Sender: <marv@lancaironline.net>
To: lml
Date: Mon, 27 Nov 2006 22:34:16 -0500
Message-ID: <redirect-1614596@logan.com>
Received-SPF: none
 receiver=logan.com; client-ip=206.190.49.115; envelope-from=randylsnarr@yahoo.com
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=yahoo.com;
  h=Message-ID:Received:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding;
  b=0H6tvTLMwX1Sw4qRlQe9uZPgUxDJQK0bisw+POBk34RcmNZGjexliM1Zmr5PUGH5Hcxnm8ccY0t7grjBnJqa5btYWRQueRlGObhjJ+14sPtVVQcx4w45PEqzYnN33TY+eDEp2pL67OrMj+4uRxoJ2IQsQp1XxP4r6KBuA79n8lU=  ;
From: randy snarr <randylsnarr@yahoo.com>
Subject: Re: [LML] Re: Electrical /Hydraulic system questionslancair235/320
In-Reply-To: <list-1610102@logan.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit

Chris,
I will check the part # on the pump tomorrow. Today
when I was at the hangar I looked at the low side of
the system. It indicated 600 psi. The high side was 0.
I opened the dump valve and both sides equalized at
around 300 or so. I closed the dump valve and turned
on the master switch. the pump came on and pumped the
down side back up to 600 or so and the up side went
back to 0.
Should the high and low sides equalize at something
other than 0?

Randy.

--- Christopher Zavatson
<Christopher.Zavatson@baesystems.com> wrote:

> Randy,
> <<I am absoluteley baffled over how both the high
> and low sides build
> pressure during flight.
> Thoughts?>>
> 
> Your case is somewhat perplexing.  The retention of
> pressure would
> indicate a reversed spool valve, but only seeing 200
> psi during
> retraction does not.  If the system only retains 200
> psi (normal while
> pumping), how does it retain 600 psi while static? 
> What bothers me is
> that the fundamental purpose for the back pressure
> circuit is to relieve
> pressure on the low side to avoid tripping the
> pressure switch
>  
> As an aside, I always view pumps coming straight
> from Oildyne as
> suspect until operational tests confirm correct
> assembly.  Back in the
> '98 time frame, I had my pump in for servicing - I
> let it run dry while
> working on some cylinders.  Their shop manager
> called me to find out why
> my spool valve was in backwards.  After several
> minutes describing the
> hydraulic system to him, he determined that my
> 'backward' spool valve
> was actually correct.  The build instructions were
> wrong.  Low and
> behold, one pump after another in the field started
> exhibiting the
> symptoms of a reversed spool valve.  I don't know if
> the paperwork ever
> got fixed.  Even the pump I had borrowed while mine
> was out had a
> reversed spool valve.  I had to crank up the high
> pressure side to get
> the gear up all the way.  Are you able you retrieve
> a part number off
> your pump?
>  
> Chris
>  
>  
>  
>  
> Chris Zavatson
> N91CZ
> 360std.
> www.N91CZ.com
> 
> 
> 


____________________________________________________________________________________
Yahoo! Music Unlimited
Access over 1 million songs.
http://music.yahoo.com/unlimited