X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao101.cox.net ([68.230.241.45] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2309788 for flyrotary@lancaironline.net; Tue, 04 Sep 2007 00:37:57 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.45; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao101.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20070904043718.SODC20651.fed1rmmtao101.cox.net@fed1rmimpo01.cox.net> for ; Tue, 4 Sep 2007 00:37:18 -0400 Received: from BigAl ([72.192.132.90]) by fed1rmimpo01.cox.net with bizsmtp id k4dG1X00T1xAn3c0000000; Tue, 04 Sep 2007 00:37:17 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Interface between Primary fuel rail and diffuser (air bleed) 20B Date: Mon, 3 Sep 2007 21:38:06 -0800 Message-ID: <000001c7eeb5$c50ca520$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C7EE72.B6E96520" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C7EE72.B6E96520 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Joe; =20 I'm not sure this is helpful; because I'm drawing on those weak memory = cells from about 6 years ago; but I recall a seal washer that went between the diffuser flange and the bottom of the injector (or injector housing of = the fuel rail). I think I was short one, and the others not in good shape, = and IIRC, I got new ones from the Mazda dealer parts dept. On an invoice in = my file they are listed as an "insulator" Part # N3A1-13-257. = Unfortunately; I can't assure that it is the part you need. They must be used on a 2 = rotor because I got a set of 2 and 1 special ordered. These seals were used = with the original diffusers. =20 I bought my fuel rail (with injectors) at that time from SR Motorsports, 915-516-7382. There was a guy there then that was very knowledgeable = about all these parts. Perhaps they could help you with the proper seals and diffusers. =20 I also recall getting 20B parts from Mazda through a service center here = in SoCAL that sold to racers using 20B engines. I can't find anything in = my file, but it was Mazda Speed, or Mazda Performance, or something. Some = of our racing friends must know - - Lynn? Call Racing Beat; they should = know. =20 Isn't there also a seal at the top of the 'hole' in the rotor housing = that seals the fuel rail so no air would leak in there. It is even possible = that those are the ones I replaced. =20 Maybe this helps, =20 Al =20 =20 =20 =20 =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Joe Ewen Sent: Monday, September 03, 2007 7:33 AM To: Rotary motors in aircraft Subject: [FlyRotary] Interface between Primary fuel rail and diffuser = (air bleed) 20B =20 Background When installing the primary fuel rail on my 20B, I noticed a gap between = the primary fuel rail and the diffuser (air bleed.) One of the original air bleeds was damaged when the rebuilder was removing. He could not locate = a replacement. He supplied new air bleeds designated for a 93-95 13B, = which he was informed were usable in the 20B. The gap between the fuel rail = and the diffuser seems to be between 0.110" and 0.145". This measurement = was determined by inserting the diffuser and measuring its depth. Then the = fuel rail was bolted in place. Through the intake port, the injector was = pushed up until it contacted the fuel rail. The fuel rail was then removed and diffuser depth was measured. The difference between the measurements = was between 0.110" and 0.145". The original diffuser returned by the = rebuilder has no apparent seal, the replacement has a rubber seal molded into the = top. =20 I took some measurements and drew up the primary, fuel rail / injector /diffuser (see attached pdf.) It looks like there are 2 differences = between the diffusers that came on the 20B and the replacements recently = purchased. The height of the diffuser above the seating surface is much lower on = the replacements and the length of the area that projects into the port/air stream is longer. The extra length extending into the port is probably = not an issue. =20 =20 The shorter height of the replacement seems like it will be a problem, = the problem being a vacuum leak around the injector. A secondary issue from = a vacuum leak in this area may be an effect on fuel droplet size. By = looking at the injector, it appears that a metered amount of air is intended to = flow into the pintle cap, presumably to aid in reducing the fuel droplet = size. A vacuum leak in this area may reduce the air flow through the pintle cap = and the resulting droplet size reduction.=20 =20 I would speculate that at medium or higher power levels the vacuum leak would probably have little noticeable effect. I would expect that the = most significant effect would be at or near idle conditions. Since smooth = idle seems to be difficult to attain in many installations, it would = certainly be prudent to try and eliminate this issue (not to mention that it would be good practice to get it right.) =20 Questions 1. There seems to be a very small gap (~0.010") between the fuel rail seating surface and the top of the original diffuser. It looks like = there should be a grommet that makes up the difference and provides a positive seal. To anyone who has disassembled a 20B, is there a grommet/seal the sits on top of the diffuser? =20 2. Same question as 1, for anyone who has disassembled a 93-95 13B (13B-REW, I believe)? =20 3. Anyone have a source for the proper 20B diffusers? =20 Any opinions and/or remedy suggestions are appreciated. =20 Thanks, Joe ------=_NextPart_000_0001_01C7EE72.B6E96520 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Joe;

 

I’m not sure this is = helpful; because I’m drawing on those weak memory cells from about 6 years = ago; but I recall a seal washer that went between the diffuser flange and the = bottom of the injector (or injector housing of the fuel rail).  I think I = was short one, and the others not in good shape, and IIRC, I got new ones = from the Mazda dealer parts dept.  On an invoice in my file they are listed = as an “insulator” Part # N3A1-13-257.  Unfortunately; I can’t assure that it is = the part you need. They must be used on a 2 rotor because I got a set of 2 = and 1 special ordered. These seals were used with the original = diffusers.

 

I bought my fuel rail (with = injectors) at that time from SR Motorsports, 915-516-7382.  There was a guy there = then that was very knowledgeable about all these parts.  Perhaps they = could help you with the proper seals and diffusers.

 

I also recall getting 20B parts = from Mazda through a service center here in SoCAL that sold to racers using 20B = engines.  I can’t find anything in my file, but it was Mazda Speed, or Mazda Performance, or something.  Some of our racing friends must know - = - Lynn?  Call = Racing Beat; they should know.

 

Isn’t there also a seal at = the top of the ‘hole’ in the rotor housing that seals the fuel rail = so no air would leak in there.  It is even possible that those are the = ones I replaced.

 

Maybe this = helps,

 

Al

 

 

 

 

 

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Joe Ewen
Sent: Monday, September = 03, 2007 7:33 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] = Interface between Primary fuel rail and diffuser (air bleed) 20B

 

Background=

When installing the = primary fuel rail on my 20B, I noticed a gap between the primary fuel rail and = the diffuser (air bleed.)  One of the original air bleeds was damaged = when the rebuilder was removing.  He could not locate a replacement.  = He supplied new air bleeds designated for a 93-95 13B, which he was = informed were usable in the 20B.  The gap between the fuel rail and the diffuser = seems to be between 0.110" and 0.145".  This measurement was determined by inserting the diffuser and measuring its depth.  Then = the fuel rail was bolted in place.  Through the intake port, the = injector was pushed up until it contacted the fuel rail.  The fuel rail was then removed and diffuser depth was measured.  The difference between = the measurements was between 0.110" and 0.145".  The original diffuser returned by the rebuilder has no apparent seal, the replacement = has a rubber seal molded into the top.

 

I took some measurements = and drew up the primary, fuel rail / injector /diffuser (see attached pdf.)  It = looks like there are 2 differences between the diffusers that came on the = 20B and the replacements recently purchased.  The height of the = diffuser above the seating surface is much lower on the replacements and the length of = the area that projects into the port/air stream is longer.  The extra = length extending into the port is probably not an issue.    =

 

The shorter height of the replacement seems like it will be a problem, the problem being a vacuum = leak around the injector.  A secondary issue from a vacuum leak in this = area may be an effect on fuel droplet size.  By looking at the injector, = it appears that a metered amount of air is intended to flow into the pintle = cap, presumably to aid in reducing the fuel droplet size.  A vacuum leak = in this area may reduce the air flow through the pintle cap and the = resulting droplet size reduction. 

 

I would speculate that at = medium or higher power levels the vacuum leak would probably have little = noticeable effect.  I would expect that the most significant effect would be = at or near idle conditions.  Since smooth idle seems to be difficult to = attain in many installations, it would certainly be prudent to try and = eliminate this issue (not to mention that it would be good practice to get it = right.)

 

Questions<= /strong>

1.  There seems to be = a very small gap (~0.010") between the fuel rail seating surface and the = top of the original diffuser.  It looks like there should be a grommet = that makes up the difference and provides a positive seal.  To anyone who has = disassembled a 20B, is there a grommet/seal the sits on top of the = diffuser?

 

2.  Same question as = 1, for anyone who has disassembled a 93-95 13B (13B-REW, I = believe)?

 

3.  Anyone have a = source for the proper 20B diffusers?

 

Any opinions and/or remedy suggestions are appreciated.

 

Thanks,

Joe

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