engine trouble on take off

[larrynimmo]

Shown is engine monitor about 600 above ground after take-off....

less than 300 hours on a factory rebuilt Lycomming...see attached from an edited copy of jpi data...things to look at..  all cylinder #2, EGT, DIF, RPM,ALT

also having issues of #2 cylinder egts dropping right after initial starting....other than that #2 runs perfectly

INDEX	DATE	TIME	E1	E2	E3	E4	C1	C2	C3	C4	OAT	DIF	CLD	MAP	RPM	HP	FF	SPD	ALT
Engine - Tach Start = 292.0	Tach End = 292.4	Tach Duration = 0.4
57	6/13/2020	14:31:20	1304	1322	1307	1347	308	322	314	329	79	43	0	29.8	2665	83	17.4	73	185
58	6/13/2020	14:31:26	1301	1316	1306	1347	312	326	317	332	79	46	0	29.8	2665	83	17.5	76	268
59	6/13/2020	14:31:32	1303	1320	1311	1343	316	329	319	334	79	40	0	29.8	2665	83	17.4	76	383
60	6/13/2020	14:31:38	1307	1327	1319	1358	320	332	322	336	79	51	0	29.2	2667	82	17.6	77	465
61	6/13/2020	14:31:44	1316	1124	1329	1353	322	334	325	337	78	229	0	29.7	2561	80	15.3	80	557
62	6/13/2020	14:31:50	1370	956	1393	1395	326	335	327	340	78	439	0	28.6	2447	73	13.1	73	684
63	6/13/2020	14:31:56	1307	1192	1319	1347	329	334	331	342	78	155	0	29	2676	82	17.1	68	769
64	6/13/2020	14:32:02	1303	1278	1308	1342	332	335	334	345	77	64	0	29	2650	81	17	74	825
65	6/13/2020	14:32:08	1299	1292	1310	1353	335	336	337	347	77	61	0	28.8	2650	80	17	80	885

Edited June 14, 2020 by larrynimmo
added info

[0TreeLemur]

Looks like something is wrong with your JPI.  The random variation of signals in an analog to digital (A/D) device like an engine monitor is almost always caused by excessive electrical noise in the signal or a problem with the A/D device itself.   Because you have weird nonsensical variation of many unrelated variables, plus signals like rpm (pulses) are pretty much immune to electrical noise, these data strongly suggest that your JPI is in need of some love.  Which model is it?   Also, if able, you should set it to 2-second recording interval.  Much more useful than 6 sec.

Also- I'd check the D-sub connection on the back of the unit and make sure it is still tight.

 

[Bob - S50]

A few questions.

When this happened, did the engine run rough or was it still smooth? (thinking about a bad signal)

Was this a one time event or does it happen on a fairly regular basis? (thinking temporary injector restriction)

How long after start before you took off? (thinking morning sickness)

What do you do with the mixture on the ground? (also thinking morning sickness)

[larrynimmo]

Let me be clear...engine went rough for about 12 seconds...enough for me to consider my options...

plane had just flown 40 nm...then sat for  10 minutes, and Then I took off

Edited June 14, 2020 by larrynimmo

[0TreeLemur]

Just now, larrynimmo said:

Let me be clear...engine went rough for about 12 seconds...enough for me to consider my options...

Ok, this makes my previous post irrelevant.  I incorrectly thought that after a flight you noticed what you suspected to be an engine problem by looking at your JPI data. 

You experienced partial power loss shortly after takeoff.  My comment about changing the JPI interval to 2 sec. is still relevant.   More frequent data recordings might show what went wrong first.  I'd change it to 2-sec before you do a full-power runup.  Usually when one plug goes inop due to fouling etc., the EGT goes up.  The fact that your EGT went down indicates that you are losing power in cyl. #2.   Unlikely to have two intermittent plugs, so the injector or injection servo would be immediately suspect.

[Browncbr1]

Pull injectors, soak in MEK or hoppes #9..  

put Dixie cups under each fuel line and run electric fuel pump while switching fuel selector back and forth rapidly.  

Do this until you can Verify no debris and each cup is filled evenly. 

[Andy95W]

Does it do this every start, and every takeoff, or only the first start/flight of the day?

If it's only the first start or flight of the day, then it could be the beginning sign of an exhaust valve starting to stick on #2.

[0TreeLemur]

8 minutes ago, larrynimmo said:

Let me be clear...engine went rough for about 12 seconds...enough for me to consider my options...

Looking at your data, it is strange that you were only generating 83% power on takeoff at most.  The altitude and mp data indicate you were near sea level.  Your engine should have been at or very near 100%.   My JPI900 indicates 100% on t/o at my home airport near sea level.  Did you enter the data from the POH into your JPI to allow it to accurately calculate percent power?  The governor requires adjustment to get the full 2700 rpm on t/o too, but I don't think that 35 rpm less will result in a 17% reduction in power.  

[larrynimmo]

13 minutes ago, 0TreeLemur said:

Looking at your data, it is strange that you were only generating 83% power on takeoff at most.  The altitude and mp data indicate you were near sea level.  Your engine should have been at or very near 100%.   My JPI900 indicates 100% on t/o at my home airport near sea level.  Did you enter the data from the POH into your JPI to allow it to accurately calculate percent power?  The governor requires adjustment to get the full 2700 rpm on t/o too, but I don't think that 35 rpm less will result in a 17% reduction in power.  

I never took the time to program join as to percentage of HP...I was at 100% (or slightly less) due to only 2660 rpm or so

[larrynimmo]

15 minutes ago, Andy95W said:

Does it do this every start, and every takeoff, or only the first start/flight of the day?

If it's only the first start or flight of the day, then it could be the beginning sign of an exhaust valve starting to stick on #2.

For the past dozen flights, issues with no 2 egts after at least 12 -18 seconds after start up.  When starting, engine is smooth, the in about 12 seconds the egt for no.2 drops from 1100 down to 600 or so for about 30 seconds or so

[Andy95W]

If that is accompanied by engine roughness, and then "fixes" itself, I think it sounds like the start of classic morning sickness signs.  As the different metal components heat at different rates, the exhaust valve can start to stick.  As the valve guide and valve reach operating temperature, the sticking goes away.  The cure, if that is the problem, is not too outrageous.  Involves reaming the valve guide with the cylinder still on the airplane and the "rope trick" to get everything back together.  Hopefully your A&P/shop has experience with that and the proper reamer.

Rich ( @N201MKTurbo) has some goood experience with it, IIRC. And of course Clarence ( @M20Doc).  

[Bob - S50]

Sounds to me like two different issues.

In one case you describe a problem after takeoff.  That sounds like debris in the #2 injector.  If it only happened once then it has probably cleared itself but it wouldn't hurt to remove, inspect, and if need be, clean the injector.

In the second case you seem to indicate a problem after start.  If that is only when the engine is cold then it sounds like morning sickness as pointed out by Andy.  Get your mechanic to ream the guides, then start running the engine brutally lean on the ground to reduce deposits so it doesn't happen again.

[N201MKTurbo]

19 minutes ago, Andy95W said:

If that is accompanied by engine roughness, and then "fixes" itself, I think it sounds like the start of classic morning sickness signs.  As the different metal components heat at different rates, the exhaust valve can start to stick.  As the valve guide and valve reach operating temperature, the sticking goes away.  The cure, if that is the problem, is not too outrageous.  Involves reaming the valve guide with the cylinder still on the airplane and the "rope trick" to get everything back together.  Hopefully your A&P/shop has experience with that and the proper reamer.

Rich ( @N201MKTurbo) has some goood experience with it, IIRC. And of course Clarence ( @M20Doc).  

I hate to disappoint you, but I’ve never done this. I watched it done a couple of times back in the 80s when the Phillips XC oil was causing the problem. It was on C-150 engines. It happened to my engine. A valve stuck and bent the push rod. I took the cylinder off and took it to a cylinder shop.

[Andy95W]

Dang.  My memory's going.  I think.  

Wait, what were we talking about?

[Guest]

I would start with reaming the valve guide.  Not a really challenging task. Once the cowl is off, about an hour per cylinder.

Clarence

[carusoam]

Larry,

Is it possible for you to share the JPI data via Savvy..?

 

For anyone considering age related memory challenges... that much data, not in a graphical format... really makes it tough to sort through...

Savvy allows us to see multiple flights, start-up issues, high power issues, and combinations of various issues...  like the run-up...

It is really cool... when we feel Engine challenges... You know there is data collected on the JPI....

So... let’s review the tape...! 
 

Getting before and after data for the valve guide reaming procedure would be great...

 

Your description sounds similar to my O360’s stuck valve experience... (Exhaust valve stuck open)  High power climb to traffic pattern turned into high vibration as one cylinder went off line....

 

Best regards,

-a-

 

[larrynimmo]

Since I do have about 300 hours on the engine, I am going to replace the spark plugs with tempest fine wire plugs...and see where I am at.  It won’t hurt to try before I assume that it’s the exhaust valve sticking...

I can understand the valve sticking as for cold starting, but I wouldn’t think it would stick under load on a warm engine...I will try and will report back

[Yetti]

1 hour ago, larrynimmo said:

Since I do have about 300 hours on the engine, I am going to replace the spark plugs with tempest fine wire plugs...and see where I am at.  It won’t hurt to try before I assume that it’s the exhaust valve sticking...

I can understand the valve sticking as for cold starting, but I wouldn’t think it would stick under load on a warm engine...I will try and will report back

That's not how spark plugs work.  I would say to pull the plugs as they tell the story.  Fuel, air, Spark.  Most everything is pointing to fuel.   What was density altitude when you launched.   I had a similar 800 foot experience as you which I chalk up to Tempest fine wire losing an electrode and full rich mixture at 5000 DA 

Could be a fuel divider.  Was the divider and fuel servo rebuilt at Engine OH?   Baby jar test - don't use dixe cups.  Fuel can melt through the wax. Is how you check the fuel divider. 

[larrynimmo]

Lycomming factory rebuilt and installed September 2018....including new fuel divider and servo.  In April 2019, the servo butterfly got so stiff to operate from fully closed, we had to send it back under warranty...and plane has flown well since then until now.   Ground level was 150’

as for spark plugs..Back in the early 70’s....when I ran leaded gas in my 1969 corvette I couldn’t get more than 6,000 miles on a set of plugs due to lead fouling...would only affect high power, high rpm operation and power would break down at about 4,000 rpm.   Once I switched to no lead amoco, my problems disappeared

Edited June 15, 2020 by larrynimmo
Additional info

[David Lloyd]

First thing I thought was sticking valve.  Don't ignore the possibility of an intake valve.  Other cylinder temps went up a little and then back to normal as #2 dropped and came back.  Sometimes valves will stick when hot, sometimes when cold.  I once had a valve suddenly stick enough to bend a pushrod at the very end of a 3 hour flight.

[PT20J]

The flow divider is pretty simple and it’s hard to see how it would cause a problem with one cylinder. An injector would affect its cylinder only. At idle, the pressure at the injectors is really low - the gas just dribbles out. I’d try cleaning the injectors before spending money on parts and labor. It may not be the problem, but it can’t hurt. 300 hours is pretty low time for a stuck valve unless the clearances were too tight to begin with which seems unlikely for a new cylinder. 

Mike Busch has an interesting column in the July AOPA Pilot explaining how running CHTs in the low 300s can cause lead deposits that stick valves especially on Lycomings with sodium cooled valves that run cooler by design.

Skip

[cujet]

Sure sounds like classic Lycoming valve sticking. My IO360 #2 exhaust valve stuck briefly at altitude, on initial descent. I have a old EM engine monitor so it's difficult to really see data. But the EGT did drop much like yours did. A single bad plug will cause EGT to rise. I flew it home and had no further in flight issues. 

Was very easy to check, the next day I pulled the valve cover and observed the valve hanging up as it closed. 

 

 

[larrynimmo]

43 minutes ago, cujet said:

Sure sounds like classic Lycoming valve sticking. My IO360 #2 exhaust valve stuck briefly at altitude, on initial descent. I have a old EM engine monitor so it's difficult to really see data. But the EGT did drop much like yours did. A single bad plug will cause EGT to rise. I flew it home and had no further in flight issues. 

Was very easy to check, the next day I pulled the valve cover and observed the valve hanging up as it closed. 

 

 

once you discovered the sticking valve, what did you do to resolve it...did you do with string push of the valve and ream the valve guide (as others have spoken about)

[PT20J]

It's colloquially called the "rope trick." 

 

[larrynimmo]

2 hours ago, PT20J said:

The flow divider is pretty simple and it’s hard to see how it would cause a problem with one cylinder. An injector would affect its cylinder only. At idle, the pressure at the injectors is really low - the gas just dribbles out. I’d try cleaning the injectors before spending money on parts and labor. It may not be the problem, but it can’t hurt. 300 hours is pretty low time for a stuck valve unless the clearances were too tight to begin with which seems unlikely for a new cylinder. 

Mike Busch has an interesting column in the July AOPA Pilot explaining how running CHTs in the low 300s can cause lead deposits that stick valves especially on Lycomings with sodium cooled valves that run cooler by design.

Skip

Skip, 

I do value your opinion.   I've been running my M20J really cool.  In the winter, my cylinder temperatures were as low as 300 degrees...#2 has always been my coolest head.  I am always reading about aircraft engines and looking for the optimum operational balance encompassing longevity, economy, serviceability....I read the Mike Busch article...why wasn't it out years ago?  It has been my belief, the cooler the heads the better....Ive been cruising for the last year  LOP 25MP, 22RPM 7GPH and yielding about 20 statue miles per gallon...when its cold out, there are some really cool cylinders....but now my operational values are at fault, because I need to cruise at over 350 cylinder temps