really,really hot!!!!!
 

The engine in my dads tmaxx(2.5r)gets real hot. like 350. he cut holes in the body and richend it up, but it still gets hot.:mad:1 :036:

Check the exhaust header and the gas tank for air leaks, and the drivetrain for binding.

Try setting it richer.

it cant get any richer.the gas tank and drive shafts are fine.

Ditch that nitro setup and get a brushless setup.

When you say that you are running it richer, I'm going to assume that you are referring to the high speed needle. If you have richened it up as much as you can and it still runs hot, the first thing that pops into my mind is that the bottom needs to be richened. Fat top and lean bottom = one hot running engine.

You might also want to check and make sure that you don't have any leaks in the pressure line between the fuel tank and exhaust pipe. This will also cause a lean situation.

No offense intended, but do you guys know how to tune a nitro engine? NEVER ever tune the bottom until the top is tuned and only tune when you have the engine up to running temps; something over 200F or so.

What I usually do is to set the bottom rich, so that the vehicle stutters from too much fuel when you take off and then it will clear out. At this point, you can tune the top so that the engine is giving good performance, while still showing a steady flow of smoke. When you have the top end tuned, I usually just tune the bottom so that it will idle for about 5 seconds before loading up.

One thing that you should avoid is tuning by temp. I've had O.S. RG engines that would run great at 275 all day long, but the Novarossis that I've had ran best at around 235. Just tune the engine until it sounds right, but I think that I'm safe in saying that 350 is way too hot and you probably damaged the piston/sleeve and maybe even the bearings or crankshaft.

I'm sorry that I can't articulate it any better than this, but tuning is a skill that you gain through experience.

Just as a start, try opening up the low speed needle by a half a turn and see what happens.

Does it smoke?

yes.

Well, if all looks fine but it runs hot, I'd look to the low speed needle.

he just set it back to the factory settings. but it still runs hot.

there has to be a leak somewherem check the tank for leaks and fuel line, also check the coupler between the pipe and header

there is no leaks at all. but the engine had five gallons of fuel run through it, could that be the problem?

If an engine is running hot like that and you don't have any binding, it pretty much has to be a lean situation.

If the motor has five gallons through it, its better days are definitely behind you. I'd first look to the bearings and check for excessive play. This is another reason why I never liked the pull starters and other gizmos that have something sticking out of the back of the engine for starting without a box. They leak.

but my tmaxx never had this problem.

Aangel we have had these trucks for 3 years, we know how to tune them. anyway, thank you everybody for trying to help.

If you have a lot of runtime on the engine, it is possible the piston isn't as snug as it used to be. Even though a previous engine didn't do it, that could be because of a slight variance in break-in, or simply motor contruction tolerances were different.

at first thats what i thought it was,but it still has lots of compression.

Even when hot? Really weird then. Something like that happened to me once and it was a leaky exhaust coupler that looked good. But I'm no nitro expert, lol.

i'm not a nitro expert, but i can tell if the coupler was tore.

Are you saying that you guys have been running the same engines for three years? If so, you're doing pretty good. I could tear up an engine in two months, or less.

If the engines are that old, I'd pull the carb and make sure that the o-rings are sealing. For some reason, more air than is supposed to is making its way into the engine.

Have you pulled the head to make sure that the gaskets are sealing? When you say that there is good compression, did you try turning the motor over with the plug removed? Are you sure it's compression that you're getting and not pinch?

I don't know, I'm just throwing things out there. Trying to diagnose an overheating problem without seeing the engine is like calling a mechanic on the phone and trying to describe a noise to him.

no. we have had the trucks for three years. together we bought about 10 engines.

I gotta agree with serum, for the price of those 10 engines you cold have bought a couple of quark/neu combos, a HUGE stack of LiPos and wouldn't be wasting your time fiddling about with glow engines that don't run right for no apparent reason.

Sounds To Me
 

like you need to clean your air filter, if it can't breathe she gets mighty hot

Actually, I would think that a dirty air filter would cause a rich situation. Too much fuel and not enough air.

naw
 

your carb decides that, a clogged air filter is like choking someones neck, watch how hot and read their head gets!

Wait a minute. That's a dumb ass comparison. Sorry, but I just had to say it. Choking someone has nothing to do with the temperature at which a two stroke internal combustion runs.

Barring any binding in the drive train or clutch or excessive running over tall grass or similar terrain, the temp of the engine is controlled by the fuel air mixture. The richer the mixture, the cooler the engine will run. The leaner the mixture, the hotter it will run.

Given any particular needle setting, choking off the air richens the mixture. A dirty air filter will richen the mixture.

sorry for the dumb ass comparison
 

but you don't tune a 2 stroke internal combustion engine with the air filter, you use, first the high speed needle, then the low speed needle, and if it is too rich or too lean only the carb adjustments will correct it, a clogged air filter can cause hot engines because of restricted breathing, i was just trying to be funny and give the guy something else to check so he could run his t-maxx with his dad, as I run nitro's daily and am trying to expand my r/c knowledge on this brushless forum and help where I can, how does negative criticism (dumbass comparison) help anybody??? Aangel you're usually so helpful!! Can't we all just hit a b?ng and get along!

oh yeah
 

notice the 4 inch k&n air filter on the t-maxx in my avatar? it is really an automotive oil breather, i got sick of the little stock air filter getting clogged and my engine running hot, so I upgraded and keeping my k&n cleaned and lubed really helps my temps stay stable

OK, sorry about the "dumb ass" comment. Your experiences are your experiences. I just disagree with what you said.

my tmaxx is fine, its my dads that is getting hot. but it might be the grass, because when he takes it to the track, he can go through a 5 lap race and it wont get hot as fast.

link doesn't work.

btw; if an airfilter is closed, the motor will run richer and therefore run cooler. rich means less air (since it can't breath, it's getting less air) a clean filter means more air, so leaner, which means more heat. You don't tune an engine with an airfilter, but you do tune an engine with the airfilter on, so if it ran okay with a clean filter, it will run richer with a dirty filter if the same settings are used.

it might be running hot because he's always on the gas he never lets off.

i think that might be why

I know that this is an old topic, but did you figure it out? If not there has to be an airleak, or resistence in the driveline, one wat to find out is to put your motor and fuel system in your dads truck and see if it works or gets hot. If with a full swap it still does, then its in the drivetrain

I would think its something with the bearings or the o-rings.