need help with overheating .16

[aj200415]

i have a megatech neo .16 engine and I'm running 10% TOP FUEL brand fuel.
It over heats really badly after about 5 min. and i dont no what to do. any help will be helpful thanx

 

[Blah420]

sounds like a tuneing issue ritchen it up a bit

 

[AC48]

Yes it sounds like a tuning issue. Richen up your HSN (the bug one that sitcks out) by turning it it counter-clockwise by 1/8th incriments until you have good performance without it overheating.

I may also suggest that you get a temp gun to help you monitor your temps.

 

[rocknbil]

Other possibilities:

Too high an idle, causing clutch to stay over-engaged
Tight gear mesh
Binding anywhere in drive train
Engine on it's last leg
Air leaks
Damaged glow plug gasket
incorrect temp glow plug

but usually, it's tuning.

 

[aj200415]

Other possibilities:

Too high an idle, causing clutch to stay over-engaged
Tight gear mesh
Binding anywhere in drive train
Engine on it's last leg
Air leaks
Damaged glow plug gasket
incorrect temp glow plug

but usually, it's tuning.

new engine, and my cluch just burned out so i have to buy a new one, and i tuned it like you said and when it runs good its to hot and when its just a click on the lean side it is slow.People say 20% keeps the motor running fast and cools the engine more cause of a higher oil content? is this true?? will it help??

 

[AC48]

Yes, the higher the nitro content the lower the temps as a general rule. The downside of this is the higher the nitro the quicker your engine will wear out becasue of the higher compression. Most people find 20% Nitro to be the best balance.

When you say it is slow a click on the lean side, do you mean rich? Usually when a enigine is too rich it boggs and is slow and when it is hotter and runs faster, but will sometimes starve for fuel and it will wear out faster.

If one click makes a huge difference, then you could have one of the thingsd that rocknbil posted. You said you burned out a clutch, this shows that your idle may be too high and will need to be lowerd. If you leave your throttle servo at neutral does the vehicle roll at all, or does it not move? At neutral the vehicle should not move. The engine should be spinning slow enough to not engage the clutch. If your engine never gets a chance to idle and cool off some this could be part of your problem.

 

[aj200415]

Yes, the higher the nitro content the lower the temps as a general rule. The downside of this is the higher the nitro the quicker your engine will wear out becasue of the higher compression. Most people find 20% Nitro to be the best balance.

When you say it is slow a click on the lean side, do you mean rich? Usually when a enigine is too rich it boggs and is slow and when it is hotter and runs faster, but will sometimes starve for fuel and it will wear out faster.

If one click makes a huge difference, then you could have one of the thingsd that rocknbil posted. You said you burned out a clutch, this shows that your idle may be too high and will need to be lowerd. If you leave your throttle servo at neutral does the vehicle roll at all, or does it not move? At neutral the vehicle should not move. The engine should be spinning slow enough to not engage the clutch. If your engine never gets a chance to idle and cool off some this could be part of your problem.

yes i ment it is hot on lean and slow on rich, and i think the idling is what burned my clutch up. thanks alot man .

 

[AC48]

Ok, hot on lean and slow on rich is what you want. Basically for any nitro engine you want to be just a tad on the rich side so you don't overheat and wear out your engine. But, if you go too rich your engine will be slow and won't run well. Finding a good balance is the hard part lol.

Use the idle adjustment screw to change your idle. Make your idle fast enough that it can stay running but slow enough that it will not move your vehicle.

As for tuning, find out the manufacture's factory settings. Set your carb to these settings. Keep in mind that these settings are almost always very rich. If your engine will not start, lean out the carb a click at a time until it fires up. Drive the vehicle around long enough for the engine to get up to temps. Once the engine is up to temp acess the performance of the vehicle. If it is slow and boggy (which it should at factory settings) lean it out a click at a time until you get good performance. If it overheats richen 1 or 2 clicks and if it still overheats you probably have something wrong with your engine like an airleak. Let us know how your tuning goes and if your problem is fixed. Good luck!

 

[parris001]

Quick question, what are you running this in :shrug: ? Do you need to cut holes in your body to get some airflow to the head? Man, I hate to be the bearer of bad news , but more nitro is going to run hotter. The nitro in the fuel makes the power :flamer: , the methanol is the agent that supports combustion and helps cool the engine, and the oil is for lubrication and a small amount of cooling. I'm not sure about your Top Fuel brand. I run Eliminator brand and have had a lot of luck with it at 20% in a HPI .15 SS in a RS4 2. If you don't have a temp gun (20 years in the hobby and I've never owned one) I just tune until I have a light haze of oily smoke under hard acceleration and under full power. I go as rich as I can stand it without sacrificing power on the bottom end.

I'd really like to know what you've got this engine in................ you may just need more ventilation.

 

[AC48]

I have heard from various members on the boards that more Nitro actually will lower your temps. I don't remember exactly why, but I posted something similar to what you said (More Nitro = More power = More heat) and I was corrected by by many people saying more Nitro actually cools the motor to some degree. Becasue of the higher compression you will get more performance, but your engine will wear out faster becasue of this.

 

[parris001]

Here's my reasoning.......... More nitro creates higher compression, right? Well, what do you think the result of the higher compression is going to be? More heat. Another way of looking at it is this. Does higher nitro content create more power? Of course it does. What is power? Power is heat. As nitro levels increase more power is available to drive the piston down. "Available" being the key word. Because no engine is 100% efficient in turning heat into power they all put off a certain amount of heat. On a nitro R/C engine not a lot of heat goes out of the exhaust if you compare it to a 1/1 car. This is because the heatsink in the head absorbs most of the lost power and converts it into heat. The bigger the heatsink, the more nitro you can run (to a point) without damaging your engine with excessive temps.

Sorry guys, nitro is power. And power if not harnessed is just excess heat.

 

[AC48]

Your reasoning makes perfect sence to me, but, other members have said it actually lowers the temps of your engine somehow. I don't understand why or how but this is what I have heard. To me, it makes more sence according to your reasoning but I'm just trying to pass on what other (More experienced) members have said to me.

 

[StaticSag]

I had that same engine and had the same overheating prob with high oil content low nitro content fuels. After trying several brands I ended up using Byrons 20% and the overheating went away. It was explained to me that high oil content will cause overheating due to the oil not burning off properly and staying in the engine to create heat.

Saggy

 

[parris001]

Byrons is good stuff. I used to use it until my LHS quit carrying it

 

[Rolex]

Unless I missed it, no one mentioned the LSN here. I once worked on a car that a guy bought from a pawn shop and knew nothing about.
At idle, it hit 310 in about 3 minutes, just sitting on a table.
There's an absolute "sweet spot" that you get only by having both needles set right.

 

[parris001]

Oh, no doubt having one in tune is the best way to keep heat down. I'm still not 100% buying StaticSag's claim that one was overheating due to high oil/low nitro content. There may have been a funky blend of oil that was causing high temps but low nitro content lets one run cool. I've ran 0% nitro content before. Not great for power but you can bet it won't run hot

 

[aj200415]

I leave the body off so dont worry bout that, and when i do run the car it fills the muffler full of really oily nitro and i have to turn it sideways to drain it all out. i dont no if i have an air leak or not. How can i tell? where can they be. Also, my LHS went out of business, so now i have to go to another LHS and they only carry 20% wildcat nitro. my clutch is still burned and I'm gettin the new one very shortly so can't do nothin right now so i dont no what to do with the over heatin prob. :shrug:

 

[rocknbil]

....and my cluch just burned out so i have to buy a new one ...

Sorry I missed this eariler.
First, I'd question WHY your clutch burned out. Are you running a particularly high idle, maybe? This would cause the premature engaging I was talking about that might be contributing to your overall heating.

Here's my reasoning.......... More nitro creates higher compression, right? ....
Sorry guys, nitro is power. And power if not harnessed is just excess heat.

I have to ask - why do you think more nitro creates more compression? While I agree with the more power and heat (to a point) I don't see how it creates higher compression, which is a function of the condition of the P/S and available squish band in the combustion chamber.

Here is my understanding of the "more nitro=cooler temp" idea (although I don't know if I agree.) When you have a higher nitro content, it allows you to run richer, and the running richer is the added lubrication to cool the engine a little more.

It's important to remember that nitromethane itself is not all that flammable and that it requires a secondary fuel to get it burning. That, for us, is alcohol. Once it DOES get burning, it still burns slower than alcohol, but at it's critical flash point it burns HOT.

If you drop a match into a pool of pure nitromethane, the match will likely sputter and go out. If you hit the same pool with a hammer, you'll get a crater the size of a car. Don't confuse the explosive power of nitromethane with it's flammability, they are two separate properties under different conditions. The methanol in our fuel is ten times as flammable as nitromethane.

Given the understanding that nitromethane burns SLOWER than alcohol, it becomes clear as to why higher nitro content might cause your engine to run cooler. As the combustion begins, the nitromethane takes longer to "get burning," and when it reaches the critical point of combustion at TDC, releases a larger combustive force. Unfortunately, the impression that more and MORE is always better is a bit of a misconception. At a certain point, too much nitromethane, under the wrong conditions, can actually douse or reduce your overall power simply because in the high-speed RPM of our 2-stroke engines, there's just not enough time to burn it all before the exhaust port opens. In an unmodified motor, anything over 30% in an unmodified motor may or may not give you more power and performance.

It's a pretty heated debate, one I've been watching and expiramenting with for years.

 

[AC48]

You siad that running higher % Nitro allows you to run richer, which means more uncompressable matter in the combustion chamber. The more fuel that is in your engine the higher the compression. At least thats why I thought more Nitro creates higher compression.

 

[rocknbil]

You siad that running higher % Nitro allows you to run richer, which means more uncompressable matter in the combustion chamber.....

Actually I'm pretty sure it just means there is a higher ratio of fuel to air. Because of nitromethane's oxidizing qualities, it allows more oxygen molecules to be packed into the C.C., but the effective volume should remain the same. (??)