Today's Message Index:
----------------------
1. 11:29 AM - Re: Thermostat question (Gilles.Thesee)
2. 11:49 AM - Re: Thermostat question (Archie)
3. 02:47 PM - Re: Thermostat question (Gilles.Thesee)
4. 05:36 PM - Re: Thermostat question (Archie)
5. 08:18 PM - Starter ring drive ratios (Jeff Orear)
Message 1
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| Subject: | Re: Thermostat question |
--> Engines-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
Ed,
Thank you for your answer. The Rotax has no thermostat, but our setup gives
too much water cooling, while cooling the oil just about right.
Our goal is to reduce water cooling without upsetting the airflow inside the
cowling.
Thanks a lot,
Gilles
> --> Engines-List message posted by: "Ed Anderson"
<eanderson@carolina.rr.com>
>
> Gilles,
>
> Not familair with the Rotax, but the Mazda Rotary engine has such a
> thermostat. When its closed there is a 1/2" hole in the water
> pump/thermostat housing that permits water to circulate back to the
engine.
> When the thermostat opens a plunger also extends and plugs the 1/2" hole
> shutting off the recirculation and forcing all the water through the
> radiators.
>
> Thats all I have.
>
> Ed Anderson
> RV-6A N494BW Rotary Powered
> Matthews, NC
> eanderson@carolina.rr.com
> ----- Original Message -----
> From: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
> To: <engines-list@matronics.com>
> Subject: Engines-List: Thermostat question
>
>
> > --> Engines-List message posted by: "Gilles.Thesee"
> <Gilles.Thesee@ac-grenoble.fr>
> >
> >
> > Hi all,
> >
> > Our project is powered by a Rotax 914.
> > Does anyone around have information about "dual acting thermostats"?
> > That is a thermostat that opens and closes a bypass passage in addition
to
> > the normal operation.
> >
> > The goal is to provide a means of stabilizing water temperature without
> > unduly loading the water pump or restricting the coolant flow inside the
> > cylinder heads.
> >
> > Any input appreciated,
> > Thanks
> >
> > Gilles
> > Grenoble, France
> >
> >
>
>
Message 2
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| Subject: | Re: Thermostat question |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
> Thank you for your answer. The Rotax has no thermostat, but our setup
gives
> too much water cooling, while cooling the oil just about right.
> Our goal is to reduce water cooling without upsetting the airflow inside
the
> cowling.
>
> Thanks a lot,
>
> Gilles
If that does not work well for you, Gilles,
We occasionally have similar instances with our race engines,
and reduce the speed of the water pump with a larger pulley.
If it needs more beyond that, the simple inexpensive cure
is a restrictor plate in place of a thermostat.
Just a flat plate with a hole in it.
(hole size may require experimentation)
Archie's Racing Service
Message 3
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| Subject: | Re: Thermostat question |
--> Engines-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
----- Message d'origine -----
De : "Archie" <archie97@earthlink.net>
: <engines-list@matronics.com>
Envoy : dimanche 16 novembre 2003 20:49
Objet : Re: Engines-List: Thermostat question
> --> Engines-List message posted by: "Archie" <archie97@earthlink.net>
>
> > Thank you for your answer. The Rotax has no thermostat, but our setup
> gives
> > too much water cooling, while cooling the oil just about right.
> > Our goal is to reduce water cooling without upsetting the airflow inside
> the
> > cowling.
> >
> > Thanks a lot,
> >
> > Gilles
>
> If that does not work well for you, Gilles,
> We occasionally have similar instances with our race engines,
> and reduce the speed of the water pump with a larger pulley.
> If it needs more beyond that, the simple inexpensive cure
> is a restrictor plate in place of a thermostat.
> Just a flat plate with a hole in it.
> (hole size may require experimentation)
> Archie's Racing Service
>
Archie,
Thanks for your message. Your racing experience may prove invaluable.
The Rotax is a very small yet proven engine. The water pump is integral
with the engine and is driven by the camshaft.
I was concerned that a restrictor might impose too much back pressure on the
pump. A friend of mine installed a thermostat on his engine, but is
experiencing coolant leaks and water pump trouble. My opinion is this could
be related to the thermostat blocking the coolant circulation and causing
the seals to fail.
Hence the idea of retaining the thermostat, but having a bypass loop to keep
the coolant circulating and limiting the back pressure at the pump.
The idea is to provide as friendly an environment as possible, while making
as little changes as practical inside the engine.
For those interesting in learning more about the model we're building, have
a peek at
http://www.avnet.co.uk/lts/pages/mcr4s.htm
Thanks again,
Regards
Gilles
Message 4
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| Subject: | Re: Thermostat question |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
Hence the idea of retaining the thermostat, but having a bypass loop to
keep
the coolant circulating and limiting the back pressure at the pump.
-----------------
In that case, a bypass loop with an inline adjustable control valve
will give you additional options to control feedback.
This is essentially similar to the fuel system design on the larger
racing engines.(2 to 6000 hp)
Archie
Message 5
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| Subject: | Starter ring drive ratios |
--> Engines-List message posted by: "Jeff Orear" <jorear@new.rr.com>
list:
What does it mean for a starter ring/flywheel assembly to have a 1.91:1 drive or
a 3.25:1 drive?
I am trying to determine if an assembly I have will work with my O320 E2D. I understand
the pitch of the teeth on the drive, either 10/12 or 12/14 as well as
the number of teeth on the ring gear determines what starter will work, as well
as what compression ratio the particular engine has. Mine being a low compression
engine, it would need the 122 tooth ring.
Does the drive ratio have something to do with the pulley size on the alternator?
I have looked at specifications for alternators and can find no reference
to such drive ratios. Does this drive ratio just determine the size of the alternator
belt? I note in a parts catalog that the E2D calls out for a starter/flywheel
that has teeth with a 12/14 pitch and a 1.91:1 drive. If I get a new
lightweight starter, it seems reasonable to be able to specify a 10/12 pitch
which the assembly I have has, but I am not sure if the 3.25:1 drive will work
with my engine.
Any clarification would be most helpful.
Regards,
Jeff Orear
RV6A
canopy, about to hang engine
Peshtigo, WI
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