Rotax coolant and hose routing

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Rotax coolant and hose routing

Postby gkremers » Wed Apr 16, 2014 8:25 am

All,
Working on the 912ULS engine install and wanted to ask what coolant you are using and how it is performing. Seems like 50% of the guys I know are running Evans. The first plane I build had a 912UL, used regular coolant (Prestone Dex Cool) and never had an issue. The 912S generates more heat so wasn't sure if the Evans may be better. The Rotax manual says the regular coolant dissipates heat better than Evans but Evans has a higher boiling point.


The coolant hoses pass very close to the exhaust pipes just downstream from the radiator, I have about 1/2" to 5/8" of clearance. Jak mentioned that was pretty good but wanted to hear from the guys that have been flying for awhile. Any pics or comments are appreciated of how you routed the hoses and what standoffs or heat shields you put on the hose for protection.

Thanks
Gary
N325AB getting closer to inspection
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Re: Rotax coolant and hose routing

Postby Johnny C! » Wed Apr 16, 2014 12:39 pm

Gary,
I used some addtional pieces of aluminum
tubing & a couple of 90 degree bends from
a "molded" store bought piece of tubing
and crossed those hoses underneath of the
engine. I can't post images from work, so
I'll try to get some on this evening.

Later!

John
There are many things that happen really fast when you are
flying an airplane. There is no sense in rushing any of the others.

I would much rather be looking down at the runway, than up at it.

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Re: Rotax coolant and hose routing

Postby scubarider2 » Wed Apr 16, 2014 8:47 pm

That problem took me almost a year to finally figure out how to keep the hoses from getting too hot and melting. I use Evans by the way. I use double wrap piece of tube and tie it on with a couple zip ties. Then use a metal shield between them and the exhaust. You can pick those up at any motorcycle place. All good and no problems since doing this. :wink:
Dennis
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Re: Rotax coolant and hose routing

Postby User GDS » Thu Apr 17, 2014 10:03 am

Hoses on my installation are about 1" from exhaust, no problems so far. I used Adel Clamps to hold the larger hoses in place where they pass close to the exhaust, I didn't want them to move around. I am having trouble using Picasa where my photos are, but if you go to Picasa, search for "Steube Highlander" you'll find my pictures, I know I have one of the coolant routing. I also remember replacing one of the smaller hoses on each side, the Rotax supplied hoses were a little short and I didn't like how they were stretched across the motor mounts.

I use the Dex, never tried the Evans. It runs cool and stays clean.
GDS
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Re: Rotax coolant and hose routing

Postby User GDS » Fri Apr 18, 2014 9:43 pm

Found the photo I was looking for:

The cushioned clamp is fastened under the locknut on the bottom of the motor mount.
Image

The smaller hose is the one that I lengthened to clear that rear bolt on the motor mount.
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Re: Rotax coolant and hose routing

Postby BRS » Wed Apr 23, 2014 10:54 am

I have a turbo-912 in my highlander and yes the hoses on cyl 1/3 are close. When I got the plane the hoses had been wrapped in a heat blanket (foil backed fiberglass mat) which worked. But recently I installed forged pistons which meant disturbing all the hoses. When I put it back together I wrapped the exhaust pipes with 1" header tape from summit racing. Much cleaner than wrapping the hoses. Works well.

Coolant. I'm currently using a mixture of about 15% antifreeze/water and a few oz of 'WaterWetter'. Just went to this mix recently. I don't see much difference (in the Rotax) as it was cooling just fine before, though I do have some comparative results on my gyroplane. Here is what I learned.

Gyro coolant. My gyroplane runs a Subaru EJ22 engine and I cruise at 4700 rpm. I was using a 50/50 mix and the temps were running 190 to 220 (coolant) and 230 (oil). I decided to try EVANS (just out of curiosity) and found that the Evans ran at about the same temps but my oil temps went up 15˚ so I installed an oil cooler. This year I tried the 15% antifreeze mix and WaterWetter and was pleasantly surprised. Now my coolant runs at about 160˚ (Cruise and OAT 55˚) and the oil 190-200˚ (with the oil cooler removed). This is much improved. BTW the thermostat is opens at about 179˚ but has a 3/8" bypass so most of the time (now) the thermostat is closed.

All this to say, I have some Evans coolant here you are welcome to come get (Vancouver WA area). BTW - keep in mind on the Rotax the coolant does not cool the oil as it does on a automotive engine since only the heads are water cooled.
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Re: Rotax coolant and hose routing

Postby SheepdogRD » Wed Apr 23, 2014 11:16 am

BRS wrote:I wrapped the exhaust pipes with 1" header tape from summit racing. Much cleaner than wrapping the hoses. Works well.

That's good to know. Summit carries a wide variety of tapes -- fiberglass composite, woven ceramic, copper coated, silica filament, etc. Which did you use?
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Re: Rotax coolant and hose routing

Postby BRS » Wed Apr 23, 2014 11:31 am

SheepdogRD wrote:That's good to know. Summit carries a wide variety of tapes -- fiberglass composite, woven ceramic, copper coated, silica filament, etc. Which did you use?



After some thought, I realize that the 1" I used was actually from NAPA that I picked up at the local store. I think it's made of fiberglass. You soak it in water to make it supple then wrap it using SS ties to hold it on. I also have some 2" that I got from Summit but I've not used it. The 2" might be easier to work with. I'll try to remember to take a picture or two next time the cowl is off.
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Re: Rotax coolant and hose routing

Postby gkremers » Wed Apr 23, 2014 5:54 pm

Thanks to all for your comments. I'm working though the final stages of routing the lines and should at least 1.5" of clearance.

I'm also installing the oil thermostat and have the routing complete. I used an invisible hinge for the oil door and it complicated the routing slightly as the "invisible" portion of the hinge interfered with the 90 degree fitting on the oil tank.

Thanks again,
Gary
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Re: Rotax coolant and hose routing

Postby accent air » Thu Apr 24, 2014 9:07 am

Johnny is your plane the one at the factory I think I have some good pictures of it its been there a while I think r you selling it or having it repaired
Kris Griewahn
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Re: Rotax coolant and hose routing

Postby Johnny C! » Tue May 06, 2014 12:44 pm

accent air wrote:Johnny is your plane the one at the factory I think I have some good pictures of it its been there a while I think r you selling it or having it repaired


Yes. It's the one with several years
of dust on it.

It's not for sale.

I'm trying to get my paper work
in to to get my inspection done.

Thanks!

John
There are many things that happen really fast when you are
flying an airplane. There is no sense in rushing any of the others.

I would much rather be looking down at the runway, than up at it.

Duane Sorenson & Rick Norton Gone West 6/8/09. Godspeed
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