X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-d22.mx.aol.com ([205.188.144.208] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2785129 for flyrotary@lancaironline.net; Mon, 10 Mar 2008 09:32:55 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.144.208; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-d22.mx.aol.com (mail_out_v38_r9.3.) id q.d09.2d93cd58 (30739) for ; Mon, 10 Mar 2008 09:32:07 -0400 (EDT) From: Lehanover@aol.com Message-ID: Date: Mon, 10 Mar 2008 09:32:06 EDT Subject: Re: [FlyRotary] Unusual Noise in Engine To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1205155926" X-Mailer: Unknown sub 36 X-Spam-Flag: NO -------------------------------1205155926 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Does it have the stock (Heavy) flywheel on it? It would be difficult to detonate the engine without a load and at least partial throttle. More typically it takes wide open throttle to do it. But low RPM is not protection against it. My driver has done it right off idle. With just a flex plate the engine can shake the transmission in acceleration and deceleration hard enough to sound like it has rocks inside it. With the stock flywheel this is not possible. Typical race car idle is at 2,000 to 2,200 RPM with no flywheel mass to avoid trans damage. That timing is fine. anywhere between 20 and 27 degrees is fine. It can be fixed at those numbers and still start and run just fine. The lowest octane fuel is fine. Check the timing on the trailing (upper most) plugs to be sure that they do not fire ahead of the leading (lower) plugs. If there is a timing split at all the trailing must be behind the leading. For your operation the stock plugs are a very cold heat range and with no load to heat the plugs, fouling will be a problem. You can run a conventional looking street plug medium or retracted tip with no problems at all. For a high load like a prop, then you need to go back the Mazda plugs. The sound you describe sounds like a cross fire or a light detonation. So put a timing light on all 4 wires and see if the sound is coincidental with one of them firing. The split timing helps torque just a bit down low. With the RPM that will be used in aircraft leading and trailing at the same time is simple and effective. Dress the wires well away from each other. Is it a direct fire ignition? Lynn E. Hanover In a message dated 3/10/2008 3:17:31 A.M. Eastern Daylight Time, tomk@telus.net writes: My question is regarding the noise that I hear. Has anyone experienced such a noise? I have noticed the engine missing sporadically at low RPM's with a load on it, and the fuel/air mixture gauge showing five to six LEDS. Can a miss, detonation, bad timing, fouled plug(s) etc cause such a noise? My timing is very close to 23 degrees BTDC. When I turn the engine over manually (i.e., with socket and ratchet) the engine feels like it has good compression, and doesn't make any strange noises, such as, anything broken or loose inside. I may tear the engine apart to inspect the inside, later this year. Thanks, Tom **************It's Tax Time! Get tips, forms, and advice on AOL Money & Finance. (http://money.aol.com/tax?NCID=aolprf00030000000001) -------------------------------1205155926 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Does it have the stock (Heavy) flywheel on it? It would be difficult to= =20 detonate the engine without a load and at least partial throttle. More=20 typically it takes wide open throttle to do it. But low RPM is not=20 protection against it. My driver has done it right off idle. With just= a=20 flex plate the engine can shake the transmission in acceleration and=20 deceleration hard enough to sound like it has rocks inside it. With the stoc= k=20 flywheel this is not possible. Typical race car idle is at 2,000 to 2,200 RP= M=20 with no flywheel mass to avoid trans damage.

That timing is fine. anywhere between 20 and 27 degrees is fine. It can= be=20 fixed at those numbers and still start and run just fine. The lowest octane=20= fuel=20 is fine.

Check the timing on the trailing (upper most) plugs to be sure that the= y do=20 not fire ahead of the leading (lower) plugs. If there is a timing split at a= ll=20 the trailing must be behind the leading. For your operation the stock=20 plugs are a very cold heat range and with no load to heat the plugs, fouling= =20 will be a problem.

You can run a conventional looking street plug medium or retracted tip=20= with=20 no problems at all. For a high load like a prop, then you need to go back=20 the Mazda plugs.

The sound you describe sounds like a cross fire or a light detonation.=20= So=20 put a timing light on all 4 wires and see if the sound is coincidental with=20= one=20 of them firing. The split timing helps torque just a bit down low. With the=20= RPM=20 that will be used in aircraft leading and trailing at the same time is simpl= e=20 and effective.

Dress the wires well away from each other. Is it a direct fire=20 ignition?

Lynn E. Hanover

In a message dated 3/10/2008 3:17:31 A.M. Eastern Daylight Time,=20 tomk@telus.net writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>

My question= is=20 regarding the noise that I hear. Has anyone experienced such a=20 noise? I have noticed the engine missing sporadically at l= ow=20 RPM's with a load on it, and the fuel/air mixture gauge showing five=20= to=20 six LEDS. Can a miss, detonation, bad timing, fouled plug= (s)=20 etc cause such a noise? My timing is very close to 23 degrees=20 BTDC. When I turn the engine over manually (i= .e.,=20 with socket and ratchet) the engine feels like it has good compression, an= d=20 doesn't make any strange noises, such as, anything broken or loose=20 inside. I may tear the engine apart to inspect the=20 inside, later this year.

Thanks,

Tom

It's Tax Time! Get tips, forms and advice on AOL= Money & Finance.

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