---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Sun 02/10/08: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:49 AM - Re: EGT Probes (Andy Silvester) 2. 08:35 AM - Re: EGT Probes (Lynn Matteson) 3. 03:24 PM - Re: EGT Probes (Andy Silvester) 4. 03:40 PM - Re: EGT Probes (Keith Pickford) 5. 05:44 PM - Re: EGT Probes (Chuck Deiterich) ________________________________ Message 1 _____________________________________ Time: 04:49:55 AM PST US From: "Andy Silvester" Subject: RE: JabiruEngine-List: EGT Probes Lynn, I think you probably have the 'edge' over me on thermocouple technology, but with these EGT senders, you're attempting to measure a pipe full of very fast moving hot gas and I doubt, with the turbulence of post-combustion, anyone can really tell where (in the pipe diameter) the best place for true measurement is. Unless of course you could spend considerable time in laboratory conditions measuring.....We've always used the 1" probes, supplied mainly from Grand Rapids Technologies and as a measure of EGT, they do a fair job. After all, EGT is very much a 'comparative' measurement and it's always the case to see a wider range of temps across all cylinders, (even when in the case of a direct-injected engine where mixture is more accurately known), than you'd see for example in a well-balanced set of CHT figures. What you'll be looking for is a temperature span of less than (say) 80F-100F across cylinders (less is good but often not worth chasing), but the absolute values will tell you more about how the engine's doing: 1. Less than 1100F will betray an over-rich condition 2. Above 1400F is too lean, particularly at full throttle. Remember, the Bing's mixture compensating needle will promote a relatively rich mixture at high throttle openings (so the high workload won't lead to detonation) and a relatively lean condition in the cruise. Prop selection, airframe type, fuel quality all have effects, but essentially I get my confidence from a good-running engine by seeing (say) cruise EGTs around 1250F-1300F, and wide-open throttle EGTs about 100F less. Opening the throttle to full while monitoring the EGTs will see a marked reduction. Comprehensive info on this subject can be found in Jabiru's Service Bulletin JSB 018-1 at: http://www.jabiru.net.au/Service%20Bulletins/Engine%20files/JSB018-1Engine%2 0tuning.pdf There's plenty of accepted wisdom about the benefits of multiple EGT measurement; noting a rising EGT on a cylinder could help to diagnose an air-leak in the induction and signal the need for maintenance before an expensive head overhaul becomes necessary. Thanks, Lynn for providing the opportunity to neatly evade your topic and (no doubt) raise discussion about another..! Cheers, Andy Suncoast Sportplanes, Inc. -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: 09 February 2008 18:08 Subject: Re: JabiruEngine-List: EGT Probes Andy- Wouldn't you want the tip of the probe to be in the center of the pipe? It's been my experience (a few years spent installing thermocouples in test cars for Chrysler Corp) that it's where the two dissimilar wires come together...usually at the tip of the thermocouple...that the reading is made. I'll certainly defer to your knowledge of the thermocouples in question....I know nothing about those particular ones. Lynn Matteson Grass Lake, Michigan Kitfox IV Speedster w/Jabiru 2200 flying w/470+ hrs On Feb 9, 2008, at 10:39 AM, Andy Silvester wrote: > Chuck, > > > Get the 1" ones; they'll span the inside diameter of the exhaust > pipes nicely. > > > Andy Silvester > > Suncoast Sportplanes, Inc > > 813 377 2716 > > > From: owner-jabiruengine-list-server@matronics.com [mailto:owner- > jabiruengine-list-server@matronics.com] On Behalf Of Chuck Deiterich > Sent: 09 February 2008 12:59 > To: Jab-list > Subject: JabiruEngine-List: EGT Probes > > > I am going to add EGT's to my 2200 (SN 988). > I can get probes that are either 1/2 inch long or 1 inch long. > Any comments on which length should I get? > > Chuck D. > > forums.matronics.com_- > ============================================================ _- > contribution_- > =========================================================== ________________________________ Message 2 _____________________________________ Time: 08:35:50 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: EGT Probes Thanks for the info, Andy. I've got all four cyls monitored with Grand Rapids Technologies probes, and their EIS. I'm not sure what length they are, but I recall having to stack about 1/8" of washers onto the probe so as to prevent it from entering the pipe too far. I can't really recall where this put the probe in relationship to the center of the pipe...maybe it just kept it from touching the other side of the pipe, which wouldn't be good for readings. My particular readings are in the 1300's F at full throttle, all within 40F, and in the 1400's F at cruise. I've got engine #2062 which had the economy tune at the time of delivery, and I haven't changed it. Sounds like maybe I'd better go a little richer, eh? Lynn Matteson Grass Lake, Michigan Kitfox IV Speedster w/Jabiru 2200 flying w/470+ hrs On Feb 10, 2008, at 7:44 AM, Andy Silvester wrote: > > > Lynn, > > I think you probably have the 'edge' over me on thermocouple > technology, but > with these EGT senders, you're attempting to measure a pipe full of > very > fast moving hot gas and I doubt, with the turbulence of post- > combustion, > anyone can really tell where (in the pipe diameter) the best place > for true > measurement is. Unless of course you could spend considerable time in > laboratory conditions measuring.....We've always used the 1" probes, > supplied mainly from Grand Rapids Technologies and as a measure of > EGT, they > do a fair job. After all, EGT is very much a 'comparative' > measurement and > it's always the case to see a wider range of temps across all > cylinders, > (even when in the case of a direct-injected engine where mixture is > more > accurately known), than you'd see for example in a well-balanced > set of CHT > figures. What you'll be looking for is a temperature span of less > than (say) > 80F-100F across cylinders (less is good but often not worth > chasing), but > the absolute values will tell you more about how the engine's doing: > > 1. Less than 1100F will betray an over-rich condition > 2. Above 1400F is too lean, particularly at full throttle. > > Remember, the Bing's mixture compensating needle will promote a > relatively > rich mixture at high throttle openings (so the high workload won't > lead to > detonation) and a relatively lean condition in the cruise. Prop > selection, > airframe type, fuel quality all have effects, but essentially I get my > confidence from a good-running engine by seeing (say) cruise EGTs > around > 1250F-1300F, and wide-open throttle EGTs about 100F less. Opening the > throttle to full while monitoring the EGTs will see a marked > reduction. > Comprehensive info on this subject can be found in Jabiru's Service > Bulletin > JSB 018-1 at: > http://www.jabiru.net.au/Service%20Bulletins/Engine%20files/ > JSB018-1Engine%2 > 0tuning.pdf > > There's plenty of accepted wisdom about the benefits of multiple EGT > measurement; noting a rising EGT on a cylinder could help to > diagnose an > air-leak in the induction and signal the need for maintenance > before an > expensive head overhaul becomes necessary. Thanks, Lynn for > providing the > opportunity to neatly evade your topic and (no doubt) raise > discussion about > another..! > > Cheers, Andy > Suncoast Sportplanes, Inc. > ________________________________ Message 3 _____________________________________ Time: 03:24:13 PM PST US From: "Andy Silvester" Subject: RE: JabiruEngine-List: EGT Probes Lynn, Actually, those temps and 'span' are very good; I wouldn't change a thing, particularly on the 2200. I have run our own engines hotter (in the 1400s at cruise) and with no ill-effects in a few hundred hours, but it's a little higher than Jabiru's own recommendations. As long as you're seeing that drop on increase in throttle, you're good with what you have, and no doubt a pretty good g.p.h. figure. Andy -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: 10 February 2008 14:31 Subject: Re: JabiruEngine-List: EGT Probes Thanks for the info, Andy. I've got all four cyls monitored with Grand Rapids Technologies probes, and their EIS. I'm not sure what length they are, but I recall having to stack about 1/8" of washers onto the probe so as to prevent it from entering the pipe too far. I can't really recall where this put the probe in relationship to the center of the pipe...maybe it just kept it from touching the other side of the pipe, which wouldn't be good for readings. My particular readings are in the 1300's F at full throttle, all within 40F, and in the 1400's F at cruise. I've got engine #2062 which had the economy tune at the time of delivery, and I haven't changed it. Sounds like maybe I'd better go a little richer, eh? Lynn Matteson Grass Lake, Michigan Kitfox IV Speedster w/Jabiru 2200 flying w/470+ hrs On Feb 10, 2008, at 7:44 AM, Andy Silvester wrote: > > > Lynn, > > I think you probably have the 'edge' over me on thermocouple > technology, but > with these EGT senders, you're attempting to measure a pipe full of > very > fast moving hot gas and I doubt, with the turbulence of post- > combustion, > anyone can really tell where (in the pipe diameter) the best place > for true > measurement is. Unless of course you could spend considerable time in > laboratory conditions measuring.....We've always used the 1" probes, > supplied mainly from Grand Rapids Technologies and as a measure of > EGT, they > do a fair job. After all, EGT is very much a 'comparative' > measurement and > it's always the case to see a wider range of temps across all > cylinders, > (even when in the case of a direct-injected engine where mixture is > more > accurately known), than you'd see for example in a well-balanced > set of CHT > figures. What you'll be looking for is a temperature span of less > than (say) > 80F-100F across cylinders (less is good but often not worth > chasing), but > the absolute values will tell you more about how the engine's doing: > > 1. Less than 1100F will betray an over-rich condition > 2. Above 1400F is too lean, particularly at full throttle. > > Remember, the Bing's mixture compensating needle will promote a > relatively > rich mixture at high throttle openings (so the high workload won't > lead to > detonation) and a relatively lean condition in the cruise. Prop > selection, > airframe type, fuel quality all have effects, but essentially I get my > confidence from a good-running engine by seeing (say) cruise EGTs > around > 1250F-1300F, and wide-open throttle EGTs about 100F less. Opening the > throttle to full while monitoring the EGTs will see a marked > reduction. > Comprehensive info on this subject can be found in Jabiru's Service > Bulletin > JSB 018-1 at: > http://www.jabiru.net.au/Service%20Bulletins/Engine%20files/ > JSB018-1Engine%2 > 0tuning.pdf > > There's plenty of accepted wisdom about the benefits of multiple EGT > measurement; noting a rising EGT on a cylinder could help to > diagnose an > air-leak in the induction and signal the need for maintenance > before an > expensive head overhaul becomes necessary. Thanks, Lynn for > providing the > opportunity to neatly evade your topic and (no doubt) raise > discussion about > another..! > > Cheers, Andy > Suncoast Sportplanes, Inc. > ________________________________ Message 4 _____________________________________ Time: 03:40:59 PM PST US From: "Keith Pickford" Subject: RE: JabiruEngine-List: EGT Probes Wasn't there a recommendation to drill the main jet out slightly on the tuning kit ? Keith -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Andy Silvester Sent: Monday, February 11, 2008 12:18 PM Subject: RE: JabiruEngine-List: EGT Probes Lynn, Actually, those temps and 'span' are very good; I wouldn't change a thing, particularly on the 2200. I have run our own engines hotter (in the 1400s at cruise) and with no ill-effects in a few hundred hours, but it's a little higher than Jabiru's own recommendations. As long as you're seeing that drop on increase in throttle, you're good with what you have, and no doubt a pretty good g.p.h. figure. Andy -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: 10 February 2008 14:31 Subject: Re: JabiruEngine-List: EGT Probes Thanks for the info, Andy. I've got all four cyls monitored with Grand Rapids Technologies probes, and their EIS. I'm not sure what length they are, but I recall having to stack about 1/8" of washers onto the probe so as to prevent it from entering the pipe too far. I can't really recall where this put the probe in relationship to the center of the pipe...maybe it just kept it from touching the other side of the pipe, which wouldn't be good for readings. My particular readings are in the 1300's F at full throttle, all within 40F, and in the 1400's F at cruise. I've got engine #2062 which had the economy tune at the time of delivery, and I haven't changed it. Sounds like maybe I'd better go a little richer, eh? Lynn Matteson Grass Lake, Michigan Kitfox IV Speedster w/Jabiru 2200 flying w/470+ hrs On Feb 10, 2008, at 7:44 AM, Andy Silvester wrote: > > > Lynn, > > I think you probably have the 'edge' over me on thermocouple > technology, but > with these EGT senders, you're attempting to measure a pipe full of > very > fast moving hot gas and I doubt, with the turbulence of post- > combustion, > anyone can really tell where (in the pipe diameter) the best place > for true > measurement is. Unless of course you could spend considerable time in > laboratory conditions measuring.....We've always used the 1" probes, > supplied mainly from Grand Rapids Technologies and as a measure of > EGT, they > do a fair job. After all, EGT is very much a 'comparative' > measurement and > it's always the case to see a wider range of temps across all > cylinders, > (even when in the case of a direct-injected engine where mixture is > more > accurately known), than you'd see for example in a well-balanced > set of CHT > figures. What you'll be looking for is a temperature span of less > than (say) > 80F-100F across cylinders (less is good but often not worth > chasing), but > the absolute values will tell you more about how the engine's doing: > > 1. Less than 1100F will betray an over-rich condition > 2. Above 1400F is too lean, particularly at full throttle. > > Remember, the Bing's mixture compensating needle will promote a > relatively > rich mixture at high throttle openings (so the high workload won't > lead to > detonation) and a relatively lean condition in the cruise. Prop > selection, > airframe type, fuel quality all have effects, but essentially I get my > confidence from a good-running engine by seeing (say) cruise EGTs > around > 1250F-1300F, and wide-open throttle EGTs about 100F less. Opening the > throttle to full while monitoring the EGTs will see a marked > reduction. > Comprehensive info on this subject can be found in Jabiru's Service > Bulletin > JSB 018-1 at: > http://www.jabiru.net.au/Service%20Bulletins/Engine%20files/ > JSB018-1Engine%2 > 0tuning.pdf > > There's plenty of accepted wisdom about the benefits of multiple EGT > measurement; noting a rising EGT on a cylinder could help to > diagnose an > air-leak in the induction and signal the need for maintenance > before an > expensive head overhaul becomes necessary. Thanks, Lynn for > providing the > opportunity to neatly evade your topic and (no doubt) raise > discussion about > another..! > > Cheers, Andy > Suncoast Sportplanes, Inc. > ________________________________ Message 5 _____________________________________ Time: 05:44:44 PM PST US From: "Chuck Deiterich" Subject: RE: JabiruEngine-List: EGT Probes Andy and Lynn, Thanks for the response. I searched around the internet and also looked at Tony Bingelis' books. His book just has a drawing that shows the tip of the probe in the center. One place said the tip should be in the center of the gas stream I suspect in the center is the hottest. So that is what I will try to do. Chuck D. ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message jabiruengine-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/JabiruEngine-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/jabiruengine-list Browse Digests http://www.matronics.com/digest/jabiruengine-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.