Cylinder Failure - M20K-231

[N9937c]

In the turbo Mooney's I have flown the #1 cylinder is the hottest both in cht and egt.

I would have your mechanic really look at the ignition ( mags, plugs and wires).

The only other time I have seen this is when a mag switch had been left on one mag and detonation was present at TO power. It was noticed the EGT's were Way hot on the TO roll.

Larry

[Jeff_S]

So, I think I know the answer to this but I haven't found it specifically written in all the literature I've read lately. Assuming my GAMI spread is acceptable (which I now know how to test) I should be able to run LOP because I have the engine monitor to do it. I even know how to run the LF LOP operation on the JPI-700. My question is, if I'm following the "red zone avoidance" technique as graphed by the APS folks, which cylinder do I use as the guide to set the LOP mixture? I'm assuming I would use the last cylinder to have peaked, because it will be the hottest and the one I need to bring down to the appropriate temp. But if that's wrong, please set me straight.

(Similarly, if running ROP, I would use the first cylinder to have peaked as the baseline as it would also be the hottest. Right?)

[carusoam]

"Similarly, if running ROP, I would use the first cylinder to have peaked as the baseline as it would also be the hottest. Right?)" - Jeff_S

 

ROP - first cylinder to peak.

LOP - last cylinder to peak.

When using the JPI 700 in Lean Find mode (LF) make sure that it is using the correct LF mode.  There is one for ROP and one for LOP.  When starting LF, the unit tells which mode it is in.  It is easy enough to switch between the modes.  I have the procedure in the plane (or I would have shared it already).

[fantom]

A good Mike Bush article on LOP operations from my library: http://www.avweb.com/news/savvyaviator/savvy_aviator_56_before_you_yank_that_jug_197497-1.html

Video of JPI-700 Operation:

Check page 21 of JPI Pilots Guide: http://www.jpinstruments.com/PG_700-800%20Rev_R%202.PDF

Lean Find Mode—“Lean of Peak” LOP

To use the “lean of peak” method, tap LF and then immediately hold both Exit and RoP/LoP until you see LeanL. You may toggle back to LeanR  by holding both buttons again. Once you begin leaning (blinking square) you cannot change leaning method. Upon power up, the EDM 700/800 always defaults to Rich of Peak mode.

Leaning Lean of Peak (LOP)

In the “lean of peak” method the columns will invert with the first to peak progressing down from the top of the display, looking like icicles. The “icicle” scale has higher sensitivity. As you continue to lean past peak the number of the each successive cylinder will blink as it peaks. The peaks will be shown as an icicle graph; when the last cylinder peaks its column will blink. The analog display is an icicle graph showing where each cylinder peaked. When the RoP/LoP button is held the display will show the delta fuel flow between the first and last to peak (GAMI Spread), as well as the richest peak EGT.

 

 

 

 

 

 

 

 

 

 

 

 

 

[Magnum]

Even when flying ROP I set my EDM 830 for LOP operations. I lean until all cylinders are on the lean side and then I enrich until all are on the rich side again. With the EDM 830 you see how many degrees you are below peak on ALL cylinders, so you can avoid running one at 50dF ROP. This happens easily when the leanest cylinder is at 25dF ROP (like it is instructed in the POH for best economy). So sometimes the leanest is at peak and the richest at 25 dF ROP. Lycoming states in the Lycoming Operators Manual (PN 60297-12) peak EGT as best economy when below 75% power, so I have no problem with that. I usually fly with 65% HP (that gives nice speeds and a quite low fuel burn), so I could even run at 50dF ROP.

I fly LOP, too, but sometimes it just doesn't feel right. It depends on OAT and RPM settings how the engine "feels". If it is not a day for LOP I fly ROP. ROP means 1-1.5 gal/hr higher FF and around 5 kts more speed. If I want to go faster (>65% HP) I fly at least 100dF ROP (on the leanest cylinder).

[tablor]

Has anyone tried the online Advance Pilot Seminar?  I suppose the best question would be, has someone gone through both the live and online courses to offer the benefits of one versus the other?  There's a few obvious differences, but the cost differential between the two is significant.  I learned of this course quite some time ago and have been interested but haven't decided to cough up the time/money.  Any advice/info specifically regarding the course they offer would likely be beneficial to all of us, although it's possible a new thread would be appropriate...

[KSMooniac]

There is at least one PIREP here about the online course that was very positive.  As close as you are to Ada, I would recommend the live course, though!  It is worth every penny!  I'm an aircraft engineer and thought I could pick up everything via the online course, but I'm so glad I went to the live one.  The live Q&A and test stand viewing is very valuable IMO and worth the cost delta.  I learned more there in 2.5 days than in many semester-long engineering courses.

[jackn]

FWIW...I have a 252 with a TSIO360SB that had 700 hours. Couple of cyl had low compression #s. #1 was 61. Did oil analysis, they told me I might want to try AVBLEND. 30 hrs later #1 is up to 68. All other cyl are higher as well. Was told these TSIOs get carbon build up after 600 hours or so.

[Piloto]

Pete

i don't think the failure was due to the way the engine was operated but rather a defective component. It looks that either the wrong piston was installed or a metalurgic failure of the piston. Do a visual inspection (thru the spark plug hole) of the other pistons to see if they have similar conditions. Have the piston inspected by Continental. This incident could be realated to a bad batch of pistons.

José

  

 

[Earl]

I've taken the online course and thought it was very good, although not as good as taking the live course as I have been told by those that have taken both.  A couple of points if you take the course.  First, when you complete a section of the online course you cannot go back.  In hindsight I wish I had done a screen shot of each page so I could at least have the info to go back and look at.  For extra money (can't remember how much) you can get the manual.

After taking the course when I am flying at anything over 65% power I run 100dF ROP.  I am convinced from the data that running 40 to 50 dF ROP produces the highest cylinder head temperatures and internal cylinder pressures.  Heat and pressure are the enemy of an engine.  I have tried LOP and the balance between my fuel flows is too large to run LOP.  I did a GAMI test and my spread was more than 0.5gph so I would need GAMI injectors and even then it might not work.  I will probably have them installed at my next annual and see if I can run LOP at higher power settings.

PM me if you want more details.