X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [199.185.220.224] (HELO defout.telus.net) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2786191 for flyrotary@lancaironline.net; Mon, 10 Mar 2008 22:19:58 -0400 Received-SPF: pass receiver=logan.com; client-ip=199.185.220.224; envelope-from=tomk@telus.net Received: from priv-edtnaa05.telusplanet.net ([207.216.205.78]) by priv-edtnes90.telusplanet.net (InterMail vM.7.08.02.00 201-2186-121-20061213) with ESMTP id <20080311021918.BAHM26951.priv-edtnes90.telusplanet.net@priv-edtnaa05.telusplanet.net> for ; Mon, 10 Mar 2008 20:19:18 -0600 Received: from familygr7vkfo2 (d207-216-205-78.bchsia.telus.net [207.216.205.78]) by priv-edtnaa05.telusplanet.net (BorderWare MXtreme Infinity Mail Firewall) with SMTP id 5BN6DDT66F for ; Mon, 10 Mar 2008 20:19:17 -0600 (MDT) Message-ID: <001f01c8831e$4f317d00$6401a8c0@familygr7vkfo2> From: "Tom-Lynn Koftinoff" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Unusual Noise in Engine Date: Mon, 10 Mar 2008 19:19:17 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001C_01C882E3.A2AC7F60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_001C_01C882E3.A2AC7F60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Yes, I'll run it for another five to ten hours to determine if the noise = disappears. I appreciate the help. Thanks, Tom ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Monday, March 10, 2008 8:46 AM Subject: [FlyRotary] Re: Unusual Noise in Engine Noises are really difficult to describe in words so this is just a = shot in the dark. You might be hearing the sound of the tension bolts suddenly releasing = residual torsional tension from the overhaul. The threads will = sometimes suddenly overcome their starting friction and spin (just a = partial turn ) until the residual tension is relieved. On a freshly = overhauled engine I noticed this on cool down after a run. In a car = with a good muffler you might gear it while it's running while warming = up. This noise sounds like a sharp metalic tick, very similar to = engine 'ping' from detonation. It also is the same sound as a Rotax = cylinder stud makes when it breaks. If this is what it is, it eventually stops when all the bolts are = 'relieved'. I then continued to fly that engine for 856 hours. If this = occasional tick doesn't stop, after a dozen or so engine runs, this = isn't it. Don't be in too big a hurry to tear the engine down until you = are sure there is a real problem. Tracy =20 On Mon, Mar 10, 2008 at 3:16 AM, Tom-Lynn Koftinoff = wrote: I am testing an '88, 13B, non turbo engine that I rebuilt according = to Tracy Crook's manual (Aviator's Guide to Mazda Rotary Conversions). = I did the rebuild, many years ago, before Tracy sold his rebuild kits, = and it's my first rotary that I rebuilt. I purchased my rebuild kit = from Dave Atkins. I am running it with Tracy's EC2 (purchased in = '02), and I wired the harness as per his plans. I fabricated my own = intake manifold. Presently, the motor is installed in an '86 Mazda RX-7 = car. I am using the transmission (i.e., most of the drivetrain) from = the car, to put a load on the engine (i.e., wheels are off the ground). = The fuel pump, fuel tank, battery, tach, coolant temp gauge, exhaust, = starter, is, stock, from the car. I have an external oil pressure = gauge, oil temp. gauge, ammeter, voltmeter, vacuum gauge, air/fuel = gauge, circuit breakers, and toggle switches. I didn't want to spend = any more money (i.e., purchasing Tracy's RD-1B, EM3, prop. etc.) on = the engine until I knew the engine was running adequately, and, = therefore, I am using the car as the test bed. The engine starts = fairly easy up here in B.C., Canada, on cold winter days, and I have = been running it, off and on, since late spring of '07. One of the = problems/issues I am trying to deal with is a random, intermittent noise = from the engine, when the engine is running cold. The noise sounds = like a coin on edge being tapped against some metal, such as a fender of = a car. After the engine warms up, and I run it up to 3000 - 6000 RPMs = I don't hear the noise. The engine hasn't used any oil, and I have run = approximately 40 gallons of gas through it. At very high RMPs (5000 to = 6000) I have placed the transmission into neutral because I have been = concerned about damaging the transmission/drive train. As a result of = running the engine with no load (i.e., transmission in neutral) on it, = at high RPM's, my plugs have fouled and stopped working or produced a = weak spark. Tracy has warned me that his EC2 was designed to run with = a propeller load, and my plugs will foul, if I don't run it with a load. = 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. =20 Thanks, Tom ------=_NextPart_000_001C_01C882E3.A2AC7F60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Yes, I'll run it for another = five to ten=20 hours to determine if the noise disappears.
 
I appreciate the = help.
 
Thanks,
 
Tom
----- Original Message -----
From:=20 Tracy=20 Crook
Sent: Monday, March 10, 2008 = 8:46=20 AM
Subject: [FlyRotary] Re: = Unusual Noise in=20 Engine

Noises are really difficult to describe in words so this is just = a shot=20 in the dark.
 
You might be hearing the sound of the tension bolts suddenly = releasing=20 residual torsional tension from the overhaul.  The threads will = sometimes=20 suddenly overcome their starting friction and spin (just a partial = turn )=20 until the residual tension is relieved.  On a freshly overhauled = engine I=20 noticed this on cool down after a run.  In a car with a good = muffler you=20 might gear it while it's running while warming up.   This = noise=20 sounds like a sharp metalic tick, very similar to engine 'ping' from=20 detonation. It also is the same sound as a Rotax cylinder stud = makes when=20 it breaks.

If this is what it is, it eventually stops when all=20 the bolts are 'relieved'.  I then continued to fly that = engine for=20 856 hours.  If this occasional tick doesn't stop, after a dozen = or so=20 engine runs, this isn't it.  Don't be in too big a hurry to tear = the=20 engine down until you are sure there is a real problem.
 
Tracy

 
On Mon, Mar 10, 2008 at 3:16 AM, Tom-Lynn = Koftinoff=20 <tomk@telus.net> = wrote:
I am = testing an=20 '88, 13B, non turbo engine that I rebuilt according to Tracy Crook's = manual=20 (Aviator's Guide to Mazda Rotary Conversions).  I did the = rebuild, many=20 years ago, before Tracy sold his rebuild kits, and = it's my=20 first rotary that I rebuilt.   I = purchased my rebuild=20 kit from Dave Atkins.    I am running it with Tracy's = EC2=20 (purchased in '02), and I wired the harness as per his=20 plans.  I fabricated my own intake manifold.  = Presently, the=20 motor is installed in an '86 Mazda RX-7 car.  I am using = the=20 transmission (i.e., most of the drivetrain) from the car, to put a=20 load on the engine (i.e., wheels are off the = ground).  =20 The fuel pump, fuel tank, battery, tach, coolant temp = gauge,=20 exhaust, starter, is, stock, from the car.   I have = an=20 external oil pressure gauge, oil temp. gauge, ammeter, = voltmeter,=20 vacuum gauge, air/fuel gauge, circuit breakers, and toggle = switches.  I=20 didn't want to spend any more money  (i.e., = purchasing Tracy's=20 RD-1B, EM3, prop. etc.)    on the engine until I = knew=20 the engine was running adequately, and, therefore, I am using = the car=20 as the test bed.   The engine starts fairly easy up here = in B.C.,=20 Canada, on cold winter days, and I have been running it, off = and on,=20 since late spring of '07.   One of the problems/issues I = am trying=20 to deal with is a random, intermittent noise from the engine, when = the=20 engine is running cold.   The noise sounds like a = coin on=20 edge being tapped against some metal, such as a fender of a = car.  =20 After the engine warms up, and I run it up to 3000 - 6000 RPMs I = don't hear=20 the noise.   The engine hasn't used any oil, and I have = run=20 approximately 40 gallons of gas through it.   At very high = RMPs=20 (5000 to 6000) I have placed the transmission into neutral = because I=20 have been concerned about damaging the transmission/drive = train.  =20 As a result of running the engine with no load (i.e., transmission = in=20 neutral) on it, at high RPM's, my plugs have fouled and stopped = working or=20 produced a weak spark.   Tracy has warned me that his EC2 = was=20 designed to run with a propeller load, and my plugs will foul, if I = don't=20 run it with a load.   My question is regarding the noise = that I=20 hear.  Has anyone experienced such a = noise?  I have=20 noticed the engine missing sporadically at low RPM's with a load on = it, and=20 the fuel/air mixture gauge showing five to six = LEDS.   Can a=20 miss, detonation, bad timing, fouled plug(s) etc cause = such a=20 noise?  My timing is very close to 23 degrees=20 BTDC.   When I turn the engine over = manually=20 (i.e., with socket and ratchet) the engine feels like it has good=20 compression, and doesn't make any strange noises, such as, anything = broken=20 or loose inside.    I may tear the engine apart = to=20 inspect the inside, later this year.  
 
Thanks,
 
 
Tom

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