywhere what does that mean ?

systemlord

Its an Unlimited Engineering name for their version of the popular T-Maxx and in the fourth picture theres a shock tower/bulkheads/diff case all is one piece which know one has ever done before, quite expensive the RacerX suspension aloan costs $470.00 dollars for all this, Suspension Kit includes:

8 Suspension arms 7075-T6
2 Shock Towers 7075-T6
4 Steering Knuckles 7075-T6
8 Pillowball Retainers Unlimited's unique O-ring design
4mm front Turnbuckles 7075-T6
Massive upper rear link & rod end
8 Titanium Hingepins
8 gigantic 6x16x5 axle bearings
8 Shock Standoffs
4 Body Post Supports
All Necessary Hardware
Easy to follow detailed Instructions

Specifications:
Kit is made from top quality aircraft aluminum
High stress areas like arms & towers & knuckles & turnbuckles are made from exotic 7075-T6. It's twice as strong and 50% harder than commonly used 6061-T6.
Weight is a mere ounce or two over stock
Massive wheel bearings have more than double the load capacity of the stock bearings.
E-clip type suspension pins are required and are NOW included. We've even gone the extra mile and used Titanium Hingepins
Finish is natural and Polished to a high luster
Installation requires "Blue" Locite

skootmaxx

I was thinking of using a kit like this http://www.integy.com/cgi-bin/webc.c...=4676&p_catid= Now when yours says !/8th scale that means its as big as say the xtm mammoth st's and cen genisis or the ae mgt ?

systemlord

If you were to put a 1/10 scale sized T-Maxx 2.5 next to a 1/8 scale sized SuperMaxx, the 1/8 scale SuperMaxx would be longer, wider and bigger. You would also notice the true size of the motor, all the TRX 3.3 is is a TRX 2.5 with a .20 piston with the same crankshaft as the 2.5 motor. A big block engine like HPI's 4.6 .28 engine has a bigger crankshaft and well a big block to house the bigger crank. My Sirio .23 is considered a medium block because the block/crankshaft in size is in-between the size of a small to large block/crankshaft motor.

On another note I wouldn't build a truck with 6061-T6 aluminum, its too soft. The much harder 7075-T6 doesn't bend as easly, thats not the only thing that makes the 7075-T6 stronger. It also has to do with the geometry of the arms and chassis, UE knows geometry well. Thats what makes their product what it is, very strong! If you really want aluminum arms go for this 7075 kit at UE, its only $215. Notice how Integy uses the term aluminum alloy and not 6061-T6 aluminum, some Integy products are of a lower grade (cheap) aluminum alloy. Anything less than 6061-T6 aluminum, I'll take plastic everytime!

http://www.unlimitedengineering.com/...re/13120B.html

skootmaxx

sorry so many questions i have the urge to learn mass amounts of info.

So with the upgrade of the chassis I will be upg7 rading to large wheels and tires . At that point i would be able able to use a xtm 457 or any other big block?

systemlord

You don't have to have a big block to go faster, My brother had a T-Maxx 2.5 and installed an OS .18TM engine and he couldn't keep the front two wheels down on the ground. Next my brother purchased an extended chassis to help to control the two front wheels from coming up soo much, it did help alot! Keep what you have and build on that, install an OS .18TM and later if you need a long chassis... But then you'll be needing some steel MIP driveshafts with that much power.

skootmaxx

I know ive seen some other threads on this . But will the o.s 21 replace the o.s 18 . also will i have to change the carb . I know 3.3 is a slid carb I'm not sure if the others are rotary . Unless rotary is better than slide.

systemlord

To run the OS .21TM you will need a tough drivetrain, mainly steel driveshafts. Why would you have to change the carbs? The OS .18 and .21 come with there own carbs designed for that engine. If the OS .21TM replaces the OS .18TM, that doesn't mean that the .18 isn't powerful. The OS .21 is $279.99, thats the cheapest that I have seen it. You have to ask yourself what is it you want, the OS .18 is the most powerful small block I have ever seen!