X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m17.mx.aol.com ([64.12.138.207] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1124800 for flyrotary@lancaironline.net; Tue, 23 May 2006 10:37:21 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.207; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m17.mx.aol.com (mail_out_v38_r7.5.) id q.45c.13fa692 (4230) for ; Tue, 23 May 2006 10:35:45 -0400 (EDT) From: Lehanover@aol.com Message-ID: <45c.13fa692.31a477c0@aol.com> Date: Tue, 23 May 2006 10:35:44 EDT Subject: Re: [FlyRotary] Re: Another case of heat-soaked coils? To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1148394944" X-Mailer: 9.0 Security Edition for Windows sub 5301 X-Spam-Flag: NO -------------------------------1148394944 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 5/23/2006 9:27:40 A.M. Eastern Daylight Time, lors01@msn.com writes: John did tell me that the threshold of 'splutter' was around 38" Hg MAP. Since the engine quickly went down hill even at lower throttle settings and he thought it was only running on one rotor at the end of testing, I suspect there are a lot of clues to what is wrong other than the 'splutter' at 38". We just don't know what they are. The coils being bad is a long shot since it would mean that two of them died at once, not likely but possible. Did the engine run well after cooling for some time? Not enough information. One quick check for secondary ignition breakdown, is to quickly install two new plugs in the leading holes, gapped at .010". If the problem is still there, it is less likely the secondary output. If the problem is gone, it is likely the secondary output. The lost spark coils of later RX-7s fire twice per revolution. They fire both of the leading plugs twice for each revolution. So they work with very short rise times. At 6,000 RPM that's 12,000 cycles per minute. Try that with a Corvette coil. Even so, ignition problems at 6,000 to 6,500 RPM should not be happening. We shift at 9,600 RPM, and with two MSDs even going a bit lean at the top causes a minor misfire or skip. Re-gap the plugs to .010" fixes that every time. Also reducing throttle setting slightly restores good ignition performance when this is the problem. Stock Rotary engine coils are very good. The lost spark coils are better. Using two lost spark coils, one for both leading and trailing on each housing would be as close to bullet proof as is possible. The trailing must be distributed otherwise. If Tracy's controller can light a stock (lost spark) coil, that is. Lynn E. Hanover -------------------------------1148394944 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 5/23/2006 9:27:40 A.M. Eastern Daylight Time,=20 lors01@msn.com writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DVerdana color=3D#000000 siz= e=3D2>

John did tell me that the threshold of 'splutter' was around 38" Hg=20 MAP. Since the engine quickly went down hill even at lower throttle=20 settings and he thought it was only running on one rotor at the end of=20 testing, I suspect there are a lot of clues to what is wrong other t= han=20 the 'splutter' at 38". We just don't know what they are. = The=20 coils being bad is a long shot since it would mean that two of them died a= t=20 once, not likely but possible.

Did the engine run well after cooling for some time? Not enough=20 information.

One quick check for secondary ignition breakdown, is to quickly install= two=20 new plugs in the leading holes, gapped at .010". If the problem is still the= re,=20 it is less likely the secondary output. If the problem is gone, it is likely= the=20 secondary output.

The lost spark coils of later RX-7s fire twice per revolution. They fir= e=20 both of the leading plugs twice for each revolution. So they work with very=20 short rise times. At 6,000 RPM that's 12,000 cycles per minute. Try that wit= h a=20 Corvette coil.

Even so, ignition problems at 6,000 to 6,500 RPM should not be happenin= g.=20 We shift at 9,600 RPM, and with two MSDs even going a bit lean at the top ca= uses=20 a minor misfire or skip. Re-gap the plugs to .010" fixes that every time.=20

Also reducing throttle setting slightly restores good ignition performa= nce=20 when this is the problem.

Stock Rotary engine coils are very good. The lost spark coils are=20 better.

Using two lost spark coils, one for both leading and trailing on each=20 housing would be as close to bullet proof as is possible. The trailing must=20= be=20 distributed otherwise.

If Tracy's controller can light a stock (lost spark) coil, that is.

Lynn E. Hanover

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