Way too early, but IO-360 A1A is kaput

[Moonbat]

850 hours on this engine SMOH. A lot of symptoms now begin to make sense after looking at the cam lobe for the input valves on cylinders 1 & 2. There was barely a bump much less a lobe! Engine comes out, big overhaul underway, might as well do the turbo, the prop, the fuel servo, the exhaust pipes, and governor while at it. They’re all due or nearly due. 

Now the “fun” begins. Given: this is a 1967 M20E, with t-n, GAMI’s and most every speed mod available, a decent panel recently upgraded With an Aspen E5 to do away with vacuum related stuff. It is the perfect plane for me and my “missions”. The paint’s nice. Then interior is nice. The glass is nice. The plastic is nice. The panel and avionics are nice... not all glass, but nice. Autopilot is STEC 55X. The tanks are long range O&N bladders. I am 68  yo, so this may well be our last hurrah as far as new planes go. (Well, not including the Starduster I’m perseverating on, but that’s another thread on another site.) My wife will have to sell the plane after I’m gone. (I’ve told her to just call Garrison or McGee at All American, assuming they outlast me!) 

What fun or practical upgrade items would you definitely do in this situation. Electronic ignition? Digital a/p? Digital servos on control surfaces? Go for an overhaul to new specs instead of to service limit specs? New engine instead of major overhaul? Other?

Let ‘er rip. I know how you like spending opm! 

Edited May 12, 2020 by Moonbat
Typo

[carusoam]

OPM is everything!

But we need to have a starting point...

A good pic of....

• Cam Lobe Nubs... very important...
• Cam followers that generated the nubs... with their moon surface pock marks... really good...
• the tsp or tbsp of metal bits that came from the oil filter or screen...
• Icing on the cake... oil sample lab results showing abnormally high Fe...

We can invite a group of specific MSers to discuss things like...

• New vs. Reman vs. OH’d
• Best cost for OH... and how to put the engine in the back of your VW... and returning it back home...safely.
• Roller devices... fancy wheeled cam followers...
• IO390s..
• 10:1 compression ratios...
• Ney nozzles
• Centrilube cams

Go for it!

Best regards,

-a-

 

[Moonbat]

The engine is on the bench and split, and all the components are arrayed over three shop tables. We spent some time just ooohiing and aaaahhing, draining oil and doing preliminary forensics. The underlying thinking was, "what the hell kept this plane in the air?" The answer is two and a half cylinders - but not for much longer. A long trip to Texas for the Mooney Formation Flying clinic might have been its last hurrah, We'll never know for certain. More detailed pictures tomorrow if I can get some good shots. Here's what we've seen on an engine that had only 850 SMOH on it (400 of those are mine in the last 3 years) so far. You can only imagine the amount of soul searching that is going on about the right and wrong ways to run an engine like this! My over-riding opinion is that I am very lucky to have followed the array of symptoms to this point before something worse than an overhaul happened. 

Extreme pitting on two tappets, but notable pitting on all of them. 

One nearly completely missing lobe of an intake cam. 

Crank shaft may be serviceable as it has only one step of an oversize bearing so far. 

Definite wear marks from metal shards on the crank shaft

Metal shards "welded" to the sides of several pistons. One can feel the roughness with a finger. 

Magnetic metal shards in the oil screen, the oil filter canister, the oil filter magnet and in the oil pan. (Oil report not back yet - due in a couple of days.) 

Several (if not all) piston rod bearings finish was worn badly down to bronze in some spots

Cylinders may not be too bad, BUT there is a circumferential rust line in all four of them indicating this plane sat somewhere for a very long time 

Savvy analysis trend report over the last year (May 2019 - May 2020, 45 flights) show: 

   Statistically significant declining HP in cruise

   Statistically significant decreasing maximum CHT during flight

   Statistically significant decreasing maximum CHT in flight

   Statistically significant decreasing maximum fuel flow during flight

As I said, perhaps photos tomorrow... 

Edited May 13, 2020 by Moonbat
typo

[carusoam]

Hmmm...
 

The FF declining over several flights will be interesting... if you always fly at the same altitude... or same MP...

 

Looking forward to the data and the pics...

Best regards,

-a-

[Moonbat]

We (Paul K from Savvy, the mechanic here named Zack) think that the fuel servo was at somewhat the culprit for the FF. It was leaking air at the grommet where the linkage enters the body. It showed a bit of play and bubbled at the input pressure test during the annual six months ago in Dec 2019. The fuel servo is to be repaired / replaced as part of this ongoing overhaul. Max FF (generally take-off) declined from ~18 gph to 14.5 gph over that time. All the while at the other end, the FF was worse for cruise regimes. Up from ~9gph to more like 11gph. The thinking here is that I was probably compensating for the engine's lost power due to it wasn't breathing properly by pushing the MP and RPMs to a higher level to get some performance out of it. 

Edited May 13, 2020 by Moonbat
clarification

[carusoam]

Great follow-up MoonBat!

Now I know a reason I always check FF with MP and RPM... just at the beginning of the T/O run...

Best regards,

-a-

[Ragsf15e]

To your original question... I would get it overhauled to new specs.  I’d also make sure I got either roller lifters or dlc lifters.  I think the only way to get roller lifters is to get a factory rebuilt or new engine.  Dlc lifters can come during a regular overhaul, I think.

Id also take this time to redo the wiring to/from the VR and the field wire from the VR through the master, to your alternator.

Maybe fuel lines?  Maybe new throttle, prop or mixture cables if they’re old?

Of course that’s just an opinion and I’m not even an A&P.  Good luck with your choices!

[tmo]

6 hours ago, Ragsf15e said:

dlc lifters

My "local" mechanic is a big fan of those, so a +1 I guess...

[Moonbat]

Here are three shots of the new paperweight, er, old camshaft. The first photo is the entire cam shaft (no yellow arrow). (I couldn’t force it to show properly vertical.) The second has a yellow arrow pointing at the missing intake lobe for cylinders 1 & 2. lobe. It is supposed to protrude to the right. There is a slight bump remaining, but about 1/2” is missing. In the third photo, the cam lobe should be coming right toward you, but all you see is the shiny, mostly flat spot where the lobe used to be. 

Edited May 14, 2020 by Moonbat

[jetdriven]

Yep that’s how they go.  The lifter face spalls, which is no longe smooth.  Then it wears down the cam.  
were you doing oil analysis?  Iron numbers tell the tale. 

[ArtVandelay]

I had same problem, 3&4 intake node, but at 2200 hours, and oil analysis was normal.

[Moonbat]

36 minutes ago, jetdriven said:

Yep that’s how they go.  The lifter face spalls, which is no longe smooth.  Then it wears down the cam.  
were you doing oil analysis?  Iron numbers tell the tale. 

Oil analysis every 25 hours or so. All seemed pretty normal except for one outlier report about two years ago. 

Savvy Analysis reports really nailed it though. The detailed declining FF, power output, CHT's over time. There was clearly something headed inthe wrong direction. However I was masking some of it by using the t-n system to get some compensated performance out of the engine. Really what I was doing was pushing a sick engine even harder, probably shortening the time to a catastrophic failure. Got to read the tea leaves so carefully! 

[Moonbat]

20 minutes ago, ArtVandelay said:

I had same problem, 3&4 intake node, but at 2200 hours, and oil analysis was normal.

Dreaming of 2200 hours the next time! (In self-defense, I did previously own a 1965 Comanche and was able to get to 2400 hours with no problems. It was not t-n'd or t-c'd. Maybe that's the issue in my case.) 

[jetdriven]

6 minutes ago, Moonbat said:

Oil analysis every 25 hours or so. All seemed pretty normal except for one outlier report about two years ago. 

Savvy Analysis reports really nailed it though. The detailed declining FF, power output, CHT's over time. There was clearly something headed inthe wrong direction. However I was masking some of it by using the t-n system to get some compensated performance out of the engine. Really what I was doing was pushing a sick engine even harder, probably shortening the time to a catastrophic failure. Got to read the tea leaves so carefully! 

What were the iron levels on the oil analysts?  25hr oil changes you have to double the metal counts to normalize it. It’s actually so many ppm/hr 

[cferr59]

I've heard this a few times where the filter and suction screen are metal free and oil analysis shows no significant metals, yet there is significant cam and lifter wear. In those cases, where does the metal go?

[Guest]

2 hours ago, cferr59 said:

I've heard this a few times where the filter and suction screen are metal free and oil analysis shows no significant metals, yet there is significant cam and lifter wear. In those cases, where does the metal go?

If the wear rate is slow enough and the filter changes are frequent enough there may not be enough metal to be seen or captured on a magnet.  

I’ve seen just the opposite.  An oil filter full of ferrous particles, yet the oil sample is clean.   

Clarence

[ArtVandelay]

If the wear rate is slow enough and the filter changes are frequent enough there may not be enough metal to be seen or captured on a magnet.  
I’ve seen just the opposite.  An oil filter full of ferrous particles, yet the oil sample is clean.   
Clarence

I think it depends on how much you fly and change your oil. My first couple of oil changes I saw some metal in the filter, but not a lot. Afterward I saw nothing. Flying 150-200 hours with 5-6 oil changes per year.

[Moonbat]

Today we spun the new engine with no spark plugs in it to pressurize the oil through throughout the engine. Tomorrow is the first engine run. So excited to get going again. New Surefly, and just about everything else is either new or newly overhauled: turbo, fuel servo, prop governor, cylinders, pistons, bearings, valves, cam shaft, 2nd magneto, ignition cables, overhauled MT-12 prop, baffles and aluminum airflow deflectors, exhaust tubes, and more. The engine has never looked so well organized, clean, tidy. Wish us luck! (I apologize in advance for the rotated photos.)

Edited September 3, 2020 by Moonbat

[carusoam]

This is the important one...

 

Good luck with the runs!

-a-
 

[Guest]

Your newly overhauled engine is well on its way to cam failure.  No on in their right mind motors an engine over to establish oil pressure.  An oil pressure port is the right way to pre fill and pressurize the oil system.

Clarence

[Jerry 5TJ]

1 hour ago, M20Doc said:

No on in their right mind motors an engine over to establish oil pressure.

That is exactly how everyone starts their engines, right?  No Mooney I’ve seen has a pre-oiler system installed.  

Spinning the engine with spark plugs removed (thus zero compression) seems ok to my engineering eye.   

[Yourpilotincommand]

In her history, I’m wondering how long she sat and where... near the coast? With evidence of cylinder rust there’s certainly going to be cam rust.. a matter of time before pitting on the lobes and then spalling. Cam guard helps inhibit corrosion for those who don’t fly every week.  Lycomings are more susceptible to cam spalling as the cam is above the crank (different than Conti’s) At least you’ll get the full 200hp when she’s done! 

[1964-M20E]

6 hours ago, M20Doc said:

Your newly overhauled engine is well on its way to cam failure.  No on in their right mind motors an engine over to establish oil pressure.  An oil pressure port is the right way to pre fill and pressurize the oil system.

Clarence

Just read in a Lycoming service bulletin and it said to do just this to prime the engine with oil after overhaul or oil cooler change. However, using an external source to prime the system is a better option if available.

Assuming proper assembly lube was used when assembling the engine and it has not sat for an extremely long time (JMHO >6 months) since it was assembled I find it hard to believe that spinning the engine without spark plugs to prime the oil system would cause any damage.  You are rotating the engine with the rotating parts unloaded.

[Nukemzzz]

I'd recommend using DLC coated tappets with the overhaul.  This is what i did with my A1A which is finally going back in the plane next week.

[J0nathan225]

Broad question I'm sure, but what did the overhaul run you and what did it include?  @Nukemzzz and @Moonbat