----- Original Message -----
Sent: Monday, June 27, 2005 11:17
AM
Subject: [FlyRotary] Re: Engine Rebuild -
Coolant Leak Cause
On 6/24/05 3:18 PM, "Ed Anderson" <eanderson@carolina.rr.com>
wrote:
Hi
John,
A couple of things. Tracy and I both discovered that one
ALL the air is out of the coolant system, the coolant pressure may jump to
21 psi almost immediately upon start up - long before the heat would cause
it to build to that point. At first, I thought "coolant Leak",
however, I could never find any evidence of coolant in the chambers nor loss
of coolant in the system. Talking to Tracy Crook, he reported the same
thing. We came to the conclusion that without a small cushion of air
that the pressure sensor was seeing hydraulic pressure caused by the pump.
With no air cushion even a small disturbance would likely cause the
pressure sensor to indicate high pressure. As the block and components
heated up the coolant volume got a tiny bit larger due to expansion of parts
and the hydraulic pressure quickly decreased. At least that was
the best theory we could come up with at the time.
During flight
the pressure would quickly decrease until it was below 10 psi and on cool
days would got to zero.
On my flight
back home (some air still in system), the coolant pressure never got above
12 psi (right after take off when hottest) and most of the time ran at 8
psi. So if you are seeing a nominal 10 psi and only seeing the
25 psi on startup, I don't think you have any problem especially if no
evidence of coolant in exhaust stacks.
Ed
A
Ed,
I think that maybe it takes few moments for the pump to accelerate the mass of
coolant inside the cooling system. That’s why the pressure at the pump outlet
is high for a while?
Buly
Could be Buly, although I would think that since
liquid is basically incompressible that it is all accelerated at
once.
Ed