O-200-A woes

Pilawt

Pilawt

Final Approach
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Pilawt
The Sport Cub was in for its annual. I was at work and got the dreaded phone call from the shop: "You might want to come down here and take a look at this ... "

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This is the oil screen of my Sport Cub's Continental O-200-A with 290 hours total time since new. All previous oil analyses had been normal, the latest 25 tach hours ago.

In addition to the obvious large aluminum flakes, the oil filter had steel shards 3/16" or so long.

Odd thing found on the crankshaft gear, P/N 656762. The starter has ridden up on the top of the teeth and “milled” off the top. About 25 teeth have some damage with some worse than others. The steel shards appeared to be coming from this gear.

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The shop took off the #1 rod and found metal in the bearing. They took the engine apart. Metal has circulated throughout the engine. Crankshaft gear appears to be the source of the steel. They think the aluminum flakes were stuck in the accessory housing from manufacture and came loose from their hiding spot. No way these pieces came up the pickup tube or went through the oil pump. They are too big and too intact.

According to the shop, it looks like the lack of a lead-in on the teeth of the crankshaft gear is forcing the bendix to “ride up” on top of the tooth instead of properly engaging. I'm told Continental recently redesigned the gear to eliminate the "lead-in" bevel.

I chose the Sport Cub because it had a legacy, "proven" engine. I've been flying Cessna 150s with the O-200-A since the mid-1960s, and have owned two of them; so I figured I had developed a good working relationship with this type of engine.

Guess not.

This is the same engine that needed a top overhaul at 125 hours because of defective valve seats that caused exhaust leaks in all four cylinders, with compression down to 40 in one of them. Continental covered the repair on that one. This time they're offering the parts at 50%, no allowance for labor.

Getting past the cost, my concern is that if the engine is repaired, will the same thing happen again in another 300 hours? Continental says the old-style beveled ring gear is no longer available. Mine is one of about 95 O-200-A-powered Sport Cubs in the fleet, and no one has heard of a similar occurrence in any of the others.

Any thoughts, suggestions, advice, shoulders to cry on, etc., would be appreciated.

redface.gif
 
This is a flat-out assembly defect. Sure, the bevel gear can be redesigned to put less axial stress on the hub. But, the fact is there are hundreds if not thousands of them out there in service. Who ever put this engine together screwed up right from the start.

I sure would go after the people who sold the engine new.
 
Pilawt said:
That would be Continental. Factory-new airplane, factory-new engine.
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I got no problem going after them for an engine with 290 hours. They've had plenty to answer for with the 470 jugs, as you well know. If you don't get satisfaction there, sue them. I've gotten to that point with a big company(Compass Bank), and their attitude changed quite a bit once they were served.
 
Beautiful, just F---ing beautiful, out sourcing to a off shore manufacturing process.

one more reason to support your local self employed A&P.
 
Pilawt said:
It has both the screen and a filter.
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What does the filter look like.?

Why didn't the manufacturing debris show up prior to this?

What starter do you have?
 
I'm betting the filter is the housing with the pressure relief bypass. So, if the pressure across the filter gets to a design pressure point, the check valve opens, and viola! no filtration.

That filter is going to be filled with metal.
 
docmirror said:
I'm betting the filter is the housing with the pressure relief bypass. So, if the pressure across the filter gets to a design pressure point, the check valve opens, and viola! no filtration.

That filter is going to be filled with metal.
Click to expand...

No doubt, but I'd like to see it.

actully steel particles make a pretty good filter medium. I don't believe it will be bypassing.
 
Well, this becomes a matter of particle physics(haha). But really, all it depends on is that the bits that are being ground off are bigger than the filter media size. Once that happens, the coating of the detritus on the media will block it quite efficiently. I have a gauge on the top of my pool filter and I see this every darn month or so. Starts at 11PSI, needs cleaning when it reaches 25PSI.
 
docmirror said:
Well, this becomes a matter of particle physics(haha). But really, all it depends on is that the bits that are being ground off are bigger than the filter media size. Once that happens, the coating of the detritus on the media will block it quite efficiently. I have a gauge on the top of my pool filter and I see this every darn month or so. Starts at 11PSI, needs cleaning when it reaches 25PSI.
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The screen he is showing us is the pressure side of the pump, the debris he is showing has already been thru the oil pump.

and the thin aluminum stuff looks like what the gears in the oil pump do to aluminum chunks. But his has sharp corners more like manufacturing debris.

All filtration is done on the pressure side in the C series Continentals.
 
No, i'm pretty sure he means you have to remove the filter from the engine, then use a tool to cut the top off, and expose the filter media. Look at what's actually being trapped in the filter element .
 
Tom-D said:
The screen he is showing us is the pressure side of the pump, the debris he is showing has already been thru the oil pump.

and the thin aluminum stuff looks like what the gears in the oil pump do to aluminum chunks. But his has sharp corners more like manufacturing debris.

All filtration is done on the pressure side in the C series Continentals.
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I know, that is where I started by saying the filter media is clogged, the pump is just pumping oil around the filter via the bypass, and that's what has crapped up all his moving parts. We need to see the filter media, just like we've seen the screen.
 
Tom brings up another point. Where was the engine actually assembled? Since the PRC now owns Conti, it certainly possible this was put together by a few 30 cent per hour Chinese in some scrub plant in Fu-chien. Not that there's anything wrong with that, but they do have a pretty bad history in the mech area.
 
Pilawt said:
B & C.
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Can you get a picture of the accessory case with the starter removed? I really would like to know why the starter gears did not mesh correctly.

The B&C uses the starter support in the engine it should never had a chance to mill off the top of the drive gear of the cam or crank.

to me this is really odd.
 
docmirror said:
Tom brings up another point. Where was the engine actually assembled? Since the PRC now owns Conti, it certainly possible this was put together by a few 30 cent per hour Chinese in some scrub plant in Fu-chien. Not that there's anything wrong with that, but they do have a pretty bad history in the mech area.
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No,,,, that's not happening yet.
 
Has the engine ever had a starter change ?

I have a theory? is it possible that some one mounted a sky tech starter and modified the starter support, then changed to a B&C?

Or was this engine a key start from day 1?
 
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Ouch. I'd be talking to a lawyer if Continental doesn't stand behind their engine.
 
I am a certified newbie regarding aircraft ownership but that sure sounds like a new engine to me from Cubcrafters and Continental. I would think Conti would want it so they could perform a post mortem and figure out what was wrong with their engine. It is possible they have some time bombs out there and I would think they would want to know it.

Did you any indication of a problem before the oil change?

Hope this turns out for you.
 
Get cubcrafters on the case as well.

I had a Husky with about 75hrs TT come into my shop one day with 15psi of oil pressure.

Found a piece of walnut shell in the pressure regulator. Lycoming didn't want to own up to it, Aviat forced the issue with them and the claim was paid.
 
Pilawt said:
This is the original starter. It was removed once (May 2010, 168 hrs TT), sent to B&C for repair, and put back on. No grinding or kickbacks, etc., just weak.
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Next question, was this starter an after market added after the engine was installed? or was it provided by Continental?

For those who do not know the 0-200 that well, there are two major types of starters used depending upon if the engine was built as a pull start, or a key start. The key start uses a needle bearing sandwiched between the case halves to support the forward end of the starter to prevent this type of disengagement.

The pull start had a stud protruding from the same spot, for the same reason.

If some how, the engine was built as a key start, and the starter was as shown to us here http://www.bandc.biz/continentalstarter12vhomebuilt-1.aspx then the starter would have no support for the front of the starter, the needle bearing would have nothing in it. If the wrong style starter was used the blame for this failure will be the person who installed the starter.

I'm not too quick to blame Continental unless of course they provided the starter.
 
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Tom-D said:
Next question, was this starter an after market added after the engine was installed? or was it provided by Continental?

For those who do not know the 0-200 that well, there are two major types of starters used depending upon if the engine was built as a pull start, or a key start. The key start uses a needle bearing sandwiched between the case halves to support the forward end of the starter to prevent this type of disengagement.

The pull start had a stud protruding from the same spot, for the same reason.

If some how, the engine was built as a key start, and the starter was as shown to us here http://www.bandc.biz/continentalstarter12vhomebuilt-1.aspx then the starter would have no support for the front of the starter, the needle bearing would have nothing in it. If the wrong style starter was used the blame for this failure will be the person who installed the starter.

I'm not too quick to blame Continental unless of course they provided the starter.
Click to expand...

Pilawt said:
The Sport Cub was in for its annual. I was at work and got the dreaded phone call from the shop: "You might want to come down here and take a look at this ... "

Odd thing found on the crankshaft gear, P/N 656762. The starter has ridden up on the top of the teeth and “milled” off the top. About 25 teeth have some damage with some worse than others. The steel shards appeared to be coming from this gear.


According to the shop, it looks like the lack of a lead-in on the teeth of the crankshaft gear is forcing the bendix to “ride up” on top of the tooth instead of properly engaging. I'm told Continental recently redesigned the gear to eliminate the "lead-in" bevel.



This is the same engine that needed a top overhaul at 125 hours because of defective valve seats that caused exhaust leaks in all four cylinders, with compression down to 40 in one of them. Continental covered the repair on that one. This time they're offering the parts at 50%, no allowance for labor.

Getting past the cost, my concern is that if the engine is repaired, will the same thing happen again in another 300 hours? Continental says the old-style beveled ring gear is no longer available. Mine is one of about 95 O-200-A-powered Sport Cubs in the fleet, and no one has heard of a similar occurrence in any of the others.

Any thoughts, suggestions, advice, shoulders to cry on, etc., would be appreciated.

redface.gif
Click to expand...


What he describes as possibly happening, think you could hear the starter slip? I can't imagine the starter sounding normal...
 
Tom-D said:
As much preaching as we do, why didn't you have a filter on it?
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What good is the filter going to do in that case?

I had essentially the same thing with my O-300...only difference was the cause of mine (Magneto gear tooth broke off). My filter didn't stop the metal savings from going through the oil distro.
 
Fearless Tower said:
What good is the filter going to do in that case?

I had essentially the same thing with my O-300...only difference was the cause of mine (Magneto gear tooth broke off). My filter didn't stop the metal savings from going through the oil distro.
Click to expand...


About the only way this outcome would have been completely different is if it was a Liconisour (thanks Duncan for the term) with starter hangin on the front...

Or properly assembled if in fact it has the wrong starter or gear.
 
Fearless Tower said:
What good is the filter going to do in that case?

I had essentially the same thing with my O-300...only difference was the cause of mine (Magneto gear tooth broke off). My filter didn't stop the metal savings from going through the oil distro.
Click to expand...

The amount of debris in the filter is the amount that did not go thru the engine. In most cases we catch the problem before we see an accident.

But no filter is going to save the engine in a catastrophic failure like yours or this one.

I may have implied that, but that isn't what I meant.
 
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