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Rick Lewis

Joined: 03 Jul 2007
Posts: 122
Location: Kingston, Tn.

Posted: Tue Dec 15, 2009 3:41 pm Post subject: Rotax 912 Question

I need to know if the Rotax 912 has a thermostat in the water system.  I'm thinking I will need one in my water cooled VW installation.  I have found on line someone who sells an inline thermostat housing.  It's a little pricey so I may build what I need myself.  

Rick Lewis



( Water Cooled VW )

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Tue Dec 15, 2009 4:36 pm Post subject: Rotax 912 Question

> I need to know if the Rotax 912 has a thermostat in the water system. 

I'm thinking I will need one in my water cooled VW installation.  I have 

found on line someone who sells an inline thermostat housing.  It's a little 

pricey so I may build what I need myself.

 	  Quote: 	
		  



 Rick Lewis


	




Rick L/Gang:



Very difficult to use a thermostat on the cooling system because the water 

pump has 4 outlets, one for each cylinder head.



To design a thermostat system for the 912 would require 4 thermostats.  That 

is too busy for me.  I want to keep everything as simple as possible.



We fabricated an inline thermostat housing, aluminum billet, for my 912 

because it was very difficult to keep the CHT up to around 180F.  The engine 

performs much better at 180F and higher, if you can get it there during cold 

weather.  The thermostat was installed in the 1" return line to the single 

water pump inlet.  It worked ok, with the exception of blowing coolant out 

of the coolant header tank.  Was not the right system.  We used a thermostat 

for a 350 Chevy.  If we had had three more to install on all four coolant 

outlet hoses, it would have worked fine.



To get around the low temp problem, in the winter months, with the 912UL 

engine, which normally runs much cooler than the 912ULS, I bypassed the 

engine oil cooler.  That exercise required swapping two hoses.  Kept the CHT 

and engine oil temps up where they belonged.  The 912 has to reach at least 

190F engine oil temp in order to boil off condensation in the oil system.



Some folks have used an aftermarket engine oil thermostat, but that gets a 

little complicated and does not perform as expected.  I let others test that 

system.  I am not interested in experiementing with it.



To get the temps up on my current 912ULS, I tape a couple wraps of gaffers 

tape on each end of the coolant radiator.  This will bring the CHT and 

engine oil temps up to normal operating range.



john h

mkIII - Suffering from severe cabin fever.  Sun is supposed to shine 

tomorrow and Gantt International Airport will be operational.  I'm gonna fly 

a little.

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Rick Lewis

Joined: 03 Jul 2007
Posts: 122
Location: Kingston, Tn.

Posted: Tue Dec 15, 2009 4:57 pm Post subject: Re: Rotax 912 Question

Thanks John, this information helps.  I feel I will have to install some kind of thermostat in my system.  This can more easily be accomplished on this with only two thermostats installed.  



Thanks John

purplemoon99(at)bellsouth
Guest

Posted: Tue Dec 15, 2009 5:03 pm Post subject: Rotax 912 Question

Rick,goto info(at)ramengines.com (info(at)ramengines.com)  Ron has some BMW thermo.that will work inline in the main hose    Joe N101HD   

   From: Rick Lewis <cktman(at)hughes.net>

To: kolb-list(at)matronics.com

Sent: Tue, December 15, 2009 6:41:23 PM

Subject: Rotax 912 Question

--> Kolb-List message posted by: "Rick Lewis" <cktman(at)hughes.net (cktman(at)hughes.net)>

I need to know if the Rotax 912 has a thermostat in the water system.  I'm thinking I will need one in my water cooled VW installation.  I have found on line someone who sells an inline thermostat housing.  It's a little pricey so I may build what I need myself.  

Rick Lewis

( Water Cooled VW )

Read this topic online  here:

http://forums.matronics.com/viewtopic.php?p=277662#277662www.homebuilthelp.com

 [quote][b]

Rick Lewis

Joined: 03 Jul 2007
Posts: 122
Location: Kingston, Tn.

Posted: Tue Dec 15, 2009 5:13 pm Post subject: Re: Rotax 912 Question

The link you have posted do not take me anywhere except an e-mail page.  I would like to check this site out if you can send me a good link to go to.



Thanks



Rick Lewis

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Tue Dec 15, 2009 5:46 pm Post subject: Re: Rotax 912 Question

They have thermostats and they are set to 180F. It has one inlet and it goes where all the lines are a single line at the radiator. FD has been using them for 3 years.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Tue Dec 15, 2009 6:14 pm Post subject: Rotax 912 Question

> They have thermostats and they are set to 180F. It has one inlet and it 

goes where all the lines are a single line at the radiator. FD has been 

using them for 3 years.

 	  Quote: 	
		  

 --------

 Roger Lee


	




Roger L/Gang:



I placed my thermostat, on my original 912, before they were tagged as UL 

and ULS, between radiator outlet and waterpump inlet.   Had a serious 

problem blowing water out of the header tank cap because the water pump is 

overpressurizing the system when the thermostat is closed.  How much?  I 

don't know.  I did not have a coolant pressure gauge installed, but would be 

interesting to know how much pressure it was creating above pressure caused 

by increased coolant temp.  This may have also caused cavitation in the 

water pump.  Never could figure out how to solve the problem without putting 

thermostats between waterpump outlets and header tank.



How did FD (?) overcome this overpressurization problem?



BTW:  Who is FD?



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

jbhart(at)onlyinternet.ne
Guest

Posted: Wed Dec 16, 2009 4:48 am Post subject: Rotax 912 Question

At 08:13 PM 12/15/09 -0600, you wrote:

 	  Quote: 	
		  



Roger L/Gang:



I placed my thermostat, on my original 912, before they were tagged as UL 

and ULS, between radiator outlet and waterpump inlet.   Had a serious 

problem blowing water out of the header tank cap because the water pump is 

overpressurizing the system when the thermostat is closed.  How much?  I 

don't know. 


	


John,



One way around this problem is to drill or to enlarge the hole in the valve 

plate.  This lets enough water pass through the valve to prevent percolation 

with in the system while the engine is warming up and the valve opens enough 

to prevent the problem.



Jack B. Hart FF004

Winchester, IN

Rick Lewis

Joined: 03 Jul 2007
Posts: 122
Location: Kingston, Tn.

Posted: Wed Dec 16, 2009 5:04 am Post subject: Re: Rotax 912 Question

Joe



     Please send me a good link so I can check out the thermostats your talking about.  The link you sent me on this list only to take me to an e-mail page.



Thanks     Rick Lewis

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Dec 16, 2009 6:44 am Post subject: Rotax 912 Question

>     Please send me a good link so I can check out the thermostats your 

talking about.  The link you sent me on this list only to take me to an 

e-mail page.

 	  Quote: 	
		  

 Thanks     Rick Lewis


	


Rick L/Gang:



Try this url:



http://ramengines.com/



Go to the bottom of the menu on the left of the page.  Click on "for sale 

items".



The BMW thermostat is on the upper left of that page.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Dec 16, 2009 6:47 am Post subject: Rotax 912 Question

> One way around this problem is to drill or to enlarge the hole in the 

valve

 	  Quote: 	
		   plate.  This lets enough water pass through the valve to prevent 

 percolation

 with in the system while the engine is warming up and the valve opens 

 enough

 to prevent the problem.



 Jack B. Hart FF004


	




Jack H/Gang:



We experimented with enlarging the weep/bleed hole in the thermostat baffle. 

Results were poor.  Still got overpressure from the thermostat being in the 

least effective location, on the wrong side of the water pump.  If you go 

too large on the weep hole, you loose most of the thermostat's 

effectiveness.



Only way to get it to work on the 912 was install a thermostat on each of 

the outlet hoses between the water pump and the header tank.



A roll of gaffer's tape solved the problem, although not as professional as 

a thermostat, it took care of bringing up the CHT and engine oil temps.



Hope it warms up enough to fly this afternoon.  First day without rain in a 

week.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Wed Dec 16, 2009 6:54 am Post subject: Re: Rotax 912 Question

Here is a link to see one on a 912. You mount it on the left side before the radiator. No pressure problems. You can also use a Perma Cool oil thermostat for the oil. No modifications to the engine are required. Just an install for plumbing.



http://www.flightdesignusa.com/dbimages/big_thermo.jpg

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

by0ung(at)brigham.net
Guest

Posted: Wed Dec 16, 2009 7:53 am Post subject: Rotax 912 Question

I need to know if the Rotax 912 has a thermostat in the water system.  I'm thinking I will need one in my water cooled VW installation.  I have found on line someone who sells an inline thermostat housing.  It's a little pricey so I may build what I need myself.    

   

   

Rick Lewis  

 	  Quote: 	
		  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>   

   
	


When checking with the experts at LEAF  I was told that the 912 has no minimum water temp.  thus no thermostat.  I added a heater in my kolb for comfort in the winter, and to keep the coolent temps up in the winter I use some aluminum backed tape and reduce the cooling area.  I considered an inline thermostat between my takeoff for my heater and the inlet to the  main radiator,  but remembered the kiss principle.   That would be just one more thing to go wrong. With the thermostat closed I would still maintain flow through the heater core which is not valved.  The only min temp in the 912 is the oil temps.  

   

Boyd Young  

MkIII  

       [quote][b]

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Dec 16, 2009 8:00 am Post subject: Rotax 912 Question

 	  Quote: 	
		   Here is a link to see one on a 912. You mount it on the left side before 

 the radiator. No pressure problems. You can also use a Perma Cool oil 

 thermostat for the oil.



 http://www.flightdesignusa.com/dbimages/big_thermo.jpg

 Here are two pictures out of a manual.



 --------

 Roger Lee


	




Roger L/Gang:



Looks like this thermostat will require a new coolant radiator tank to 

accept the bypass circuit?  How much does Rotax want for the header tank 

with additional outlet?



Price of the BMW thermostat is reasonable, 18.95.



Had a couple Fiat Spyders that used the same thermostat bypass system.



The PDF files out of the manual for coolant and oil thermostats did not come 

through.  Pages won't open.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Vic Peters

Joined: 30 Oct 2009
Posts: 54
Location: Millinocket, Maine

Posted: Wed Dec 16, 2009 8:12 am Post subject: Rotax 912 Question

Boyd, Can you tell us more about your  heater?

 -3 wind chill in Maine.

 Vic

 912ul

   [quote][b]

_________________
Vic
912ul Xtra
Maine
Too old to cut the mustard but not the cheese.

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Dec 16, 2009 9:59 am Post subject: Rotax 912 Question

Boyd/Gang:

  

 The 912 runs a lot better if the temps are kept  up, at least 180F CHT.

  

 Back in 1994, on the way to Alaska, I started  having engine problems.  Plugs were telling me I was over-rich.  CHT  would barely get the needle off 120F.  In actuality, the 912 was running  very lean in midrange, plus the cold CHT was not vaporizing the fuel well enough  to get a good burn.  Gave me lots of problems until I learned how to fix  it, increase CHT and drop the fuel needles a notch.  I also bypassed the  oil cooler by changing two oil line connections.  Did that on the gravel  parking pad at Teslin Lake Airport, Yukon Territory.  Left it bypassed  until I eventually got back into warmer weather in the lower 48 some time  later.

  

 john h

 mkIII

  

  The only min temp in the 912 is the oil  temps.

 [quote]      

    

Boyd Young   

 

[b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

by0ung(at)brigham.net
Guest

Posted: Wed Dec 16, 2009 12:02 pm Post subject: Rotax 912 Question

John,  you are exactly right.    Rotax does not publish a minimum cylinder head temps,, but it does work much better when it gets properly warmed up.   My heater works better when it gets warmed up as well.  Instead of bypassing the oil cooler,  I just run tape over it,   between 20 and 40 deg outside temps, I put tape over the front,,, and below 20 I have to tape front and back.  The main radiator gets tape over ½ to 2/3   depending on the outside temps.  

   

Boyd Young MKIII  

   

 	  Quote: 	
		  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>   

   
	


Boyd/Gang:  

   

The 912 runs a lot better if the temps are kept up, at least 180F CHT.  

   

Back in 1994, on the way to Alaska, I started having engine problems.  Plugs were telling me I was over-rich.  CHT would barely get the needle off 120F.  In actuality, the 912 was running very lean in midrange, plus the cold CHT was not vaporizing the fuel well enough to get a good burn.  Gave me lots of problems until I learned how to fix it, increase CHT and drop the fuel needles a notch.  I also bypassed the oil cooler by changing two oil line connections.  Did that on the gravel parking pad at Teslin Lake Airport,  Yukon Territory.  Left it bypassed until I eventually got back into warmer weather in the lower 48 some time later.  

   

john h  

mkIII  

   

 The only min temp in the 912 is the oil temps.  

   

Boyd Young  

    	  Quote: 	
		   	
  

   

       [quote][b]

by0ung(at)brigham.net
Guest

Posted: Wed Dec 16, 2009 12:02 pm Post subject: Rotax 912 Question

Boyd, Can you tell us more about your heater?  

-3 wind chill in Maine.  

Vic  

912ul   	  Quote: 	
		   	
  

 	  Quote: 	
		  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>   

   
	


I don’t think I have any photos…   but I will try and get some next time I go out.  

   

In my radiator hoses just before the main radiator I cut in 2 tees  1”  X  5/8”.   Connected to the tees I routed some heater hose into the back area behind the fuel tank connected to a small heater core.   I built a copper wire frame around the heater core,  on one side I built it to fit a computer cooling fan,  on the other side I built an adapter to fit a 2” duct. I covered the frame work with poly fiber.  The duct runs to the front of the nose cone.  My attempt was to warm my feet and have the air pull all the way back through the cabin back to the heater.  There is not enough heat to drive you out but it will take the edge off.  On my first trip I took off with the outside temps around 20 deg F  and the temps were around 10 when I landed.   I thought it was not working till I opened the doors and the outside air rushed in.  it would probably work better if all the exterior  surfaces had some type of insulation.    I run the fan summer and winter.   In the summer it helps with the cooling of the engine, and I open up the area behind the doors to help with ventilation, and in winter I have to tape up the main radiator to keep the heat up.    

The tees and heater core I picked up at Napa auto parts.   I had to go through their heater core catalog to find one that looked like it would work.  ( both inlet and outlet had to point the same direction, it had to fit in the available  space,  and be light weight)   I soldered the copper frame work to the header tanks…  but you could get an aluminum core and build some aluminum housing,   you would have to come up with some type of resilient mounting system to keep from rubbing a hole through.   I  cant remember if the tees were in stock or they had to be ordered.  The heater core only took a few days to order.   A higher capacity fan would also help in the winter.  

   

Boyd Young  

MKIII  Utah  

       [quote][b]

slyck(at)frontiernet.net
Guest

Posted: Wed Dec 16, 2009 12:02 pm Post subject: Rotax 912 Question

I have an inline thermostat on my suzuki. It has to be pushed into a chunk of (large) radiator hose.

Carquest CTH31179

This was the recommended way to go from the conversion redrive supplier.

I had a problem initially as the volume capacity was too small.

Carquest evidently had two suppliers for this part and the one I got first wasn't up to the task.

I went back and bought another which turned out to have a larger opening which worked ok.

BB

On 16, Dec 2009, at 10:27 AM, John Hauck wrote:

 	  Quote: 	

> Here is a link to see one on a 912. You mount it on the left side before the radiator. No pressure problems. You can also use a Perma Cool oil thermostat for the oil.

> 

> http://www.flightdesignusa.com/dbimages/big_thermo.jpg

> 

> 

> Here are two pictures out of a manual.

> 

> --------

> Roger Lee

 Roger L/Gang:

 Looks like this thermostat will require a new coolant radiator tank to accept the bypass circuit?  How much does Rotax want for the header tank with additional outlet?

 Price of the BMW thermostat is reasonable, 18.95.

 Had a couple Fiat Spyders that used the same thermostat bypass system.

 The PDF files out of the manual for coolant and oil thermostats did not come through.  Pages won't open.

 john h

 mkIII

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Wed Dec 16, 2009 12:23 pm Post subject: Re: Rotax 912 Question

Hi John H,



I don't believe you need any different coolant tank. It is only a difference in plumbing. If there is anyone around you with a Flight Design CTLS you could stop by and take a look at theirs.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

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