Morning sickness

[ArtVandelay]

I had a case of severe morning sickness a week ago, see attached JPI graph, the log was started about 30 seconds after start, it appear to only be running on 1 cylinder, which is rather impressive. I've had this before but it's always been on cold mornings

After it recovered everything was normal, I flew it for another 20 hours and engine ran great, I put in some Marvel Mystery Oil and flew for an hour today, then changed oil, any other preventive measures I can do?

 

 

 

 

[Guest]

SB 388 and ream the guides.

Clarence

[carusoam]

Saw-tooth pattern EGT is a subtle hint...

Its not just one valve, either...

+1 on cleaning valve guides.  See what chunky carbon comes out of them...

cleaning the valve guides will improve the oil flow through there.  

Oil flow improves valve cooling as well. 

PP thoughts only, Clarence's guidance is one to follow...

Sticky valves bight.

Best regards,

-a-

[Yetti]

Ream the valves

[bradp]

Ream the valve guides.  Find someone who knows the rope trick.   Save your lifters, cylinders and maybe even cam.  

[Bob - S50]

And then lean the crap out of it while you are on the ground so it doesn't happen again.  Lean it until it starts to stumble, then enrichen just enough to smooth it out.  Leave it that way until it's time for the run up.

I won't start the fight about ROP/LOP again.  However, just out of curiosity, do you cruise LOP or ROP?

[Hank]

I lean hard enough on the ground that I have to enrichen when I advance the throttle to taxi uphill. Parked in the grass once, engine nearly died pulling the nose wheel up onto the pavement; then I remembered to richen it some, pulled completely onto the asphalt, reduced throttle and pulled back towards lean again. 

This generally ends up with the mixture 2/3 towards Idle Cutoff. Same for landing, pull towards lean as I leave the runway.

Edited June 18, 2017 by Hank

[Yetti]

coking the valve guides is not about fuel mixture as much as it is a crappy design from Lycoming

[bradp]

There ain't oil flow to those valve guides.  That's our problem with the 4 banger lycomings.  

Sometimes I wonder if use of a multiviscocity oil might help when the engine is first starting up - maybe get some better lubrication to the guides...?  

[ArtVandelay]

I think that the take home point is to idle at 1000 RPM or higher whenever possible in order to increase oil flow to the valves.  If you lean as much as possible while dong this you will also avoid fouled plugs. I use under 2 GPH as my personal benchmark. 

Its not lack of leaning, I'm at 1.5 GPH when on the ground and always run LOP except on takeoff, climb out. I generally taxi around at 1000 and only go to slow idle on landing. The motor does have over 2000 hours on it.

[Mooneymite]

Of interest:  https://generalaviationnews.com/2005/05/20/marvel-mystery-oil-and-tcp-a-cure-for-valve-sticking/

[Yetti]

So the flight school that I trained at where the Chief flight instructor was a WWII Flight engineer, Navion Test pilot, A&P   Had all the plane run at 1100-1200 RPM  unless you were taxiing    Cooling and more oil flow seems to make sense

[kortopates]

Cyl #4 is definitely showing signs of a sticking valve a.k.a. morning sickness. But the data on #1 is inconclusive and I doubt you'll find #1 sticking. It should really be sticking from startup and thus show a cold EGT from startup, but a normal EGT at startup that then goes cold temporarily may not be a sticky valve. More commonly, its sticking at startup and then as power as applied it will un-stick itself - till the day comes when it doesn't. Or during low power cruise as it cools it will begin sticking open again. But anytime while its sticking, you're engine is at serious risk of eating a valve which makes it well worth addressing asap to avoid. 

[ArtVandelay]

I read the one SB that recommends bumping up RPM before shutting down, I definitely don't do that, and it's happened before when traveling, I think it's because of more slower, longer taxiing and dirtier oil (I normally change at 30 hours but long cross country trips I go almost 50).

I talk to my local mechanic, he recommended pulling the cylinder(s), which I declined.

The writeup Mooneymite referred to is wrong. The author says MMO is just a light oil, actually is 25% mineral spirits plus 1% lard (NTSB tested it). There is YouTube videos where they do a before and after shots of engines after running just a few minutes with MMO, and it's definitely not snake oil. Very effective on carbon build up.

For now, the engine runs beautifully, and the oil change showed almost no metal in the filter and none in the drained oil. I'll keep an eye on it, and will try to do an oil change on the road next time.

Edit, I looked it up, from safety data sheet...

Petroleum Distillates (Hydrotreated Heavy Naphthenic) also known as mineral oil 60-100%

Petroleum Distillates (Stoddard Solvent) also known as white spirit 10-30%

Tricresyl phosphate 0.1-1.0%

Ortho Dichlorobenzene 0.1-1.0%

Para Dichlorobenzene

 

 

[PTK]

If we assume the mineral spirits help valves from sticking wouldn't Avblend be a better choice than MMO?

[ArtVandelay]

If we assume the mineral spirits help valves from sticking wouldn't Avblend be a better choice than MMO?

Hmmm, $22 for 12oz of Avblend or $3.88 for a quart of MMO?!

I also only use MMO for an hour, I don't like the idea of it being used all the time.

Also I should mention I added Camguard before the start of the trip because I figured if extending time between oil changes, I should have extra protection, may be that cause the problem by letting the oil stick to the valve stems,guides?

[Andy95W]

I'm quite sure Peter was being sarcastic.  He's not a believer in oil additives and is usually pretty quick to point that out.

We had a discussion here a little while ago abut Avblend.  One of the things attributed to Avblend, possibly apocryphal,  was its ability to help with valve sticking.  I cut and pasted a big article from The Aviation Consumer magazine about it.

 

[Yetti]

This covers some of the mechanics

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0ahUKEwj0hIbLos_UAhUK6YMKHegJBBcQFgg-MAQ&url=http%3A%2F%2Fwww.shortwingpipers.org%2Fforum%2Fattachment.php%3Fattachmentid%3D6881&usg=AFQjCNFFJoQVENwBIYTzpx_0F3kPM4XgPQ&sig2=xd_nyzU876hM96-KR6V5dQ&cad=rja

 

[carusoam]

Yetti,

I was expecting a picture of a mechanic covered with oil...   

Nice article.

Best regards,

-a-

Edited June 22, 2017 by carusoam

[dhc]

I had an unpleasant experience with morning sickness on my factory reman IO360-A3B6. The symptoms were classic: severe engine roughness immediately after cold-start for upwards of a minute, followed by smooth operation. The unusual part was that the engine was only about 1.5 yrs and 100 hrs SFRM. Additionally, as the attached EGT/CHT data shows, two cylinders were suffering non-combustion simultaneously. Valve guide coking seemed an unlikely culprit, with the only reasonable explanation being poor manufacturing tolerance at Lycoming.

In any case, the purpose of this post is to share with fellow members:

1- The engine monitor data, which shows what the event looks like.

2- The fact that SB-388 data (procedure to measure valve guide clearance) produced clearly corroborating results

3- The fact that SI-1425A (procedure to ream valve guides) fully cured the problem. After it was done the problem has never resurfaced in over a year.

All of the above are summarized in the attached PDF file, which was part of my warrant claim with Lycoming. I should point out that Lycoming (and AirPower, the engine retailer) were decent in their warranty response. After initially insisting that I pull both cylinders and sent them back to the factory for rework (Hell no! Didn't want the wear and tear on the engine even if they were willing to pay shop costs.), Lycoming eventually came through and paid for the field performance of SB-388 and SI-1425A at my mechanic's shop.

So I am left with residual outrage that it happened in the first place, ameliorated by at least having had a good customer service experience, coupled with some appreciation at the engineering level that the data were so clean and the fix so decisive.

Dan

morning_sickness_data_summary.pdf

[PTK]

Here's what Lycoming recommends...

https://www.lycoming.com/sites/default/files/Recommendations to Avoid Valve Sticking.pdf

[rbridges]

On 6/17/2017 at 4:03 PM, teejayevans said:

I had a case of severe morning sickness a week ago, see attached JPI graph, the log was started about 30 seconds after start, it appear to only be running on 1 cylinder, which is rather impressive. I've had this before but it's always been on cold mornings

After it recovered everything was normal, I flew it for another 20 hours and engine ran great, I put in some Marvel Mystery Oil and flew for an hour today, then changed oil, any other preventive measures I can do?

 

 

 

 

Thanks for posting the pic.  I pulled my data because I was worried about the same issue.  I didn't have a graph for reference at the time.