X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 01 Apr 2013 11:21:45 -0400 Message-ID: X-Original-Return-Path: Received: from nm29-vm0.bullet.mail.ne1.yahoo.com ([98.138.91.43] verified) by logan.com (CommuniGate Pro SMTP 6.0.4) with ESMTPS id 6173893 for lml@lancaironline.net; Mon, 01 Apr 2013 09:49:10 -0400 Received-SPF: none receiver=logan.com; client-ip=98.138.91.43; envelope-from=chris_zavatson@yahoo.com Received: from [98.138.90.54] by nm29.bullet.mail.ne1.yahoo.com with NNFMP; 01 Apr 2013 13:48:36 -0000 Received: from [98.138.89.175] by tm7.bullet.mail.ne1.yahoo.com with NNFMP; 01 Apr 2013 13:48:36 -0000 Received: from [127.0.0.1] by omp1031.mail.ne1.yahoo.com with NNFMP; 01 Apr 2013 13:48:36 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 479715.98957.bm@omp1031.mail.ne1.yahoo.com Received: (qmail 66063 invoked by uid 60001); 1 Apr 2013 13:48:36 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=18uNfGfXQLS4MZ2L2LaTC2DLS4pnvAVZ0UKvGqZIe6WqATIrK/Ux7rMME/zz7Pjm96eBncXTr6RVgh07GvfheqwVkrpX2y148i+lsCzGwMTSfdL80+Z90m/5TNOeI+AekYuKGhyv6m0BEW40uYS/ziSv5I0OO+vVrbqunIlNixY=; X-YMail-OSG: tvd85z0VM1moEihSIFcHxgSPZDFzlKkj61KtBhRXxDmhioD PnVNEfCg3VH9h3QhY3O1ZuNZmPXC1n.0R3FZdx1e1j4K4DXFIugrmPZ30sN9 LS4dA.mc_q.0ijLB8KV8nLt4sBP35B7qqyTvce8h4gGIgZnR4I_ddwlc7kaS c4aHDHuQRtiPiz4RbLAeKwyx3vnt6NWr01wegXDUpPjxtOGygHQaDcLhdfRf qNwV3aLj1mgG3Dd1CUYiogogBFEvIg7BQBnU.DpvRo6G0aFBbpl7z_nlemIb SdCMHkIKIL_m7CgAi527FMfD2ixvYbO4lvUNmO9U91TQcmWpK3zJGOn0jVn4 i4xYxbMlfYvbCl7viJ7QzX32Pqb23BPwJbtqdZtb5IQZt4eIk3wzDVC8R5Qw GqLvJ6jTee71Z3TMBWSXa.eOMCbCvDLh..1uXkPb7u4hp3BGli0qM77LbxMu _Yivm5a.d9MxQ0TjkC5Aq4tVfCVDRgBPJd9qJzFIQR.TE5r.hZLeqbKYFrOu oC9q0ZEcDs6HD9og5khd7hk7ZWtxUHiJb35PZfU8iu76juVl7V.hO.XpoTxk 8TvsNL1myfhJEmMJ5y_oAKfbzMOvKs.44cIiVnFr0KodsBaOuUJHu_CHZJCC g__f0np6zjv17aRwJcVMWUmcaEvMOKhgIPUBl7l8SJfvs9kM- Received: from [108.82.44.32] by web121606.mail.ne1.yahoo.com via HTTP; Mon, 01 Apr 2013 06:48:33 PDT X-Rocket-MIMEInfo: 002.001,Q2hyaXMsClRoZSBiZWhhdmlvciB5b3UgZGVzY3JpYmUgaW5kaWNhdGVzIHRoZSBsYWNrIG9mIGEgZnVuY3Rpb25pbmcgYmFjayBwcmVzc3VyZSBjaXJjdWl0LsKgIERvZXMgeW91ciBwdW1wIHBhcnQgbnVtYmVyIGhhdmUgYW4gIkxCIiBpbiB0aGUgbnVtYmVyP8KgIElmIGluc3RlYWQgaXQgaGFzIGFuICJMTCIsIHRoZSBwdW1wIHByZS1kYXRlcyB0aGUgTEIgYmFjayBwcmVzc3VyZSBjaXJjdWl0LsKgIElmIGl0IGlzIGFuICJMQiIgcHVtcCwgeW91ciBzcG9vbCBpcyBpbiBiYWNrd2FyZHMgYW5kIGp1c3QgbmUBMAEBAQE- X-Mailer: YahooMailWebService/0.8.140.532 References: X-Original-Message-ID: <1364824113.64374.YahooMailNeo@web121606.mail.ne1.yahoo.com> X-Original-Date: Mon, 1 Apr 2013 06:48:33 -0700 (PDT) From: Chris Zavatson Reply-To: Chris Zavatson Subject: Re: [LML] LNC2 Old Pump Hydraulics Grief X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="1458340343-1126587087-1364824113=:64374" --1458340343-1126587087-1364824113=:64374 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Chris,=0AThe behavior you describe indicates the lack of a functioning back= pressure circuit.=C2=A0 Does your pump part number have an "LB" in the num= ber?=C2=A0 If instead it has an "LL", the pump pre-dates the LB back pressu= re circuit.=C2=A0 If it is an "LB" pump, your spool is in backwards and jus= t needs to be flipped around.=0AUnfortunately, the photo hints at an older = pump.=C2=A0 I see only one=C2=A0TRV and the dip-stick through hole is drill= ed out.=C2=A0 Also, there is no stand pipe for the return to reservoir.=0AI= f it is indeed and older pump=C2=A0without a back pressure circuit (and the= y are not retrofittable according to Parker),=C2=A0 you'll need to raise th= e operating pressure of the high side circuit to perhaps 1,500 psi.=C2=A0 R= ight now your net working pressure on the high side is reduced to: High sid= e settings minus low side PRV setting.=C2=A0=C2=A0 -not enough to get the g= ear up cleanly.=0AThe ball a spring you removed are for the thermal relief.= =C2=A0=0A=C2=A0=0AChris Zavatson=0AN91CZ=0A360std=0Ahttp://www.n91cz.net/= =0A =0A=0A________________________________=0A From: Christopher Skelt =0ATo: lml@lancaironline.net =0ASent: Monday, April 1, 20= 13 4:08 AM=0ASubject: [LML] LNC2 Old Pump Hydraulics Grief=0A =0A=0AThis i= s for the aficionados of old hydraulic pumps.=C2=A0 Mine is from 1989 =0Aan= d I=E2=80=99m having trouble with the retract cycle.=C2=A0 Since my post se= veral =0Amonths ago I have installed pressure gauges, rebuilt the nose leg = actuator, =0Asequence valve and gear door actuator, and serviced the pump w= ith the kit from =0ALancair.=C2=A0 Same problems, but at least the pressure= gauges help =0Adiagnose. =0A=0AOn the retract cycle pressure builds up on = the low side as well as the high =0Aside and the pump stops until the low s= ide pressure drops, the pump restarts, =0Araises the gear a bit further, st= ops, and so on.=C2=A0 Once the gear is up, the =0Apressure on the low side = drops off and high side pressure is maintained.=C2=A0 =0AThese are symptoms= of a reversed spool valve, but this pump=E2=80=99s is symmetrical =0Awith = a single o-ring. =0A=0ALowering is OK, and pressure is maintained in the do= wn and locked position, =0Aso apparently no internal leaks.=C2=A0 =0A=0AI = guessed the return line was blocked, or the ball valve sticky.=C2=A0 See = =0Athe attached photos.=C2=A0 The spring is very stiff and takes about 15 l= b to =0Aclose it about 0.1 inches.=C2=A0 With a port diameter of less than = 1/10 inch, =0Athis translates into about 2000 psi to overcome that force.= =C2=A0 This doesn=E2=80=99t =0Alook like it=E2=80=99s offering only 100 psi= resistance and it seems=C2=A0 beefier than =0Athe example on Chris Zavatso= n=E2=80=99s figure 14 on N91cz.com...=C2=A0 Can anyone =0Aconfirm that the = spring looks right or wrong=E2=80=94maybe Friday afternoon at the =0Afactor= y?=C2=A0 And where can I get a replacement return line spring and =0Aball?= =C2=A0 =0A=0AThe photo of the pump shows the return valve location on the = left.=C2=A0 =0A=0AThanks in advance. =0A=0ARegards, Chris. =0A=0A=0A=0A= =0A=0A=0A =0A--=0AFor archives and unsub http://mail.lancaironline.net:81/l= ists/lml/List.html --1458340343-1126587087-1364824113=:64374 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Chris,
The behavior you describe indicates the lack of a functioning back= pressure circuit.  Does your pump part number have an "LB" in the num= ber?  If instead it has an "LL", the pump pre-dates the LB back pressure circuit.  If it is an= "LB" pump, your spool is in backwards and just needs to be flipped around.=
Unfortunately, the photo hints at an older pump.&nb= sp; I see only one TRV a= nd the dip-stick through hole is drilled out.  Also, there is no stand= pipe for the return to reservoir.
If it is indeed a= nd older pump without a back pressure circuit (and they are not retrofittable according to Parker),=   you'll need to raise the operating pressure of the high side circuit to pe= rhaps 1,500 psi.  Right now your net working pressure on the high side= is reduced to: High side settings minus low side PRV setting.   -not enough to get the gear= up cleanly.
The ball a spring you removed are for t= he thermal relief. 
 
Chris Zavatson
N91CZ
360st= d

From: Christopher Skelt <cskelt@earthlink.net>
To: lml@lancaironline.net
Sent: Monday, April 1, 2013 4:08= AM
Subject: [LML] LNC2 Old Pump Hydraulics Grief

=0A
=0A
=0A<= div dir=3D"ltr">=0A
gauges, rebuilt the nos= e leg actuator, =0Asequence valve and gear door actuator, and serviced the = pump with the kit from =0ALancair.  Same problems, but at least the pr= essure gauges help =0Adiagno= se.
=0A
 
=0A
On the retract cycle pressure builds u= p on the low side as well as the high =0Aside and the pump stops until the = low side pressure drops, the pump restarts, =0Araises the gear a bit furthe= r, stops, and so on.  Once the gear is up, the =0Apressure on the low = side drops off and high side pressure is maintained.  =0AThese are sym= ptoms of a reversed spool valve, but this pump=E2=80=99s is symmetrical =0A= with a single o-ring.
=0A
 
=0A
Lowering is OK, and = pressure is maintained in the down and locked position, =0Aso apparently no= internal leaks. 
=0A
 
=0A
I guessed the retu= rn line was blocked, or the ball valve sticky.  See =0Athe attached ph= otos.  The spring is very stiff and takes about 15 lb to =0Aclose it a= bout 0.1 inches.  With a port diameter of less than 1/10 inch, =0Athis= translates into about 2000 psi to overcome that force.  This doesn=E2=80=99t =0Alook like it=E2= =80=99s offering only 100 psi resistance and it seems  beefier than = =0Athe example on Chris Zavatson=E2=80=99s figure 14 on N91cz.com...  Can anyone =0Aconfirm that t= he spring looks right or wrong=E2=80=94maybe Friday afternoon at the =0Afac= tory?  And where can I get a replacement return line spring and =0Abal= l? 
=0A
 
=0A
The photo of the pump shows the = return valve location on the left.  =0A
=0A
 
=0AThanks in advance.
=0A
 
=0A
Regards, Chris. =0A
 
=0A
 
=0A
 
=0A
 = ;
=0A
 
=0A
 
=0A
 
=0A

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For archives and unsub http://mail.lancaironline.net:81/lists/lml/= List.html


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