X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 12 May 2008 16:41:06 -0400 Message-ID: X-Original-Return-Path: Received: from [204.127.217.105] (HELO fmailhost01.isp.att.net) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2919012 for lml@lancaironline.net; Mon, 12 May 2008 14:40:32 -0400 Received-SPF: pass receiver=logan.com; client-ip=204.127.217.105; envelope-from=paulhershorin@bellsouth.net Received: from fwebmail09.isp.att.net ([204.127.218.109]) by isp.att.net (frfwmhc05) with SMTP id <20080512183952H05006ppgse>; Mon, 12 May 2008 18:39:52 +0000 X-Originating-IP: [204.127.218.109] Received: from [74.233.232.208] by fwebmail09.isp.att.net; Mon, 12 May 2008 18:39:51 +0000 From: paulhershorin@bellsouth.net X-Original-To: "Lancair Mailing List" Subject: Re: [LML] Re: Lancair 320 low fuel pressure X-Original-Date: Mon, 12 May 2008 18:39:51 +0000 X-Original-Message-Id: <051220081839.19720.48288EF700023B7300004D0822218675169B0A02D2089B9A019C04040A0DBF02079D01089C9D0A08049A0E9F@att.net> In-Reply-To: X-Mailer: AT&T Message Center Version 1 (Mar 10 2008) X-Authenticated-Sender: cGF1bGhlcnNob3JpbkBiZWxsc291dGgubmV0 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_19720_1210617591_0" --NextPart_Webmail_9m3u9jl4l_19720_1210617591_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit I had 87 hours on my plane and the fuel flow stared to go to "0" and return to normal--this happened four or five times but EGT and CHT never changed a degree--I called Grand Rapids and the informed me that the sending unit only lasted 100 hours--the cost was $35--I ordered two and I now have a spare on my bench when it goes to "0" again. They have an upgrade unit that requires three wires, however I am maxed out on wires throw the bulk head. Paul Hershorin 360-- 471LA -------------- Original message from Gary Casey : -------------- For years I flew a Cherokee 180 that had a similar problem. When going high, above 8,000 feet and especially when the outside temperature was warm, the fuel pressure would gradually drop to about 2 psi. At low altitude it would be in the high end of the green and at high altitude the low end of the green. I could never come up with an explanation and the condition didn't change with a new fuel pump. It would rise slightly when turning on the electric pump. I doubt that it is a tank vent problem, but I have no likely explanations. Never caused a problem, but always bothered me. I always wondered if it was something to do with the way the gage read the pressure, but that didn't make sense either. Gary Casey I normally have had around 4-6 psi flying around my airport, however, yesterday, I flew on my first cross country. Cruising at 220mph, I noticed my fuel pressure slowly start to drop as I got faster and higher. It went down to 2 psi. I climbed higher in case I needed time to find a place to land. Luckily I didn't. I turned on my fuel pump with only a slight increase of 1 psi as a result. I switched tanks and same results. I learned my engine requires .5 psi minimum so I have remained about that, however I don't like it. I want 4-6 to keep my peace of mind. Top psi limit is 8. So, I asked around to a couple A&P's. They all think it could be my vent on the tanks is not providing enough positive pressure in the tanks. I thought of maybe increasing or decreasing the angle of the vent into the relative wind to increase the fuel positive pressure in my tanks, however I know it is bad to have too much pressure in the tanks as well. So, I am seeking input on this problem or if you guys think I shouldn't even worry about it. Interesting that when I reduced power and got into my pattern, the psi went up to 5 psi. Matt Reeves --NextPart_Webmail_9m3u9jl4l_19720_1210617591_0 Content-Type: multipart/related; boundary="NextPart_Webmail_9m3u9jl4l_19720_1210617591_1" --NextPart_Webmail_9m3u9jl4l_19720_1210617591_1 Content-Type: text/html Content-Transfer-Encoding: 8bit
I had 87 hours on my plane and the fuel flow stared to go to "0" and return to normal--this happened four or five times but EGT and CHT never changed a degree--I called Grand Rapids and the informed me that the sending unit only lasted 100 hours--the cost was $35--I ordered two and I now have a spare on my bench when it goes to "0" again.  They have an upgrade unit that requires three wires, however I am maxed out on wires throw the bulk head.
Paul Hershorin
360-- 471LA
-------------- Original message from Gary Casey <glcasey@adelphia.net>: --------------

For years I flew a Cherokee 180 that had a similar problem.  When going high, above 8,000 feet and especially when the outside temperature was warm, the fuel pressure would gradually drop to about 2 psi.  At low altitude it would be in the high end of the green and at high altitude the low end of the green.  I could never come up with an explanation and the condition didn't change with a new fuel pump.  It would rise slightly when turning on the electric pump.  I doubt that it is a tank vent problem, but I have no likely explanations.  Never caused a problem, but always bothered me.  I always wondered if it was something to do with the way the gage read the pressure, but that didn't make sense either.
Gary Casey
I normally have had around 4-6 psi flying around my airport, however,
yesterday, I flew on my first cross country. Cruising at 220mph, I noticed my
fuel pressure slowly start to drop as I got faster and higher. It went down
to 2 psi. I climbed higher in case I needed time to find a place to land.
Luckily I didn't.

I turned on my fuel pump with only a slight increase of 1 psi as a result.
I switched tanks and same results.

I learned my engine requires .5 psi minimum so I have remained about that,
however I don't like it. I want 4-6 to keep my peace of mind. Top psi limit
is 8.

So, I asked around to a couple A&P's. They all think it could be my vent on
the tanks is not providing enough positive pressure in the tanks. I thought
of maybe increasing or decreasing the angle of the vent into the relative wind
to increase the fuel positive pressure in my tanks, however I know it is bad
to have too much pressure in the tanks as well.

So, I am seeking input on this problem or if you guys think I shouldn't even
worry about it.

Interesting that when I reduced power and got into my pattern, the psi went
up to 5 psi.

Matt Reeves

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