First Nitro RC: Got aT-Maxx; Could use some help here please!

[Robles4242]

A buddy of mine had a brush-less motor RC car at work. I was immediately in love when he tore from the gravel lot at like 50 mph over the ditch and across the like foot high grass field and just going faster!! So we saw on Facebook someone selling a used T-Maxx for a good price with accessories! So I picked it up! I got a T-Maxx RC Truck with a 3.3 motor in it, and a Radio. It came with a spare 2.5 motor in a little tool box with a few odds and ends parts including a glow plug igniter. All I needed was a Battery and charger for the E-Z start wand. So i went and ordered one online, waited a week to get it, charged it, couldnt get it to fire! The Glow plug light wouldn't even come on; on the wand. We tried the Glow Plug Igniter instead and it still wouldnt fire. So we trouble shot that, and determined the Igniter was bad, and easiest would be to just get a new wiring harness for the E-Z wand. I went back online and got one with a new E-Z wand just to rule that out as well. Also threw in a new Glow Plug and Air cleaner.

Wired it all up another week later, and today she wouldnt fire!! So i watched videos, downloaded the manual, tried just about everything I could with no knowledge of these Nitro RCs. I decided the motor and frame was horribly dirty, and greasy, and that it needed a good tear down and cleaning. So i watched another video, and used the 2.5 for practice. Tore it all the way down, and cleaned it out, put it back together and felt ready to tackle the 3.3 motor. I tore it down tonight. Cleaned it up really good and inspected all the parts.

Brand new Glow Plug in the head. Copper ring for between the head and jug. The piston was minor black on top, no blue color or major burns on piston, exhaust port, or inside the motor. The Cylinders sleve is shiney as could be with no marks or scratches or anything and it spins really nicely. It had compression when it was in one was piece. The Clutch and flywheel, and all the bearings and o-rings look good. I just need something to lube the motor with really good before a final assembly tomorrow. So i have it "dry fit" together, and i understand to star pattern and use equal torque on bolts for the head and other pieces.

I dont know these carbarators at all, i only know the motor becuase of my dirtbike and auto mechanical background but i feel enclined enough this wont be a problem. The Carb is cleaned as videos say, and i set the High needle all the way in and backed it out 3.5 turns, and the low needle all the way in and backed it out 2.5 turns as one video told me thats where i should start.

So tomorrow i will fully assemble the motor, and put it back on the chassis and be trying to fire it again. Can anyone give me some tips as to why i can't get it to fire and how to get it to? Previous to this cleaning I tried the priming method, non primed method, and all i ever get is turning over and turning over and no fire...

I would eventually like to get this part down, you know STARTING IT and driving it, and eventually doing any types of upgrades i can!

Can anyone help me? We do have a hobby shop not too far away, they charge more then the internet where I've gotten these previous parts, i dont want to have to take it in there and ask them for help unless i absolutley HAVE to because everythings an arm and a leg....

Tips? Tricks? Advice? DO's & DONT's, Anything would be GREAT!! Thanks in advance!!

 

[Rolex]

Okay, we'll get you running. Welcome to the world of nitro.
First off, the carburetor needles were probably gummed up from old fuel that has dried up in there. The original factory settings that you reset the carb to are ONLY for starting the initial break-in. That's too rich to run an engine on, but it is a starting point. Lean both needles about a half turn before trying to start it or you'll just have flooding problems.
The starting wand has had problems with the glow circuit since the day they introduced it. Do BOTH green light come on when you try to start it? If yes, continue trying to start. If no, get a separate ignitor like everyone else with a Traxxas.
Look through the following information and print out the flow chart and keep it with you for a reference. Don't go randomly twisting needles. It's a delicate process and when it's done right your engine will run right.
Keep us posted and we'll have you smelling burned nitro till your eyes burn.

https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/

 

[Cat]

So tomorrow i will fully assemble the motor, and put it back on the chassis and be trying to fire it again. Can anyone give me some tips as to why i can't get it to fire and how to get it to? Previous to this cleaning I tried the priming method, non primed method, and all i ever get is turning over and turning over and no fire...

To rule out the carb dump the fuel inside the carb to see if it fires. (Remove the fuel line from the carb and airfilter. And dump fuel inside the carb itself)

 

[TMaxxMike]

Sounds like you are on the right track.Keep checking for air leaks. Make sure you are getting fuel all the way to the carb. Check glo plug again. You will get it. Be patient. Soon you will be smoking right on by your bud`s brushless.

 

[SMaxxin]

I would bet the starting want is the problem, they have always given me problems, the pins get pushed to far in an don't make contact in the plug. Buy yourself a hand held warmer!

 

[Robles4242]

I'm thinking of switching to pull start and hand GP igniter. Both lights do work tho. What should i use to reassemble the motor for interal lubrication??

 

[Cornholio]

I'm thinking of switching to pull start and hand GP igniter. Both lights do work tho. What should i use to reassemble the motor for interal lubrication??

Anytime I re-assemble an engine I coat everything with ARO.(After Run Oil)

 

[Robles4242]

I tore down both motors, and cleaned them. And Reassembeled them. Both back plates had bad bad o-rings and the hobby shop only had ONE in stock. So i completed the 3.3 of course. To me (not knowing NITRO at all) it feels to have compression... but it feels the 2.5 has more. When you spin the flywheels and cycle the piston you can hear it kinda compress to TDC and when you come back down you hear a "suck" sound..., if that makes sense... But for some reason, more so after i installed the back plate it feels like its compressing (like your at TDC) but not there yet- your at like 1-2 o'clock (going counter clockwise) and youd expect a full revolution but once you hit between 11-10 o'clock it kind of binds/ hangs up like your at TDC again...

So i tried to just install the back plate on the 2.5 with its origional (but a little stretched) o-ring seated and seems to have the same feeling of hanging up in almost the same spots...

I did a star pattern on those 4 screws with a "stepping-up" torque routine.... i made sure the circle piece with the two divits was lubed and in correctly matching the side with the warn divit on the crank shaft nub that holds the connecting rod...
I'm getting highly discouraged with this thing already. By the time i gathered all the parts needed, or rebuild either motor i might as well just buy a brand new one, and at that point i might as well just have bought a new truck and that defeats the whole porpuse of even getting this thing; i really only did was because it was cheap initially..,,

 

[Rolex]

Don't get discouraged. Wrenching on anything, new OR old, is part of this hobby. It's all part of the learning process.

 

[Robles4242]

'Can anyone explain to me why its doing this? And what can i do to tell if the compression is compressiony enough lol I'm troubleshooting right now.... lets see what i can do.. its easier to work on my v8 turbo Diesel lol

 

[hotrodrob]

The flywheel should have a good resistance to it when trying to turn it past the compression stoke with the tip of of your finger,..buy using short pulls on a pull start it should have nice tight pop,with your finger it should feel like it's under some solid spring pressure......if not the p/s is worn out bud

 

[polishpete]

so did you finish cleaning everything out? that old fuel will cause havoc on trying to start one of these guys, when you had the engine apart did you try pushing the piston in the sleeve, see how far it went up? you might have a worn out engine already bud these days kids dont care and mistreat these rc models and can barely get a couple gallons of fuel through them.

i just went through the same thing kinda wish i bought a new one since i spent just as much but i do have a decently modified 3.3 tmax with a new engine so i guess i made out.

my suggestion is to go and trade your motor in for a new one for 110 bucks and be done with that break it in as per traxxas directions and get some afterrun oil, trust me this is the easiest route and will net you great longevity so you can be out there tearing it up, i dont regret going that route one bit I've had a blast with mine since i put it together.

 

[Robles4242]

I did clean it out. I removed piston and sleeve. It goes to the top but there is alnost an 8th inch till top of sleeve. A hair under so maybe a 16th. Built it back up put the car together. Cleaned fuel tank and lines. New exhaust coupler. Brand new glow plug. And some After Run oil. I'm gonna try to fire it up tomorrow if i can get the time. If it runs ill drive it till it goes and then motor trade in.

Unless its bad, like something that is off in a mil spec measurement, like low compression, or something off a thousandth of an inch somewhere i can't noticably see or tell then i feel confident on my workmanship and my behalf.

I hope she will fire up!

 

[Rolex]

There's always some room on top of the piston. You can't compress the air and fuel to nothing. There are no other adjustments to make. You MIGHT have put the connecting rod in backwards, but that's all that could have gone wrong.
If you turn the flywheel and feel a resistance from the compression, it will start as long as the carb is working. If you turn the crank very slowly, the compression will bleed past the piston. That's normal.
Make sure you have a fully charged ignitor and a good working glow plug. With the air cleaner removed, drop a little fuel directly into the carb and start it immediately. If it runs for a few seconds the engine is good but you have a carb problem. Let us know.

 

[Robles4242]

I had it running! It took alot of carb tuning to get it to idle and respond without dieing. I finally got it going until about a minute drive until i flew into the neighbors garbage can and it flipped it and it shut off.

Then i got it going again after more finageling but it wasn't near as good as the first time.

I HATE it not having reverse..... but now i have to charge my ez wand again and when i try to start it it sounds like it did in the very beginning... not such a wine noise as it was running but it is deep toned.... might just be ez wand not having enough juice or its flooded a little.

I need to learn tuning better for sure lol

 

[Rolex]

Big time congrats! You're getting there. Soon you won't even have to think about how to set your tune.
Once you have it idling with a good take off, that's where you leave the LSN. You'll only have to adjust your HSN for top end and to compensate for ambient temp and humidity.

 

[Robles4242]

Thanks! I forgot about that link posted for helping tune. Ill try again tomorrow with that info.

Whats the red flip switch on the remote do??

 

[Rolex]

Whats the red flip switch on the remote do??

It causes tall buildings to collapse. Whatever you do, DON'T flip it!!!

 

[hotrodrob]

That's the nitrous button

 

[TMaxxMike]

Woo hoo. Glad to see you are getting somewhere now. All these problem solving issues will come in handy later on. I pretty much did the same thing you are doing. I would suggest a new motor for $110 bucks. It should come with a pull start and new cab. As long as you take your time and break it in properly you will be golden. Don't get discouraged!!!