scottfromiowa Posted November 29, 2011 Report Posted November 29, 2011 Flew tonight with G3 engine monitor again. -Noticed 380 (cylinder temps) in the climb up to 5500... No leaning in climb indicated 120MPH... My #2 was at 430 indicated! (I'm getting the probe changed and having it put in the OEM location) IT ALWAYS reads 50 degrees high. Here is my question/observations. At 2500RPM and 25MP Leaning from 11.5GPM I could lean NO LOWER than 50ROP without engine roughness. Climbed to 5500 and could only get a fuel flow of 10GPH and 50ROP without engine roughness. On my GEM I was able to pull to engine roughness and enrichen to peak. and then go LOP. Any ideas whats going on. My plugs have 461 hours REM38E Massives...Would replacement with Fine Wire UREM38S Tempest plugs help here? I plan to have injectors pulled and soaked in MEK at annual in two weeks. Other thoughts? I could NOT get a fuel flow lower than 8.5GPH at that power setting/altitude. Do I have to lower MP down low to get LOP? Does this matter? Quote
scottfromiowa Posted November 29, 2011 Author Report Posted November 29, 2011 My Timing is 25 BTDC... Quote
jetdriven Posted November 29, 2011 Report Posted November 29, 2011 Our timing is now 25. We have the tempest fine wires. Do a GAMI spread. Make sure those nozzles are clean. Take the richest cylinder nozzle and swap it to the leanest cylinder. Our GAMI spread went from 1.2 GPH to .2-0 doing that. We can now do ~100 LOP. Ross has massives and he reports the same LOP on his F, so maybe its no so critical. Quote
scottfromiowa Posted November 29, 2011 Author Report Posted November 29, 2011 So if I tell my A&P to do a G-Spread I think he will look at me cross-eyed. How do you do? Quote
scottfromiowa Posted November 29, 2011 Author Report Posted November 29, 2011 I just read more about GAMI spread. I need to do WHILE flying. I'm NOT getting peak so can't get the spread. I read another thread. I think I need to drop the MP back. Suggestions? I flew with Ram Air closed on this flight and power backed off to 25MP at 2500 and 24MP (full throttle) at 5500. I'm guessing I need to lower my MP? Will this help get LOP? Quote
jetdriven Posted November 29, 2011 Report Posted November 29, 2011 The GAMI spread test is still useful if you cannot get peak. You are logging the EGT at several incremental fuel flows to establish which cylinders are leaner and which are richer. Perhaps you have an induction leak, that could mess things up as those cylinders run way leaner than the artight ones. You could tell your mechanic to check the induction tube seals at the pan and the gasket at the head on, say, #2 rather than a general comment. Perhaps you have a bad plug lead. LOP stresses the system more, of you have a deficiency, LOP will show it. EDIT: one more thing. An -A3B6D engine will get LOP at any altitude with the throttle full open. Just Saturday we were at 9.5 GPH LOP at 1500' with the manifold pressure at 29.5" and the RPM at 2450. Hottest CHT was 310 and it was smooth. Quote
takair Posted November 29, 2011 Report Posted November 29, 2011 Quote: scottfromiowa I just read more about GAMI spread. I need to do WHILE flying. I'm NOT getting peak so can't get the spread. I read another thread. I think I need to drop the MP back. Suggestions? I flew with Ram Air closed on this flight and power backed off to 25MP at 2500 and 24MP (full throttle) at 5500. I'm guessing I need to lower my MP? Will this help get LOP? Quote
jetdriven Posted November 29, 2011 Report Posted November 29, 2011 25" and 2400 RPM is not above 75% power. 24 square uis about 70%. Lycoming recommends operating at peak at 75% and below. Quote
KSMooniac Posted November 30, 2011 Report Posted November 30, 2011 Like Byron I suspect you have an induction leak or a bad plug (or plug wire). While leaning to 50 ROP before roughness did you notice one EGT go higher than the others, and then start falling before you felt the roughness? You can pressurize the induction system through the air filter and spray soapy water on all of the joints and look for bubbles. Every Lyc IO-360 in my research has been able to run LOP just fine so long as the induction, fuel and ignition systems are up to PAR. My -A3B6D runs fine down to 100 LOP at WOT and low altitudes. Quote
Shadrach Posted November 30, 2011 Report Posted November 30, 2011 Quote: scottfromiowa I just read more about GAMI spread. I need to do WHILE flying. I'm NOT getting peak so can't get the spread. I read another thread. I think I need to drop the MP back. Suggestions? I flew with Ram Air closed on this flight and power backed off to 25MP at 2500 and 24MP (full throttle) at 5500. I'm guessing I need to lower my MP? Will this help get LOP? Quote
scottfromiowa Posted November 30, 2011 Author Report Posted November 30, 2011 My run-ups/mag check have been fine. I was focused on the cylinder temps after climb. The ACTUAL readings of the temps (in the 380 range) surprised me (second flight with G3). I am going to replace all plugs (massives) with Tempest fine wire's at annual (two weeks out). Plugs have 361 hours. One plug failed bomb test last annual and was replaced...I will have mechanic look at induction. Filter (oil impregnated) was replaced last annual. I had NO problem getting LOP prior to a few weeks ago. Quote
scottfromiowa Posted November 30, 2011 Author Report Posted November 30, 2011 Quote: Shadrach Are you saying that the engine gets rough before peak EGT?? Quote
scottfromiowa Posted November 30, 2011 Author Report Posted November 30, 2011 Quote: scottfromiowa Are you saying that the engine gets rough before peak EGT?? Quote
scottfromiowa Posted November 30, 2011 Author Report Posted November 30, 2011 Mystery solved on G3. As it is a "loaner" I didn't connect the fuel flow as you must remove and return. Without the fuel flow the actual # R or L is NOT correct. I was LOP, but without the fuel flow input into G3 it doesn't know level from peak... All is well. I plan to lean and note the EGT spread at each cylinder peaking for reference. Quote
Shadrach Posted December 1, 2011 Report Posted December 1, 2011 That makes sense, though I do not undertsand why the G3 cares about fuel flow when calculating EGT movement. So you need to imput the K-value from your transducer? Quote
scottfromiowa Posted December 2, 2011 Author Report Posted December 2, 2011 It doesn't Ross. I was just fixated on the erroneous information regarding the "R50" indication. I thought the solid white or Cyan meant "peak reached" for cylinder which is correct, but dthe indication through me off. I didn't look to see what the actual egt number was... Quote
jetdriven Posted December 2, 2011 Report Posted December 2, 2011 That G3 must use a FF to decide when cylinders are LOP. Wthout a FF, the G3 could be fooled if you richen slightly. It must use FF to decide if the mixture is moving rich or lean. smart. But yes, can cause problems. I like the idea of the G2. Keep us posted, Scott. Quote
carusoam Posted December 2, 2011 Report Posted December 2, 2011 Nice feature improvement... With the ff integrated into the system, it can decide if you are leaning ROP or lop. Nice feature, since the JPI requires additional button pushing to tell it which mode you are using. With the two-button system, this requires button pushing and holding to get to LF (LOP). LF=lean find. Best regards, -a- Quote
jetdriven Posted December 2, 2011 Report Posted December 2, 2011 Our old Masten engine analyzer (ca. 1991) just shows the 4 EGT and CHT digitally. Plus FF and fuel remaining. Surprisingly applicalbe even now. Quote
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