Overheating problem!

muckwarrior

Ok I've been using my tmaxx for a couple of weekends now and this is really starting to frustrate me.

Basically after a couple of minutes of running the engine seems to overheat. I don't have a temperature gague but I think the symptoms point toward overheating. The engine starts to loose power under acceleration then will cut out. The head seems very hot with smoke sometimes seen comming from it. It's usually pretty hard, or even impossible, to start at this point. When I leave it for a few minutes it'll start no bother and run fine for another few minutes.

I first noticed this during break in and put it down to a fouled glowplug. However I've since tried a couple of new glowplugs to no effect. Of course the obvious cause would be that the engine is running too lean, but at this point i've richened it to almost a full turn past factory setting. There is a clear trail of blue smoke from the exhaust and sometimes excess fuel can be seen spitting from the exhaust so i know that it is running very rich. Can running it too rich cause any harm? I've also checked the fuel lines for any holes and the cap is sealed properly on the fuel tank. At this stage the only other thing I can think of is the fuel. I'm runnin 10% nitro which I would assume would be less likely to cause overheating than a higher percentage? I've also used fuel from two different bottles, although they're probably both from the same batch. So could it be the fuel?
I haven't bothered cutting any holes in the bodywork yet coz the ambient temperatures were never above 20C and i'm not sure it would do any good.

So anyone else ever come accross this? Could it be a faulty motor that was supplied with it? If so how would I prove this and would there be any chance of getting it replaced? I've looked after it as per instructions, cleaning the air filter regularly and putting some WD40 through it when I'm leaving it up for a while.

SLIM19198

oh man, get different nitro, T-MAXX is designed to run 10-20%, but on 10% it sounds like a tank.

Minimum I would run it at is 16%, try some of that and see if it runs better.


Buddy bought 5% by mistake last month, buy that was funny in a T_MAXX!

coolwings

muckwarrior wrote:

There is a clear trail of blue smoke from the exhaust and sometimes excess fuel can be seen spitting from the exhaust so i know that it is running very rich. Can running it too rich cause any harm?

At every setting rich and lean,it SHOULD put oil out the exhaust, because 20% of the fuel is oil, and the oil that isn't burn't into blue smoke (most of the oil) is supposed to come out the exhaust taking heat out with it.
Is this your first glowfuel engine? ... are you really really sure it is rich? cos it sounds too lean to me from your description. I think that possibly u have being doing opposite to what u need, to cure ur problem.

muckwarrior wrote:

I'm runnin 10% nitro which I would assume would be less likely to cause overheating than a higher percentage? I've also used fuel from two different bottles, although they're probably both from the same batch. So could it be the fuel?

It is more likely to be something you are doing, than the fuel. (No offence intended.) NOTE If u put more nitro in the fuel the temp will RISE(unless you compensate with different settings). If it is overheating now, this would make things worse.
Slim is dead right about the nitro for T-Maxx BTW. The T-Maxx DOES like high-ish nitro, but that high nitro can sometimes make running-in harder, because it's more difficult to keep it cool while running-in on high nitro.

muckwarrior wrote:

I haven't bothered cutting any holes in the bodywork yet coz the ambient temperatures were never above 20C and i'm not sure it would do any good.

No need to do this. Not a factor. Irish temperature variations don't bother glowfuel engines, they just change the settings slightly from summer to dead of winter.

muckwarrior wrote:

So anyone else ever come accross this?

Yes ... all the time ... very common difficulty for beginners. Not unusual at all. Just hard to solve without seeing it and showing u. Maybe 60%-70% of nitro engine beginners.

muckwarrior wrote:

Could it be a faulty motor that was supplied with it? If so how would I prove this and would there be any chance of getting it replaced?

Weeell... yes it could be. Not likely, but it could be. It would be like me blaming Esso or Texaco if my full size car stopped running. Could be the petrol - but what about the other million cars using the same fuel no problem? Unfortunately, this is down to what you are doing/not doing.

muckwarrior wrote:

I've looked after it as per instructions

The instructions aren't much help if you are new to this.
At least the solution is very easy.
Just take it back to where you got it from and the shop will reset the settings no charge, and show u what to do, that is what your LHS does. (and from ur description settings is the problem)
If on the other hand you got it internet, then U are on your own by choice, soldier on, and try to not get too frustrated with this little problem, (a couple more are to follow seing u have now toasted the engine during running-in).
U must deduct the hassle cost from the bargain u thought u got by internetting it in the first place.

Idea. Do you have friends who know glowfuel engines who can help? Where are u based? Direct contact with modellers/the shop is what u need right now to get u up and going.

Quick solution(from what u said) .... I guess unscrewing (anticlockwise) the carb needle 1/4 turn will help. I would like to be more precise, but I can't because not all of what u said is consistent. Some points of info conflict with others. I "suspect" that u might be leaning it out when u think u are richening it. Cannot be sure tho. Please check carefully.

SLIM19198

I would say first to switch nitro, then to reset to factory setting the carb needles (its all in the owners manual) then start the tuning process.

The buddy that had the 5% was running like a tank with blue smoke everywhere and going nowhere by the way (serves him right!)

coolwings

If opening the carb needle helps, then u could try another 1/4 turn, to see it it makes things better.
U will know when u have opened it too much, because the engine dies slowly when u try to accellerate.
That is different from too lean ... in that case engine dies quick (as if switched off) when u try to accellerate. And it tends to slow down after 30-60 seconds if u leave it on full throttle.

muckwarrior

Firstly, yes I am a noob to nitro.

coolwings wrote:

re you really really sure it is rich? cos it sounds too lean to me from your description.

I'm sure alright. I keep opening it more and more but it still overheats.
I bought online unfortunately, so can't bring it back to the shop.

I just remembered something strange that happened the very first time I tried to run it. Basically the EZ start turned the motor for about half a second then stopped. I figured it must be flooded so I removed the glowplug and tried turning the motor with the EZstart again but it still wouldn't turn. Then I tried turning the flywheel with my finger as per the troubleshooting instructions, but it still wouldn't turn. Eventually I managed to get it to turn by levering a screwdriver against the flywheel. Even this almost didn't work, it really was seriously stuck. I just assumed that this was normal at the time, but now that I know how easy it should be to turn I think maybe there was somethin wrong with it. Could the engine be damaged in some way?

SLIM19198

When an engine is new, the piston might get stuck at top dead centre where it would be really tight (new piston and all) so that is not that unusual, they say that to prevent it happening, heat the head with a hairdryer before you start the engine (heat expands the head)

I wouldnt be too worried about that really.

SLIM

coolwings

muckwarrior wrote:

Firstly, yes I am a noob to nitro.

OK We know where you are regarding expertise.

muckwarrior wrote:

I'm sure alright. I keep opening it more and more but it still overheats.

Richening it up stops overheating, so if u have already set it rich there is another thing wrong. Try to find it.

muckwarrior wrote:

I bought online unfortunately, so can't bring it back to the shop.

Now u know why the mail order place charges less, they don't give u all the backup that the LHS gives. Just a box. They even make more money selling u replacements for the bits u break while u figure it out.
FWI Just so u know - the trade values (the lack of) mail order backup at €60-€110 based on preventable things that happen to a newbie, and the parts that break (avoidable break), as a result of "going it alone", (eg average 2 x pullstarts, 3-4 x glowplugs, 1-2 x clutch, approx 15% engine life consumed, occasional seizings & other nasty stuff). Ten mins demo in LHS avoids all that. An LHS resetting ur car in front of u shows u how to do it right for ever.

muckwarrior wrote:

... very first time I tried to run it. ...turned the motor for about half a second then stopped....so I removed the glowplug and tried turning the motor with the EZstart again but it still wouldn't turn....Eventually I managed to get it to turn by levering a screwdriver against the flywheel.

Don't worry about that at the moment. It's not connected with your problem. Unless you have had a soft seize already. Then it is connected, and your car will be hard to start until after the burnt oil is polished off the liners.

muckwarrior wrote:

Could the engine be damaged in some way?

Yes, but most likely your settings are wildly off, so it is likely OK.

Is there nobody at all near who can put u right? Club? Local car guy? LHS? We do our best to help here. BUT We can make suggestions in discussion till the cows come home, matter of luck if we get it right, because u may introduce another problem while removing the one present now.

I assume you have called the supplier already to troubleshoot this before coming here ... remember .... they have your money.

If no help there ... get the book out...set it up methodically exactly as shown in book. Work step by step. Be very very fussy. No "just about right" kind of approach.

Stick at it. The cars will go right. You just don't know how yet. You have to figure it out without breaking stuff while doing so. Try again.

muckwarrior

coolwings wrote:

Richening it up stops overheating, so if u have already set it rich there is another thing wrong. Try to find it.

I really am very confident that it's running plenty rich. The factory default is to open the HSN 4 turns. I did this and gradually richened it to well over five turns, at which point the engine would barely run. All the time it kept overheating.

Is there nobody at all near who can put u right? Club? Local car guy? LHS?

Fraid not.

If no help there ... get the book out...set it up methodically exactly as shown in book. Work step by step. Be very very fussy. No "just about right" kind of approach.

Read the instructions, watched the DVD, gone through the traxxas website and forums and tried everything suggested there. Still no luck . Thats why i'm starting to think theres something wrong with the motor. If I took it apart how could I tell whether it was healthy or not?
(Btw I know I'm new to nitro but I've worked as a mechanic in the past and am probably a bit more capable than your typical noob.)

Thanks guys.

coolwings

Loosen the glowplug ... just a tiny bit. Finger-tip tight on the wrench.
When the engine turns over a little bubble of pressure should be able to escape under the conical copper plug washer.
This drops the compression and takes stress off the ez start-also reduces the heat of running, tho the plug will want to unscrew and stop the engine if it loosens more.
See how it goes....

BTW You didn't get fuel with only 12% oil in it, did you? We are all using 18 - 20% minimum, the best oil we can afford in the fuel for car engines, because of the relatively high temps. eg Go-Glo Plus is 15% synthetic + 3% castor oil (+ the nitro of course).
But if you managed to get 12% oil fuel, that is for 4-strokes only, and you engine will overheat and be damaged. It would explain a lot.

SLIM19198

My reconnendation is still to up the nitro content of the fuel (16% minimum, 20% is cool too though), that way the engine will run smoothly without boggin down in oil.

The trx 2.5 engine runs better with higher content nitro (racers are known to use 30%)

muckwarrior

I'll try new fuel alright. It doesn't say on it how much oil is in it. I just asked the guy in the model shop on Capel street for fuel for a monster truck and 10% nitro is what he gave me. Goin on holidays next week so it'll be a couple of weeks before I can let yas know whether it works or not. Tahnks for the help!

coolwings

Stick at it. Break it in. Don't let it break you in !

It's worth it.

dts

You could have an air leak. This would cause the engine to over heat!

Plug

Get 16% fuel its perfect, 20% could burn out your engine quicker. Set it back to factory settings (high speed 4 turns out, low speed flush with the end of the slide, idle speed about 1 or 2 mm out from closed). Get a brand new plug in it, this will help it idle longer. This might help you . Also try emailing them

boyracer87

muckwarrior wrote:

I just asked the guy in the model shop on Capel street for fuel for a monster truck and 10% nitro is what he gave me.

That fuel should be fine.seemingly the english 10% is the same as the american 16%. i think it is just your idle speed. try opening it up a small bit. it should help its running.