Thanks to Murry, it seems a whole new set of cool possibilities
 hasarisen for warming up our Wankels.

It's been a long time since I worked on diesel trucks, so I was'nt
aware
of Evans coolants. I just read through a couple long threads on
 an RXforum debating the issue. For more than a year now I have
 read thisforum and have not heard of this stuff. If it's true the
 pressureremains low, or even zero, then we should be chasing this
 one down in ahurry. I have used water wetter for a long time in
 my porsches and MXbikes. According to what I have read so far, I
 would have saved myself,and a lot of other people, many headaches
 by using Evans coolantproducts.

So what is it? Are the diesel guys wrong, and are the few RX
enthusiasts
similarly deluded, by promoting Evans products? Obviously, there
 are alot of advantages in using a coolant that does not vaporize
 within thepassages at or near zero psi; and what sort of pressure
 will we see ifwe use it in our pressurized systems? If it does'nt
 vaporize, orvaporizes very little, then we have a winner don't we?

The stuff's not that expensive. Who wants to be the first to try?

Search for Evans NPG+, on ebay.

Anyone have a good set of specs on this stuff?

Ed Carver

I know people have used it but someone mentioned the heat transfer
coefficient between coolant and metal is lower than ethylene
 glycol.
Evans coolant is mostly propylene glycol.
In order to properly test it one must have a "cylinder" head temp
sensor.

Paul Lamar

We had many long discussions about it a few years back.  I have
 tried
it.  I was using it when I lost all my coolant and landed on a
 road in  2006.  You cannot run zero PSI.  All of mine squirted out
 past a 7 PSI  cap and that is why I landed on the road.  It is used
 in diesel engines  to raise the temp without boiling the coolant.
 But we don't need or  want our temps as high as the boiling temp of
 regular 50/50 coolant.  At  a given temperature, Evans will not
 remove the heat as well as regular  coolant.

No benefit to our application.

--
David Leonard

I guess that means the stuff expanded when it got hot and that was
 the  end of it. I was wondering about that while reading on the RX
 forums as  some of the guys ran it at zero psi and never had a leak.
 Some of them  used 13psi caps, I guess it just expanded and went
 into the catch can to  be drawn back when it cooled off. I'll sort
 out the expansion issue.

It appears a radiator size increase is required in many
 applications,  cars or trucks.

Seems to me a big advantage to Evans would be the coolant would
 not boil  around the spark plugs.

Ed Carver

-- -----------------------------------------

Dave nailed it on the head. To summarize:

1. The heat transfer from metal surfaces to the coolant is not as
 good as a  Eth-Glycol  coolant. This is because of three factors,
 lower heat capacity,  higher viscosity, and lower thermal
 conductivity (all moved in the wrong  direction)
 a. In terms of heat transfer 'goodness' , water  50-50 Eth
 glycol  Evans coolant.
 b. To compensate for the poorer thermal transfer properties of
 the Evans  coolant, a system has to either run hotter (greater delta-
 T) or have  increased heat transfer area (bigger radiators)
 c. The viscosity of the Evans coolant at low temperatures is
 pretty
high, and the pump may not circulate it adequately until it is
 warmed up.  Could be a problem in the winter, and may have affected
 Dave Leonards  incident.

2. The 'advantage' of Evans coolant is the lower vapor pressure
 when at  operating temperature.

3. If I recall, Dave's incident happened after he switched from a
 water mix  to Evans, then flew to Mammoth and it cold soaked
 overnight before taking  off.  IF he didn't get ALL the water out of
 the system, and the high  viscosity of the coolant kept circulation
 through the heat exchangers slow,  THEN the temperature in the
 engine could rise to where the residual water  would generate
 pressure, flash to steam, and blow the coolant out of the  system,
 even though the temps in the rads was low.

4. Diesel trucks like Evans coolant, but they can run at an
 elevated  temperature, whereas with the rotary we are limited
 because of the O-rings.

I have a whole presentation that Evans Coolant made to Argonne
 National
Laboratory  a number of years ago that shows the need for
 increased coolant  temperature, etc. Looking at those charts made it
 clear to me that it was  NOT appropriate for aircraft use with a
 Rotary engine.

Bill Schertz
KIS Cruiser #4045
N343BS
Phase one testing Completed

 Paul,

 Whats the best stuff to use to flush the coolant system? I've heard
 of CLR, TSP
 (tried both), that stuff u can get @ auto part stores in the lil
 yellow jugs, vinegar...and a 2-part system that is no longer
 available, but apparently worked really well (go figure).

 I'm lookn for something that would be strong enough to flush the
 crude out of the heater core too..

 Thanks -Dan

If you have a very dirty system, a few oz's of muriactic acid mixed to
 dilute and then top up cooling system.  Run for about 15 minutes.
 Drain
 and flush with water from the garden hose.  Pull the small hose,
the cooler
 one, return to the engine and back flush the heater core.  If you can
 remove the pipe plugs from the block to fully drain it is good.  Refill
 with new coolant and distilled water.  Distilled does not have the
minerals
 in it that drop out and plug the cooling system.  A pressure test
is a good
 idea to find out if you have any corroded welch plugs with pin holes in
 them.

 Dale Davies

Engines are designed to run hotter today than they did in the days
before emissions raised their ugly collective heads.
jd



Be very careful with muriatic acid, It will eat right through aluminum.
It is used to clean up cast cylinders after sticking 2 cycle pistons.
It takes the aluminum residue off the walls, but left too long will
start to dissolve everything.

Randy