Return-Path: Received: from fed1rmmtao12.cox.net ([68.230.241.27] verified) by logan.com (CommuniGate Pro SMTP 5.0) with ESMTP id 814392 for flyrotary@lancaironline.net; Fri, 04 Nov 2005 02:27:32 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.27; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao12.cox.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20051104072550.EQOM2059.fed1rmmtao12.cox.net@BigAl> for ; Fri, 4 Nov 2005 02:25:50 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Timing Date: Thu, 3 Nov 2005 23:26:46 -0800 Message-ID: <000001c5e111$1d1cfda0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C5E0CE.0EF9BDA0" 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 V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C5E0CE.0EF9BDA0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 =20 But I'm in a bit of a quandary. I set TDC on the flywheel as Lynn = described and it looked so perfect. But the timing light is showing it firing at 40+Deg. ATDC and when I turn the Crank Angle sensor as far as it will go trying to advance it I can only get up to about 20Deg ATDC. The engine, however, sounds MUCH, MUCH better as I advance the timing - although = that may also be because I pickup about 100RPM when I do that. =20 Oh, and the little red and yellow dots on the main pulley seem to be correlating with the flywheel marks at this point. =20 I guess I'll have to see if I can re-position my Crank Angle sensor this weekend and see what happens when I can advance it further. =20 If you're confident that the TDC mark is correct; then, yeah; 40 ATDC is "WAY" retarded. I don't recall how many cogs are on the CAS drive, but = it seems you will have advance it just a bit more than 1/16th of a turn. That's at least one, and maybe to cogs. =20 It's amazing how far the timing can be off on these engines and still = have them run. At first I thought my engine was running quite well. Then I = ran first on leading ignition only, then on trailing. It was about the same either way; whereas it should run quite noticeably better on leading = only. Giant clue that the timing was very late. Do you have any way to switch = off leading and trailing ignition? =20 Al =20 ------=_NextPart_000_0001_01C5E0CE.0EF9BDA0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

 

 

But I’m in = a bit of a quandary.  I set TDC on the flywheel as Lynn described and = it looked so perfect. But the timing light is showing it firing at 40+Deg. ATDC = and when I turn the Crank Angle sensor as far as it will go trying to advance it = I can only get up to about 20Deg ATDC. The engine, however, sounds MUCH, MUCH = better as I advance the timing – although that may also be because I = pickup about 100RPM when I do that. 

Oh, and the = little red and yellow dots on the main pulley seem to be correlating with the = flywheel marks at this point.

 

I guess = I’ll have to see if I can re-position my Crank Angle sensor this weekend and see = what happens when I can advance it further.

 

If you’re confident that = the TDC mark is correct; then, yeah; 40 ATDC is “WAY” = retarded.  I don’t recall how many cogs are on the CAS drive, but it seems you will have = advance it just a bit more than 1/16th of a turn.  That’s = at least one, and maybe to cogs.

 

It’s amazing how far the = timing can be off on these engines and still have them run.  At first I = thought my engine was running quite well.  Then I ran first on leading = ignition only, then on trailing.  It was about the same either way; whereas = it should run quite noticeably better on leading only.  Giant clue = that the timing was very late.  Do you have any way to switch off leading = and trailing ignition?

 

Al

 

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