Oil Consumption 2.5 qts in 1 hour! IO-360 A1A

[Grandmas Flying Couch]

It's Been awhile!  I bought my 67F two years ago the engine was overhauled 10 years ago and has about 450 hours since OH, I put 150 of the hours on it since purchase.  This last weekend I flew for 1 hour 15 minutes from Goodyear AZ to Bisbee AZ and went from 6 quarts to 3.5 quarts.  I suspect a bad cylinder as the exhaust was coked up and the breather had pooped oil all over the belly.  Plane was down on power upon landing.  I have a channel changer EGT, gami injectors and have usally ran 100 degree ROP.  There have been a couple occasions where I tried lean of peak at 7500+ feet.  I would run it rich of rough by a few turns on the mixture knob,  did I cause the damage to the cylinder(s)?  I usually get bored at LOP and go ROP for the extra power.  I don't lean down low.  If climbing out of a high altitude airport I will lean to get the egt needle off the bottom peg (noticeable increase in power).  Mechanic is coming out today to check it out.  Before all this oil was 1qt for 5 or 6 hours compression in the mid 70s.  

Should I just fix the offending cylinder and be on my way?  Has this happened to others as a bad ring or a fluke, or did I do this?, I hate to think I was stupid enough to ruin a 25k engine.  

 

 

[TTaylor]

You can relax your mind, running lean of peak did not hurt your engine. The pressure and temperatures for your engine are lower LOP when you are running less than 65% power at altitude. I fly about 90% of the time at 9 gph at 8500 to 10500 feet.  Running LOP does not mean trying to run at Carson numbers, jut more efficiently.  I see about 139 knots at 9 gph or 144 at 10.5 gph.  This is the difference of 15.4 nm/gal versus 13.8.  That amounts to about 5 minutes more on a 300 nm trip, but a savings of about 3 gallons of fuel.  Leaning to roughness on a fuel injected engine is not the best way to get LOP.  An engine monitor and fuel flow system is much better.

I hope you can find the issues and it is not too expensive to repair.  Don't beat yourself up over leaning the engine.

[ArtVandelay]

First, pull the plugs, the really oily ones will tell you which cylinder(s) are bad.


Tom

[Grandmas Flying Couch]

That's a good Idea 

6 minutes ago, TTaylor said:

7 minutes ago, TTaylor said:

You can relax your mind, running lean of peak did not hurt your engine. The pressure and temperatures for your engine are lower LOP when you are running less than 65% power at altitude. I fly about 90% of the time at 9 gph at 8500 to 10500 feet.  Running LOP does not mean trying to run at Carson numbers, jut more efficiently.  I see about 139 knots at 9 gph or 144 at 10.5 gph.  This is the difference of 15.4 nm/gal versus 13.8.  That amounts to about 5 minutes less on a 300 nm trip, but a savings of about 3 gallons of fuel.  Leaning to roughness on a fuel injected engine is not the best was to get LOP.  An engine monitor and fuel flow system is much better.

I hope you can find the issues and it is not too expensive to repair.  Don't beat yourself up over leaning the engine.

Thanks TTaylor, I will probably stick to ROP till I get a JPI installed

3 minutes ago, ArtVandelay said:

First, pull the plugs, the really oily ones will tell you which cylinder(s) are bad.


Tom

That's a simple and easy solution!  I have a bore scope so will take a gander inside as well.  

 

[Rwsavory]

We had a similar issue arise after a cylinder was removed for an exhaust valve replacement.  High oil consumption and ultimately so much oil in the cylinder that it interfered with ignition.  Re-honing the cylinder and new piston rings solved the problem.

[1964-M20E]

Yes repair the offending cylinder or cylinders and move on.  While the cylinder is off the A&P should look closely at your cam since it is visible at that time.  The way these engines are designed you can do one or all cylinders at a time.

[EricJ]

A check of the cylinders or pop the cowl open to look for leaks, etc., is certainly not a bad idea.    If nothing conclusive is found and it's running okay, I'd suggest flying it to see if it keeps doing that.

Has it done this before or is this the first time?    When I first bought my airplane it was a bit schizo on oil consumption.   It'd be fine, doing the usual 6-7hours/qt and then suddenly a quart in a couple of hours, then back to normal, then a quart in a couple of hours.    In other words, I had to keep an eye on it in case it decided to drink a bunch of oil, but usually it was okay.

The engine had been torn down due to a prop strike not long before I bought it, and the facility that did the tear down told me that this behavior sometimes means that the ring gaps in a cylinder may be nearly lined up, and when they happen to line up the consumption goes up, then the rings move and it's okay, and if they move back the consumption will go up again.   In my case it eventually settled down and consumption has been normal for a long time without any crazy consumption episodes.

So I suppose that that's a possibility and if there are no other indications of problem areas it might be worth just running it a while to see what it does.

 

Edit:   I first read your post as 2.5 hours to a quart, but now I see it's 2.5 qts in an hour.   That's past the limit Lycoming allows, so  ignore my above advice and sort out where it's going before you fly it again.

Edited April 1, 2019 by EricJ

[Yetti]

check plugs for oil,  check filter for metal.

[Ross Taylor]

Hey there, I'm sorry to have heard about your troubles but it was nice to meet you (briefly) at "Bisbee International Airport."  :-)

As EricJ said, that oil consumption is past the Lycoming limit... but the thought about ring alignment might be a factor.  Maybe, see if the mechanic is open to trying a solvent ring wash before tearing things down?

But, your comment about oil on the belly and the exhaust pipe residue sounds to me (a PP only) like a valve issue... I think?  I'll bet that borescope will reveal something helpful.

I'm following along with fingers crossed for you,

Ross 

[carusoam]

1) Sounds like the case is getting pressurized, by a leaky ring...

A mechanic should be able to tell if the case is getting pressurized...

 

2) If the oil ring isn’t keeping the oil from leaking up into the cylinder... the oil is leaving through the exhaust...

A pilot should be able to tell if the exhaust pipe has an extra quart or two of oil running through it...

 

3) Coked oil in the valve guides... that can lead to stuck valves... I’m no fan of stuck valves... not to be confused with sticky valves, similar but not as treacherous...  there is a maintenance procedure known as the rope trick... for cleaning the valve guides...

4) Quarts of oil went missing... if it went through the cylinder, Expect the lower spark plug in the bad cylinder to become pretty obvious with even the most basic engine monitor... look for a failing plug causing a hotter EGT on that cylinder...

 

+1 on immediate fix of what is wrong... not an LOP/ROP issue...if it was... that would show up slowly with increased wear of the cylinder walls... this just showed up in one flight...?

PP thoughts only, not a mechanic...

Best regards,

-a-

[ArtVandelay]

If he had a stuck exhaust valve, he would know it, a 4 cylinder engine running on only 3 is going to have noticeable roughness.

I always ask, what does the engine monitor tell you?

But he doesn’t have one, just a channel changer EGT gauge.

 

It’s anecdotal but seems like people who post about engine problems don’t have or use engine monitors?

 

Tom

 

[Grandmas Flying Couch]

Looks like the rings are leaking and pressuring the case.  Mechanic came out and everybody is mid 70s/80 except cylinder 4 which was "Really Low" and with air rushing out of the crank case vent.  I don't know how low is low but I believe it.  They are going to bore scope it today and send pictures.  

Hey Ross, hope you and your family had a fun outing in the E

[bonal]

4 hours ago, ArtVandelay said:

If he had a stuck exhaust valve, he would know it, a 4 cylinder engine running on only 3 is going to have noticeable roughness.

I always ask, what does the engine monitor tell you?

But he doesn’t have one, just a channel changer EGT gauge.

 

It’s anecdotal but seems like people who post about engine problems don’t have or use engine monitors?

 

Tom

 

Not to be argumentative but there have been countless numbers of threads where one of us is having an engine problem that is accompanied with screen shots of their engine monitor data. The advantage is in the diagnosis which can be much quicker. To the OP likely number 4 is bad. Pull it hone it re ring it surface the valves and put it back together. Easy Peasy the one advantage to our engine design is the ability to repair or replace an individual cylinder without having to pull the engine.

[bonal]

As for the stuck valve totally agree you would know it. We had one stick on our c150 just after takeoff and it felt like the engine was going tear itself off the airframe 

[carusoam]

Same with the O360... stuck the exhaust valve on departure (first 10 hours of ownership)... the vibration is tremendous... the power was just enough to hold altitude... @1k’ASL.

The pilots were planning on landing straight ahead while trying to determine what was still working... Apollo 13 emergency checklist style... without any ground control support...

An engine monitor would have given a great hint to the answer of “how many cylinders are still working?”

From inside the cockpit without an engine monitor, it felt like the case had let loose all of its oil...  that would have been a land straight ahead decision...  oilP and oilT were fine... and nothing spraying on the windshield...

The piston bent the valve rod... when they crashed together...

So...if knowing the difference between a single cylinder failure vs. complete engine failure makes a difference in your thought process... Go graphic engine monitor... count the vertical bars if you only see three... one has gone on hiatus... 

Land on the next available runway...

Not having an engine monitor was a drag... they aren’t much more affordable today than they were 20years ago... but there are ways to get them used, and installed with a mechanic watching over your progress...

there isn’t enough time to click through four switch positions to see all the cylinders to try and figure out what the old monitor can be telling you...

Pp thoughts only, of a really crummy memory...

Best regards,

-a-

[Grandmas Flying Couch]

What does everyone think of the insight G2 vs the JPI 830?  The insight will fit in my panel where the channel changer is for my EGT and replaces egt and cht as primary.  The 730 or 830 will require panel work.  Also insight is 600 cheaper

[gsxrpilot]

I've had a G2 and really liked it. The only one I like better is the 900 from JPI which allows you to replace all your factory engine gauges. If you're just looking for a good data logging engine monitor for EGT and CHT, the G2 can't be beat.

The data logging on the SD card in the face of the unit is just so easy. And that SD card will hold much more than 2000 hours (TBO) of your engine. 

The full color screen is just so much better, more modern, and easy to read than the comparable entry-level engine monitors from either JPI or EI.

[Grandmas Flying Couch]

After losing this cylinder and thinking I may have cooked it (I don't know cause yet), I'm paranoid, will probably run rich of peak but want to monitor chts.  I like the extra speed from ROP.   I feel like I cooked that cylinder, it's number 4 I have the factory probe on cyl 3 so that one never got too hot, hopefully the other two being up front in the cool air means they never got cooked.  I feel like there is a 75% chance I could have prevented this crap with an Engine monitor.  Do you know if the alarm points can be changed to 400F for the cht or is it stuck at the factory 415?  

[jaylw314]

The advisory instruments have alarm limits that can be freely changed, like the EDM 730/830.  Most newer primary instruments like the 900/930 have fixed alarm limits, but they allow you to set an advisory alarm at a lower limit.  Some older primary instruments, though, like the 711 I had, don't allow you to change alarm limits at all.

[gsxrpilot]

I think you can get other redline settings by talking to Insight at the time you order it. But I wouldn't worry about that. I'd mount it on the left side of the panel right in front of me where it's easy to watch. Unlike the low end JPI's and EI's, the G2 is super easy to read and will show you the actual numbers for CHT's at all times. There's no scrolling through to see the actual temps. They are always there and easy to see. Therefore I don't believe the alarms are nearly as important as they are with the old JPI and EI monitors.

Having an engine monitor and knowing how to read it, will give you so much more confidence with regards to your engine. In fact, you'll probably learn that if you want to be really gentle with your engine, you'll run in LOP any time you can.

Personally I wouldn't own an airplane without a modern engine monitor. You won't be sorry with the G2.

[Cyril Gibb]

On 4/1/2019 at 11:52 AM, Grandmas Flying Couch said:

 I have a channel changer EGT, gami injectors and have usally ran 100 degree ROP.  There have been a couple occasions where I tried lean of peak at 7500+ feet.  I would run it rich of rough by a few turns on the mixture knob,  did I cause the damage to the cylinder(s)?

You won't cook a cylinder running LOP that way,  but every documented, instrumented, scientific analysis done since the 1930's says you will running 100 ROP.

[PT20J]

 

4 hours ago, Cyril Gibb said:

On 4/1/2019 at 8:52 AM, Grandmas Flying Couch said:

 I have a channel changer EGT, gami injectors and have usally ran 100 degree ROP.  There have been a couple occasions where I tried lean of peak at 7500+ feet.  I would run it rich of rough by a few turns on the mixture knob,  did I cause the damage to the cylinder(s)?

You won't cook a cylinder running LOP that way,  but every documented, instrumented, scientific analysis done since the 1930's says you will running 100 ROP.

I use LOP and ROP depending on what I'm trying to accomplish, so I don't claim to have any bias. That's a pretty strong statement you made there. Can you back it up with copies of every (or even some) "documented, instrumented, scientific analysis done since the 1930's" that shows running a normally aspirated engine at 7500' at 100 ROP will "cook" (very scientific term, BTW) a cylinder?

[bradp]

You’re unlikely to cook a cylinder at 7500 ft either.  Less than 75% power generated.  You should know a little about ICP (internal cylinder pressures) and what that does to heat mass and how it’s different LOP and ROP.  I think there’s pretty good evidence that running an engine >75% power at approximately 50F ROP settings below 5000 will result in conditions that are more likely to correlate with need for replacement cylinders or cylinder repair before the TBO (ie a TOP).  I’d also argue that an improperly cooled or “tuned” engine will also have a higher likelihood of needing cylinder work prior to TBO. Look at every IO-540 in a Malibu that every had a top overhaul - they things a total setup for running though cylinders.. high powered, hot, turbocharged.  

I aim for CHTs in the 360s.  If I can’t run LOP or ROP there, then something need to be addressed (cooling / baffling / AF mix injectors / ignition etc).  I alarm at 380F on a JPI.  If I’m above 400 I am really doing something wrong and need to make a change ASAP.  I’d like to believe that I’m preserving my rings by using a more conservative CHT methodology.  I am not opposed to ROP even though I spend most of my time at LOP.  I will just use the ICP/heat mass “red box” methodology and stay 100-200F ROP below 5000 and not approach 50 ROP unless 7000 or above. 

I also wouldn’t run any engine these days without a monitor and I probably wouldn’t buy an airplane that didn’t have a previous owner that knew how to use one. My little JPI has paid for itself, 4 cylinders and in the 2000 gallons of a gas it’s saved me since I put it in. 

[carusoam]

It’s not where we’ve been that counts... it’s where we’re going....  

1) Take your pick...

JPI, EI, or insight.... all make good engine monitors...

2) Decide if you want to dump the old engine instruments... which can be pretty lame after their 50th year....

This will limit your choices and bump the costs a bit... Primary engine instruments have a few special requirements...

3) Go all in... because it’s your forever plane...Primary instruments all in one device, with a flight recorder, including FF and location... add the fancy fuel level sensors because you can...

Be sure to read the details of which instruments are primary and which devices handle the primary instruments appropriately...

4) EI is best known for their service... JPI is best not known for their service... And Insight doesn’t seem to need any service because nobody has complained about them, and there are plenty of MSers using them....

PP thoughts only, I have an insight Strike Finder... it has worked well for years...

Best regards,

-a-

[PT20J]

1 hour ago, bradp said:

You’re unlikely to cook a cylinder at 7500 ft either.  Less than 75% power generated.  You should know a little about ICP (internal cylinder pressures) and what that does to heat mass and how it’s different LOP and ROP.  I think there’s pretty good evidence that running an engine >75% power at approximately 50F ROP settings below 5000 will result in conditions that are more likely to correlate with need for replacement cylinders or cylinder repair before the TBO (ie a TOP).  I’d also argue that an improperly cooled or “tuned” engine will also have a higher likelihood of needing cylinder work prior to TBO. Look at every IO-540 in a Malibu that every had a top overhaul - they things a total setup for running though cylinders.. high powered, hot, turbocharged.  

I aim for CHTs in the 360s.  If I can’t run LOP or ROP there, then something need to be addressed (cooling / baffling / AF mix injectors / ignition etc).  I alarm at 380F on a JPI.  If I’m above 400 I am really doing something wrong and need to make a change ASAP.  I’d like to believe that I’m preserving my rings by using a more conservative CHT methodology.  I am not opposed to ROP even though I spend most of my time at LOP.  I will just use the ICP/heat mass “red box” methodology and stay 100-200F ROP below 5000 and not approach 50 ROP unless 7000 or above. 

I also wouldn’t run any engine these days without a monitor and I probably wouldn’t buy an airplane that didn’t have a previous owner that knew how to use one. My little JPI has paid for itself, 4 cylinders and in the 2000 gallons of a gas it’s saved me since I put it in. 

Help me understand some things, because I’m confused. 

I know what heat is, and I know what mass is, but what is heat mass and how does ICP affect it?

If I fly a M20J at 3000’ density altitude at 75% BHP and 50F ROP with CHT of 360F, exactly what damage would you expect that would shorten cylinder life and how do you know that?