Engine Overhaul woes

[skywagon8a]

...RPM 2450, Oil temp 205, Oil Press 52, CHT just over 400 steady,...

What was the ambient temperature on the day of the test flight? I get nervous when I see CHTs hit 400 and above. (I know the limit is 500) Anything continuously over 400 has proven to me over time to cause trouble. Was this just one cylinder or all four? With the oil temp being above normal and the oil press on the low side with the 400 CHT, there are indications of something not quite right even on a new overhaul. What is the condition of the baffles? Are there any big holes for air to bypass the engine? Tight or tight and broken rings could lead to high CHTs and high oil temp/low oil press. None of this explains the damage to the top of the pistons.

 

[Steve Pierce]

ECI new cylinders come pre-lubricated and the rings fit and installed. There is a note that if excessive lubricant has leaked into the bag the cylinder is shipped in or it has been more than 6 months since assemble you should remove the piston and lube. The piston weights are marked on the outside of the cylinder box.

 

[Aviator]

Whacha got in the bag, son?

Had to fly an apprentice mechanic and parts to a remote lake once to change a jug on a Beaver (P&W-985). The o'hauled jug, piston and all, came from a well-known and trusted shop (Aviation Electric). My helper insisted on pulling the piston out of the jug only far enough to slide in the piston pin, and gave me an argument when I wanted to have a look-see (grumbled something about the skeeters eating him alive). Sure enough, the shop stuffed waxed paper above the piston to prevent it from floating around during shipping, but didn't bother to tell anyone. Live and learn... and live.

 

[nanook]

ECI doesn't rate a "pull it out of the bag and slide the piston pin out just far enough to install it" rating from me....sorry....if I'm signing off on installing a cylinder... The ring gaps aren't going to all be lined up (how you going to tell?) the first three letters of ASSume are, and you could just put DUMB in front of those three letters, if you can't take the time to do your job correctly... What flunky at ECI is doing those final assemblies?

 

[aktango58]

even if damage happened in the last three hours, it does not absolve everyone.

what if it took that long for parts to work loose?

oil samples only tell some of the story...

 

[Helmetfire]

...........

What was the ambient temperature on the day of the test flight?
Temp that day was around 50F

Was this just one cylinder or all four?
Just the #3 cylinder, plug gasket type thermocouple...I know these are not ideal but its all i got...

What is the condition of the baffles?
Baffles werent in the best shape, but definately no gaping holes or anything that would cause abnormally high CHT, IMO .

 

[Helmetfire]

Heres the crank. You can clearly see where the main bearing surfaces were grinding. running my fingernail across it was rough. Looking at the prop flange you can see it has no lightening holes, and a squared off edge on the back side. I've seen other A2B's and they all had a beveled edge there. I also thought the narrow decks had the lightening holes. The only ID's I could find on the crank was on the edge of the prop flange it had this number: 13B17020...probably a serial number. Also a "DU" and "170" raised letters on the casting between the rod bearing surfaces. Again my engine is an O-320 dash nothing narrow deck...even though he wrote on the overhaul log entry that it was an A2B...how's that for attention to detail?!?

He couldn't remember what cylinder it was that he took apart prior to shipping out...

 

[aktango58]

looks like lube deficiency and heat to me.

But what do I know, I am working on a 2 cylinder engine that did the same on top...

 

[tempdoug]

The crank thats bad on my 1962 year B2b narrow deck has the holes in the flange and the new crank thats going in it is solid. I think that holed flange is a new vs. old deal. In your logs does it say the crank was changed at one time? I think that holed shaft would probably be a lot better deal for the engine with a hard prop strike but like with the 2 piece cam your wasting your time looking for a new one.

 

[Aviator]

I ain't no engine-man per se, but looking at the damage I'd have to go with the FOD theory. What kind if strip do you operate from and what kind of air filter element do you have? Does the door on your carb heat box close properly? Any leaks, missing gasket under the air cleaner? What kind of oil filter do you have, screen or spin-on? It almost looks like sand got into your oil. What's the security like at the field you're at? Anybody you can think of would want to do this to you deliberately?

 

[nanook]

There are many issues here...getting hard to keep them separated. Sorry if you have already answered these...

Do you have an oil filter?
Was your oil cooler flushed before this engine was installed?
There was a failure that contaminated or there was a source of contamination introduced into your engine.
(Where is this material at now? Why has it not been identified?)...
The failure could be a result of oil starvation. But what failed? Tappet Face? Rolled Rings? Spalling is easy to identify. Rolled rings (slivers) are easy to identify... Did the bearings fail? Lack of oil will gall the bearings. Contamination is a pattern of striations? You should control this situation and protect the evidence. Get a qualified person to access this situation. Right now you have the fox guarding the hen house so to speak.... Keep all this material so you can find out what happened.
The oil testing that took place prior to this last one needs to be obtained. To just say that it was normal is not good enough. New O/H engines all make metal during the breaking-in process. The rings, bushings etc... All shed a bit... This should show up as elevated iron, copper...etc.... Obtain copies of these reports and compare to the new test....

The solid flange crank is not an early "no letter designation" O-320 crank. You should be talking to Lycoming about what part #crank is eligible for that engine. The early 0-320 is considered an -A model, they are the same...

I can't stress enough, that you need to find an independent third party expert. They need to access this situation....it requires detective work that is not possible on this site. Don't let the evidence get away. Don't let it be sent out. Protect all of these parts and remove them from the premises... From what I've heard I wouldn't let that shop do any more work until you find out what caused this failure....

 

[tempdoug]

....it requires detective work that is not possible on this site. Your wrong there, the majority of the people on this website i would trust with my life. Not a doubt in my mind.

 

[Alaska_Rallyer]

Wow that sucks. Looks like major oil contamination. Maybe blast media ? Bet the oil sample silica is very high.

I think everyone is thinking the same thing that you are getting the big one.

That engine is hosed. Will need a complete overhaul again. Everything needs to be flushed, crank polished or even ground, new pistons and rings, probably hone the cylinders, oil pump? and that would be to just repair the thing... boom new 10k - 20k bill for you.

 

[nanook]

Tempdoug, you are missing the point. While there is plenty of expertise on this site... We can't access all the information needed to come to the proper conclusions. You need to go through this with a fine tooth comb. This is important for the owner and the shop that did the work. Nobody wants to see this sort of thing happen... This is why this investigation needs to be done in a controlled environment. This site, these pictures, this shop with the engine, are not a controlled environment.

 

[aktango58]

how long did the overhaul take, and was the final assembly done in a 'clean room'?

Flushing cooler, good point.

It looks like LOTS of whatever, hence my heat thought.

 

[Steve Pierce]

New or overhauled cylinders? Yellow tags for crankshaft, cam shaft, rocker arms, tappets, hydraulic units, crank case?

 

[myskyjeep]

My ECI cylinders came with a note saying something like:
" this cylinder is ready to install, but if you think you know more about our cylinders than we do, do your thing."

I resisted the temptation to pull the piston out. I can't say I've ever heard of an ECI cylinder being assembled incorrectly.
If you have the proper ring compressor it's probably a good idea to double check though.
Dave

 

[aktango58]

nanook,

sound thinking!

Very Sound.


When you guys assemble, do you slather oil on all surfaces for pre-lube? does it matter what kind?

 

[Darrel Starr]

If this helps, this is the flange on our ND O-320-Nothing engine. Also shows B&C 40 Amp Alternator and B&C Starter.

 

[T.J.]

Nanook.
I mentioned the yellow tag/new carb as an example. If the cyls installed were new/yellow tagged, according to the regs, they are ready for installation. I agree with you about the inspection. I like to check ring gap, ring part number and condition of the cross hatch on the cyls.
The scouring on the piston is not severe. However, that much damage in 30 hours would raise my eyebrows! I suspect wrong rings, improper make up lube on the cyls or improper break in. The OP stated 2 short ground runs then a 30 min flight for break in. Were the ECI breakin procedures followed?
The crank P/N, engine vibration, prop changing, FOD damage to the top of one piston are different problems. Like you said, there's a lot of different crooks and turns to the story, so it is hard to figure out.
This is exactly why I never warranty any engine overhaul I do. What you see is what you get. I have no control how the pilot will run the engine.

PS...My Lycoming Parts Catalog doesn't list an 0-320 (no number). The 0-320 A2B (150HP) narrow deck and the 0-320 B2B (160) narrow deck is the same part number.

 

[tempdoug]

Helmetfire, make sure you come back to this with whatever you find. So many ask for help or a direction to go and never reveal the results. And thats how we all learn is by our mistakes.;-)

 

[S2D]

Looks to me like you got some bad stuff in the oil or something came apart in the engine. If you never found a bad part, I'd suspect the oil cooler. If you have a yellow tag from cooler shop that cleaned your cooler, then you should be able to eliminate that. In spite of a possibilty of something going thru the intake, I don't think it would have done that kind of damage. I'm pretty sure your crank is legal, If you want to check everything , get all the Lycoming manuals and service bulletins, letters and instructions and you figure out what does and doesn't go there.

I just saw an engine with 20 minutes on it eat a tach shaft. Turns out the supplier sent a chrome plated tach shaft to the unsuspecting mechanic. I don't even know if that is a legal or an experimental part. Needless to say, the chrome came off and locked up in the accy housing.

So if you can verify that none of the parts in the engine are defective, I'd try to find out where all the crap came from. that top ring looks pretty shot for 30 hrs, is it the right material?

 

[mike mcs repair]

.....Maybe blast media ? Bet the oil sample silica is very high.
...

that was my thought too... someone didn't clean out all the oil galleys or nooks and crannies, and some sand was floating around....

 

[Cub Builder]

You know, last time I saw a piston that looked like the one in your picture, the sides were loaded with pieces of camshaft. Check your cam followers for corrosion pitting on the faces. It it's there, the cam is starting to spaul and will load the sides of the pistons with steel particles that will look just like your picture and also cause scoring in the cylinders. At less than 30 hours since the engine was assembled, the cam lobes will still be mostly intact, but faces of the cam followers will show the pitting IF that's the problem. That's not to say that is what caused the damage, but it is a possibility that will cause the pistons to look like what you are showing.

If you run your hand or a cotton rag up or down the side of the scored piston, it will snag if there are steel particles imbedded into the sides.

-CubBuilder

 

[MN_flyer1]

According to the O-320 TCDS the no dash = A1A.

 

[aviationinfo]

First flight oil pressure below the green arc for 30+ minutes... 52 psi vs 60 for the beginning of the green. One would think if oil starvation was the issue it would affect more than one cylinder though. Is 8 psi low enough to be an issue on a short flight?

 

[180Marty]

First flight oil pressure below the green arc for 30+ minutes... 52 psi vs 60 for the beginning of the green. One would think if oil starvation was the issue it would affect more than one cylinder though. Is 8 psi low enough to be an issue on a short flight?

The club Cherokee with 180 hp here at Paullina was overhauled many years ago. When it was flown home it had very low oil pressure so was taken back to see what was wrong. The mechanic forgot to install some plugs in the oil galley and when they were installed the oil pressure was good. The plane went on to teach quite a few people to fly with just a couple of cylinders replaced.

 

[mike mcs repair]

..... The mechanic forgot to install some plugs in the oil galley and when they were installed the oil pressure was good. ....

FYI... That will show up as lots of air bubbles in oil, you can see it on dipstick...

 

[skywagon8a]

Is 8 psi low enough to be an issue on a short flight?

It is not the 8 psi low that is the question. It is the 8 psi low coupled with the high oil & CHT combination that raises some questions.

 

[nanook]

I think in this instance, (Helmetfire's engine) the issue is more about not pre-oiling and how long the engine was run initially with NO oil pressure. Also when you see the striations down the pistons/cylinder walls and look at the small chunks missing out of the rings. You have to wonder what the hell was in the oil or fuel or air intakes to cause this kind of damage! Running an engine at 52lbs rather than 60lbs isn't going to make any diff in the normal range of operation... My gut feeling on this engine is there was contamination introduced during assembly/run-up... There also could be issues with improper fit/tolerance. The rough running part makes me wonder if the valve/rocker clearances were ever checked with the lifter flat, also was it ever checked with the lifter pumped up? And on and on .....