X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m27.mx.aol.com ([64.12.137.8] verified) by logan.com (CommuniGate Pro SMTP 5.1.1) with ESMTP id 1503492 for flyrotary@lancaironline.net; Wed, 25 Oct 2006 11:16:26 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.8; envelope-from=WRJJRS@aol.com Received: from WRJJRS@aol.com by imo-m27.mx.aol.com (mail_out_v38_r7.6.) id q.cd3.118dc8b (45284) for ; Wed, 25 Oct 2006 11:15:57 -0400 (EDT) Received: from FWM-M20 (fwm-m20.webmail.aol.com [64.12.168.84]) by ciaaol-m05.mx.aol.com (v113.6) with ESMTP id MAILCIAAOLM052-b0e4453f7fad22f; Wed, 25 Oct 2006 11:15:57 -0400 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: Rotary Roundup Date: Wed, 25 Oct 2006 11:15:56 -0400 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: wrjjrs@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8C8C65F9AD36551_F94_87DD_FWM-M20.sysops.aol.com" X-Mailer: AOL WebMail 20836 Received: from 65.161.241.3 by FWM-M20.sysops.aol.com (64.12.168.84) with HTTP (WebMailUI); Wed, 25 Oct 2006 11:15:56 -0400 Message-Id: <8C8C65F9AD5C7A9-F94-466F@FWM-M20.sysops.aol.com> X-AOL-IP: 64.12.168.84 X-Spam-Flag: NO ----------MB_8C8C65F9AD36551_F94_87DD_FWM-M20.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" For the mechanical engineering comment of the day; Most o-ring seals REQUIRE a 32 microinch finish. This will NOT happen with a drill. For your injector o-rings you are sealing gasoline. (obviously) No halfway measures here! You simply MUST have a totally leak-free seal. Get the correct reamer. They are easily available in metric sizes. For the best finish leave .002-.005 in. of material when drilling. A 32 microinch isn't mirror-like, rather it is flaw free. (no scratches at all) Usually a shiny surface. Bill Jepson -----Original Message----- From: dale.r@cox.net To: flyrotary@lancaironline.net Sent: Wed, 25 Oct 2006 7:50 AM Subject: [FlyRotary] Re: Rotary Roundup Hi All, This sounds like a "what I learned from that" moment. Good practice for holes that need to be fluid tight is to drill or bore the hole slightly undersize and then finish the cut with a reamer. Reamers come sized in thousandths of an inch, so it's not usually much of a problem to get exactly the correct size. Moreover, a reamed hole is going to be truly cylindrical, something you can't count on when honing or polishing a drilled hole. A chucking reamer - suitable for use in a drill press - will run about $20 from suppliers like Rutland and ENCO, sometimes considerably less, depending on the size and what's "on sale" at the moment. Good Building, Dale R. Stephen Brooks wrote: It appears that I won't be able to attend this years round up, htough I was hoping that I would have time to get there. I came to SC yesterday, intending to finally take my plane to NC. I've only flown it once in that last 4 months, so I pulled the cowling, checked things out, and started the engine. After a couple of minutes run time, I shut it down, and checked everything out. I found that I now have a fuel leak from one of the injectors, at the fuel rail. Apparently I have an o ring that is not leaking. I've ordered a new set of seals from Mazatrix, and I'm going to go back to the airport today, and remove the fuel rail so that I can take it back home with me. When I drilled the fuel rail for the injectors, the holes are not perfectly smooth. I think that the roughness of the bore probably led to the o ring failure. I'm going to polish the bore, without hopefully enlarging it any. I think that I'm going to use a dremel with a fine stone on it. This weekend I also have to help our yougest dughter and son-in-law frame up a new house they are building. I hope that everyone has a great time at the roundup, and I hope to make it next year. Steve Brooks Cozy MKIV N75CZ Turbo Rotary 13B -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ________________________________________________________________________ Check out the new AOL. Most comprehensive set of free safety and security tools, free access to millions of high-quality videos from across the web, free AOL Mail and more. ----------MB_8C8C65F9AD36551_F94_87DD_FWM-M20.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/html; charset="us-ascii"
For the mechanical engineering comment of the day; Most o-ring seals REQUIRE a 32 microinch finish. This will NOT happen with a drill. For your injector o-rings you are sealing gasoline. (obviously) No halfway measures here! You simply MUST have a totally leak-free seal. Get the correct reamer. They are easily available in metric sizes. For the best finish leave .002-.005 in. of material when drilling. A 32 microinch isn't mirror-like, rather it is flaw free. (no scratches at all)  Usually a shiny surface.
Bill Jepson
 
 
-----Original Message-----
From: dale.r@cox.net
To: flyrotary@lancaironline.net
Sent: Wed, 25 Oct 2006 7:50 AM
Subject: [FlyRotary] Re: Rotary Roundup

Hi All,

   This sounds like a "what I learned from that" moment. 

   Good practice for holes that need to be fluid tight is to drill
or bore the hole slightly undersize and then finish the cut with a
reamer.  Reamers come sized in thousandths of an inch, so it's not
usually much of a problem to get exactly the correct size. 
Moreover, a reamed hole is going to be truly cylindrical, something
you can't count on when honing or polishing a drilled hole.

   A chucking reamer - suitable for use in a drill press - will
run about $20 from suppliers like Rutland and ENCO, sometimes
considerably less, depending on the size and what's "on sale" at
the moment.

Good Building,
Dale R.


Stephen Brooks wrote:
It appears that I won't be able to attend this years round up, htough I was hoping that I would have time to get there.
 
I came to SC yesterday, intending to finally take my plane to NC.  I've only flown it once in that last 4 months, so I pulled the cowling, checked things out, and started the engine.
 
After a couple of minutes run time, I shut it down, and checked everything out.  I found that I now have a fuel leak from one of the injectors, at the fuel rail.  Apparently I have an o ring that is not leaking.  I've ordered a new set of seals from Mazatrix, and I'm going to go back to the airport today, and remove the fuel rail so that I can take it back home with me. 
 
When I drilled the fuel rail for the injectors, the holes are not perfectly smooth.  I think that the roughness of the bore probably led to the o ring failure.  I'm going to polish the bore, without hopefully enlarging it any.  I think that I'm going to use a dremel with a fine stone on it.
 
This weekend I also have to help our yougest dughter and son-in-law frame up a new house they are building.
 
I hope that everyone has a great time at the roundup, and I hope to make it next year.
 
Steve Brooks
Cozy MKIV N75CZ
Turbo Rotary 13B

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