Today's Message Index:
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1. 10:37 AM - Re: Re: overheating (Marco Menezes)
2. 11:05 AM - Re: overheating (mikeperkins)
3. 12:32 PM - Re: overheating (malpass)
4. 02:18 PM - (kitfoxmark .)
Message 1
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I respectfully disagree, Mike, that Rotax 2 strokes "don't tolerate mixture
changes."
There has been much written about seasonal adjustment of mid-range needles
on Bing carbs and mixture as it effects EGT's. See http://www.cps-parts.com
/cps/pdf/Part11.pdf=C2- as a jump-off point.=C2- I've done for years it
and it works as advertised. Granted, by itself it probably won't have a gr
eat effect on the coolant temps, but we're just throwing out ideas here. In
combination with some of the other suggestions made, it might be an elemen
t to be considered. A degree here, a couple there, and you're back in the g
reen arc.
Marco Menezes N99KXHersey, MI
Kitfox 2, 582-90, C-Box, GSC w/clutch
=C2-
From: mikeperkins <flybyewire@gmail.com>
To: kitfox-list@matronics.com
Sent: Tuesday, September 1, 2015 12:15 PM
Subject: Kitfox-List: Re: overheating
I routinely fly my 532 with a coolant temp of 180 and sometimes see 200-210
on a warm-day climb-out. That is no problem assuming you have the proper m
ix of coolant. Running 50/50 mix will provide a boiling point of 260 degree
s at sea level. (As you climb, the engine puts out less power, so the coola
nt requirements decrease, keeping the coolant temp about the same. I've bee
n at 10,000 feet on several occasions, and the coolant did not overflow the
overflow bottle and the temp stayed reasonable.
Also, coolant flowing into the overflow will reduce the volume of the coola
nt in the system, reducing the coolant pressure. The overflow should always
have some coolant in it, and after a long, high flight I often see 10-12 o
unces of coolant in it, which then returns to the cooling system an hour or
so after the flight.=C2-
It might be a good idea to determine if your coolant sensor and gauge are r
eading correctly by placing the sensor in a pot of boiling water.
You likely have a 140-degree thermostat. The thermostat just speeds up the
warming process, and also prevents the coolant temp from getting too low in
cold weather. Mine is a 140-degree thermostat, but the engine should not e
ven be run at full power at only 140 degrees. But with coolant temperatures
of 180-200 on a warm day, and as long as your coolant bottle is not overfl
owing, your aircraft should need no changes.
Whatever you do, don't change the mixture. 2-cycles are not like 4-cycle en
gines - they do not tolerate mixture changes. Also, renrichening the mixtur
e will change the engine's temperature so little that it won't be noticeabl
e. The engine should be fine with the factory setup. The prop pitch is used
to adjust EGTs, believe it or not. There's a great video on the EAA websit
e about 2-cycle mixture and prop pitch. It's called "Is your 2-cycle engine
about to fail?" Worth watching.
--------
Mike Perkins
Havana, Illinois
Model I, 532, B gearbox, GSC prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=446655#446655
S -
-
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
Message 2
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Hi Marco,
You're right - making mixture changes for getting the correct EGTs is quite acceptable.
I wrote what I did because over the years I've heard people suggest changing
the mixture for a quick-fix of various ailments. Yes, they do tolerate
mixture changes, but I believe those changes should be made only for the purpose
of bringing EGTs into spec.
What problem do you foresee with a coolant temp of 200 degrees? Is there a green
arc specification somewhere that I've missed?
Mike
--------
Mike Perkins
Havana, Illinois
Model I, 532, B gearbox, GSC prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=446694#446694
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In regard to coolant temp being 200 degrees, If you talk to the techs at Lockwood
they will tell you that the "weak link" in the 582 is the design of the head
and the rectangular gasket. I have been told that the gasket material has
has a much greater chance of failure when the water temps go even into the 195
range, but the concensus is that for a brief period of these hot temperatures
may be OK, such as short term climb-out. I was always told that the water temp
should be about 175 max and at 180 was too hot and if you look at the specs
this is about right, so I added another radiator in series and it did no good,
added water wetter and amazingly it helped, but making sure that the level
of the 50/50 is slap full at the cap and even the overflow tube also helps. Other
than that, on a super hot day, full bore climbout, mine will do about 190-195
until I go into cruise, then it goes to about 178 degrees. It seems that
with high water temps that this should effect the cht temp, but mine always runs
just slightly in the green at 200 degrees. It seems it should show a hotter
temp on the cht guage but it doesnt. 200 degrees is just a hair away from the
yellow caution area. I am not sure if I should be concerned here or not.
--------
kitfox III w/ 582 greyhead
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=446698#446698
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