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Freezing cold hard to start CTSW


procharger

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Its been cold for the last couple of weeks. around 5 to 10 degrees, tried to start CT last Sat. with no luck been keeping

light in cowl but it was burnt out, tried it anyway it tried to start about time battery starting to go so I stopped trying. Any tips

for starting in very cold weather? Motor was turning a little slow because of the cold battery is good.

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Its been cold for the last couple of weeks. around 5 to 10 degrees, tried to start CT last Sat. with no luck been keeping

light in cowl but it was burnt out, tried it anyway it tried to start about time battery starting to go so I stopped trying. Any tips

for starting in very cold weather? Motor was turning a little slow because of the cold battery is good.

 

5f and 10f is too cold to start a Rotax engine.  you need to put a crankcase heater on your engine to get the oil warm and get the engine block to expand.  take a look at this video:   http://www.rotax-owner.com/en/all-videos/product-reviews/149-tanis

 

If the battery is good and the engine turns slowly, you are probably not getting enough lubrication and the tolerances have been made too tight for smooth turnover.

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I use a 1200W hair dryer with  3" aluminum dryer venting inserted into the round air intake on the front of the cowling.  Nice fit, easy to blow warm air over the block and cylinder heads,  and even at about -10C the whole engine compartment warms to 10-20C nicely in about a half an hour or so, while completing preflight chores.

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I use a 1200W hair dryer with  3" aluminum dryer venting inserted into the round air intake on the front of the cowling.  Nice fit, easy to blow warm air over the block and cylinder heads,  and even at about -10C the whole engine compartment warms to 10-20C nicely in about a half an hour or so, while completing preflight chores.

 

I do the same, but wedge the dryer at the opening at the bottom of the cowling, so the warm air can rise up through the whole compartment.  As you say , in 45-60min you can open the oil door and feel the whole engine space is pretty warm.  Here in Georgia that is probably enough.

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If the battery is good and the engine turns slowly, you are probably not getting enough lubrication and the tolerances have been made too tight for smooth turnover.

 

Clearances. Tolerance is the deviation from a dimension. To have "tight tolerances" means the part needs to be machined very precisely.

 

The rest is good though!

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I do the same as Andy..but with  'hot gun'  .

 

for the cabin.. open cabin heat and blow warm air through the air intake (below the rad)

 

I start warming the engine when it's +5°C  [ 40°F ]  or below

 

..............save that sprag clutch..............

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since ..cold start = kickback  (if not warmed enough) 

and...kickback = sprag clucth damage

and  sprag clutch damage = painfull work $$

 

here is a video found on Utube that explain the thing

 

https://www.youtube.com/watch?v=tmmCm8KAdM0

 

and another video showing the kickback  (twice)

 

https://www.flickr.com/photos/djipibi/15878120213/in/photostream/

 

that last video was shoot 2 weeks ago ,at 0°F (after a too short pre heating)

 

the video is a courtesy of JP Bonin...you can watch his other pictures on flicker,  they will give you an idea of our winter flying activity around here

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I do the same as Andy..but with  'hot gun'  .

 

for the cabin.. open cabin heat and blow warm air through the air intake (below the rad)

 

I start warming the engine when it's +5°C  [ 40°F ]  or below

 

..............save that sprag clutch..............

 

I do both, actually.  I have a heat gun with some tubing attached that blows very warm air.  If it's 30°F or below, I'll use that to make very warm air and the dryer to push the air around.  If it's in the 40s I will just use the hair dryer.

 

I have wondered...could one put the heat gun on the exhaust pipe, blowing warm air "backwards" up into the engine?  Getting that really warm air inside the engine seems ideal, but it also seems like you could do some damage by putting even small amounts of positive pressure into the engine that way.  I have never done it, but was wondering if it might work.

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BTW, in spite of installing new ROTAX "Soft Start Modules" a while back, my last couple of cold starts have kicked back a few times pretty hard. Cold temps but closer to 40º F than 30º F.

 

Enough so that I really want to check and make sure the wiring to the starter relay is intact.

 

Battery certainly seemed adequate, though cold temps and lithium iron batteries don't seem to go well together. I've heard that as they heat up, even from starting attempts, they become markedly more efficient.

 

One issue with the Sky Arrow is the cable run from the battery is probably close to 8 feet, and that can't help.

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Andy - regarding heat into the exahust - those cylinders with a closed exhaust valve would get no heat.  Those cylinders with an open exhaust value would get no circulation of warm air if the corresponding intake valve was closed.  You would get flow only if both, the exhaust and intake valves were open, which may not even occur, depending on the grind of the cam.  If it did occur, it would be by luck, since such overlap would occur for only a few degrees of crankshaft rotation.  And, If it did occur, you would push air backwards through the carbs to exit the engine. 

 

Also, the approach would not get heat in direct contact with the crankshaft nor with most of the engine oil, which is kept (as you know) mostly outside of the engine (dry sump). 

 

Overall, I would not expect that approach to be effective.

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Andy - regarding heat into the exahust - those cylinders with a closed exhaust valve would get no heat.  Those cylinders with an open exhaust value would get no circulation of warm air if the corresponding intake valve was closed.  You would get flow only if both, the exhaust and intake valves were open, which may not even occur, depending on the grind of the cam.  If it did occur, it would be by luck, since such overlap would occur for only a few degrees of crankshaft rotation.  And, If it did occur, you would push air backwards through the carbs to exit the engine. 

 

Also, the approach would not get heat in direct contact with the crankshaft nor with most of the engine oil, which is kept (as you know) mostly outside of the engine (dry sump). 

 

Overall, I would not expect that approach to be effective.

 

That's pretty much what I thought, but air is a much worse heat conductor than metal, so I wonder if the parts of the engine that do get warm air might conduct that heat to other parts of the engine better than through warm air around the engine.

 

Just an academic question really, what I'm doing works fine.

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Good morning,

 

I purchased and installed the Reiff 912 heating system for my aircraft and been very happy with the results. There are a few different wattages that can be purchased.

 

For my winter climate, northeast PA, the 150 watt unit is sufficient. It comes with a 100w block heater and a 50w thermo controled oil tank band that wraps around the oil tank. Suggested time in really cold wx is approx 3-5 hours and can be controlled by your cell phone for about $3.00 per month. I just ask the mechanic or airport opperator to plug me in the night before I plan to fly.

 

The cost for the 150w unit is $189.00. Installation time is approx 1.5 hours. Cure time is approx 24 hours for a solid bond.

 

I think it's worth a look. Just Google Reiff aircraft heaters and scroll down to the 912 link.

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One might see if a heavier cable could be installed.

It's a good thought, but the engine spins with a lot of "authority" with a fully charged battery.

 

My guess is they considered the run of the cable in determining its length.

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Good Morning,

 

I agree with Rich.  I installed a Reiff preheater while living in Minnesota but still use it here in Arizona.  Being cheap, I want that engine to last darned near forever.  Personally, I preheat at 40 degrees and below.  Plus, the oil temperature rises much more quickly to 122 degrees.

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since ..cold start = kickback  (if not warmed enough) 

and...kickback = sprag clucth damage

and  sprag clutch damage = painfull work $$

 

here is a video found on Utube that explain the thing

 

https://www.youtube.com/watch?v=tmmCm8KAdM0

 

and another video showing the kickback  (twice)

 

https://www.flickr.com/photos/djipibi/15878120213/in/photostream/

 

that last video was shoot 2 weeks ago ,at 0°F (after a too short pre heating)

 

the video is a courtesy of JP Bonin...you can watch his other pictures on flicker,  they will give you an idea of our winter flying activity around here

Hi Jaques - thanks for the post.

 

The first video is not entirely accurate, I think.  

 

He says that the sprag clutch will be damaged after kicking back 'only a few times', but I've seen engines that have kicked back a lot more than a few times without any damage to the sprag.

(Over here we avoid kick back by switching off the mags and then spinning the engine over two or three times. While it's still spinning, switch on the mags and it'll start without kicking back.  (This may not work at some of the sub-zero temps mentioned.)

 

Second question about the video: I can't figure out how a damaged sprag could contribute to kickback.  Surely it's only a very slow engine rotation (by the starter motor) that could cause a kick back - ?

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Kickback cause sprag clutch problems. When the spring dogs engage they are held firmly in place during a normal start until the engine rpm passes the starter rpm and then it dis-engages. During kickback the spring and dogs associated with it are forced backward in an un-natural state. This causes the spring to stretch. This can happen a few times, but eventually the spring gets so stretched it will not engage normally any longer. Then the engine has to come out and the back part removed to install a new sprag clutch spring. You don't want to go there. If you have kickback find out what it is immediately and correct it.

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If the sprag gets damaged (stretched out spring) the starter will not engage.

There are a number of things that contribute to kickback. It is usually caused by a bad battery, cold weather, bad gearbox maint. (belleville washers need replacement), bad carb sync and or bad starting procedures between throttle and choke use. If you start to have kickback get it fixed right away. You don't want to have to replace the sprag.

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I'll confirm the sprag replacement PITA, but on the bright side my starts got all the better for it.

In addition to replacing the sprag, a new flywheel  (with different timing) was put in for those harder start cold days.  Sorry I can't remember the details.

 

Coupled with the soft start module, and the dryer blower, cold starts haven't a problem at all since.

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