X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from sccrmhc12.comcast.net ([204.127.202.56] verified) by logan.com (CommuniGate Pro SMTP 4.3.6) with ESMTP id 613007 for flyrotary@lancaironline.net; Sat, 23 Jul 2005 19:39:40 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.202.56; envelope-from=n3773@comcast.net Received: from rv8 (c-24-21-140-241.hsd1.or.comcast.net[24.21.140.241]) by comcast.net (sccrmhc12) with SMTP id <2005072323385501200c2704e>; Sat, 23 Jul 2005 23:38:55 +0000 Message-ID: <002001c58fdf$ae5ac370$f18c1518@rv8> Reply-To: "kevin lane" From: "kevin lane" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] FUEL FLOW was Re: [FlyRotary] Lycoming debugging test - -HELP! Date: Sat, 23 Jul 2005 16:37:34 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001B_01C58FA4.D3DD6E80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_001B_01C58FA4.D3DD6E80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable thank you for the reply. I will start looking into my fuel supply. I = do have a flow meter but haven't been watching it too much since I was = so concerned with the very high CHT's that I've been hitting. the mesh = filter in the carb is good, brand new in fact. I have two auto mesh = fuel filters ahead of the facet pump. they look clean thru the glass, = but I will remove them and look more closely. I have been reluctant to = remove the wing tanks in order to check the pick-up tubes since it is so = much work, plus my tanks are quite full. I suppose I could try to back = flush them first with an air hose if I am VERY careful. now that I = think about it I don't think I have tried switching tanks yet. that = would certainly be an easy task. I believe that my fuel flow meter was showing 8.5+ gals/hr at full = throttle. now that I think about it that may be low, and 10.5 more = typical. thanks for your help. we are having absolutely beautiful weather = here and I was so anxious to do some flying, but....at least I can hang = out at the airport some more. it's nice to find someone who doesn't = immediately say "I'd get rid of that electronic ignition to begin with"! to answer Tracy, yes I have EGT's, shows low 1100's since I am = running full rich, I have manifold pressure but never looked at it(I'd = make a hell of an experimental test pilot-wait, I am one, oops). in my = defense, I have been nervous running my CHT's up past 400 degrees in = order to replicate this problem, since I just had three cylinders welded = because of who knows what? I've been thinking about attaching my leaf = blower to my plenum to help cool things on the ground runups. it = produces 220mph wind, or so the box says. Kevin Lane Portland, OR e-mail-> n3773@comcast.net ----- Original Message -----=20 From: Leon Promet=20 To: Rotary motors in aircraft=20 Sent: Saturday, July 23, 2005 2:48 PM Subject: [FlyRotary] FUEL FLOW was Re: [FlyRotary] Lycoming debugging = test - -HELP! Hey Kevin, Check your fuel FLOW RATE, especially at your normal climb angle (on = the ground). It sounds like it's losing fuel flow on take-off - the = carb is using whatever fuel is in the bowl, and then running lean. You = might have to jack the fuselage to the required angle in case there is = something in the tank that is occuding the pick-up(s). However, if you = can reproduce it on the ground doing a run-up, it definitely sounds = like lack of fuel FLOW (not pressure) to me. If the engine will = maintain 1700 RPM, then it is getting almost but not quite enough fuel = FLOW at WOT. Various things come to mind. FIrstly, (and most easily), a = partially blocked fuel filter (just because it's new doesn't mean it'll = work!!). So change that first. Use a different brand to eliminate = faulty batch manufacture.=20 I once had a mysterious problem with an RX4. Chased it for weeks. = Turned out to be a bee in the fuel line. (I'm serious - the guy who = owned the car used to work for me and is still around and will verify = this!!). Anyway, Jack's pride & joy would work just fine around town. = But out on the open road, it would run out of fuel in 3rd gear (usually = when overtaking). Turned out that a bee (very dead at this stage) had = got into the fuel tank. (The problem occurred soon after Jack filled up = at some outback petrol station when he was on holidays). The bee = immediately got stuck in the fuel supply line. At normal cruising flow = rates, there was sufficient fuel to run the car. On hard acceleration, = the bee's wings & body would PARTIALLY block the supply line in the = tank. We only found it when we removed the tank, replaced it with = another one, and cut the old one open. You just wouldn't read about it = in Ripley's or the War Cry! I've also had pieces of fuel gum (and one instance a piece of = cardboard) block the fuel pick-up. When fuel sits a long time at a = bowser storage tank, especially if there is water at the bottom of the = tank, it will form a sheet of gum at the fuel/water interface, almost = like condom latex, (but nowhere near as strong). This film of gum gets = broken up the next time a tanker does a dump, and bits of this will = very effectively block a fuel pick-up, or cripple a fuel filter. =20 I've seen it happen on several occasions over the years. It was = particularly prevalent in the early '70s during the phase out of = "standard" petrol before the introduction of unleaded into this country = (all rotaries used to run on standard not super - which was heavily = leaded back then). I found out the hard way soon after I had purchsed = my RX2 Coupe in 1971. Filled up at an "out of the way" petrol station = (where the fuel sales volume on standard was virtually nil), and = immediately had problems. After eventually getting back to Sydney, we = quickly diagnosed it as a tank problem. Even steam cleaning the tank = didn't fix it. The tank was replaced, and we cut open the old one, = and there was all these bits of gum, just like a thin membrane tyhat = had been cut up. So the place I'd be looking is in your fuel SUPPLY system, as it = seems you have done everything else except check fuel FLOW rate. Can't = guarantee that this IS the problem, but the quick and easy way would be = to check your open flow rate at the carb, and then compare it with = somebody else's. Alternatively, you can work backwards as you know = that the engine requires at least 0.55 Lbs per hour per BHP at WOT. = (First convert that to litres or pints or quarts per minute and you can = direct measure it, or run the fuel into a can for 1 minute and then go = and weigh it). Fuel flow rate should be at least 25% more than the max = required at WOT so that your carb doesn't run dry. One other area of the problem could be the incorrect needle/seat = arrangement on the carb, or a partially blocked filter at the banjo - = I'm not privvy to what carb you are running so this is conjectural as I = plead total ignorance of Lycoming carbs. However, all stock Mazda = carbs have fine brass gauze mesh filters, both at the banjo, and on = top of the needle& seats. Additionally, in the racing 13Bs, an IDA Weber would run out of fuel = as the float bowl was just way too small for anything over 250 BHP. We = used to replace the 2.5 needle/seat assys with 3.0 units. But we would = STILL run out of fuel on long straights. Extended float bowls were then = added, which did fix the problem, but welding the Weber material was = tricky, especially if it had been saturated with oil laced fuel for a = long time (sometimes the castings were slightly porous).. My final solution was to add an EXTRA float bowl (from an SU carb), = with it's own needle & seat, and a fuel return. We could then go back = to a 2.5 Weber needle & seat, as the 3.0 one was prone to flooding at = idle and on the over-run. (Nothing good has ever come of fuel dilition = of engine oil in a race engine). This fixed all fuel flow issues. Some = time later, affordable aftermarket EFI came along, and all this passed = into history. But fuel SUPPLY issues are even MORE critical with EFI. So these are just a few areas where you can look. Be systematic, and = start at the connection between the carb and the supply line. You will = then quickly eliminate either the supply to the carb, or the carb = needle & seat itself. If the open pipe fuel flow is more than adequate, = then I'd be looking inside the carb for restrictions. As I have said, = this is only a guide. Feel free to contact me off line if you feel the = need. Cheers, Leon ----- Original Message -----=20 From: kevin lane=20 To: Rotary motors in aircraft=20 Sent: Sunday, July 24, 2005 6:33 AM Subject: [FlyRotary] Lycoming debugging test - -HELP! I realize that this isn't exactly the right forum, but you guys seem = to have excellent debugging skills. my local RV group is totally = worthless ("I find the carnauba wax doesn't show fingerprints as much as = the....")(except Mike!) the on-field mechanics are sick of me coming = by. my O-320 RV-6A is having RAG (rpm attention getter) problems. = it runs fine until about 300' on take-off, then the rpm's drop to like = 1700 (from 2200). switching mags to electronic ignition(Rose) makes no = difference. mixture no diff. pulling the throttle it will seem to run = fine at 1700rpm. I have 4 new cyls that I am attempting to break in. = ground run ups can only go like 2 minutes before CHT's exceed 400 = degrees. I discovered I can get the rpm drop on the ground if I run it = a minute or so full power. cht's will typically approach 415 degrees = when the drop takes place. I don't know if the temp is significant or = not, it does seem that way. I have a brand new slick left mag. rose = checked the electronic ignition and could find nothing wrong, even put = it in an oven to test. I installed a new carb since the old one showed = signs of leakage (and I'm at whits end). no change. my fuel pressure = has been showing 8psi this last year, up from 6 psi when originally = installed.(no idea why) I installed a pressure regulator in-line which = works like a charm. I can dial whatever pressure I like. 2 psi makes = no difference. I bypassed the mechanical fuel pump and ran it just on = the facet electric. 2 psi, no difference. I discovered that you can run = the carb for maybe 30 secs with no fuel pressure while it burns off the = bowl gas. premier engines suggested induction leak making the engine run = lean. no leaks detected cold or hot engine. (pressurized intake with = vacuum, sprayed soapy water) if the engine didn't run right to start with then many = explanations would hold. but it runs fine for several minutes. it runs = the same under mag or electronic ignition both before and after the = problem kicks in. everyone really wants to blame the rose ignition, but = I'm not seeing any connection. with such a quick run-up my oil temp = barely registers, so I doubt parts are seizing. I have new mineral oil = in it for breakin right now. there is a bit of MMO in the fuel too I = believe, left over from a mechanics "what the hell" attempt from way = back. my cyls are all new, rebuilts, so no valve problems. I checked = the push rod lengths when I reinstalled them. the engine isn't missing = when the problems occurs, it simply won't run faster and it seems to = prefer the throttle pulled back to match the rpm it is putting out. I = can't figure out any more lean mixture scenarios to try. the new carb = runs just like the old one did. I recently replaced the mag harness = with a much newer, used one. I tested it and it was fine. the plugs = are all new, but again, no diff between mag and elec ignition. if I = flip the ignition to R and shut off the elect ig then the engine quits = as would be expected, no wiring problems. fuel, spark, air, timing, that's all there is. this damn = lycoming lawn mower has me stumped. my engine has been running fine up = until this (hey, we all have "cracked" cylinders, get out your = microscope and look!). you guys have any ideas? Kevin Lane Portland, OR e-mail-> n3773@comcast.net ----- Original ------=_NextPart_000_001B_01C58FA4.D3DD6E80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
thank you for the = reply.  I will=20 start looking into my fuel supply.  I do have a flow meter but = haven't been=20 watching it too much since I was so concerned with the very high CHT's = that I've=20 been hitting.  the mesh filter in the carb is good, brand new in=20 fact.  I have two auto mesh fuel filters ahead of the facet = pump. =20 they look clean thru the glass, but I will remove them and look more=20 closely.  I have been reluctant to remove the wing tanks in order = to check=20 the pick-up tubes since it is so much work, plus my tanks are quite = full. =20 I suppose I could try to back flush them first with an air hose if I am = VERY=20 careful.  now that I think about it I don't think I have tried = switching=20 tanks yet.  that would certainly be an easy task.
    I believe = that my fuel=20 flow meter was showing 8.5+ gals/hr at full throttle.  now that I = think=20 about it that may be low, and 10.5 more typical.
    thanks for = your=20 help.  we are having absolutely beautiful weather here and I was so = anxious=20 to do some flying, but....at least I can hang out at the airport some=20 more.  it's nice to find someone who doesn't immediately say "I'd = get rid=20 of that electronic ignition to begin with"!
    to answer = Tracy, yes I=20 have EGT's, shows low 1100's since I am running full rich,  I have = manifold=20 pressure but never looked at it(I'd make a hell of an experimental test=20 pilot-wait, I am one, oops).  in my defense, I have been nervous = running my=20 CHT's up past 400 degrees in order to replicate this problem, since I = just had=20 three cylinders welded because of who knows what?  I've been = thinking about=20 attaching my leaf blower to my plenum to help cool things on the ground=20 runups.  it produces 220mph wind, or so the box says.
Kevin Lane  Portland, OR
e-mail-> n3773@comcast.net
----- Original Message -----
From:=20 Leon=20 Promet
Sent: Saturday, July 23, 2005 = 2:48=20 PM
Subject: [FlyRotary] FUEL FLOW = was Re:=20 [FlyRotary] Lycoming debugging test - -HELP!

Hey Kevin,
 
Check your fuel FLOW RATE,  = especially at=20 your normal climb angle  (on the ground).  It sounds like it's losing fuel flow on take-off = - the carb=20 is using whatever fuel is in the bowl,  and then=20 running lean. You might have to jack the fuselage to the = required=20 angle in case there is something in the tank that is occuding the=20 pick-up(s).  However,  if you can reproduce it on the ground = doing a=20 run-up,  it definitely sounds like lack of fuel FLOW (not = pressure) to=20 me.  If the engine will maintain 1700 RPM,  then it is = getting=20 almost but not quite enough fuel FLOW at WOT.
 
Various things come to mind.  = FIrstly, =20 (and most easily),  a partially blocked fuel filter (just because = it's=20 new doesn't mean it'll work!!).  So change that first.  Use = a=20 different brand to eliminate faulty batch = manufacture. 
 
I once had a mysterious problem with = an=20 RX4.  Chased it for weeks.  Turned out to be a bee in the = fuel line.=20 (I'm serious - the guy who owned the car used to work for me and is = still=20 around and will verify this!!).  Anyway,  Jack's pride & = joy=20 would work just fine around town.  But out on the open = road,  it=20 would run out of fuel in 3rd gear (usually when overtaking).  = Turned out=20 that a bee (very dead at this stage) had got into the fuel=20 tank. (The problem occurred soon after Jack filled up at some = outback=20 petrol station when he was on holidays).  The bee = immediately got=20 stuck in the fuel supply line.  At normal cruising flow = rates, =20 there was sufficient fuel to run the car. On hard acceleration,  = the=20 bee's wings & body would PARTIALLY block the supply line = in the=20 tank.  We only found it when we removed the tank,  replaced = it with=20 another one,  and cut the old one open.  You just wouldn't = read=20 about it in Ripley's or the War Cry!
 
I've also had pieces of fuel gum (and = one=20 instance a piece of cardboard) block the fuel pick-up.  When fuel = sits a=20 long time at a bowser storage tank,  especially if there is water = at the=20 bottom of the tank,  it will form a sheet of gum at the = fuel/water=20 interface,  almost like condom latex,  (but nowhere near as=20 strong).  This film of gum gets broken up the next time a = tanker=20 does a dump,  and bits of this will very effectively block a fuel = pick-up,  or cripple a fuel filter. 
 
I've seen it happen on several = occasions over the=20 years.  It was particularly prevalent in the early '70s = during the=20 phase out of "standard" petrol before the introduction of unleaded = into this=20 country (all rotaries used to run on standard not super - which was = heavily=20 leaded back then).  I found out the hard way soon after I had = purchsed my=20 RX2 Coupe in 1971. Filled up at an "out of the way" petrol station = (where the=20 fuel sales volume on standard was virtually nil),  and = immediately had=20 problems.  After eventually getting back to Sydney,  we = quickly=20 diagnosed it as a tank problem.  Even steam cleaning the tank = didn't fix=20 it.  The tank was replaced,  and we cut open the old = one,  and=20 there was all these bits of gum,  just like a thin membrane tyhat = had=20 been cut up.
 
So the place I'd be looking is in = your fuel=20 SUPPLY system,  as it seems you have done everything else except = check=20 fuel FLOW rate.  Can't guarantee that this IS the problem,  = but the=20 quick and easy way would be to check your open flow rate at the = carb, =20 and then compare it with somebody else's.  Alternatively,  = you can=20 work backwards as you know that the engine requires at least 0.55 = Lbs per=20 hour per BHP at WOT. (First convert that to litres or pints or = quarts per=20 minute and you can direct measure it,  or run the fuel into a can = for 1=20 minute and then go and weigh it).  Fuel flow rate should be at = least 25%=20 more than the max required at WOT so that your carb doesn't run=20 dry.
 
One other area of the problem could = be the=20 incorrect needle/seat arrangement on the carb,  or a partially = blocked=20 filter at the banjo - I'm not privvy to what carb you are running = so this=20 is conjectural as I plead total ignorance of Lycoming carbs. =20 However,  all stock Mazda carbs have fine brass gauze mesh=20 filters,  both at the banjo,  and on top of the needle&=20 seats.
 
Additionally, in the racing = 13Bs,  an IDA=20 Weber would run out of fuel as the float bowl was just way too small = for=20 anything over 250 BHP.  We used to replace the 2.5 needle/seat = assys with=20 3.0 units.  But  we would STILL run out of fuel on long=20 straights.  Extended float bowls were then added,  which=20 did fix the problem,  but welding the Weber material was=20 tricky,  especially if it had been saturated with oil laced fuel = for a=20 long time (sometimes the castings were slightly porous)..
 
My final solution was to add = an EXTRA float=20 bowl (from an SU carb),  with it's own needle & seat,  = and a=20 fuel return.   We could then go back to a 2.5 Weber needle = &=20 seat,  as the 3.0 one was prone to flooding at idle and on the=20 over-run. (Nothing good has ever come of fuel dilition of engine = oil in a=20 race engine). This fixed all fuel flow issues.  Some time=20 later, affordable aftermarket EFI came along,  and all = this=20 passed into history.  But fuel SUPPLY issues are even MORE = critical with=20 EFI.
 
So these are just a few areas where = you can=20 look.  Be systematic,  and start at the connection between = the carb=20 and the supply line.  You will then quickly eliminate either the = supply=20 to the carb,  or the carb needle & seat itself.  If the = open=20 pipe fuel flow is more than adequate,  then I'd be looking inside = the=20 carb for restrictions.  As I have said,  this is only a = guide. =20 Feel free to contact me off line if you feel the need.
 
Cheers,
 
Leon
 
 
----- Original Message -----
From:=20 kevin = lane=20
To: Rotary motors in = aircraft=20
Sent: Sunday, July 24, 2005 = 6:33=20 AM
Subject: [FlyRotary] Lycoming = debugging=20 test - -HELP!

I realize that this isn't = exactly the=20 right forum, but you guys seem to have excellent debugging = skills.  my=20 local RV group is totally worthless ("I find the carnauba wax = doesn't show=20 fingerprints as much as the....")(except Mike!)  the on-field = mechanics=20 are sick of me coming by.
    my = O-320 RV-6A is=20 having RAG (rpm attention getter) problems.  it runs fine until = about=20 300' on take-off, then the rpm's drop to like 1700 (from = 2200). =20 switching mags to electronic ignition(Rose) makes no = difference. =20 mixture no diff.  pulling the throttle it will seem to run = fine at=20 1700rpm.  I have 4 new cyls that I am attempting to break = in. =20 ground run ups can only go like 2 minutes before CHT's exceed 400=20 degrees.  I discovered I can get the rpm drop on the ground if = I run it=20 a minute or so full power.  cht's will typically approach 415 = degrees=20 when the drop takes place.  I don't know if the temp is = significant or=20 not, it does seem that way.  I have a brand new slick left = mag. =20 rose checked the electronic ignition and could find nothing wrong, = even put=20 it in an oven to test.  I installed a new carb since the old = one showed=20 signs of leakage (and I'm at whits end).  no change.  my = fuel=20 pressure has been showing 8psi this last year, up from 6 psi when = originally=20 installed.(no idea why)  I installed a pressure regulator = in-line which=20 works like a charm.  I can dial whatever pressure I like.  = 2 psi=20 makes no difference.  I bypassed the mechanical fuel pump and = ran it=20 just on the facet electric.  2 psi, no difference. I = discovered=20 that you can run the carb for maybe 30 secs with no fuel pressure = while it=20 burns off the bowl gas. premier engines suggested induction leak = making the=20 engine run lean.  no leaks detected cold or hot engine. = (pressurized=20 intake with vacuum, sprayed soapy water)
    if the = engine=20 didn't run right to start with then many explanations would = hold.  but=20 it runs fine for several minutes.  it runs the same under mag = or=20 electronic ignition both before and after the problem kicks = in. =20 everyone really wants to blame the rose ignition, but I'm not seeing = any=20 connection.  with such a quick run-up my oil temp barely = registers, so=20 I doubt parts are seizing.  I have new mineral oil in it for = breakin=20 right now.  there is a bit of MMO in the fuel too I believe, = left over=20 from a mechanics "what the hell" attempt from way back.  my = cyls are=20 all new, rebuilts, so no valve problems.  I checked the push = rod=20 lengths when I reinstalled them.  the engine isn't missing = when=20 the problems occurs, it simply won't run faster and it seems to = prefer the=20 throttle pulled back to match the rpm it is putting out.  I = can't=20 figure out any more lean mixture scenarios to try.  the new = carb runs=20 just like the old one did.  I recently replaced the mag harness = with a=20 much newer, used one.  I tested it and it was fine.  the = plugs are=20 all new, but again, no diff between mag and elec ignition.  if = I flip=20 the ignition to R and shut off the elect ig then the engine quits as = would=20 be expected, no wiring problems.
    fuel, = spark, air,=20 timing, that's all there is.  this damn lycoming lawn mower has = me=20 stumped.  my engine has been running fine up until this (hey, = we all=20 have "cracked" cylinders, get out your microscope and look!).  = you guys=20 have any ideas?
Kevin Lane  Portland, OR
e-mail-> n3773@comcast.net
----- Original=20
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