Marc_B Posted February 1, 2023 Report Posted February 1, 2023 Working on some ignition/plug issues and curious to see if y’all might post up your graphs for in flight mag checks and what engine/mags you have. Trying to get a feel for what normal looks like…and to share how specific issues appear. TSIO360SB2, Slick 6324, massives initially, now with Tempest fine wires Here is mag check from previous annual: Here is the latest in flight mag check: Plugs were getting worn and tired; decided to replace with a set of Tempest Fine Wires thinking this was more of a plug issue and here's my ground mag check: 1 Quote
carusoam Posted February 1, 2023 Report Posted February 1, 2023 There are a few things going on… but, procedure wise… I have got this… 1) Notice how the peaks continue to increase before switching back to both…. Too quick on the switch… the temps haven’t quite stabilized that quickly… Recommend… waiting for them to stabilize… this will improve your data. 2) The next set of data… the mag check happens so quickly… data doesn’T show much of a peak at all… Probably could hear it fine… but data being collected every two or six seconds… can mask what is really going on… 3) Something might be showing… but not clear enough… when the mags are timed differently… one peak will be taller than the other… the graphs show a couple of plugs on one mag climbing higher than the others… I usually use about 15 seconds for data collection, while the rate on my JPI is 2second Intervals… The physics and thermodynamics takes time to stabilize… I have a NA Continental IO550… Best regards, -a- 1 Quote
kortopates Posted February 2, 2023 Report Posted February 2, 2023 You need a minimum of 30 sec on each mag; preferably at a 1 sec sampling rate.plus you need to be leaned out to stress ignition; preferably at 50F LOP on richest cyl at less than 65% power. ground mag test will only show severe anomalies and are otherwise generally useless. Sent from my iPhone using Tapatalk 1 1 Quote
rbp Posted February 2, 2023 Report Posted February 2, 2023 here's the flight check that Savvy recommends, similar to @kortopates instructions https://resources.savvyaviation.com/resources/other-documents/flight-test-profile/ 1 Quote
Marc_B Posted February 2, 2023 Author Report Posted February 2, 2023 Yes, I’m aware of Savvy flight profile and a subscriber. The inflight mag checks were lean and ~30 sec., except for the most recent the right was short due to running rough and chugging down and didn’t want to just let it flame out. It looks like I switched while it was still climbing but that’s cause it ran rough until all egts were dropping. But it was close to 25sec or so. The ground checks were a ground run up prior to a flight that I scrubbed as i’m still having issues despite changing plugs. still I’m curious what your typical mag checks in flight look like. Why are left mag top plugs on left flat vs rising? Went from bottom plugs 2/4/6 to maybe cylinder 5/6 top on right mag with new plugs. But it’s never been an entire mags worth. yes, wires will be tested and mags will be sent off for IRAN. 1 Quote
carusoam Posted February 2, 2023 Report Posted February 2, 2023 Another thing to consider… Run a Gami spread test… To see if any of these EGT issues are related to the fuel injectors mis-behaving… All six EGTs should be pretty close to one another… If the spread is wide, or there are outliers… it might be time to clean the FIs again… PP thoughts only, not a mechanic… Best regards, -a- Quote
carusoam Posted February 2, 2023 Report Posted February 2, 2023 And another thing… If you can share the data files…. The MS eyes can get a better view of the data scaling…. Time elapse, and temp ranges… I love the annotations on these screen shots! That’s something we don’t usually get from the shared data files… Best regards, -a- Quote
jlunseth Posted February 2, 2023 Report Posted February 2, 2023 (edited) 22 hours ago, kortopates said: plus you need to be leaned out to stress ignition; preferably at 50F LOP on richest cyl at less than 65% power. @kortopates . A little different question than the OPs, but is this something we should be doing during our pre-flight run up? Specifically I am asking whether we should lean out for that run up? My POH says full rich so that is what I have always done. Edited February 2, 2023 by jlunseth Quote
kortopates Posted February 3, 2023 Report Posted February 3, 2023 On 2/2/2023 at 6:52 AM, jlunseth said: @kortopates . A little different question than the OPs, but is this something we should be doing during our pre-flight run up? Specifically I am asking whether we should lean out for that run up? My POH says full rich so that is what I have always done. Leaning out the ground mag test does stress the mags more to better show an anomaly. But in so doing, passing comes down to seeing each plug fire with a rise in EGT. Not so much on the RPM drops and differential any more. Quote
Raymond J1 Posted February 4, 2023 Report Posted February 4, 2023 (edited) By removing a magneto, you only operate on a candle, which helps to reduce the speed of the flame front... In other words, during a determined engine time, you send more unburned gases into the exhaust, where your EGT probe is located... Where the reduction process continues. This is what makes you notice the increase in EGT. If you increase the engine time (reduction in RPM), you will notice a decrease in EGT... And if you lean in LOP, the reduction will be faster, your EGT will also decrease. Once you have noticed this trend, which is that of all engines with an EGT probe in the exhaust, you will not be able to say that it works well, not well, better or is optimum. Just to be able to say that it works logically and like the previous time. Edited February 4, 2023 by Raymond J1 1 Quote
carusoam Posted February 4, 2023 Report Posted February 4, 2023 If you decide to lean prior to the run up… Be sure to Add a fail proof / two step means for assuring that the mixture goes back in prior T/O… check lists are good… memories are pretty crummy… especially if rushing out onto the runway for any reason… Being leaned during the T/O is a sure way to be in the darkest red box… Risk of pre-ignition is very high, and power is at the max… and the engine won’t be misbehaving in an obvious manner… until something lets go… Except for deep leaning… this way the engine stumbles going to full throttle… My second step for this…. Just after the knobs go all in…. A quick scan of MP, RPM and FF…. PP thoughts only, not a CFI… Best regards, -a- 1 Quote
Raymond J1 Posted February 4, 2023 Report Posted February 4, 2023 The "Gami" theories (and others) are not very popularized in Europe. It's not that they are weird or unreal, on the contrary, it's just that it's incomplete and we could say "a bandage on a wooden leg". Here are the reasons : 1) The first reason is that everything is based on an exhaust gas temperature measured elsewhere than in the combustion chamber... Which in no way reflects the quality of the combustion (we can have an excessive temperature and an incomplete reduction). 2) The rule is supposed to preserve an air-cooled engine that does not have the functional capacity to be thermally stable when it is operating at EGT peak, that is to say optimally... It is therefore not an absolute method but a palliative of exploitation according to each use and each engine. I can cite as an example the Rotax or other engines used on various automobiles, they are capable of operating all the time at "peak EGT", for all speeds and load conditions, in addition to being able to develop much higher specific powers (a Rotax 912 makes 74 Hp / liters while IO 550 makes 34.2 Hp / liters at most). And because its engines are viable on this operating condition, it is possible with them to draw trouble or driving statistics. For the other engines, technically unable to allow you to take off at "peak EGT", because the engine will break, so you have to adapt a particular driving and that's where "Gami" makes its butter, and it necessarily has a lot of work. But as you know, the engine manufacturer has already said from the beginning that the CHT are limited... So it's enough to follow the rule, mix so that everything remains within the norm, and that's enough. The day Lycoming and Continental introduce liquid cylinder head cooling with lambda probe combustion control, we will be able to start by seriously discussing driving the engine in "poor" or "rich" mode and possibly with an optimal mixture. In the meantime, keep an eye on your exhaust valves and the cylinder head temperature. 1 Quote
carusoam Posted February 4, 2023 Report Posted February 4, 2023 @Raymond J1 early morning! -a- 1 Quote
Pinecone Posted February 4, 2023 Report Posted February 4, 2023 8 hours ago, Raymond J1 said: The "Gami" theories (and others) are not very popularized in Europe. It's not that they are weird or unreal, on the contrary, it's just that it's incomplete and we could say "a bandage on a wooden leg". Here are the reasons : 1) The first reason is that everything is based on an exhaust gas temperature measured elsewhere than in the combustion chamber... Which in no way reflects the quality of the combustion (we can have an excessive temperature and an incomplete reduction). 2) The rule is supposed to preserve an air-cooled engine that does not have the functional capacity to be thermally stable when it is operating at EGT peak, that is to say optimally... It is therefore not an absolute method but a palliative of exploitation according to each use and each engine. Realize that GAMI has instrumented engines to a much higher level than we have. Including real time combustion chamber pressure measurements. But in the test chamber and in the air. Their operating advice comes from that information, but translated so that we can use it with the instrumentation we have in our aircraft. And the basis for what they teach comes from the airlines and the military when they ran piston engines. Quote
Raymond J1 Posted February 4, 2023 Report Posted February 4, 2023 (edited) 3 hours ago, Pinecone said: Realize that GAMI has instrumented engines to a much higher level than we have. Including real time combustion chamber pressure measurements. But in the test chamber and in the air. Their operating advice comes from that information, but translated so that we can use it with the instrumentation we have in our aircraft. And the basis for what they teach comes from the airlines and the military when they ran piston engines. Others also did it before "GAMI" and still do it, for example manufacturers who manufacture between 1500 and 2000 engines per day, for the general public... Engines far more efficient and more complex than a "Lyco-Conti" of 1955 (technology of 1930). The installations of "GAMI" are in all respects comparable to those available to automotive engine manufacturers to test series engines by sampling... You are not unaware that since 1985-1990, in the automotive industry and because of pollution standards, "lean" or "peak EGT" operations has become the operating standard, with an optimization of the power supply and ignition depending on the load and speed, that this is done in real time under the engine cover... In addition, there is added the reprocessing of unburned emissions, which "GAMI" has not yet considered, Lycoming and Continental either, since they do not mention in the engine range the issue of emissions of monoxides - dioxides resulting from an incomplete reduction (the engine is neither more nor less than an energy converter operating by oxidation-reduction). Yes, as you write, "GAMI" sells a dream, that of optimal engine control, comparable to that used on the "liners" of the 50s assuming real-time monitoring of the main parameters... The objective is to save consumption and maintenance. The approach of "GAMI" is honorable and makes sense, I repeat, Except that, unlike the engine or engines of the 50s which were specifically more efficient and almost capable of operating according to these operating standards, our small Lyco-Conti engines are not able to operate in this way due to lack of sufficient thermal stability. If we look at the efforts of this company to try to optimize a single-point injection without pressure control, via the development of calibrated flow rate injectors, it is a fantastic job... For not much. Because you have understood that the simple car on the street now uses a controlled injector operating under high pressure for 15 years, that the control is proactive depending on the load and the speed... And coupling to the ignition diagram... And we could talk about the ignition... Supercharging... Depollution that "GAMI" has not yet addressed. The main obstacle to the "GAMI" is the regulations, they block and freeze all the solutions of technical progress in the name of sacrosanct SECURITY. The engine drive according to the "lean mixture" technique existed long before "Curtiss-Wright" became aware of it, in addition to being carried out on engines much more efficient than those of this firm. In short, the approach of "GAMI" is 80 years behind schedule, it is ancient history since, today, technology allows a spark-ignition engine to operate all the time in "peak EGT" or "lean mixture", in the entire range of speeds and loads... In addition to being optimized in pollution. Take a ROTAX, you no longer have a mixing lever, it is capable of providing more than 100 hp / l of displacement... If your Continental 550 Cu.inch although the 310 hp has been optimized as a Rotax engine, it would be capable of providing 600 hp and would constantly run at peak EGT for lower consumption... And there is no "GAMI" solution in a Rotax, just an engineering from 1985 / 1990. Edited February 4, 2023 by Raymond J1 1 Quote
Pinecone Posted February 4, 2023 Report Posted February 4, 2023 Part of the issue in adopting auto technology for aircraft engines is the the feedback control in auto requires an oxygen sensor. Which is not possible with leaded fuels. You can automate aircraft engines more. But you need to get things past the FAA approval and the inertia of the pilots/owners. Continental went this route and came up with a fully automated engine, that no one would buy. Actually, as I understand it, the test cell and instrumentation at GAMI is far in advance what the manufacturers have. It is designed, specced, and run by engineers, not bean counters. BTW, have a modern engine control system they have had running for years. Once G100UL is up and running and not using up their time, they may work on getting that through the FAA process. Quote
EricJ Posted February 4, 2023 Report Posted February 4, 2023 Lycoming has their iE (integrated electronics) engines that are fully certified. The experimental world has a lot of full electronic controls that people have been putting on various Lycoming engines (that I know of, and probably Continental, but I've not seen one yet). An O2 sensor helps for tuning to optimize AFR with feedback, but isn't strictly necessary. Even automotive engines have "open loop" strategies, depending on the conditions, that ignore the O2 sensor and just use the fuel map based on other sensors. I recently helped with an engine swap in an experimental airplane where they did use an O2 sensor just for data and figured they'd just run it until it dies. The G3X displays and logs it just fine. There are quite a few FADEC reciprocating aircraft engines, even for the certified market, but the quantities aren't enough and the FAA barriers to innovation are big enough that they are obviously not universal, and certainly not retrofittable to most GA aircraft. 3 Quote
Raymond J1 Posted February 5, 2023 Report Posted February 5, 2023 7 hours ago, Pinecone said: Part of the issue in adopting auto technology for aircraft engines is the the feedback control in auto requires an oxygen sensor. Which is not possible with leaded fuels. You can automate aircraft engines more. But you need to get things past the FAA approval and the inertia of the pilots/owners. Continental went this route and came up with a fully automated engine, that no one would buy. Actually, as I understand it, the test cell and instrumentation at GAMI is far in advance what the manufacturers have. It is designed, specced, and run by engineers, not bean counters. BTW, have a modern engine control system they have had running for years. Once G100UL is up and running and not using up their time, they may work on getting that through the FAA process. This leaded fuel constraint is a technical choice, which it is possible to modify easily, just the reduction of the volumetric ratio, if necessary (which will impact the compression ratio) or the control of the cylinder head temperature. Don't tell me Lycoming or Continental can't do... Rotax has chosen a much higher volumetric ratio than Lyco Conti (it is 11), and the engines work with Mogas RON 98 because the temperature of the cylinder head is controlled. So today, the will is that of not doing rather than the technical impossibility of doing. However, I have not seen "GAMI" offer an OH cylinder kit for IO 550 with "liquid" cooled cylinder head and increased compression ratio... It is difficult to create this easily because of the regulations. There is no lambda probe on a 912 S with 100 hp for 1352 cm3 and a compression ratio of 11, working with SP98... No automaton either and it is not necessary at the current stage of the thermodynamics of the Lyco-Conti to resort to automation. The main part of the performance deficiencies of these engines comes from the technical choices of construction which have their interests and their foundations moreover. And the additional automation generates a higher cost on a product that is already too expensive for what it is worth. As you say, indeed, no one buys what is not justified! No, the test cell of "GAMI"is not technically in advance, to convince you of this, visit the workshops "test benches"of a car engine manufacturer, there is enough to make "GAMI" shudder who does not know how to process in ten years what the average car engine manufacturer processes in a day. Knowing that in the automotive industry, where production rates are close to 1 engine per minute, the non-compliance index / non-compliance rate (INC-TNC) is of the order of 4500 PPM, i.e. 4500 defects per 1 million engines produced... This is less than 1 defect for every 200 engines manufactured. I do not believe that the aviation industry is capable of following such a performance indicator for its engine production tool. And indeed, these very modern control facilities are managed by bean counters and not by engineers... Which should appeal. The efforts of "GAMI" are enormous and remarkable, they are to be commended, but after 40 years of activity they are enough to convince of the use of unleaded fuel in a GA... The owner of an "experimental" has been doing this for 15 years... See the gap! Which means that the main part of "GAMI's" efforts is pushing the legs of the FAA elephant lying on its side, so it's not won. Quote
carusoam Posted February 5, 2023 Report Posted February 5, 2023 One thing for sure…. There is over 500hp available in an IO550… but, it’s TBO is a bit lower than the 310hp version… The lead fuel alternatives are starting to look more interesting… JR, great posts! Lots of detail! Quote
jlunseth Posted February 5, 2023 Report Posted February 5, 2023 On 2/3/2023 at 10:47 PM, carusoam said: If you decide to lean prior to the run up… Be sure to Add a fail proof / two step means for assuring that the mixture goes back in prior T/O… check lists are good… memories are pretty crummy… especially if rushing out onto the runway for any reason… Being leaned during the T/O is a sure way to be in the darkest red box… Risk of pre-ignition is very high, and power is at the max… and the engine won’t be misbehaving in an obvious manner… until something lets go… Except for deep leaning… this way the engine stumbles going to full throttle… My second step for this…. Just after the knobs go all in…. A quick scan of MP, RPM and FF…. PP thoughts only, not a CFI… Best regards, -a- The bane of my existence. As everyone knows we need full rich in a turbo for takeoff power or the temps get up there pretty fast. Let’s say you pull up to the line, are ready to go, but there are three planes ahead of you, or one landing but a long way out and Tower won’t let you go. So you lean out just to keep the plugs clean. Then something happens in the pattern and they want you to go in a hurry. Too easy to forget to enrich again. I do it about once a year. If I lean before takeoff I generally leave my hand on the mixture as a reminder, but things happen, something else on the panel needs attention. But I have a habit of checking the engine monitor during takeoff so I usually see it quickly and push the mix in. 1 Quote
Ragsf15e Posted February 6, 2023 Report Posted February 6, 2023 7 hours ago, jlunseth said: The bane of my existence. As everyone knows we need full rich in a turbo for takeoff power or the temps get up there pretty fast. Let’s say you pull up to the line, are ready to go, but there are three planes ahead of you, or one landing but a long way out and Tower won’t let you go. So you lean out just to keep the plugs clean. Then something happens in the pattern and they want you to go in a hurry. Too easy to forget to enrich again. I do it about once a year. If I lean before takeoff I generally leave my hand on the mixture as a reminder, but things happen, something else on the panel needs attention. But I have a habit of checking the engine monitor during takeoff so I usually see it quickly and push the mix in. Lean more. If you’re on the ground leaned as you described waiting for a few people to land, lean farther. So far that the engine is right on the edge of roughness/stopping. To see if you’re lean enough, try to add power… it should stumble/die. If you consistently get that lean on the ground, it’s pretty hard to takeoff like that since the engine will die when you add power. 1 Quote
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