Running Too Hot
04-08-2008, 05:49 PM
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Running Too Hot
Hey Everyone,
I recently purchased a MT2 G3.0 and have been running it in the cooler weather. I broke it in and always made sure that the temps were in the 220 - 250 (250 at the most). I took it out today (16 degrees C, YAY!) and opened up all the holes I had covered up before because it was too cold. I'm running the motor rich and haven't even tuned it to a leaner setting and the temps reached 280 - 290 at times after a few WOT runs. I ran a few 1/2 - 3/4 throttle runs and was down to 250. What can I do to get the temps down? Is it because it's too rich?
Thanks in advance!
I recently purchased a MT2 G3.0 and have been running it in the cooler weather. I broke it in and always made sure that the temps were in the 220 - 250 (250 at the most). I took it out today (16 degrees C, YAY!) and opened up all the holes I had covered up before because it was too cold. I'm running the motor rich and haven't even tuned it to a leaner setting and the temps reached 280 - 290 at times after a few WOT runs. I ran a few 1/2 - 3/4 throttle runs and was down to 250. What can I do to get the temps down? Is it because it's too rich?
Thanks in advance!
04-08-2008, 05:56 PM
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RE: Running Too Hot
Yeah, that's the weird part, I have quite a bit of smoke from the exhaust, which usually means you're running too rich, right?
04-08-2008, 06:33 PM
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RE: Running Too Hot
Not always, because it could be loading up from a rich idle mix [:-] another thing to check is that it leans out more toward the end of a tank of fuel [&o] if thats the case go richer on a full tank...............need all the power at the end of the race anyway...........lol
04-09-2008, 04:43 PM
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RE: Running Too Hot
ORIGINAL: the evader crusader
i agree 100% could be loaded up. Just remember the temp gun doesn't lie
i agree 100% could be loaded up. Just remember the temp gun doesn't lie
It kinda just seems lik eyou over compensated with a lean HSN for a rish LSN. Just richen the HSN up 1/8th of a turn and see how that goes.
04-09-2008, 08:54 PM
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RE: Running Too Hot
I haven't really touched the LSN and HSN settings as they are from the factory. That's the strange thing about it, is that those settings should be very rich for break in, and that's what confuses me as to it being possibly set too lean.
04-10-2008, 06:28 AM
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RE: Running Too Hot
ORIGINAL: 125cchyperman
Actually thats not true, temp guns are known to be extremely innacurate at times, especially if you bought a cheap one or if you have it on the wrong setting. Just because you have a ton of smoke coming form the exhaust doesnt mean your rich. Different fuels will smoke differently, and if you are running a fuel with a high amount of oil content in it then it will smoke more then a fuel with a lesser oil content in it. You could have an air leak, but dont think that this is the problem. And loading up wouldnt do this, loading up just means when you sit and idle all the fuel is not being burnt in the cylinder. After a while when you go to accelerate the excessive fuel will make it seem sluggish at first. But it very quickly clears out after a quick full speed run. So a engine that has loaded up will not do this, or cause this type of temp change. You could be running rich on the bopttom end but overly lean on the top end though which is what I think your doing. Richen up the HSN 1/8th of a turn and see if that helps, I think you just overcompensated with a rich LSN setting for a little lean HSN setting which happens more then u think.
It kinda just seems lik eyou over compensated with a lean HSN for a rish LSN. Just richen the HSN up 1/8th of a turn and see how that goes.
ORIGINAL: the evader crusader
i agree 100% could be loaded up. Just remember the temp gun doesn't lie
i agree 100% could be loaded up. Just remember the temp gun doesn't lie
It kinda just seems lik eyou over compensated with a lean HSN for a rish LSN. Just richen the HSN up 1/8th of a turn and see how that goes.
Ok i take that back a good temp gun doesn't lie like the fluke one that i use at work and at home to tune my engine
04-10-2008, 10:09 AM
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RE: Running Too Hot
Only other thing to look for are very small air leaks............if its pretty new it could be in the carb area..........other than that I would have to see it to figure it out [&:]
04-10-2008, 10:40 AM
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RE: Running Too Hot
As above....try richening the HSN a little bit. As for airleaks, ....if you have one, you have to richen the needles a lot, so even the factory spec settings may be still too lean. Typically the carb pinch bolt (what you tighten to hold the carb tight) is a cause for leaks. RTV is good to fix that (I've used regular with no noticeable problems, but the oxygen sensor stuff is the recommended RTV).
Long runs really build up heat. You have to tune a bit more rich for this type of running.
Is there lots of air getting to the cooling head? Some people cut more out of their bodies to help with this.
As far as temps go, I've accidently run one of my engines up to 400F once and over 300F several times and it was fine, but I like to keep the temps between 200 and 300F. It's nice to get temps around 240ish with a peak no higher than 270F as the vehicle runs out of fuel. The 290F probably won't hurt it, but you are getting to the point where the fuel (lubrication) may not be enough, or might boil off, etc.
With some engines, performance vs temp can be a trade-off. After-market cooling heads are "cool" and work well, but you could mask an overly lean condition if you arn't careful. A shorty cold plug, such as the OS A5 works great (reduces compression in an engine designed for a normal long plug, and retards the timing). An extra head shim can help, but you may have to re-break-in your engine a bit for the new cooler running depending on the shim thickness.
Inreasing heat as the tank fuel level drops can be reduced by shortening your pressure line as short as possible. Helps, but you are always going to be stuck with it too some extent. Hmmmm....I take it your pressure line is hooked up.....
All this aside, judging from your post, do as the other fellows suggest....richen the HSN and see what happens. As they said, if your HSN is too lean, the engine will get hot. But you may see a lot of smoke because the LSN is probably too rich and it takes a while for the engine to burn off the excess fuel during a high speed run. If the high-speed run was long enough, you'd probably see a reduction in smoke. Unless the LSN is very rich, you can tell this is happening....when you suddenly get off the throttle, the engine will race for a little bit and then settle down to a normal idle.
Some people say things like "if you over 240 your engine is toast", etc. Others say things like "Don't worry about the temps, just tune for best performance". I think the real truth is a bit of both. The exact temp isn't so important, but too hot is bad, and too cold is bad.
There...I've said enough that I've opened myself up for criticizm. That's fine. I'm not an expert, but I did own the most annoyingly over-heating engine known to man.....the Force 26!!!
Long runs really build up heat. You have to tune a bit more rich for this type of running.
Is there lots of air getting to the cooling head? Some people cut more out of their bodies to help with this.
As far as temps go, I've accidently run one of my engines up to 400F once and over 300F several times and it was fine, but I like to keep the temps between 200 and 300F. It's nice to get temps around 240ish with a peak no higher than 270F as the vehicle runs out of fuel. The 290F probably won't hurt it, but you are getting to the point where the fuel (lubrication) may not be enough, or might boil off, etc.
With some engines, performance vs temp can be a trade-off. After-market cooling heads are "cool" and work well, but you could mask an overly lean condition if you arn't careful. A shorty cold plug, such as the OS A5 works great (reduces compression in an engine designed for a normal long plug, and retards the timing). An extra head shim can help, but you may have to re-break-in your engine a bit for the new cooler running depending on the shim thickness.
Inreasing heat as the tank fuel level drops can be reduced by shortening your pressure line as short as possible. Helps, but you are always going to be stuck with it too some extent. Hmmmm....I take it your pressure line is hooked up.....
All this aside, judging from your post, do as the other fellows suggest....richen the HSN and see what happens. As they said, if your HSN is too lean, the engine will get hot. But you may see a lot of smoke because the LSN is probably too rich and it takes a while for the engine to burn off the excess fuel during a high speed run. If the high-speed run was long enough, you'd probably see a reduction in smoke. Unless the LSN is very rich, you can tell this is happening....when you suddenly get off the throttle, the engine will race for a little bit and then settle down to a normal idle.
Some people say things like "if you over 240 your engine is toast", etc. Others say things like "Don't worry about the temps, just tune for best performance". I think the real truth is a bit of both. The exact temp isn't so important, but too hot is bad, and too cold is bad.
There...I've said enough that I've opened myself up for criticizm. That's fine. I'm not an expert, but I did own the most annoyingly over-heating engine known to man.....the Force 26!!!
04-10-2008, 07:35 PM
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RE: Running Too Hot
ORIGINAL: Argess
As above....try richening the HSN a little bit. As for airleaks, ....if you have one, you have to richen the needles a lot, so even the factory spec settings may be still too lean. Typically the carb pinch bolt (what you tighten to hold the carb tight) is a cause for leaks. RTV is good to fix that (I've used regular with no noticeable problems, but the oxygen sensor stuff is the recommended RTV).
Long runs really build up heat. You have to tune a bit more rich for this type of running.
Is there lots of air getting to the cooling head? Some people cut more out of their bodies to help with this.
As far as temps go, I've accidently run one of my engines up to 400F once and over 300F several times and it was fine, but I like to keep the temps between 200 and 300F. It's nice to get temps around 240ish with a peak no higher than 270F as the vehicle runs out of fuel. The 290F probably won't hurt it, but you are getting to the point where the fuel (lubrication) may not be enough, or might boil off, etc.
With some engines, performance vs temp can be a trade-off. After-market cooling heads are "cool" and work well, but you could mask an overly lean condition if you arn't careful. A shorty cold plug, such as the OS A5 works great (reduces compression in an engine designed for a normal long plug, and retards the timing). An extra head shim can help, but you may have to re-break-in your engine a bit for the new cooler running depending on the shim thickness.
Inreasing heat as the tank fuel level drops can be reduced by shortening your pressure line as short as possible. Helps, but you are always going to be stuck with it too some extent. Hmmmm....I take it your pressure line is hooked up.....
All this aside, judging from your post, do as the other fellows suggest....richen the HSN and see what happens. As they said, if your HSN is too lean, the engine will get hot. But you may see a lot of smoke because the LSN is probably too rich and it takes a while for the engine to burn off the excess fuel during a high speed run. If the high-speed run was long enough, you'd probably see a reduction in smoke. Unless the LSN is very rich, you can tell this is happening....when you suddenly get off the throttle, the engine will race for a little bit and then settle down to a normal idle.
Some people say things like "if you over 240 your engine is toast", etc. Others say things like "Don't worry about the temps, just tune for best performance". I think the real truth is a bit of both. The exact temp isn't so important, but too hot is bad, and too cold is bad.
There...I've said enough that I've opened myself up for criticizm. That's fine. I'm not an expert, but I did own the most annoyingly over-heating engine known to man.....the Force 26!!!
As above....try richening the HSN a little bit. As for airleaks, ....if you have one, you have to richen the needles a lot, so even the factory spec settings may be still too lean. Typically the carb pinch bolt (what you tighten to hold the carb tight) is a cause for leaks. RTV is good to fix that (I've used regular with no noticeable problems, but the oxygen sensor stuff is the recommended RTV).
Long runs really build up heat. You have to tune a bit more rich for this type of running.
Is there lots of air getting to the cooling head? Some people cut more out of their bodies to help with this.
As far as temps go, I've accidently run one of my engines up to 400F once and over 300F several times and it was fine, but I like to keep the temps between 200 and 300F. It's nice to get temps around 240ish with a peak no higher than 270F as the vehicle runs out of fuel. The 290F probably won't hurt it, but you are getting to the point where the fuel (lubrication) may not be enough, or might boil off, etc.
With some engines, performance vs temp can be a trade-off. After-market cooling heads are "cool" and work well, but you could mask an overly lean condition if you arn't careful. A shorty cold plug, such as the OS A5 works great (reduces compression in an engine designed for a normal long plug, and retards the timing). An extra head shim can help, but you may have to re-break-in your engine a bit for the new cooler running depending on the shim thickness.
Inreasing heat as the tank fuel level drops can be reduced by shortening your pressure line as short as possible. Helps, but you are always going to be stuck with it too some extent. Hmmmm....I take it your pressure line is hooked up.....
All this aside, judging from your post, do as the other fellows suggest....richen the HSN and see what happens. As they said, if your HSN is too lean, the engine will get hot. But you may see a lot of smoke because the LSN is probably too rich and it takes a while for the engine to burn off the excess fuel during a high speed run. If the high-speed run was long enough, you'd probably see a reduction in smoke. Unless the LSN is very rich, you can tell this is happening....when you suddenly get off the throttle, the engine will race for a little bit and then settle down to a normal idle.
Some people say things like "if you over 240 your engine is toast", etc. Others say things like "Don't worry about the temps, just tune for best performance". I think the real truth is a bit of both. The exact temp isn't so important, but too hot is bad, and too cold is bad.
There...I've said enough that I've opened myself up for criticizm. That's fine. I'm not an expert, but I did own the most annoyingly over-heating engine known to man.....the Force 26!!!
04-10-2008, 08:30 PM
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RE: Running Too Hot
Nice post Argess!
The only thing I would debate you over is the re-breaking in thing. I would argue that once the engine has been properly heat cycled, adding or removing shims, installing short plug, or doubling up on plug washers only warrants a re-tune.
And since you eluded to it in your post...converting to run without a pressure line eliminates the fluctuating pressure, and the varying tune associated with it...
....But that's a different talk show altogether
The only thing I would debate you over is the re-breaking in thing. I would argue that once the engine has been properly heat cycled, adding or removing shims, installing short plug, or doubling up on plug washers only warrants a re-tune.
And since you eluded to it in your post...converting to run without a pressure line eliminates the fluctuating pressure, and the varying tune associated with it...
....But that's a different talk show altogether
04-11-2008, 07:31 AM
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RE: Running Too Hot
Well....I escaped pretty much unscathed....LOL.
The break-in thing....I broke a crank pin in an engine because I added a head shim. The engine already had an aftermarket cooling head on it, the body was off, and I test drove it in very cold weather. Trying to build heat, I ran it hard. Temps were only about 180 and the engine was used to running about 240F. I figured the pinch was too tight for that kind of running, but I admit.....it was an old engine and the crank could have broken anyway.
The pressure line thing.....I was having trouble once with engines leaning out too much as the fuel level in the tank dropped. Shortening the pressure line helped an almost empty tank pressurize faster during acceleration. And it would seem an almost full tank would pressurize quickly during acceleration. So now the pressure during acceleration was now closer to being consistent between an almost empty tank and an almost full one. Adding in the factor that fuel pressurize change due to a decreasing fuel level (gravity) is less significant in a presurized tank, I went ahead and shortened pressure lines in my vehicles. Even if my theory is all screwed up, I noticed a lot less temperature change as the tank emptied, and no noticeable engine leaning (performance,power) until the engine started to run out of fuel.
It would be really cool to invent a pressure regulator for RC fuel tanks...maybe they have them, but I havn't seen any. I thought of using a 1-way valve in the pressure line, but it was pointed out to me the tank would remain pressurized if the engine stopped and then flooding would occur.
Oh well....hopefully Marky will cure his heating woes based on our suggestions.
edit: ps: Avg Joe: I've never noticed this pulsing tune thing.....is it very noticeable? I only bash. Is it something that only is a problem for Racers who need very precise throttle control?
The break-in thing....I broke a crank pin in an engine because I added a head shim. The engine already had an aftermarket cooling head on it, the body was off, and I test drove it in very cold weather. Trying to build heat, I ran it hard. Temps were only about 180 and the engine was used to running about 240F. I figured the pinch was too tight for that kind of running, but I admit.....it was an old engine and the crank could have broken anyway.
The pressure line thing.....I was having trouble once with engines leaning out too much as the fuel level in the tank dropped. Shortening the pressure line helped an almost empty tank pressurize faster during acceleration. And it would seem an almost full tank would pressurize quickly during acceleration. So now the pressure during acceleration was now closer to being consistent between an almost empty tank and an almost full one. Adding in the factor that fuel pressurize change due to a decreasing fuel level (gravity) is less significant in a presurized tank, I went ahead and shortened pressure lines in my vehicles. Even if my theory is all screwed up, I noticed a lot less temperature change as the tank emptied, and no noticeable engine leaning (performance,power) until the engine started to run out of fuel.
It would be really cool to invent a pressure regulator for RC fuel tanks...maybe they have them, but I havn't seen any. I thought of using a 1-way valve in the pressure line, but it was pointed out to me the tank would remain pressurized if the engine stopped and then flooding would occur.
Oh well....hopefully Marky will cure his heating woes based on our suggestions.
edit: ps: Avg Joe: I've never noticed this pulsing tune thing.....is it very noticeable? I only bash. Is it something that only is a problem for Racers who need very precise throttle control?
04-11-2008, 01:08 PM
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RE: Running Too Hot
The pulsing presure thing I have never experienced. Some will say the shorter the pressure line is you will start to notive a pulse with the pressure from the pressure line. Since the pressure form the engine pulses and it's more noticable with a shorter pressure line. But I have a pressure line shorter then 3 inches and have never experienced the pulsing from the engine and from any of the engine that I had run on my xxx-nt. But some say it will pulse with a shorter pressure line but I have never experienced it though, so to me it's more of a myth or rumor then anything. But maybe I'm just doing somethign right or am getting lucky
But again nice post agress
But again nice post agress
04-11-2008, 02:55 PM
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RE: Running Too Hot
my pressure line was like 3 inches long and it wouldnt even put any pressure into the tank... oh right the motor was blown... thats the dey i found out... k im out of this convo lmao
04-11-2008, 09:18 PM
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RE: Running Too Hot
I was referring to the varying pressure from a full tank to an almost empty. If you tune it while it's full, it's off when it's almost empty...if you tune it for performance at the end of the tank, it is off for the first half tank.
It isn't a big deal for the most part, as you can find a happy medium that covers both ends of that spectrum.
But you can convert a nitro engine to run without the pressure line, and not have to deal with that at all.
It gives the throttle a more linear feel in the lower part of the powerband...Not quite so peaky, and easier to control.
It isn't a big deal for the most part, as you can find a happy medium that covers both ends of that spectrum.
But you can convert a nitro engine to run without the pressure line, and not have to deal with that at all.
It gives the throttle a more linear feel in the lower part of the powerband...Not quite so peaky, and easier to control.
