My pressure cap and pressure sensor is at the low pressure side of the system so I don't know how high it goes in the block. In typical cruise conditions I run about 10 psi since I keep the coolant tank 1/2 full to give the air spring effect. If kept full it goes to full cap pressure almost immediately .
I did once have a blow off of coolant (steam) at high altitude (18,000) when climbing at Vx getting over a cloud bank. I had an 11 psi cap at the time. That's when I decided to go with a higher pressure cap.
If 30 to 40 psi blows out the engine o rings something is very wrong with how the engine was built. Those o rings have to contain combustion chamber pressures.
Tracy
Sent from my iPad
Interesting, Tracy,
With that high cap pressure setting, what is the actual water (coolant)
pressure that you experience.
With those using lower caps, are you experiencing coolant blow off??(or
out).
It has been my understanding, perhaps incorrectly, that the increase in
pressure, of the coolant, is a product of the expansion of the coolant body due
to the increase in temperature. At the specified coolant max
temperature, wouldn't the pressure relatively the same. Wouldn't it
increase, only with greater temps which would endanger the "O" rings?
OR, am I full of it (coolant).
I will be the first to admit that my engine is not running yet and thus
have not had to deal with problems of the pressure, or even radiator persuasion
yet.
Rich
In a message dated 10/22/2012 3:24:24 P.M. Central Daylight Time,
rwstracy@gmail.com writes:
I think One of the most restrictive points in the system is the passage
to the outlet of the water pump housing. Remember this is NOT the outlet
of the water pump itself. In the pump housing is an oval passage
that is too small to get two fingers through. It has been my assumption
that this was to make the pressure high in the block at high rpm in order to
avoid local boiling in the combustion chamber area. Hi pressure in the
block is a good thing. I run a 29 PSI cap.
Tracy
Sent from my iPad
Charlie, I am using two evap cores in parallel, with system pressure
limited to 10 psi on the expansion bottle. When the engine is running, the
pressure measured at the inlet to the cores (exit of the pump) is a function
of RPM and can rise to as much as 20 psi (10 psi over system pressure in the
expansion bottle).
Having the flow enter the bottom of the radiator and out the top, then
going to the inlet of the pump sounds like a good way to avoid
problems.
Bill
Schertz
KIS Cruiser #4045
N343BS
Phase one testing Completed
Sent: Monday, October 22, 2012 1:06 PM
Subject: [FlyRotary] Re: flow path in conventional
radiator
Unless there is a serious restriction through the
radiator I can't imagine there would be anything greater then 1 psi
over system pressure caused by pump output. As for the reverse flow,
ie, bottom to top,,, It's called counter flow, and yes it can work. My set
up has worked flawlessly for 500 hours and I use the Moroso swirl / pressure
tank and a air bleed line from the output of the radiator... About 3
minutes into this video shows my set up.....
http://www.youtube.com/watch?v=rCNnEgRkdXc&context=C3e091d3ADOEgsToPDskKmHo69I6bUDuoBHd5YSUfu
Ben Haas
www.haaspowerair.com
To: flyrotary@lancaironline.net
Date:
Mon, 22 Oct 2012 12:40:11 -0500
From: ceengland7@gmail.com
Subject:
[FlyRotary] flow path in conventional radiator
I've been doing research on radiators, & my 1st
'experiment' will be a conventionally configured radiator (downflow
design) with inlet & pressure cap on top. In reading about issues with
conventional radiators, a common complaint is pressure venting due to the water pump + system pressure exceeding the
cap's rating. Crossflow types like
the Sirocco are supposed to avoid this because the cap is at
the mid-point in the flow through the rad, which drops some of the
pressure seen by the cap.
Here's my question: Is there any reason a conventional rad
can't be fed from the bottom, instead of the top? This would achieve similar effect as the crossflow cap location (all the way to the end of the flow path) & any air could be
vented using the existing fittings. I'm also considering the removal of the spring loaded seal, &
moving the pressure cap function to a separate swirl can. By doing this, the existing over-pressure port could function as the air removal port
in the top tank of the radiator.
What am I
missing?
Thanks,
Charlie
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