RV-List Digest Archive

Wed 07/04/12


Total Messages Posted: 4



Today's Message Index:
----------------------
 
     1. 05:31 AM - Re: #3 overheating (Carl Froehlich)
     2. 06:17 AM - Re: #3 overheating (Doug Gray)
     3. 06:31 AM - Overheating (Ian Brown)
     4. 02:39 PM - #3 overheating (MLE)
 
 
 


Message 1


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    Time: 05:31:42 AM PST US
    From: "Carl Froehlich" <carl.froehlich@verizon.net>
    Subject: #3 overheating
    I would expect the "Coke Bottle" test flow rate to not be a good representation of actual engine running conditions, just a gross "looks about right". As you did, I also swapped highest to lowest injectors on to help balance the cylinders. I based highest and lowest however on steady state fuel flow going lean of peak. In other words, I swapped the first to peak cylinder injector with the last to peak cylinder injector. Recommend a data run where you log total fuel flow when each cylinder peaks. If you can get first peak fuel flow and last peak fuel flow to within .2GPH or so, you should be good. If not, then it is time to consider changing the cylinder that is way out with a new injector, either next size larger (first to peak is out) or next size smaller (last to peak is out). Take several data runs to make sure you really have good information so you don't end up chasing your tail. The actual CHT temperature reflect more than fuel flow. Once you get peak EGT fuel flows close, if you still have CHT variation then look at cooling air. For example a 1/8" shim between the #3 cylinder and the aft baffle wall tends to have a significant cooling effect on #3 CHT. Also remember the specific value of EGT at peak means little as variability of sensors and sensor placement are unpredictable. The change in EGT however when the last cylinder peaks tells most of the story. If you have a range say of -40 degrees on the first to peak and -20 degrees on the last to peak, you are close. Carl RV-8A (800 hrs) RV-10 (17 hrs) From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of mr.gsun@gmail.com Sent: Wednesday, July 04, 2012 1:01 AM Subject: Re: RV-List: #3 overheating I mainly look at #3 as the rest are all lower and somewhat closer together. I have seen #3 as high as 425 climbing full power on a warm day. I flew recently and it seems cooler so will leave it that way for more testing. I was just curious if those flow rates were different enough to worry about. Greg On Jul 3, 2012 9:01 AM, "Matt Dralle" <dralle@matronics.com> wrote: What are your CHTs? Before and after the swap? - Matt Dralle RV-8 #82880 N998RV "Ruby Vixen" http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel Status: 172+ Hours TTSN - Rebuilding Fuselage After Landing Mishap... RV-6 #20916 N360EM "The Flyer" http://www.mattsrv6.com - Matt's RV-6 Revitalization Log Status: 100+ Hours Since Purchase - Upgrades Complete; Now In Full Flyer Mode At 11:17 PM 7/2/2012 Monday, you wrote: >RV-List, > >I've had issues with overheating on my 2004 RV7, IO 360 with about 560 hours. I had the cowl off for other reasons and did the "coke bottle test" and measured the fuel coming out of the injectors with just the electric boost pump on and the mixure & throttle full in. > >At 28 psi as registered on my Skyview system, I got: >#1 110 ml in one minute >#2 115 ml in one minute >#3 108 ml in one minute >#4 112 ml in one minute > >I had cleaned the injectors by soaking them in Hoppe's cleaner as per Lycoming instructions less than 8 months ago and the spray pattern was identical in all four. >So I swapped #3 (the lowest) for #2 (the highest) thinking that if I ran the overheating cylinder a bit richer, my problem would be solved. I soaked them again, inspected and dried them before installation. > >Does this seem reasonable? > >do not archive > ========== get="_blank">http://www.matronics.com/Navigator?RV-List ========== http://forums.matronics.com ========== le, List Admin. ="_blank">http://www.matronics.com/contribution ==========


    Message 2


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    Time: 06:17:18 AM PST US
    Subject: Re: #3 overheating
    From: Doug Gray <dgra1233@bigpond.net.au>
    I wonder do you have a heat muff on the exhaust that might be be impeding th e air from exiting beneath cylinder #3? I have a marginal issue on my rv6 a nd am suspecting the muff and the scat tubing may be interfering with the ai rflow exit. I simply keep the running on the ground to a minimum and climb o ut at 110 to 120 kts. At some stage I will remove the muff at scat tubing t o test my theory. Doug Gray Sent from my iPad On 03/07/2012, at 4:17 PM, mr.gsun@gmail.com wrote: > RV-List, > > I've had issues with overheating on my 2004 RV7, IO 360 with about 560 hou rs. I had the cowl off for other reasons and did the "coke bottle test" and measured the fuel coming out of the injectors with just the electric boost p ump on and the mixure & throttle full in. > > At 28 psi as registered on my Skyview system, I got: > #1 110 ml in one minute > #2 115 ml in one minute > #3 108 ml in one minute > #4 112 ml in one minute > > I had cleaned the injectors by soaking them in Hoppe's cleaner as per Lyco ming instructions less than 8 months ago and the spray pattern was identical in all four. > So I swapped #3 (the lowest) for #2 (the highest) thinking that if I ran t he overheating cylinder a bit richer, my problem would be solved. I soaked t hem again, inspected and dried them before installation. > > Does this seem reasonable? > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= >


    Message 3


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    Time: 06:31:05 AM PST US
    From: Ian Brown <ixb@videotron.ca>
    Subject: Overheating
    Maybe it would be a good idea, if you really care about the results of the coke bottle test, just to repeat it several times. You need to bracket the variability in the results themselves before you decide whether you care about a 5ml difference from one to another. I'd be willing to bet most of the list running a four cylinder engine would read highest temps on #3 anyway.


    Message 4


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    Time: 02:39:54 PM PST US
    Subject: #3 overheating
    From: MLE <rv6awingman@gmail.com>
    Greg, AirFlow Performance has a wealth of knowledge on FI systems, I suggest giving them a call and talking with Don Rivera the owner, phone number 864-576-4512. Marty RV-6A Time: 10:02:15 PM PST US Subject: Re: RV-List: #3 overheating From: mr.gsun@gmail.com I mainly look at #3 as the rest are all lower and somewhat closer together. I have seen #3 as high as 425 climbing full power on a warm day. I flew recently and it seems cooler so will leave it that way for more testing. I was just curious if those flow rates were different enough to worry about. Greg On Jul 3, 2012 9:01 AM, "Matt Dralle" <dralle@matronics.com> wrote: > > What are your CHTs? Before and after the swap? > > > - > Matt Dralle > > RV-8 #82880 N998RV "Ruby Vixen" > http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log > http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log > http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel > Status: 172+ Hours TTSN - Rebuilding Fuselage After Landing Mishap... > > RV-6 #20916 N360EM "The Flyer" > http://www.mattsrv6.com - Matt's RV-6 Revitalization Log > Status: 100+ Hours Since Purchase - Upgrades Complete; Now In Full Flyer > Mode > > > At 11:17 PM 7/2/2012 Monday, you wrote: > >RV-List, > > > >I've had issues with overheating on my 2004 RV7, IO 360 with about 560 > hours. I had the cowl off for other reasons and did the "coke bottle test" > and measured the fuel coming out of the injectors with just the electric > boost pump on and the mixure & throttle full in. > > > >At 28 psi as registered on my Skyview system, I got: > >#1 110 ml in one minute > >#2 115 ml in one minute > >#3 108 ml in one minute > >#4 112 ml in one minute > > > >I had cleaned the injectors by soaking them in Hoppe's cleaner as per > Lycoming instructions less than 8 months ago and the spray pattern was > identical in all four. > >So I swapped #3 (the lowest) for #2 (the highest) thinking that if I ran > the overheating cylinder a bit richer, my problem would be solved. I > soaked them again, inspected and dried them before installation. > > > >Does this seem reasonable? > > > >do not archive > > > >




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