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Piece of cotter pin found in oilscreen!?

swisseagle

swisseagle

Well Known Member
Hello,

My buddy found a piece of a cotter pin in the oilscreen!?

ZusammenstellungJPG.JPG


It is the bent part, that is broken of at the tight bent. Close to the broken surface, there are very small "start" cracks, so the material there was hard or stressed too much. It also looks like the pin was hammered down, but thats normal.The edges at the broken surface are polished, but this is because I had it together with coins im my pocket for a week or two.

The size is about 0.088" diam and 1/8" long. From the color I would guess it is SS material, but it is a bit magnetic (not strong as normal steel)

The is a TMX-IO360, horizontal induction, Mattituck build it, about 150h on it.

now the BIG QUESTIONS:

- From where it could be?
- Does it is harmfull to continue to run the engiene/fly the plane?
- What would be the next steps?

Thanks for any heads up and information.
 
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There are 3 case bolts that have cotter pins or safety wire. They are under the sump. Pull the sump and look there.
I would think you would want to know what else is in your engine before you put a piece of steel through your oil pump.
 
The fact that the "Tails" of the pin are in the sump tells you that the body of the pin is no longer secured and is likely to be loose inside the engine or about to be loose. Following that, whatever the cotter pin was securing will no longer be secured.

In addition to the sump bolts mentioned previously in the thread, I'd pull the mags and see if the cotter is from one of the nuts attaching the drive gears. Then, IIRC, there is a cotter on the bolt which secures the cam drive gear to the crank. I'd look at all of those things before I considered running the engine again. The only way I'd run the engine is if I found the remainder of the pin, verified that no damage was done, re-torqued whatever the pin secured, and re-safetied it.

That said, it would better to talk to a really knowledgeable and reputable engine person like Mahlon and get an expert opinion.

Just my $0.02.
 
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Cotter Pin

jmodguy said:
There are 3 case bolts that have cotter pins or safety wire. They are under the sump. Pull the sump and look there.
I would think you would want to know what else is in your engine before you put a piece of steel through your oil pump.
Click to expand...
My recollection of the three 1/4" diameter case bolts hidden above the sump is that the Lyc bulletin specifies safety wire only. In any event if someone used cotter pins on those bolts the cotter pins would be smaller than .080. The drilled stud that is at the rear of the case near the cam is 3/8" diameter and probably takes a 3/32" cotter pin. I'm not sure about this but I think the 3/8 stud could be seen thru a mag hole, might require a borescope. The question is why did that cotter pin come out?? Never bent over???
If the bolts/studs are properly torqued there is virtually no load on the cotter pins. Remember the cylinder hold down nuts and connecting rod nuts do just fine with no safety.
 
Mags

The retaining nut on magneto drive gears has a cotter key in them as well. It is on the accessory side so you wouldn't think it would end up in the sump, but who knows. Pull them and check them.

Vic
 
Collateral damage

My vote also is that the cotter pin came from a mag driven gear.
If it was my engine - I'd be pulling the pan & accessory cover, checking for other gear tooth damage, and if found, than also for idler shafts for cracked mounts or signs of other damage.
Hope no 'collateral damage' is found & this bird flys again soon!
 
One more. There's a cottered case bolt above the cam behind the gear. It looks to me like it could be the snipped off end of a pin that got lost?
 
Notice how polished the ends are. That means it's been banging around inside the engine for a while before it ended up in the screen. I'd disassemble the entire engine to inspect.

If it had fallen straight down into the sump, it would still have a sharp edge where it broke off from the main part of the pin.

Heinrich
 
vic syracuse said:
The retaining nut on magneto drive gears has a cotter key in them as well. It is on the accessory side so you wouldn't think it would end up in the sump, but who knows. Pull them and check them.

Vic
Click to expand...

The bottom of the accessory case is open to the sump. The pieces would fall straight down.

I vote for the magneto gear cotter pin since that is the most likely one to have been installed by a person who isn't an engine assembler...:)

Pull the magnetos and look...
 
Pin exactly measured

Thank you for all your inputs.

The diam. I could measure it with a caliper, it is 0.088" diam.

The end of the part straight and has straight marks inside and outside. I would think it comes from a flat of a nut or so.

I will go through all your answers and then decide what to do, together with a A&P.
 
Oil Anlaysis

Have you been doing routine oil analysis?

Oil analysis by itself is not the entire answer, yet it is an important piece of the puzzle.

If you have a history of oil analysis on this engine, then it can be helpful.

A large piece of metal in the screen or filter can be a non-event, if that piece hasn't caused damage in the engine elsewhere.

On the other hand, it might have bounced around in the engine and caused some damage. To me, the cotter pin end, or whatever it is, appears relatively undamaged. If it had traveled through the engine and done damage, it would seem that it would also have been damaged.



Oil analysis can help determine which might have happened.

........One more part of the puzzle!.......

As always, one person's opinion, and YMMV. Worth the $2 you paid for it. Etc.
 
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I would look to the mag drives. That is the only place I can think of that uses a cotter pin, that is inside the engine. The bolts on the bottom of the case use safety wire and so does the nut behind the cam gear.
Good Luck,
Mahlon
 
I think I recall that the oil pick-up in the sump has a screen over it. Unless the cotter pin was holding the screen on the pick-up and has come loose, I don't know how it would have made it's way through the system. Am I missing something?
 
mahlon_r said:
I would look to the mag drives. That is the only place I can think of that uses a cotter pin, that is inside the engine. The bolts on the bottom of the case use safety wire and so does the nut behind the cam gear.
Good Luck,
Mahlon
Click to expand...

Dominik
Here is the answer you've been waiting for. :)
 
YES!

Yes, I hopped that Mahlon join in, I asked him with a private mail :)

Anyway a big thank you to all of you for your quick answers! It is so helpful to have contact to so many people which can help!

I will come back with the analysis after the magnetos were removed.

Oil-Analysis and the opening of the filter does not show anything bad! It was just this small part.
 
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Apexeon said:
I think I recall that the oil pick-up in the sump has a screen over it. Unless the cotter pin was holding the screen on the pick-up and has come loose, I don't know how it would have made it's way through the system. Am I missing something?
Click to expand...

You are not correct. The oil free flows through the sump through a passage into the sump screen area, provided of course that you do not have the inverted plug installed. Remember the whole purpose of the sump screen that you remove through the rear sump plug, is to catch stuff just like this. You would NOT want a screen in the sump tank over the orifice to the rear sump screen as you would have to remove the sump every time you wanted to check for any debris.
 
I also found a cotter pin tail in my sump screen. I removed the left mag and it had the tail that normally wraps over the end of the bolt broken off. The tail that went through the castelations was still there and the beginning of the bend was still pesent on the broken tail, so the cotter pin wasn't going anywhere. I removed and replaced it after checking for what the proper size was. The specified size was a different size than the one that broke.
 
Kahuna said:
You are not correct. The oil free flows through the sump through a passage into the sump screen area, provided of course that you do not have the inverted plug installed. Remember the whole purpose of the sump screen that you remove through the rear sump plug, is to catch stuff just like this. You would NOT want a screen in the sump tank over the orifice to the rear sump screen as you would have to remove the sump every time you wanted to check for any debris.
Click to expand...

Thanks for the correction
 
Oil Pickup

Kahuna said:
You are not correct. The oil free flows through the sump through a passage into the sump screen area, provided of course that you do not have the inverted plug installed. Remember the whole purpose of the sump screen that you remove through the rear sump plug, is to catch stuff just like this. You would NOT want a screen in the sump tank over the orifice to the rear sump screen as you would have to remove the sump every time you wanted to check for any debris.
Click to expand...

Many of the earlier Lycoming's had a oil pickup that was a tube assembly that bolted to the accessory case. IIRC the screen assembly was installed vertically in the bottom of the sump near the center. Large hex retainer in the bottom of the sump, much larger than the current horizontal oil screens.
 
jrs14855 said:
Many of the earlier Lycoming's had a oil pickup that was a tube assembly that bolted to the accessory case. IIRC the screen assembly was installed vertically in the bottom of the sump near the center. Large hex retainer in the bottom of the sump, much larger than the current horizontal oil screens.
Click to expand...

Yes... that would be correct. I've had a couple with this set-up. :)
 
Magneto sketch and oil analysis

This is where we will looking very close:
Magneto%2520Gear.jpg


And the oil analysis (sorry, in french language):
Oilanalyse.JPG


It was a NEW engine and NEW magnetos, assembled by Mattituck in Long Island NY. 2 or 3 Years ago.

Thats it for the moment, I will post more when we found the root, thanks!
 
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Just another data point. I have installed hundreds of cotter pins as many of us have. Last year I was safetying something, cant even remember, and the cotter pin snapped a leg off. It was obvious in the break that crystalization had occurred at this one point only.
I am not sure how to test for this other than hope when you bend it over, it breaks.
Not implying anything was wrong with the cotter pin here, but....
 
FYI, There are two oil sump and oil pick ups used on the O-320. There is a style that is the same as a O-235 sump and has a pick up that uses cotter pined nuts to hold the pick up onto the accessory housing. Most common O-320 with this setup is the O-320-E2G. This type services a internal non removable suction screen through a large cap located just forward of the carburetor mount. The majority of the O-320's and all O-360's use the type that has a pick up galley in the sump with a suction screen under a cap at the rear of the sump.
Good Luck,
Mahlon
 
Added Security!!!

... One of these would have collected the piece, and any other steel debris from possible collateral damage if existent. These will collect steel particles in suspension that are so small, you cant see or detect them. Very inexpensive added insurance.Thanks, Allan...:D
.
 
mahlon_r said:
FYI, There are two oil sump and oil pick ups used on the O-320. There is a style that is the same as a O-235 sump and has a pick up that uses cotter pined nuts to hold the pick up onto the accessory housing. Most common O-320 with this setup is the O-320-E2G. This type services a internal non removable suction screen through a large cap located just forward of the carburetor mount. The majority of the O-320's and all O-360's use the type that has a pick up galley in the sump with a suction screen under a cap at the rear of the sump.
Good Luck,
Mahlon
Click to expand...

Here is a picture of the accessory case from my old O-290-d2 with the pickup tube in place. (This accessory case was replaced with one machined for a fuel pump.)
inside%2Bof%2Baccessory%2Bcase.jpg
 
PerfTech said:
... One of these would have collected the piece, and any other steel debris from possible collateral damage if existent. These will collect steel particles in suspension that are so small, you cant see or detect them. Very inexpensive added insurance.Thanks, Allan...:D
.
Click to expand...

Sorry for the thread drift, but personally, I don't need another maintenance item. This also has the potential for a false sense of security and could lead to a disaster if the owner or mechanic was not aware the device existed, like if you sold the plane, or your mechanic was not aware of the device. The average mechanic isn't going to know what this discreet looking plug even is.
The screen did it's job. I prefer to find my metal the old fashioned way, in my filter, with my magnet and magnifier... but that is just me....
 
JonJay said:
Sorry for the thread drift, but personally, I don't need another maintenance item. This also has the potential for a false sense of security and could lead to a disaster if the owner or mechanic was not aware the device existed, like if you sold the plane, or your mechanic was not aware of the device. The average mechanic isn't going to know what this discreet looking plug even is.
The screen did it's job. I prefer to find my metal the old fashioned way, in my filter, with my magnet and magnifier... but that is just me....
Click to expand...

...An oil drain plug is not a maintenance item, and one would like to think anyone changing the oil would poses the intelligence to wipe off the drain plug before re-installing it. The oil screen will stop large debris, but doe's nothing to impede small particles that can destroy an engine prematurely. These particles you troll for in the oil filter, have already been through the oil pump and done their damage to the pump in doing so. I prefer to collect my particles prior to them racing around, permanently damaging engine components and bearings inside my engines...but that is just me... Thanks, Allan:D
 
P-Mags also use a Cotter Pin, and with regard to:
vote for the magneto gear cotter pin since that is the most likely one to have been installed by a person who isn't an engine assembler...
Click to expand...
yes! P-Mag advise you pull the P-Mag each annual to check the gear / drive, so add the pin to something to check.

For some reason the P-Mag pins seem very long - I took advice on a more suitable pin when replacing it.
 
Magnetic plugs are common in helicopters and jet engine oil systems are they not? A false sense of security? Leading to disaster? Seriously? I can't see a downside personally.
 
sblack said:
Magnetic plugs are common in helicopters and jet engine oil systems are they not? A false sense of security? Leading to disaster? Seriously? I can't see a downside personally.
Click to expand...

Don't want to derail the thread. If folks want to discuss the merits or lack of, probably should open a new thread. If you want a device that will alert you to an impending issue, put in a proper chip detector.
 
Found it!

YES! Due to all of your comments and inputs, he pulled the mags and found where the missing part belongs to:
Missing%2520cotter%2520pin.JPG


He also showed it to an A&P, he has never seen that a cotterpin broke off like this!?

He will replace both cotter pins ... just to be sure.

I think we could catch it in time and react fine to not end up with a bigger damage. Thank you all!
 
Excellent! That is how maintenance is supposed to work. Many people don't even know to check that screen.
This break looks eerily like the one that broke on me. Just goes to show that a simple thing like a cotter pin can be manufactured with a defect, assuming that is why it broke. I think that is a pretty good assumption though.
Again, good catch and kudo's to all the sleuths that guessed correctly on where it came from.
 
swisseagle said:
YES! Due to all of your comments and inputs, he pulled the mags and found where the missing part belongs to:
Missing%2520cotter%2520pin.JPG


He also showed it to an A&P, he has never seen that a cotterpin broke off like this!?

He will replace both cotter pins ... just to be sure.

I think we could catch it in time and react fine to not end up with a bigger damage. Thank you all!
Click to expand...

Wow! That makes you want to look at your own. This had the potential of falling into the accessory case gears and spelling disaster for your engine. The piece doesn't show any signs of that so looks like all is well. Good Find, Allan..:eek:
 
swisseagle said:
YES! Due to all of your comments and inputs, he pulled the mags and found where the missing part belongs to:

He also showed it to an A&P, he has never seen that a cotterpin broke off like this!?

He will replace both cotter pins ... just to be sure.

I think we could catch it in time and react fine to not end up with a bigger damage. Thank you all!
Click to expand...

Great Find - It is always luck that FOD does not get caught in something. The systems worked this time and it was an accessible component too. I will be checking my screen regularly!
Thanks!!
 
This is a good example of why you should remove your ignitions at every condition inspection, regardless if they are mags, P-mags, or whatever.
 
part numbers and true differences?

This reminds me of a friend handing me some 'real Piper' cotter pins to use on my main axle nuts. they were real pretty gold anodized ones, and looked like they might even be worth the $5 list price!
....but most of us buy the 'case of 1000 assorted cotter pins' and use whatever fits our needed application.
This makes me think twice about that practice!

....are 'real' cotters a softer alloy or higher strength than the dime store ones?
 
Cotter Pins

I have seen people use "water pump pliers" oriented to the ends of cotter pins to squeeze the cotter pins after installation. If this is done too aggressively it can leave tool marks on the cotter pin, which in turn could lead to failure. It would be of interest to examine the failed cotter pin under a magnifying glass to see if any tool marks can be seen.
 
Toolmarks

Hello,

Yes there are toolmarks from plyers.

Interestingly the lower leg ist just cut off :eek: and only the upper leg is bent over. I asked a A&P and he told ... thats the way it is done :confused:

I'm not sure to install it that way ...
 
proper cotter pin install technique?

what is the proper method to install a cotter pin? in the past I have just bent them over with whatever tool was close. makes me think twice about them now. maybe I need a set of smooth duckbills someone spoke of a week ago.
 
Cotter Pins

AC43 details the proper installation of cotter pins. Both portions of the cotter pin should be bent over. AC43 details how to trim the ends. For "tightening" the cotter pin after installation, a few layers of duct tape on the jaws of the water pump pliers will prevent tool marks.
 
It happend past warranty

Hello Mitch

The engine is actually not anymore within the warranty period. As I remember correctly, it was 100h or one year, after the first engine start (mus be within a 2 year period after assembling).

So far, nothing happend, my buddy learnd much about his engine, he bought 2 new pins, gaskets and will mount the magnetos together with a A&P, so that he has no fear to pull and reinstall a mag in the future.

For sure it is not good that things where not correctly made ...
 
Pmag and wrong cotter pin

Thought I would resurrect this thread in an attempt to help get the word out.
EMGair has been shipping the Pmag out with an incorrect cotter pin installed or supplied with the bare mag. I know of 5 now that have failed and when I contacted Brad he told me he had heard of others. If your lucky it will just fall into the sump, if unlucky like me it will fall into the gears. It did a lot of damage to a fairly new engine (case repair, cam gear, crank gear and yellow tag all the steel in the accessory case). I also found another one about to fail on a used Pmag I bought from a friend. They have issued a service bulletin, but really they need to be more aggressive and notify everyone.
I would recommend using the slick part number cotter pin, $1 ea from ACS but cheap insurance IMO. Make certain it's crimped down tight, no tool marks, no wiggle.
If you have a Pmag I strongly suggest pulling it and inspecting the cotter pin(s).
Tim Andres
 
Even if you are not planning on using an actual Slick magneto, it might be worth adding a few of these to your next Spruce order -

SLICK M2556 COTTER PIN

At 98 cents, it's cheap insurance. :)
 
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