Engine overhaul questions

[Godfather]

I'm currently looking for an older Mooney c/e/g and looking through the logs have noticed two different field overhauls that incorrectly assembled the engines causing cylinder/etc failure within 100 hrs. In both cases the problem was addressed and the engine logs look good otherwise. Should I be concerned about damage to the crank or other parts?  Should the quality of the overhaul be questioned?

[Yetti]

If you don't get it the first time... try try again

If the engine now has several hundred hours on it then all should be good.  Also depends on what failed the first time.

[MB65E]

What was the spicific failure? The first 100hrs can be the scariest. I strongly feel field overhauls done right can be better than shop overhauled engines. There is an SB listing of required components that need to be replaced during overhaul. Was the list followed? or was it "essentially an overhaul" big delta there...

I would ask to see paperwork on the overhaul and repairs

-Matt

[Yetti]

other than getting the push rods wrong or torque values wrong... how do you miss assemble a cylinder.  Maybe a bad overhaul on the cylinder.

[PTK]

Engine incorrectly assembled on two different occasions?!

Were they done by the same shade tree mechanic under the same tree?! Must've been pretty shady under there!! 

[Alain B]

1 hour ago, Godfather said:

I'm currently looking for an older Mooney c/e/g and looking through the logs have noticed two different field overhauls that incorrectly assembled the engines causing cylinder/etc failure within 100 hrs. In both cases the problem was addressed and the engine logs look good otherwise. Should I be concerned about damage to the crank or other parts?  Should the quality of the overhaul be questioned?

A failed part after an overhaul , maybe once ! Two time in a row , it look suspicious ! 

[Godfather]

Sorry for not explaining my non A&P observations better.  I'm referring to two different aircraft and the last overhaul on record (15-25 years ago).  On one, detonation was recorded and the cylinder was replaced. The other three cylinders were removed and discovered the push rod length and thrush washer was improperly installed. I can't remember the specifics on the other one without digging through the logs again. 

I guess my question is if there is proof that the major parts were sent off to be inspected (yellow tagged) and the engines have performed well for 800-1000 hrs should I be concerned about slight errors in assembly?

[RobertGary1]

My piston backed out the end cap bolt and departed the crank at 1100 hours after Lycoming factory assembly. So even the factory can make mistakes and hours don't always tell you if you are out of the woods.

 

-Robert

[tigers2007]

I read a final report published a couple years ago when I was Google searching a certain engine rebuilder (Kline Aviation in Michigan). It was a Piper in PA that went down just after takeoff with about 700 or so SMOH. fatal. NTSB report noted how incorrect rods were installed by Kline Aviation. I don't have a direct reference to the report but what scared me was how the engine surpassed the "infant mortality" stage just fine. IIRC the rods were appropriate to the engine series but not the exact model.


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[DXB]

1 hour ago, tigers2007 said:

I read a final report published a couple years ago when I was Google searching a certain engine rebuilder (Kline Aviation in Michigan). It was a Piper in PA that went down just after takeoff with about 700 or so SMOH. fatal. NTSB report noted how incorrect rods were installed by Kline Aviation. I don't have a direct reference to the report but what scared me was how the engine surpassed the "infant mortality" stage just fine. IIRC the rods were appropriate to the engine series but not the exact model.
 

My engine was overhauled by a well known  shop in Florida in 2000, long before I owned the plane.  Last December I had 2 jugs pulled for reconditioning with 800 hrs on the engine, and my A&P noticed the intake tubes didn't seem to fit quite right while reinstalling.  He checked the part numbers and found that  all my intake tubes were for an O-320.  No harm done  to my engine as far as I can tell, but it does illustrate how easy (and common?) it is to end up with the wrong part during an overhaul. What else did they get wrong?? This is the stuff of nightmares because no amount of vigilance short of becoming an A&P and doing your own overhaul can prevent it.  It does bias me toward paying a premium for one of the top tier shops like Penn Yann or Zephyr to do the work when my number finally comes up.

[PTK]

For my money it has to be genuine Lycoming factory. Nothing less.

[Guest]

That would be a good policy, other than the screwing Lycoming has given many owners for years.  The only issues I've ever had with the many engine done by my local shop is the odd loose crankshaft seal.

Clarence 

[RobertGary1]

The worst engine I ever had was a Lycoming "new" (not reman, not rebuild, not overhaul). Had early cylinder wear (out of round), engine stoppage due to fuel servo failure, oil pressure occasional oddities, stuck piston pins resulting in high metals, and then finally a loose piston end cap nut. Knock on wood I've got 50 hours in my Lycoming reman this time and almost out of warranty.

 

-Robert

Edited March 27, 2017 by RobertGary1

[FloridaMan]

I've heard that there are bolts that are designed to stretch when torqued. Some of them don't stretch and you're supposed to discard them. If a mechanic was unaware of this, I could see this being an issue. 

[N201MKTurbo]

23 minutes ago, Antares said:

I've heard that there are bolts that are designed to stretch when torqued. Some of them don't stretch and you're supposed to discard them. If a mechanic was unaware of this, I could see this being an issue. 

The rod bolt tightening procedure is explicitly spelled out in the manual. If I recall you tighten them until they are 0.006 longer. If they get more than 0.008 longer you have to throw away your $100 bolt. They cannot be reused or retorqued. 

[RobertGary1]

1 hour ago, Antares said:

I've heard that there are bolts that are designed to stretch when torqued. Some of them don't stretch and you're supposed to discard them. If a mechanic was unaware of this, I could see this being an issue. 

Yes but it was not a mechanic it was the factory who built my factory new engine.