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Re: [FlyRotary] water boiling point
There's one coolant design that's substantially better than the others. I
discovered it when doing severe ground testing...deliberately overheating my
engine.
Three basic requirements:
1) Place your radiator cap and reservoir above engine. The higher the
better. This allows trapped air in system to rise out of the flow and stay
there.
2) Put a 24 psi cap on the system. You can throw away your overflow stuff.
Not needed.
3) Always keep around 2 cups of air under the cap. This is the key item. It
brings a big safety advantage. It allows you to use coolant pressure to predict
well in advance how good your system is doing. It minimizes pressure. Mine never
exceeds 7 psi. But if something goes wrong, then my pressure rises and I gain
boilover protection due to the increase in system pressure.
If you have compression leak into the cooling system, it shows immediately
as spike in pressure that reaches 24psi. But when all is normal, you never see
pressure above 7 psi. If you have any cooling problem, the pressure gage will
respond quicker than any other sensor.
Sounds like many of you don't have that 2 cups of air. As result, your
coolant pressure regularly reaches 24 psi. Stressing components (radiator welds
actually). It masks compression leaks. Makes it difficult to predict your
safety margin.
Tough to explain this stuff in text, but it's a big improvement in
safety margin. No downside.
To qualify the system, I omit the two cups of air. This causes pressure to
rise to 24 psi. Thus proving all of my welds and connections have safety margin.
Then I add the 2 cups of air and the system never rises above 7 psi unless
something goes wrong....whereupon I have extra margin preventing boilover. Your
biggest cooling risk as it cascades and is nearly
irreversible.
On Sun, 18 Mar 2007 11:41:33 -0400 "Tracy Crook" < lors01@msn.com> writes:
Higher coolant pressure will naturally increase the risk of a leak due to
blown hose, loose clamp, radiator tank failure, etc. As in many of these
matters, it is the builders choice as to which potential problem is most
important.
BTW, I do recommend doing a system pressure test at
annual inspection time or after making any changes. I intentionally
over-pressure the system by 50% by hooking a regulated air pressure source to
the overflow port on the cap fitting.
I could be wrong but the likelihood of a blown rotor housing coolant seal
from coolant pressure is very low. If coolant pressure causes them
to leak there was a problem that needed to be addressed long before the leak
happened. Most coolant seal leaks happen at the inner seal which
normally have to seal combustion chamber pressure. Even 30
psi coolant pressure is a very tiny fraction of that.
Tracy (still waiting on Bluemountain)
----- Original Message -----
Sent: Sunday, March 18, 2007 8:21
AM
Subject: [FlyRotary] Re: water boiling
point
My same thought, the higher pressure the better chance of leaks,
for the last 1400 hrs I have been running a 7 lb cap with no problem, I
normally run about 180 for water temp but do see 220 on a hard climb out on
a hot day and when at high altitude its usually so cold outside that cooling
is not an issue.
Ken Welter
Thanks for your reply Tracy!
I did
a google search on water boiling point. Coolant should be
higher,
but it seems that water boils at 183 degrees at 16,000 feet.
But that
is with no added pressure. I could not find the
corrected number for the 12 psi cap.
I wonder how many blown rotor
housing seals are due to higher coolant pressure
?
George Graham
Sarasota Florida
Mazda RX7
EZ
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