X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from smtp109.sbc.mail.mud.yahoo.com ([68.142.198.208] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with SMTP id 1127117 for flyrotary@lancaironline.net; Wed, 24 May 2006 23:42:04 -0400 Received-SPF: none receiver=logan.com; client-ip=68.142.198.208; envelope-from=dcarter11@sbcglobal.net Received: (qmail 57360 invoked from network); 25 May 2006 03:41:21 -0000 Received: from unknown (HELO davidsdell8200) (dcarter11@sbcglobal.net@67.41.226.150 with login) by smtp109.sbc.mail.mud.yahoo.com with SMTP; 25 May 2006 03:41:20 -0000 Message-ID: <19b701c67fad$687dc320$6401a8c0@davidsdell8200> From: "David Carter" To: "Rotary motors in aircraft" References: Subject: Spark plug gap (was Re: Another case of heat-soaked coils? Date: Wed, 24 May 2006 21:43:37 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_19B4_01C67F7B.1D26E0F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_19B4_01C67F7B.1D26E0F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I saw Lynn's recent thing about troubleshooting using a spark plug with = .010 gap. Then this exchange about there being adjustable gap plugs = that can be used in addition to the "stock" non-adjustable plugs. I can't remember the reason for using the "test spark plug gapped at = .010". Lynn, would you cover that again? . . . I'm familiar with the fairly well know characteristic that the = "spark" has more difficulty jumping the gap as the gap increases in = size, and, as the compression increases. . . . Thus, I associate the large .060 gap in my 1995 Ford Escort with a = "high energy" (high voltage) coil pack electronic ignition system, as = contrasted with my former 1954 Ford 6 cylinder with 7 to 1 or so = compression ratio and old 30,000 volt (maybe) cylindrical coil and = distributor system, then stock on most cars. . . . . . A friend had a 1956 Chevy V8 "power pack" that had a miss: We = took my 6 known good plugs from my Ford and put in his 8.5 to 1 = compression ratio V8 for trouble shooting (after grounding indivual = plugs and not seeing much change in miss, so assumed the plugs were = bad), so put my 6 "good" spark plugs, which weren't missing, into his V8 = - still missed, so we mentally "eliminated" spark plugs as the culprit = and started pulling the heads to look for bad valves. A cooler, older = head interrupted our course of action - we ended up by simply buying 8 = new stock plugs for the V8 and the miss went away - my "known good" = spark plugs that fired at 7:1 compression simply wouldn't fire in his = 8.5:1 engine. So, how does all this relate to a "process of elimination" = troubleshooting of the fellow who recently had the severe miss in his = rotary and discussion of ignition systems and bad coils? . . . I can see that a .010 gap plug ought to fire at about any = compression and even with a crummy/degraded ignition system = (bad/weak/cracked/arcing-through-cracks coil block). . . . . . If the coils are degraded, why would we want to get them to = fire with the smaller gap in plugs? Speaking of coil packs, I replaced a bad (cracked and arcing) coil block = on the 1993 Escort which fixed the miss. I later found on the internet = an article about looking at the coils with engine idling AT NIGHT IN THE = DARK and you could see sparks jumping out of the coil block onto the = metal mount, etc. The article said such coils could be "repaired" by = coating/pototing them with epoxy or some such stuff. That works - when = my 1995 Escort developed the same problem, I repaired it rather than = replacing it. . . . So, I suggest as one of several trouble shooting steps to = "visually inspect the igniter coils in the dark to look for visible = arcing" - "then repair or replace as necessary". David Carter ----- Original Message -----=20 From: Lehanover@aol.com=20 To: Rotary motors in aircraft=20 Sent: Tuesday, May 23, 2006 6:17 PM Subject: [FlyRotary] Re: Another case of heat-soaked coils? In a message dated 5/23/2006 6:55:35 P.M. Eastern Daylight Time, = sladerj@bellsouth.net writes: The plugs I'm using BUR7EQ/BUR9EQ don't allow for gap adjustment. John Just for trouble shooting there are a world of cold plugs that will = work just fine and do have adjustable gaps. There total loss of engine = power seems more fuel related, like boiling fuel in a pump or similar. = Similar to a loss of prime without a return bleed port. We boiled fuel = in the regulator a few times, and that had a similar outcome. Lynn E. Hanover ------=_NextPart_000_19B4_01C67F7B.1D26E0F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I saw Lynn's recent thing about troubleshooting using a spark plug = with=20 .010 gap.  Then this exchange about there being adjustable gap = plugs that=20 can be used in addition to the "stock" non-adjustable plugs.
 
I can't remember the reason for using the "test spark plug gapped = at=20 .010".  Lynn, would you cover that again?
. . . I'm familiar with the fairly well know characteristic that = the=20 "spark" has more difficulty jumping the gap as the gap increases in = size, and,=20 as the compression increases.
. . . Thus, I associate the large .060 gap in my 1995 Ford Escort = with a=20 "high energy" (high voltage) coil pack electronic ignition system, as = contrasted=20 with my former 1954 Ford 6 cylinder with 7 to 1 or so compression ratio = and old=20 30,000 volt (maybe) cylindrical coil and distributor system, then stock = on most=20 cars.
. . . . . A friend had a 1956 Chevy V8 "power pack" that had a = miss: =20 We took my 6 known good plugs from my Ford and put in his 8.5 to 1 = compression=20 ratio V8 for trouble shooting (after grounding indivual plugs and = not=20 seeing much change in miss, so assumed the plugs were bad), so put my 6 = "good"=20 spark plugs, which weren't missing, into his V8 - still missed, so we = mentally=20 "eliminated" spark plugs as the culprit and started pulling the heads to = look=20 for bad valves.  A cooler, older head interrupted our course of = action - we=20 ended up by simply buying 8 new stock plugs for the V8 and the miss went = away -=20 my "known good" spark plugs that fired at 7:1 compression simply = wouldn't fire=20 in his  8.5:1 engine.
 
So, how does all this relate to a "process of elimination" = troubleshooting=20 of the fellow who recently had the severe miss in his rotary and = discussion of=20 ignition systems and bad coils?
. . .  I can see that a .010 gap plug ought to fire at about = any=20 compression and even with a crummy/degraded ignition system=20 (bad/weak/cracked/arcing-through-cracks coil block).
. . . . .   If the coils are degraded, why would we want to = get them=20 to fire with the smaller gap in plugs?
 
Speaking of coil packs, I replaced a bad (cracked and arcing) coil = block on=20 the 1993 Escort which fixed the miss.  I later found on the = internet an=20 article about looking at the coils with engine idling AT NIGHT IN THE = DARK and=20 you could see sparks jumping out of the coil block onto the metal mount, = etc.  The article said such coils could be "repaired" by=20 coating/pototing them with epoxy or some such stuff.  That works - = when my=20 1995 Escort developed the same problem, I repaired it rather than = replacing=20 it.
. . . So, I suggest as one of several trouble shooting steps to = "visually=20 inspect the igniter coils in the dark to look for visible arcing" - = "then repair=20 or replace as necessary".
 
David Carter
----- Original Message -----
From:=20 Lehanover@aol.com
Sent: Tuesday, May 23, 2006 = 6:17 PM
Subject: [FlyRotary] Re: = Another case of=20 heat-soaked coils?

In a message dated 5/23/2006 6:55:35 P.M. Eastern Daylight Time, = sladerj@bellsouth.net = writes:
The=20 plugs I'm using BUR7EQ/BUR9EQ don't allow for gap=20 adjustment.

John
Just for trouble shooting there are a world of cold plugs that = will work=20 just fine and do have adjustable gaps. There total loss of engine = power=20 seems more fuel related, like boiling fuel in a pump or = similar. Similar=20 to a loss of prime without a return bleed port. We boiled fuel in = the=20 regulator a few times, and that had a similar outcome.
 
Lynn E. Hanover
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