Hi,

I am in Mongolia and the weather now averages -10 C to -40C. I took my Hyper 7 out the other day (-12 Celsius or about 10 Fahrenheit). I’ve taken necessary precaution - tuning it rich and putting aluminium foil over the head to keep the engine temperature maintained at a minimum of 70 Celsius (160 Fahrenheit). The engine was running fine but the problem occurred after about 5 minutes when the clutch did not want to disengage. The engine revved fine but the car was not moving. Has anyone else experienced this problem in cold weather? Any suggestions or advice would be much appreciated. Thanks.

thats just to cold brrr

Damn! That's freezing cold.

Check your clutch springs... could be they were old and the cold just did them in. That isn't too cold to run as long as you take proper precautions... Preheating your engine is a good idea to prevent more wear on the piston and sleve than necessary. But you should be fine in the cold check out this race..... [link=http://www.rbproducts.com/mainEn.php?part=Events&page=results2006/tempo/January%208_Russia%20round%201%20off%20road.htm]winter race[/link]

You said "wont disengage"which means the car wont stand still, "car wont move" means the clutch wont engage car wont move.
Please could you clear this up as it will affect the advice given thanx

clutch spring problem is most likely your problem. i always drive in the cold/ snow anyways and the only big thing to me is that it is easier to break parts(plastic)

160F?!! Needs to be in the 220's at least. Or is it beacause its rich? Ohh i get it now.

Annie 220 is a little high for minimum temp for these big blocks. 190 to 200F is good but no lower otherwise your wearing out your engine pretty quick.

NitroK I think you have a drive tran problem not an engine problem. Check over your diffs, drive shafts, and clutch carefully. If you don't find anything wrong then I don't know what else it could be.

I know of racers that run their engines up to 270F and race like that all season. Ive even heard of a race when a guy tuned his engine to the 300's. I don't see whats wrong with it, its been ton tons of times and all the racers do it.

Yeah a safe temp is 270 but I wouldn't go higher (it also depends on the materials that the sleeve is made of so some engines could do great at that temp and last a long time). When you get up to about 300 degrees the sleeve expands and just doesn't quite shrink all the way back like it normally would after it cools making your engine lose compression sooner. Try to take the sleeve out of a worn out engine that ran at 270+ degrees for its life... its going to be very tough because the sleeve expanded against the engine block and stayed that way... when you overheat an engine so many times you just lose more and more compression. If an engine runs cold the sleeve wears out because material is taken away from it because of the friction of a cold, tight sleeve. Thats why you should run your engine anywhere between 190F to 270F and no higher or lower.

big mis conception to cold weather is to think you need to fatten in cold wheather ...in reality you often need to lean...i race here in michigan and on cold days under 20f i need to lean my motor to raise the engine temp....dont think of it as conventional 2 stroke ....ambient air temp is everything th e colder it is the fatter your motor will run

I agree with you motopro , then engine is already going to be rich with the cold weather . Definatly would need to lean it out to keep it at running temps.

I know what you are saying but the air is thinner at 20F so you need to richen the mixture to compensate for the amount of air you will need. And wrap the head in foil.

and how cold does it get in LA ...im guessing not very.......trust me ...here in michigan today it hit 45 degrees the forcarst for sunday(race day) is 20 degrees....i live this kinda change everyweek...air thickness doesent have that much to do with it....running temp is the mmost important....anything under 200 degrees your just wearing out the engine,,,,you need to get it above 200 and to raise temp you need to lean.....

we race indoors in the winter here and it is very cold inside for about half the day then with the use of a heater the temp will increase by 10-20 degrees in the afternoon often resulting in re- tuning before the 3rd round of qualifying....

oh yeah

to the thread starter nitro k ...it sounds like a clutch problem probably a spring or the flywheel nut loosened up a bit....probably has nothing to do with cold weather.....the clutch dont care how cold it gets

Thanks. I will take it apart this weekend and a have look at the clutch spring. Expecting a low of -43 Celsius this weekend, don't think there will be any bashing even if I fix the problem.

WEATHER CONDITIONS

It’s a simple fact: for optimum performance, you must retune your nitro engine every time you run it. Anyone who assumes that the needles can be left alone once they have been set is sadly mistaken. An overnight change in weather conditions may prevent an engine from running or may put it at risk of some damage if adjustments aren’t made to the fuel-mixture settings. Ignoring an engine’s tuning needs compromises its ability to make horsepower. In response to certain changes in weather, equipment and other variables, nitro engines must be regularly retuned.

Temperature. Hot weather requires a leaner mixture setting; cold weather requires a richer setting. Most people assume the opposite because they treat the mixture needle like a thermostat. It is wrong to assume that colder weather requires a leaner setting to keep heat in the engine and vice versa. Cold air is denser than hot air. The denser, colder air packs more oxygen into the engine, so going from hot weather to cold needs a commensurate increase of fuel to balance ratio of fuel-burning oxygen and the fuel itself. The opposite is true in hotter weather. Going from cold to hot weather requires a leaner mixture setting.

Humidity. Humidity is the amount of moisture (water vapor) in the air. Moisture in the air takes up volume that would otherwise be occupied by fuel-burning oxygen. Less oxygen means less fuel is required to maintain a proper ratio of air and fuel. High humidity requires a leaner mixture setting than dry conditions.

Barometric pressure. A barometer measures the atmospheric pressure (generally listed in the local newspaper or on the local weather forecast on TV). Higher barometric pressure readings mean more air is getting into the engine, requiring a richer mixture setting to balance the air/fuel ratio.

Altitude. Altitude is an important factor that most of us ignore, yet it affects the engine’s performance possibly more than any other element. The general formula for power loss with increases in altitude is 3 percent for every 1,000 feet above sea level. If you race in Colorado at 5,000 feet instead of in California at sea level, you can expect to lose about 15 percent of the engine’s potential power output, if the engine is tuned properly.
Air is thinner at higher altitudes, which means there’s less fuel-burning oxygen than at sea level. You might sense a common theme here: less air (oxygen) means less fuel to maintain the proper air/fuel ratio. So, running at higher altitudes requires a leaner mixture setting than running at sea level.
TUNING
This chart indicates the direction in which you should adjust the fuel mixture when faced with changing weather and other conditions. It assumes the engine is currently well tuned. You could face any combination of conditions listed in the chart; knowing which way to go with the mixture adjustments is half the battle.
Higher air temperature Lean
Lower air temperature Rich
Higher humidity Lean
Lower humidity Rich
Higher barometric pressure Rich
Lower barometric pressure Lean
Higher altitude Lean
Lower altitude Rich
Higher nitro content Rich
Lower nitro content Lean
Higher oil content Lean
Lower oil content Rich
Hotter glow plug Rich
Colder glow plug Lean

So many things wrong in this thread.

Air gets denser when it's cold and contains more oxygen. That means you can burn more fuel ---> richen up = more power.
Tuning by engine temp alone is wrong. Richen it up until it starts to 4-stroke down the straigh and then lean out until it runs clean. That's when it produces the most power. If it's still running cold you need to put a smaller cooling head on it and you will gain even more power. (Wrap it in foil could work too).

edit:
Forgot to add that the effect of high altitude can be somewhat compensated by adding more nitro, it contains oxygen. That's also the reason you need to richen up when running higher nitro.

ok guys....you do it your way if it works for you......but engine temp tells the most tale.....

are they fast i was thinking of getting 1

you will have the right answear posted atleast a 1000 times with the same anwear just noted differently lol nobody seems to agree with each other at all ,but puting it in different words hmm so basicall your answear will probobly be posted on the first page but you are going to thank the guy on page 9 lol so wait a little before you change that light bulb
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got this from another forum...still hilarious.
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Q: How many forum members does it take to change a lightbulb?

A: 1,368


1 to change the light bulb.

1 to post that the light bulb has been changed.

14 to share similar experiences of changing light bulbs and how the
light bulb could have been changed differently.

7 to caution about the dangers of changing light bulbs.

27 to point out spelling/grammar errors in posts about changing light
bulbs

53 to flame the spell checkers.

6 to argue over whether it's "lightbulb" or "light bulb".

Another 6 to condemn those 6 as anal-retentive.

2 industry professionals to inform the group that the proper term
is "lamp".

15 know-it-alls who claim they were in the industry, and that "light
bulb" is perfectly correct.

156 to email the participants' ISPs complaining that they are in
violation of their "acceptable use policy".

109 to post that this forum is not about light bulbs and to please
take this discussion to a lightbulb forum.

203 to demand that cross posting to hardware forum, off-topic forum,
and lightbulb forum about changing light bulbs be stopped.

111 to defend the posting to this forum saying that we all use light
bulbs and therefore the posts are relevant to this forum.

306 to debate which method of changing light bulbs is superior, where
to buy the best light bulbs, what brand of light bulbs work best for
this technique and what brands are faulty.

27 to post URL's where one can see examples of different light bulbs.

14 to post that the URL's were posted incorrectly and then post the
corrected URL's.

3 to post about links they found from the URL's that are relevant to
this group which makes light bulbs relevant to this group.

33 to link all posts to date, quote them in their entirety including
all headers and signatures, and add "Me too".

6 that flame them for not using the Search feature.

12 to post to the group that they will no longer post because they
cannot handle the light bulb controversy.

19 to quote the "Me too's" to say "Me three".

4 to suggest that posters request the light bulb FAQ.

44 to ask what is a "FAQ".

4 to say "didn't we go through this already a short time ago?"

143 to say "do a Google search on light bulbs before posting questions
about light bulbs".

16 posts of two forum members that are exclusively talking to each
other only about lightbulbs and what they did that weekend.

24 posts of telling them to take it to PM's.

1 moderator that comes in and says something about doing it wrong and
that everyone who disagrees gets a warning.

1 new forum member to respond to the original post 6 months from now
and start it all over again.

this is exactly how rcu is lol

mgtman - Do you by any chance frequent ATOT or /.

what the hell is that ?never heard of it so i would say no unless that means something else [8D]

Anandtech Off Topic forum or Slash-dot forums.
Never mind.

how was i of topic actually he got his anweear allready but its been reapeted a couple time thats why i posted that to compare it to the light bulb lol and you fell for what that joke meant exactly and responded lol actually i guess its a normal reaction but please restrain yourself to take it any farther or ill be forced to unleash myself thank you ,mr typical anyway its all cool [>:]