AirTalk.org Aviation discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  EGT on a 447          AirTalk.org Forum Index -> Light aircraft View previous topic :: View next topic   Author Message David D Cowell Guest Posted: Fri Jan 09, 2004 3:10 am    Post subject: EGT on a 447 Anyone know why all the Rotax manuals are blank for the 447 EGT? (The CHT is listed but no EGT) Is it the same as 503? -- David D Cowell Wildcat Computers, Inc. http://www.wildcatcomputers.net 800-686-4685 Back to top DCLXVI Guest Posted: Fri Jan 09, 2004 7:29 am    Post subject: Re: EGT on a 447 Anyone know how much the spark gap will effect the EGT? ON climbout today I had EGT of 1350-1400 @ 6500 rpm. I've lowered the clip in the jet needle to the bottom and turned the airscrew to .5 turns out. Our mechanic at the airpark recommends .018" and when I had the conversion from points to electronic ignition the paper recommended .025". I used .018". "David D Cowell" <dcowell (AT) NOSPAM (DOT) wildcatcomputers.net> wrote Quote: Anyone know why all the Rotax manuals are blank for the 447 EGT? (The CHT is listed but no EGT) Is it the same as 503? -- David D Cowell Wildcat Computers, Inc. http://www.wildcatcomputers.net 800-686-4685 Back to top D. Grunloh Guest Posted: Fri Jan 09, 2004 2:00 pm    Post subject: Re: EGT on a 447 DCLXVI wrote: Quote: Anyone know how much the spark gap will effect the EGT? ON climbout today I had EGT of 1350-1400 @ 6500 rpm. I've lowered the clip in the jet needle to the bottom and turned the airscrew to .5 turns out. Our mechanic at the airpark recommends .018" and when I had the conversion from points to electronic ignition the paper recommended .025". I used .018". Those temperatures are impossible. You could have a vibration induced error in an analog guage. Lowering the needle clip won't change it much if you are climbing at full power. It's the main jet that controls it. I don't know if you could have a blockage (or a timing problem). Where is your temperature probe mouned? Do you have the threaded version? What kind of tach do you have.? Excess rpm will give very high EGT The 447 should give EGT at 1125-1150 at cruise, maybe less at full power. --Dan Grunloh Quote: "David D Cowell" <dcowell (AT) NOSPAM (DOT) wildcatcomputers.net> wrote in message news:BWoLb.125$rj3.115 (AT) fe01 (DOT) usenetserver.com... Anyone know why all the Rotax manuals are blank for the 447 EGT? (The CHT is listed but no EGT) Is it the same as 503? -- David D Cowell Wildcat Computers, Inc. http://www.wildcatcomputers.net 800-686-4685 Back to top Mark Smith Guest Posted: Fri Jan 09, 2004 4:14 pm    Post subject: Re: EGT on a 447 D. Grunloh wrote: Quote: DCLXVI wrote: Anyone know how much the spark gap will effect the EGT? ON climbout today I had EGT of 1350-1400 @ 6500 rpm. I've lowered the clip in the jet needle to the bottom and turned the airscrew to .5 turns out. Our mechanic at the airpark recommends .018" and when I had the conversion from points to electronic ignition the paper recommended .025". I used .018". Those temperatures are impossible. You could have a vibration induced error in an analog guage. Lowering the needle clip won't change it much if you are climbing at full power. It's the main jet that controls it. I don't know if you could have a blockage (or a timing problem). Where is your temperature probe mouned? Do you have the threaded version? What kind of tach do you have.? Excess rpm will give very high EGT The 447 should give EGT at 1125-1150 at cruise, maybe less at full power. --Dan Grunloh "David D Cowell" <dcowell (AT) NOSPAM (DOT) wildcatcomputers.net> wrote in message news:BWoLb.125$rj3.115 (AT) fe01 (DOT) usenetserver.com... Anyone know why all the Rotax manuals are blank for the 447 EGT? (The CHT is listed but no EGT) Is it the same as 503? -- David D Cowell I agree with Dan, those values are sky high, but his questions are valid, probe placement for sure,,,,,,,, also, cold weather will raise the EGT due to denser air, but I have seen above 1200 numbers with what I consider proper probe placement, rotax jetting, good fuel suppy, etc, also, choice of fuel may control EGT, high octane burns slower, and more likely to still be burning in the manifold, also, slower burning means less power developed in the cylinder, thus the expanding gase have less chance to cool due to expansion,,,,,,,thus higher EGT's too,,,,,,,,, did the values go up all of a sudden or gradually with coller weather,,,,,,, -- Mark Smith Tri-State Kite Sales http://www.trikite.com 1121 N Locust St Mt Vernon, IN 47620 mailto:mark (AT) trikite (DOT) com Back to top DCLXVI Guest Posted: Sat Jan 10, 2004 3:28 am    Post subject: Re: EGT on a 447 The probe is after the "y" in the exhaust manifold by about 1". I'm burning Union 76 87 octane with yamalube 2r oil at 50:1. Lowering the clip lowered the values by about 25-50 degrees. I'm using a "tiny tach". The temp gradually increased over about 15 seconds. This temp increase was initially noticed during a break in procedure after Steve at Airscrew did a major overhaul and replaced the point ignition with a CDI. The timing should be good. I then took it out and flew the pattern around the airpark. The engine was smooth and sounded good. No funny smell I would associate with high temps. I talked to Steve today, he feels the guage or sensor are in error. I'm wondering if I might have an airleak. Will be checking that tomorrow. "Mark Smith" <mark (AT) trikite (DOT) com> wrote Quote: D. Grunloh wrote: DCLXVI wrote: Anyone know how much the spark gap will effect the EGT? ON climbout today I had EGT of 1350-1400 @ 6500 rpm. I've lowered the clip in the jet needle to the bottom and turned the airscrew to .5 turns out. Our mechanic at the airpark recommends .018" and when I had the conversion from points to electronic ignition the paper recommended .025". I used .018". Those temperatures are impossible. You could have a vibration induced error in an analog guage. Lowering the needle clip won't change it much if you are climbing at full power. It's the main jet that controls it. I don't know if you could have a blockage (or a timing problem). Where is your temperature probe mouned? Do you have the threaded version? What kind of tach do you have.? Excess rpm will give very high EGT The 447 should give EGT at 1125-1150 at cruise, maybe less at full power. --Dan Grunloh "David D Cowell" <dcowell (AT) NOSPAM (DOT) wildcatcomputers.net> wrote in message news:BWoLb.125$rj3.115 (AT) fe01 (DOT) usenetserver.com... Anyone know why all the Rotax manuals are blank for the 447 EGT? (The CHT is listed but no EGT) Is it the same as 503? -- David D Cowell I agree with Dan, those values are sky high, but his questions are valid, probe placement for sure,,,,,,,, also, cold weather will raise the EGT due to denser air, but I have seen above 1200 numbers with what I consider proper probe placement, rotax jetting, good fuel suppy, etc, also, choice of fuel may control EGT, high octane burns slower, and more likely to still be burning in the manifold, also, slower burning means less power developed in the cylinder, thus the expanding gase have less chance to cool due to expansion,,,,,,,thus higher EGT's too,,,,,,,,, did the values go up all of a sudden or gradually with coller weather,,,,,,, -- Mark Smith Tri-State Kite Sales http://www.trikite.com 1121 N Locust St Mt Vernon, IN 47620 mailto:mark (AT) trikite (DOT) com Back to top Mark Smith Guest Posted: Sat Jan 10, 2004 8:48 pm    Post subject: Re: EGT on a 447 DCLXVI wrote: Quote: The probe is after the "y" in the exhaust manifold by about 1". I'm burning Union 76 87 octane with yamalube 2r oil at 50:1. Lowering the clip lowered the values by about 25-50 degrees. I'm using a "tiny tach". The temp gradually increased over about 15 seconds. This temp increase was initially noticed during a break in procedure after Steve at Airscrew did a major overhaul and replaced the point ignition with a CDI. The timing should be good. I then took it out and flew the pattern around the airpark. The engine was smooth and sounded good. No funny smell I would associate with high temps. I talked to Steve today, he feels the guage or sensor are in error. I'm wondering if I might have an airleak. Will be checking that tomorrow. the probe is in the wrong place,,,,,,,, it should be 2 inches from the gasket, measured along the center of the pipe, yours is several inches too far out, ricjening just addds fuel which may even raise the temps -- Mark Smith Tri-State Kite Sales http://www.trikite.com 1121 N Locust St Mt Vernon, IN 47620 mailto:mark (AT) trikite (DOT) com Back to top DCLXVI Guest Posted: Sun Jan 11, 2004 1:27 am    Post subject: Re: EGT on a 447 Whats most perplexing is that the same guage read lower , 1200, before the rebuild.Now with the same jetting and needle its reading 1350 to 1400 at take off. I do appreciate the input. I have previously considered moving the probe, but it did't seem to be a problem. It came to me the way it's located. "Mark Smith" <mark (AT) trikite (DOT) com> wrote Quote: DCLXVI wrote: The probe is after the "y" in the exhaust manifold by about 1". I'm burning Union 76 87 octane with yamalube 2r oil at 50:1. Lowering the clip lowered the values by about 25-50 degrees. I'm using a "tiny tach". The temp gradually increased over about 15 seconds. This temp increase was initially noticed during a break in procedure after Steve at Airscrew did a major overhaul and replaced the point ignition with a CDI. The timing should be good. I then took it out and flew the pattern around the airpark. The engine was smooth and sounded good. No funny smell I would associate with high temps. I talked to Steve today, he feels the guage or sensor are in error. I'm wondering if I might have an airleak. Will be checking that tomorrow. the probe is in the wrong place,,,,,,,, it should be 2 inches from the gasket, measured along the center of the pipe, yours is several inches too far out, ricjening just addds fuel which may even raise the temps -- Mark Smith Tri-State Kite Sales http://www.trikite.com 1121 N Locust St Mt Vernon, IN 47620 mailto:mark (AT) trikite (DOT) com Back to top GASSITT Guest Posted: Sun Jan 11, 2004 4:31 am    Post subject: Re: EGT on a 447 Mark is correct , by putting the sender after the Y its almost useless except for maybe telling you that the engine is running if you couldn't see it or hear it As far higher EGTs after an overhaul or C.D.I. conversion , # 1 with the Nippon Denso ignition you are burning much more of the mixture now then you were with the point ignition and also firing it at the proper time. # 2 after an overhaul you'll have more compression and more power also causing a higher EGT. You have failed in any post to say, but isn't the engine running better than it ever has ? Steve @ Airscrew Performance Back to top DCLXVI Guest Posted: Sun Jan 11, 2004 5:04 am    Post subject: Re: EGT on a 447 I wondered if you read this group. Yes it does seem to run better than ever. Although when it first read 1400 it smelled like burnt steel. Like a cast iron pan with no oil in it. But that might be just normal after working on an engine. It hasn't smelled since. I had planned to go out and fly today, but duty called. Had to work OT. I'll get back out on Tue and return the clip to the proper grove on the jet needle. I will be ordering a second gauge and putting the sensors in the right places. Even if the guages are designed to read over temp, they are a guide. Larry in Las Vegas "GASSITT" <gassitt (AT) aol (DOT) com> wrote Quote: Mark is correct , by putting the sender after the Y its almost useless except for maybe telling you that the engine is running if you couldn't see it or hear it As far higher EGTs after an overhaul or C.D.I. conversion , # 1 with the Nippon Denso ignition you are burning much more of the mixture now then you were with the point ignition and also firing it at the proper time. # 2 after an overhaul you'll have more compression and more power also causing a higher EGT. You have failed in any post to say, but isn't the engine running better than it ever has ? Steve @ Airscrew Performance Back to top John Ginger Guest Posted: Sun Jan 11, 2004 7:03 am    Post subject: Re: EGT on a 447 Quote: the probe is in the wrong place,,,,,,,, it should be 2 inches from the gasket, measured along the center of the pipe, yours is several inches too far out, ricjening just addds fuel which may even raise the temps -- Mark Smith Tri-State Kite Sales http://www.trikite.com 1121 N Locust St Mt Vernon, IN 47620 mailto:mark (AT) trikite (DOT) com Mark is right about the probe location. Do you know your CHT/s? If CHT is low and EGT is high, I'd wonder about prop pitch. 6500 sounds a bit high, I could be wrong. I'd put the EGT, preferably dual, where they belong as a first step. A "real" 1400 degrees is going to cause damage in a short period of time. Back to top DCLXVI Guest Posted: Thu Jan 15, 2004 6:50 am    Post subject: Re: EGT on a 447 The CHT was 375 to 400 at max rpm. Perhaps even a 425 reading at one point. That's on the rear cylinder. Would the egt probe being after the "y" be a higher reading or lower? "John Ginger" <jjginger (AT) cuisp (DOT) com> wrote Quote: the probe is in the wrong place,,,,,,,, it should be 2 inches from the gasket, measured along the center of the pipe, yours is several inches too far out, ricjening just addds fuel which may even raise the temps -- Mark Smith Tri-State Kite Sales http://www.trikite.com 1121 N Locust St Mt Vernon, IN 47620 mailto:mark (AT) trikite (DOT) com Mark is right about the probe location. Do you know your CHT/s? If CHT is low and EGT is high, I'd wonder about prop pitch. 6500 sounds a bit high, I could be wrong. I'd put the EGT, preferably dual, where they belong as a first step. A "real" 1400 degrees is going to cause damage in a short period of time. Back to top D. Grunloh Guest Posted: Thu Jan 15, 2004 2:31 pm    Post subject: Re: EGT on a 447 DCLXVI wrote: Quote: The CHT was 375 to 400 at max rpm. Perhaps even a 425 reading at one point. That's on the rear cylinder. Would the egt probe being after the "y" be a higher reading or lower? It could actually be higher if it's after the Y pipe. The exhaust gases are pulsing back and forth in the pipe due to the nature of 2-strokes and the effect of the tuned muffler. Changes in RPM may cause changes in the readings which are not meaningful. The manufactures temperature reccomendations are based on the probe being placed at a certain point a little more than 2 inches from the cylinder wall. If it's a single carb engine you can get away with measuring the EGT only one cylinder. I have mine on the rear. --Dan Quote: "John Ginger" <jjginger (AT) cuisp (DOT) com> wrote in message news:2207866f.0401102303.3fcba23c (AT) posting (DOT) google.com... the probe is in the wrong place,,,,,,,, it should be 2 inches from the gasket, measured along the center of the pipe, yours is several inches too far out, ricjening just addds fuel which may even raise the temps -- Mark Smith Tri-State Kite Sales http://www.trikite.com 1121 N Locust St Mt Vernon, IN 47620 mailto:mark (AT) trikite (DOT) com Mark is right about the probe location. Do you know your CHT/s? If CHT is low and EGT is high, I'd wonder about prop pitch. 6500 sounds a bit high, I could be wrong. I'd put the EGT, preferably dual, where they belong as a first step. A "real" 1400 degrees is going to cause damage in a short period of time. 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