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----- Original Message -----
Sent: Saturday, December 06, 2003 4:31
AM
Subject: [FlyRotary] Re: Expansion
Chambers
Ed, very interesting
phenomenon. I would suppose a different explanation for your
findings.
When the system is
cold an there is no air. With no air in the system, as soon as you add
ANY heat there is expansion. ANY expansion must flow against the
radiator cap and will need to be under its rated pressure in order to get
passed. As the system continues to heat up, this expansion and pressure
will continue. Once the system more or less reaches a steady state temp,
there is no more expansion and the pressure decreases. That last 2-4 psi
is accounted for by small amounts of remaining air, and the expansion of
rubber hoses.
David
Leonard
The Rotary
Roster:
Hi David,
I like your explanation
better, its simpler and that generally means more likely. Although, the
speed with which it goes to 18-20 psi is quick, it is not as immediate as I
first implied. Probably 5-10 seconds total. So that is probably
sufficient for some heat to migrate from the combustion chamber metal to the
coolant. And with little or no air, the expansion of the coolant due to the
heat would probably show up immediately on the pressure sensor.
It was however, disconcerning when it first
occured as I was certain I had a bad coolant "O" ring. Even though I
never lost any coolant, it bothered me until Tracy told me he observed the
same thing. So thought I would mention it in case someone else ran into
it.
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