X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost05.isp.att.net ([204.127.217.105] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2368216 for flyrotary@lancaironline.net; Thu, 04 Oct 2007 10:04:13 -0400 Received-SPF: pass receiver=logan.com; client-ip=204.127.217.105; envelope-from=bbradburry@bellsouth.net Received: from arptk8ng400 (adsl-146-124-76.mco.bellsouth.net[72.146.124.76]) by bellsouth.net (frfwmhc05) with SMTP id <20071004140330H05006vgj7e>; Thu, 4 Oct 2007 14:03:30 +0000 X-Originating-IP: [72.146.124.76] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" In-Reply-To: Subject: RE: [FlyRotary] Re: Problem? [FlyRotary] Re: Coolant Water Pressure Date: Thu, 4 Oct 2007 10:03:31 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0033_01C8066D.D1AE4480" X-Mailer: Microsoft Office Outlook, Build 11.0.5510 Thread-Index: AcgGE9eEE4x21ylLSvic9GnB8/9g5gAd7KNA X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6000.16480 Message-ID: This is a multi-part message in MIME format. ------=_NextPart_000_0033_01C8066D.D1AE4480 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Yep, Ed. I have your original prop=85a Performance Prop 76 X 88. Tractor configuration=85It is a Lancair Legacy. The air going through the radiator after the fan is picking up 80*, = which seems like a lot to me=85.This is measured after the fan and may not be representative of the rest of the core. But prop blast should be = supplying the balance of the core with at least some air=85. I was running at 2100-2200 rpm during this test which I failed to = mention. If you look at your calculations you were doing before you were = distracted by the prop question, I think you were about to arrive at the conclusion that it should be cooling=85?? My coolant is a 50/50 antifreeze mix. I mention this because of the = next question. Back in my car repair days, you could tell if the thermostat was = sticking by removing the radiator cap and watching to see if the water started to = flow as the engine heated up. I don=92t have a thermostat, so can I remove = the radiator cap and start the engine to determine flow, or will the high = flow pump shoot antifreeze all over my plane? =20 I am interested in your completed calculations to see what you determine = my cooling results should be. =20 Without the folks on this list, only really gifted people like you and = Tracy could ever hope to =93get er done=94. =20 Thanks, Bill B =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Wednesday, October 03, 2007 7:19 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Problem? [FlyRotary] Re: Coolant Water Pressure =20 Grass? what grass? {:>) =20 Yes, it sounds like the air should rise to the top of your slanted = radiator. However, My experience has been that unless I run the engine up to = around 5000 rpm for about 15-30 seconds (does not have to be long) that I do = not have much success getting air out of the block. It seems to take that velocity of coolant flow to drag the water out of the block. =20 You have over 700 cubic inches of core, so that should be plenty for = cooling a two rotor. =20 =20 A multi pass radiator (two pass in your case) can require more coolant = pump flow as indicated by this extract from a pretty respected name in racing/cooling circles: =20 Double pass Double pass radiators require 16x more pressure to flow = the same volume of coolant through them, as compared to a single pass = radiator. Triple pass radiators require 64x more pressure to maintain the same = volume. Automotive water pumps are a centrifugal design, not positive = displacement, so with a double pass radiator, the pressure is doubled and flow is = reduced by approximately 33%. Modern radiator designs, using wide/thin cross sections tubes, seldom benefit from multiple pass configurations. The decrease in flow caused by multiple passes offsets any benefits of a high-flow water pump. =20 =20 Again, these are just back of the envelope calculations based on a great deal of assumption about your parameters. My gut feel is that 700 cubic inches should have no problem cooling your installation at those power settings even being a double pass radiator. So I would look else where. =20 You indicate you have an approx. 80F delta T across your radiator core = with the coolant temp a 210F. You have a fan which apparently has the spec = to draw 970 CFI across the 11" dia of the Fan. Lets assume that was the = flow through the entire core. Then that would give you 970*.0765 =3D 74 = lbm/min of air mass. =20 Q =3D 75 * .25 * 80 =3D 1500 BTU/Min just due to the flow resulting from = your fan - it would seem that plus whatever flow you are getting from your = prop - Prop??. =20 =20 Hey, this dumb question just occurred to me - I assume you are = running with a prop?? in a tractor configuration. I lose track of who has what. =20 =20 Ed =20 =20 =20 =20 =20 =20 =20 ----- Original Message -----=20 From: Bill Bradburry=20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 03, 2007 5:12 PM Subject: [FlyRotary] Re: Problem? [FlyRotary] Re: Coolant Water Pressure =20 I have an aluminum double pass radiator with the finned core size of = about 18.25 X 18.25 X 2.25. It is behind the engine and leaning rearward at = the top at about a 30-35* angle. The water from the engine enters on the = left lower and crosses the bottom half of the radiator to the right side then rises and goes back across the top of the radiator and exits the top = left side and returns to the engine. My radiator cap is at the top right corner of the radiator at the point where the water starts its second pass through the top half. My = pressure port is just below the radiator cap. The pressure sending unit is in a = =93T=94 with the hose which goes to the =BC=94 port at the top of the rear iron connected to the other side of the =93T=94. I thought that this hose = could have some effect on the pressure, but I am not certain why it would. =20 Any air in the system should either rise to the top of the radiator, or = if it was trapped in the block, it could come through the hose to the = radiator. All air should be found therefore? Under the radiator cap. I have never found any air there. =20 I think I found out a little something about the fuel system today. I = only put a few gallons in the right tank and have been checking for leaks and running the engine on this fuel. I wanted to run it down to the =93non-usable=94 level and then do the same thing with the left tank. = So I have been really low on fuel. My pressure has been holding, but I thought = that I could hear bubbles from time to time going through the lines. =20 Anyway, before, I could get a good start by setting the mixture at about = 4 PM oclock and it would fire up in a couple of blades. Today, I tried hitting the primer button a couple of times and it would start and immediately die. I finally had to set the cold start on and leave it on just to get the engine to run! Finally after it warmed up, it ran with = the mixture set at 12 oclock, but it was not steady. As my fuel ran out, = the pressure dropped finally to about 28 lbs and the engine started its = death rattle. I shut it off at that time. =20 The temperature had risen to 210* the ambient temp was 87-88* and the = air after the radiator was 168* This is with my radiator fan running. = (11=94 and 970 CFM) probably about 10-12 minutes of running the engine . My oil temp was only 160* and the air temp after the oil cooler was 145* = , I think that this would gone higher if I ran longer, because the oil in = the pan was up to 170-180* or so. The pan holds 5 qts, 8 qts in the system. Water pressure was up to 22-23 lbs and oil pressure was 70 lbs. =20 All my temp probes are within a degree or so of one another and with a mercury thermometer in the hangar when reading ambient temp and the = engine is cold. I think they are all correct. =20 I have the air/fuel ratio setup that comes with the EM-2, but it = doesn=92t work till the O2 sensor gets to about 800* or so, no help on trying to figure out starting ratio. =20 The timing brings up a good point. I got the Renesis out of a wrecked = car with 1800 miles on it, so the timing is set to the factory setting for = the Renesis. I have never checked it. Does anyone know what the factory setting would be for the Renesis?? =20 Staging is a good point, but I think that you are correct about having enough fuel to run a low speeds and not enough to run faster. I was = running out of fuel and probably didn=92t have enough to rip it. =20 You really have good insights when you are helping folks.. You are = pretty right on with your advice. =20 Thanks, Bill B (Must mow yard=85Must mow yard..) _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Wednesday, October 03, 2007 12:53 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Problem? [FlyRotary] Re: Coolant Water Pressure =20 Yes, too hot for that rpm, I agree. =20 Assuming you followed the good suggestions offered by Al, Lynn and = others regarding getting all the air out of the block - really important! I = almost cooked engines two times because of excess air in the coolant system. = Here is something that may quickly tell you something about the air you may = have in the system. =20 I can't recall what type of radiator set up you have, but with the Two = GM cores I use which are mounted vertically, you can touch the side tank of = the radiator and determine if there is air in the system. In my case, if I = do a complete drain and refill of the system, on the first run up the core's tanks will be hot approx 2/3 of the way up and then they are much = cooler - indicating that the remaining 1/3 of my core is filled with air. It generally takes me 3 runups reaching 5000 rpm before I can touch the = core tanks and find them hot all the way from top to bottom. So depending on your radiator set up that might be something you can quickly check. =20 If the mixture is too lean, you can get a backfire out the intake, too = rich and its generally the exhaust - where unburned fuel cooks off. So that = and black smoke would indicate to me too rich a mixture. I presume you do = not have an Air/Fuel ratio indicator - strongly recommend you get one, that tells you right away whether you are running rich or lean. Even a cheap = one can be a tremendous help in finding out whether too rich or too lean. =20 One thing you may want to check is your ignition timing. If using = Tracy's EC2 you need to set the static timing around 35 Deg BTDC. The EC2 backs = off 10 deg from that (25Deb BTDC) as its default starting point for ignition timing. So if you set the static timing to say 25 Deg then the EC2 = would be having the engine operate at a 25 - 10 deg =3D 15 Deg BTDC which is = pretty retarded timing for the rotary. OR if you set it too far advanced then = the timing might be too advanced. So just recheck it when you get the chance. =20 Another possibility is your injection system might not be staging = properly. IF that were the case, the engine might work fine below the staging = point but not above it. Could possibly be a sticking secondary injector (if = too rich or lean). But, that is a bit down the likely list. Something impeding the fuel flow might provide sufficient fuel and low rpm but not sufficient to run at high rpm. =20 Hope some of this helps =20 Ed =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.dmack.net/mazda/index.html =20 =20 =20 =20 =20 =20 ----- Original Message -----=20 From: Bill Bradburry=20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 03, 2007 11:23 AM Subject: [FlyRotary] Re: Problem? [FlyRotary] Re: Coolant Water Pressure =20 Ed, this is at about 2000 rpm. Like a fast idle. I am getting all = kinds of fuel cut like stoppages if I try to run the engine faster. I haven=92t = seen more than about 3700 rpm, but I just started it and have not tried to = tune anything. I figure I will have to run longer to get it tuned and the cooling is holding that back. =20 Speaking of that, you guys were talking a while back about the effects = you see when the engine is too lean, or too rich. Talking about backfires, = etc and what each effect represents. I have forgotten what means = what=85senior days, not moments! Do any of you remember how that went? I am having some problems getting started and am not certain if I am too rich or too lean. I am getting backfires out the exhaust at times and smoke from the exhaust at that = time. (black) I ran the batteries down yesterday trying to get started due to this. = When I originally started the engine, I flooded it. I am trying to prevent = this now and am concerned that I may not be using enough mixture. =20 Bill B =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Wednesday, October 03, 2007 10:05 AM To: Rotary motors in aircraft Subject: [FlyRotary] Problem? [FlyRotary] Re: Coolant Water Pressure =20 Bill,=20 =20 You indicate you get overheating after 10-15 minutes run time. I may = have missed it, but is this at idle, max throttle or what. Also what is your OAT. If at idle or low power then, yes what you are seeing is not what = it should be. On the other hand, if at WOT or high power settings, then = 10-15 minutes run time would be indication of a great cooling capacity. I can = not run my engine more than a minute or two at WOT on a 80F day without = temps getting into the 200F range. But, that is at 5800-6000 rpm. At idle, = the temps stabilize and I can idle all day with safe temps. =20 My coolant system runs with no air cushion and yes, I get a hydraulic = "lock" pressure reading of as high as 25 psi immediately upon engine start up. After a 30 - 60 seconds of running the pressure drops down to zero and = then after a few minutes running builds back up as the coolant warms up to operating temperatures. =20 =20 Plenty of suggestion have been made about what to check - all good. =20 =20 Good luck. =20 Ed =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.dmack.net/mazda/index.html ----- Original Message -----=20 From: Al Wick =20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 03, 2007 9:30 AM Subject: [FlyRotary] Re: Coolant Water Pressure =20 Bill, the definitive test is the one I described below. Really encourage = you to do it as described. Resist assumptions. Convert your ideas to measurements. =20 -al wick ----- Original Message -----=20 From: Bill Bradburry=20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 03, 2007 6:08 AM Subject: [FlyRotary] Re: Coolant Water Pressure =20 I think that I would see air under the radiator cap if I had a = compression gas leak? I never see any air.=20 To check a piston engine for head gasket leaks, you would put the = cylinder at TDC and pressurize the cylinder to about 150 lbs with compressed air = and check the radiator for air bubbles=85How do you check a rotary? I will check the pressure sender against a mechanical gage. =20 There is obviously a heating problem, but I think the pressure is higher than it should be until just ready to boil. I shut the engine off at = 210*, and at 22+ lbs, the boiling point should be well above 250*?? =20 Thanks for the suggestions of where to look, guys=85 =20 Bill B =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al p Wick Sent: Tuesday, October 02, 2007 7:49 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Coolant Water Pressure =20 Your coolant reservoir should be above engine.=20 =20 1) If it is, remove two cups of air from the reservoir. Then repeat your test.=20 2) If you now see pressure rise above 22 psi within 5 minutes of cold = start, you clearly have compression gases leaking into cooling system or bad = gage. =20 3) Air in the block is 10 times more significant than any other cooling factor. Make darn sure you don't have any. It causes local boiling, high temps, strange behavior. =20 Operating with two cups of air under cap is an important safety and diagnosis advantage. Everyone should do it. With that two cups, you only = see 22 psi if you have a genuine problem. You only see 0 psi if you have = genuine problem. The pressure is then a very fast and reliable indicator of = system integrity. So two cups of air has no negative effect on system = efficiency, just a substantial improvement in safety. Only time it could be a = negative would be if your reservoir was way too small, way too low, or flowed way = too much coolant. =20 Since you describe high temps AND pressure, I suspect you have = temperature problem. =20 I deliberately overheated my engine many times so that I was intimate = with pressure and temperature patterns. Then tested various concepts. Don't recommend you do the same. =20 -al wick =20 =20 On Tue, 2 Oct 2007 12:38:55 -0400 "Bill Bradburry" writes: I just recently got my Renesis started again after finishing my cowl. I seem to be getting very high coolant pressures. I can only run the = engine about 10-15 minutes before hitting the redline at 210*. My water = pressure is at 27 Lbs at that time. I only have a 22 Lb radiator cap, so I = assume that I am blowing into the recovery tank, but I have not confirmed that. = My oil temp has never exceeded about 165*. It might have gone higher if I could have run longer??? =20 This whole water pressure thing has me a little baffled. Since this is = a closed system and the only way pressure can build is due to the = expansion of the coolant after heating???, I am confused by some comments that have = been made from time to time. I remember something that Tracy said about his pressure would build for a time, then go to zero. It seems to me that = the pressure should correlate to the temp pretty closely since it is a = closed system??=20 =20 Can someone enlighten me a little on the science of this pressure? It = seems to me that there could be some pressure build up on the positive side of = the pump, but it would go negative on the suction side, so the net effect of = the pump should be close to zero?? =20 Also, my Renesis had only 1800 miles on it when I bought it, so I did = not have to tear it down. As a result, I am somewhat in the dark as to how = the water flows through the system. Could someone help me with that? I had = to remove the thermostat tower for height clearance , so I made an adapter plate that takes water from the top outlet of the pump and sends it to = the radiator (double pass), then from the radiator, it returns to the lower inlet of the pump. =20 Thanks, Bill B =20 -al wick Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam timing.=20 Artificial intelligence in cockpit, N9032U 240+ hours from Portland, = Oregon Glass panel design, Subaru install, Prop construct, Risk assessment = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html -Al Wick Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam timing.=20 Artificial intelligence in cockpit, N9032U 240+ hours from Portland, = Oregon Glass panel design, Subaru install, Prop construct, Risk assessment = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ------=_NextPart_000_0033_01C8066D.D1AE4480 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Yep, = Ed.

I have your original prop…a Performance Prop 76 X 88. Tractor configuration…It is a Lancair = Legacy.

The air going through the radiator = after the fan is picking up 80*, which seems like a lot to me….This is = measured after the fan and may not be representative of the rest of the core. But = prop blast should be supplying the balance of the core with at least some = air….

I was running at 2100-2200 rpm = during this test which I failed to mention.=A0 If you look at your calculations you = were doing before you were distracted by the prop question, I think you were = about to arrive at the conclusion that it should be = cooling…??

My coolant is a 50/50 antifreeze = mix.=A0 I mention this because of the next question.

Back in my car repair days, you = could tell if the thermostat was sticking by removing the radiator cap and watching = to see if the water started to flow as the engine heated up.=A0 I don’t = have a thermostat, so can I remove the radiator cap and start the engine to = determine flow, or will the high flow pump shoot antifreeze all over my = plane?

 

I am interested in your completed calculations to see what you determine my cooling results should = be.

 

Without the folks on this list, = only really gifted people like you and Tracy could ever hope to “get er = done”.

 

Thanks,

=

Bill B

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Wednesday, October = 03, 2007 7:19 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Problem? [FlyRotary] Re: Coolant Water Pressure

 

Grass?  what grass? = {:>)

 

Yes, it sounds like the air should rise to the top of = your slanted radiator.  However, My experience has been that unless I = run the engine up to around 5000 rpm for about 15-30 seconds (does not have = to be long) that I do not have much success getting air out of the block.  It = seems to take that velocity of coolant flow to drag the water out of the = block.

 

You have over 700 cubic inches of core, so that = should be plenty for cooling a two rotor. 

 

A multi pass radiator (two pass in your case) can = require more coolant pump flow as indicated by this extract from a pretty = respected name in racing/cooling circles:

 

   Double pass Double pass = radiators require 16x more pressure to flow the same volume of coolant through = them, as compared to a single pass radiator. Triple pass radiators require 64x = more pressure to maintain the same volume. Automotive water pumps are a = centrifugal design, not positive displacement, so with a double pass radiator, the pressure is doubled and = flow is reduced by approximately 33%. Modern radiator designs, using wide/thin = cross sections tubes, seldom benefit from multiple pass = configurations. The decrease in flow caused by multiple passes offsets any benefits of a high-flow water = pump.

 

 

=

Again, these are just back of the envelope = calculations based on a great deal of assumption about your parameters.  My gut = feel is that 700 cubic inches should have no problem cooling your installation = at those power settings even being a double pass radiator.  So I would look = else where.

 

 You indicate you have an approx. 80F delta T = across your radiator core with the coolant temp a 210F.  You have a fan = which apparently has the spec to draw 970 CFI across the 11" dia of the Fan.  Lets assume that was the flow through the entire core.  = Then that would give you 970*.0765 =3D 74 lbm/min of air = mass.

 

Q =3D 75 * .25 * 80 =3D 1500 BTU/Min just due to the = flow resulting from your fan - it would seem that plus whatever flow you are = getting from your prop - Prop??. 

 

Hey, this  dumb question just occurred to me  -  I assume you are running with a prop?? in a tractor configuration.  I lose track of who has = what.

 

 

Ed

 

 

 

 

 

=

 

=

 

----- Original Message ----- =

Sent: = Wednesday, October 03, 2007 5:12 PM

Subject: = [FlyRotary] Re: Problem? [FlyRotary] Re: Coolant Water = Pressure

 

I have an aluminum double pass = radiator with the finned core size of about 18.25 X 18.25 X 2.25.  It is = behind the engine and leaning rearward at the top at about a 30-35* angle.  = The water from the engine enters on the left lower and crosses the bottom half of = the radiator to the right side then rises and goes back across the top of = the radiator and exits the top left side and returns to the = engine.

My radiator cap is at the top right = corner of the radiator at the point where the water starts its second pass = through the top half.  My pressure port is just below the radiator cap.  = The pressure sending unit is in a “T” with the hose which goes = to the =BC” port at the top of the rear iron connected to the other side = of the “T”.  I thought that this hose could have some effect = on the pressure, but I am not certain why it = would.

 

Any air in the system should either = rise to the top of the radiator, or if it was trapped in the block, it could = come through the hose to the radiator.  All air should be found = therefore? Under the radiator cap.  I have never found any air = there.

 

I think I found out a little = something about the fuel system today.  I only put a few gallons in the right = tank and have been checking for leaks and running the engine on this = fuel.  I wanted to run it down to the “non-usable” level and then do = the same thing with the left tank.  So I have been really low on = fuel.  My pressure has been holding, but I thought that I could hear bubbles = from time to time going through the lines.

 

Anyway, before, I could get a good = start by setting the mixture at about 4 PM oclock and it would fire up in a = couple of blades.  Today, I tried hitting the primer button a couple of times = and it would start and immediately die.  I finally had to set the cold = start on and leave it on just to get the engine to run!  Finally after it = warmed up, it ran with the mixture set at 12 oclock, but it was not = steady.  As my fuel ran out, the pressure dropped finally to about 28 lbs and the = engine started its death rattle.  I shut it off at that = time.

 

The temperature had risen to 210* = the ambient temp was 87-88* and the air after the radiator was 168*  = This is with my radiator fan running.  (11” and 970 CFM) probably = about 10-12 minutes of running the engine

.

My oil temp was only 160* and the = air temp after the oil cooler was 145* , I think that this would gone higher if I = ran longer, because the oil in the pan was up to 170-180* or so.  The = pan holds 5 qts, 8 qts in the system.

Water pressure was up to 22-23 lbs = and oil pressure was 70 lbs.

 

All my temp probes are within a = degree or so of one another and with a mercury thermometer in the hangar when = reading ambient temp and the engine is cold.  I think they are all = correct.

 

I have the air/fuel ratio setup = that comes with the EM-2, but it doesn’t work till the O2 sensor gets to = about 800* or so, no help on trying to figure out starting = ratio.

 

The timing brings up a good = point.  I got the Renesis out of a wrecked car with 1800 miles on it, so the = timing is set to the factory setting for the Renesis.  I have never checked it.  Does anyone know what the factory setting would be for the = Renesis??

 

Staging is a good point, but I = think that you are correct about having enough fuel to run a low speeds and not = enough to run faster.  I was running out of fuel and probably didn’t = have enough to rip it.

 

You really have good insights when = you are helping folks.. You are pretty right on with your = advice.

 

Thanks,

=

Bill B  (Must mow = yard…Must mow yard..)

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Wednesday, October = 03, 2007 12:53 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Problem? [FlyRotary] Re: Coolant Water Pressure

 

Yes, too hot for that rpm, I = agree.

 

Assuming  you followed the good suggestions = offered by Al, Lynn and others regarding getting all the air out of the block - = really important!  I almost cooked engines two times because of excess air = in the coolant system.  Here is something that  may quickly tell you something about the air you may have in the = system.

 

  I can't recall what type of radiator set up = you have, but with the Two GM cores I use which are mounted vertically, you = can touch the side tank of the radiator and determine if there is air = in the system.  In my case, if I do a complete drain and refill = of the system, on the first run up the core's tanks  will be hot approx = 2/3 of the way up and then they are much cooler - indicating that the remaining = 1/3 of my core is filled with air.  It generally takes me 3 runups reaching 5000 rpm before I can touch  the core tanks and = find them hot all the way from top to bottom.  So depending on your = radiator set up that might be something you can quickly = check.

 

If the mixture is too lean, you can get a backfire = out the intake, too rich and its generally the exhaust - where unburned fuel = cooks off.  So that and black smoke would indicate to me  too rich a mixture.  I presume you do not have an Air/Fuel ratio indicator - = strongly recommend you get one, that tells you right away whether you are running = rich or lean.  Even a cheap one can be a tremendous help in finding out = whether too rich or too lean.

 

One thing you may want to check is your ignition timing.  If using Tracy's EC2 you need to set the static timing around 35 Deg BTDC.  The EC2 = backs off 10 deg from that (25Deb BTDC) as its default starting point for = ignition timing.  So if you set the static timing to say 25 Deg then the EC2 = would be having the engine operate at a 25 - 10 deg =3D 15 Deg BTDC which is = pretty retarded timing for the  rotary.  OR if you set it too far = advanced then the timing might be too advanced.

So just recheck it when you get the = chance.

 

Another possibility is your injection system might = not be staging properly. IF that were the case, the engine might work fine = below the staging point but not above it.  Could possibly be a sticking secondary injector (if too rich or lean).   But, that is a bit = down the likely list.  Something impeding the fuel flow might provide sufficient fuel and low rpm but not sufficient to run at high = rpm.

 

Hope some of this helps

 

Ed

 

 

 

 

 

 

 

----- Original Message ----- =

Sent: = Wednesday, October 03, 2007 11:23 AM

Subject: = [FlyRotary] Re: Problem? [FlyRotary] Re: Coolant Water = Pressure

 

Ed, this is at about 2000 = rpm.  Like a fast idle.  I am getting all kinds of fuel cut like stoppages if = I try to run the engine faster.  I haven’t seen more than about = 3700 rpm, but I just started it and have not tried to tune anything.  I = figure I will have to run longer to get it tuned and the cooling is holding that = back.

 

Speaking of that, you guys were = talking a while back about the effects you see when the engine is too lean, or too rich.  Talking about backfires, etc and what each effect = represents.  I have forgotten what means what…senior days, not = moments!

Do any of you remember how that went?  I am having some problems getting started and am not certain = if I am too rich or too lean.  I am getting backfires out the exhaust at = times and smoke from the exhaust at that time. = (black)

I ran the batteries down yesterday = trying to get started due to this.  When I originally started the engine, = I flooded it.  I am trying to prevent this now and am concerned that = I may not be using enough mixture.

 

Bill B

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Wednesday, October = 03, 2007 10:05 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] = Problem? [FlyRotary] Re: Coolant Water Pressure

 

Bill,

 

You indicate you get overheating after 10-15 minutes = run time.  I may have missed it, but is this at idle, max throttle or what.  Also what is your OAT.  If at idle or low power then, = yes what you are seeing is not what it should be.  On the other hand, if at = WOT or high power settings, then 10-15 minutes run time would be indication of = a great cooling capacity.  I can not run my engine more than a minute or = two at WOT on a 80F day without temps getting into the 200F range.  But, = that is at 5800-6000 rpm.  At idle, the temps stabilize and I can idle all = day with safe temps.

 

My coolant system runs with no air cushion and yes, I = get a hydraulic "lock" pressure reading of as high as 25 psi = immediately upon engine start up.  After a 30 - 60 seconds of running the pressure  drops down to zero and then after a few minutes = running builds back up as the coolant warms up to operating temperatures.  =

 

Plenty of suggestion have been made about what to = check - all good. 

 

Good luck.

 

Ed

 

----- Original Message ----- =

From: Al Wick =

Sent: = Wednesday, October 03, 2007 9:30 AM

Subject: = [FlyRotary] Re: Coolant Water Pressure

 

Bill, the definitive test is the one I described = below. Really encourage you to do it as described. Resist assumptions. Convert = your ideas to measurements.

 

-al wick

----- Original Message ----- =

Sent: = Wednesday, October 03, 2007 6:08 AM

Subject: = [FlyRotary] Re: Coolant Water Pressure

 

I think that I would see air under = the radiator cap if I had a compression gas leak?  I never see any air. =

To check a piston engine for head = gasket leaks, you would put the cylinder at TDC and pressurize the cylinder to = about 150 lbs with compressed air and check the radiator for air = bubbles…How do you check a rotary?

I will check the pressure sender = against a mechanical gage. 

There is obviously a heating = problem, but I think the pressure is higher than it should be until just ready to boil.  I shut the engine off at 210*, and at 22+ lbs, the boiling = point should be well above 250*??

 

Thanks for the suggestions of where = to look, guys…

 

Bill B

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al p Wick
Sent: Tuesday, October = 02, 2007 7:49 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Coolant Water Pressure

 

Your coolant reservoir should be above engine. =

 

1) If it is, remove two cups of air from the reservoir. Then = repeat your test.

2) If you now see pressure rise above 22 psi within 5 = minutes of cold start, you clearly have compression gases leaking into cooling = system or bad gage.

 

3) Air in the block is 10 times more significant than any other = cooling factor. Make darn sure you don't have any. It causes local boiling, high = temps, strange behavior.

 

Operating with two cups of air under cap is an important safety = and diagnosis advantage. Everyone should do it. With that two cups, you only = see 22 psi if you have a genuine problem. You only see 0 psi if you have = genuine problem. The pressure is then a very fast and reliable indicator of = system integrity. So two cups of air has no negative effect on system = efficiency, just a substantial improvement in safety. Only time it could be a negative = would be if your reservoir was way too small, way too low, or flowed way too much coolant.

 

Since you describe high temps AND pressure, I suspect you have temperature problem.

 

I deliberately overheated my engine many times so that I was = intimate with pressure and temperature patterns. Then tested various = concepts. Don't recommend you do the same.

 

-al wick

 

 

On Tue, 2 Oct 2007 12:38:55 -0400 "Bill Bradburry" = <bbradburry@bellsouth.net>= writes:

I just recently got my Renesis started again after = finishing my cowl.  I seem to be getting very high coolant pressures.  I = can only run the engine about 10-15 minutes before hitting the redline at 210*.  My water pressure is at 27 Lbs at that time.  I only = have a 22 Lb radiator cap, so I assume that I am blowing into the recovery tank, = but I have not confirmed that.  My oil temp has never exceeded about = 165*.  It might have gone higher if I could have run = longer???

 

This whole water pressure thing has me a little baffled.  Since this is a closed system and the only way pressure = can build is due to the expansion of the coolant after heating???, I am = confused by some comments that have been made from time to time.  I remember = something that Tracy said about his pressure would build for a time, then go to zero.  It = seems to me that the pressure should correlate to the temp pretty closely since = it is a closed system??

 

Can someone enlighten me a little on the science of = this pressure?  It seems to me that there could be some pressure build = up on the positive side of the pump, but it would go negative on the suction = side, so the net effect of the pump should be close to = zero??

 

Also, my Renesis had only 1800 miles on it when I = bought it, so I did not have to tear it down.  As a result, I am somewhat in = the dark as to how the water flows through the system.  Could someone help = me with that?  I had to remove the thermostat tower for height clearance , = so I made an adapter plate that takes water from the top outlet of the pump = and sends it to the radiator (double pass), then from the radiator, it = returns to the lower inlet of the pump.

 

Thanks,

Bill B

 


-al wick
Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam = timing.
Artificial intelligence in cockpit, N9032U 240+ hours from Portland, Oregon
Glass panel design, Subaru install, Prop construct, Risk assessment = info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html

-Al Wick
Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam = timing.
Artificial intelligence in cockpit, N9032U 240+ hours from Portland, Oregon
Glass panel design, Subaru install, Prop construct, Risk assessment = info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html<= /span>

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