Metal flakes in the C-145

How to keep the Cessna 170 flying and airworthy.

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chrishartis
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Joined: Mon Sep 10, 2018 6:41 pm

Metal flakes in the C-145

Post by chrishartis »

As I was about to go for a nice Monday breakfast yesterday I had a sinking feeling in my stomach like I was forgetting something important. I checked my oil change log and noticed that I was overdue for an oil change of my 1948 Cessna 170 with a C-145. I usually change the oil every 30 hours, but I was at 50 (I forgot about my 35 hour round trip to Oshkosh that I took with my father back in July). I changed the oil, (my plane does not have an oil filter, just an oil screen) and began wiping out the inlet where the oil screen rests. After closely looking at the oil that I wiped out of my engine I found about 10 or so incredibly small metal flakes. They were flat, magnetic, and if they all sat flat and connected together they might have taken up half of my pinky fingernail.

My heart immediately dropped so I started thinking about all of the possible causes. On my way home from Oshkosh back in July I noticed that my exhaust pipes were white when I landed. I was flying heavy, and hot with the airplane leaned as far as it would go without affecting how the engine performed. My EGT reading was at 14 or just above 14. Just before Oshkosh I also had a clutch on my starter go bad which made me think that maybe pieces of the clutch that were destroyed by my crankshaft might have fallen into the engine (they would have had no where else to go when the clutch went out).

After talking to my A&P and a few other A&P's at work they all said the same thing. "You're probably ok, you should expect to see flakes of metal from the clutch at some point. Due to the fact that you ran the engine so hot for an extended period of time going to Oshkosh you probably knocked the flakes loose. Check the oil at 10-15 hours and do another oil change. If you see the less metal or no metal at all, then you're fine and shouldn't worry. If you see more metal or larger chunks, then you have a problem."

My engine has been running perfectly with absolutely no hickups and no problems to date. I have just over 1000 hours left on the engine life. I do trust the opinion of my A&P, but I want to ask around and get more than just one or two opinions on the matter. Has anyone else had experience with some small metal flakes in the engine after a starter failure?

Any input is appreciated, Thank you!

Chris Hartis
Cessna 170 1948 Ragwing
N2675V, Felts Field WA KSFF
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GAHorn
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Re: Metal flakes in the C-145

Post by GAHorn »

Chris, the pull-starter clutch is a set of rollers similar to tapered-bearing rollers, which when the starter is rotated roll up into a ramp within the clutch-housing and "jam" so as to cause the entire clutch housing to turn with the starter, thereby imparting a "spin" to the gear on the front of the clutch housing which engages the crankshaft gear.
If the rollers cause the clutch housing to crack... the starter clutch appears to "slip". The clutch is not "destroyed by the crankshaft".
When you send it in for repair the clutch may be condemned because if the housing is cracked and you will lose the "core charge" value because it cannot be rebuilt. It is possible that the rollers may have become diminished in size over time, and you may have found small pieces of the rollers in the screen area.... or...The pieces found in your oil screen area may not...have come from that clutch at all.

Your A&P has given you good advice, IMO. Fly it about 5-10 hours and check the screen again.

BTW, most folks without a filter change oil and clean the screens at 25 hrs. The Operators Manual for this engine recommends "ever 20 to 30 hours" It's your engine and therefore your choice, of course. I fly so infrequently that I still plan changes at 25 hrs even tho' I have a spin-on filter.... that's just me, tho'.

Here's an illustration plagiarized from a non-pertinent site which might help one visualize how the starter roller clutch works:
Attachments
Starter pull engaged
Starter pull engaged
overrunning-clutch-powered.gif (22.95 KiB) Viewed 22157 times
Starter not engaged,
Starter not engaged,
overrunning-clutch-freewheel.gif (14.17 KiB) Viewed 22157 times
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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Joe Moilanen
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Re: Metal flakes in the C-145

Post by Joe Moilanen »

Oil and filter are the cheapest insurance that you can buy, I would never go over 20 hours without changing them, I never go over 30 even though I have a filter.

Joe
chrishartis
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Re: Metal flakes in the C-145

Post by chrishartis »

Gahorn and Joe,

Thank you for the input. I'm already looking at filters that I want to install. Trying to decide how much room I have in the engine compartment. Hopefully my 10 hour check goes well. Flew again yesterday. The engine is still running great! I would be lying if I said I wasn't nervous about what I might find, but I'm hopeful!

All thoughts and prayers are appreciated. She's an old bird, but she has a lot of life left in her!

Chris Hartis
1948 Cessna 170 Ragwing
N2675V
Felts Field, WA KSFF
chrishartis
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Re: Metal flakes in the C-145

Post by chrishartis »

I just purchased and installed my TEMPEST SPIN EZ oil filter (PN AA48108-2) and she fit GREAT! However, as I attempted to put in my oil temperature probe into the back of the oil transfer cylinder I realized that the oil probe was too big to fit in the hole! The tip of the oil probe goes in fine, but the “neck/collar” at the base of the oil temperature probe is too big to fit in the hole which also means that fastener nut which secured the oil probe to the oil filter is too if as well! We have the original Cessna 170 (1948 model) which is what this part number of oil filter is meant for. To my knowledge the oil probe is also the original and has not been changed. Wondering if anyone else has heard of this oil probe problem?

Chris Hartis
N2675V
KSFF Felts Field, WA
goodair
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Re: Metal flakes in the C-145

Post by goodair »

Did your screen have a fitting in the rear of it that the temp sensor screwed into? Mine did, and I just swapped it over to the filter adaptor. If yours is a different thread you may need to purchase an adaptor. Normally the probes do not screw directly into the screen housing as they "seat" on a cone shaped part of the temp bulb.

The threads do not seal your temp sensor, its the cone part of the bulb seating inside these adaptors. If screwed directly in they will leak I believe. Check this out.

https://www.aircraftspruce.com/catalog/ ... auges3.php

or

https://www.aircraftspruce.com/catalog/ ... mpbulb.php

You just need to find the thread type for your probe.
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Bruce Fenstermacher
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Re: Metal flakes in the C-145

Post by Bruce Fenstermacher »

And there are several, well more than on anyway, degrees of bevel for the oil probe nut which can not be replaced or changed and it must match the adapter you put into the screen or filter adapter in this case. Make sure what ever you get matches the nut on the oil temp probe.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
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GAHorn
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Re: Metal flakes in the C-145

Post by GAHorn »

Chris, either remove the adapter from your old oil-screen and use that...or order an entirely new gauge with a new adapter. Do not use a new adapter with an old gauge unless you confirm they have the same sealing-seat.
Here' a link to a previous discussion in which that problem was the subject, and our cousins over at the 120/140 Assoc'n had fully developed an article you can download. http://cessna170.org/forums/viewtopic.p ... obe#p83440
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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170C
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Re: Metal flakes in the C-145

Post by 170C »

Regarding the F&M (Tempest) oil filter adapter, is there anything special about the FM7 leak proof fiber gasket that goes with this adapter? Spruce has them in a so called "kit", but I don't find them listed anywhere in the Spruce catalogue. The AN 900-28 gasket (crush washer) is available at Spruce (and at many other sources). Spruce gets $.89 ea so I am wondering if there may be other gasket materials that would work just as well, in the future, as the FM7. Considering the price of the AN900-28, that fiber gasket must be impregnated with platinum. $14.95 for the kit :oops: and although the kit supposedly has instructions, mine didn't contain them. I have the original installation instructions so didn't need them.
One other mystery, the instructions say to safety the adapter. Mine has no place to attach safety wire. The 1 inch nut does, but that doesn't safety the adapter??
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GAHorn
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Re: Metal flakes in the C-145

Post by GAHorn »

170C wrote:Regarding the F&M (Tempest) oil filter adapter, is there anything special about the FM7 leak proof fiber gasket that goes with this adapter? Spruce has them in a so called "kit", but I don't find them listed anywhere in the Spruce catalogue. The AN 900-28 gasket (crush washer) is available at Spruce (and at many other sources). Spruce gets $.89 ea so I am wondering if there may be other gasket materials that would work just as well, in the future, as the FM7. Considering the price of the AN900-28, that fiber gasket must be impregnated with platinum. $14.95 for the kit :oops: and although the kit supposedly has instructions, mine didn't contain them. I have the original installation instructions so didn't need them.
One other mystery, the instructions say to safety the adapter. Mine has no place to attach safety wire. The 1 inch nut does, but that doesn't safety the adapter??
In it's original form, the oil filter adapter known as the "FM Enterprises" and also the "El Reno" adapters utilized the copper crush-gaskets. They inadvertently allowed the adapter to rotate too easily when replacing the filter at oil change time.... so the design was changed to use the fiber gasket at the interface between the adapter and the accy case. While using the copper gaskets MAY work for you... it will not meet the most-current Instrucitons for Continued Airworthiness and any loosening of the adapter and the consequences of that failure to follow the latest ICAs will reside with yourself. I suggest the more recent fiber washers be used where directed.
Personally, I have had absolutely NO problem with the adapter moving when I change the filter because I'm aware of the problem and I make certain to not rotate the adapter when loosening the filter. Therefore I have little need to expect to need those gaskets except very occasionally and I keep a spare on-hand.

Also, owner-produced-parts is available to you, and NAPA sells fiber gasket material suitable for oil and head gaskets very inexpensively if you have gasket-making talents and need to save very small bucks relative to the consequences of error. :wink:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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n2582d
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El Reno / F&M / Tempest / Stratus CO-300 Filter Adapter

Post by n2582d »

Tempest has revised their ICA and Installation Instructions to again use an AN900-28 copper crush gasket on both sides of the sleeve. The fiber gasket, p/n FM07, is no longer used between the sleeve and the accessory case. Mandatory Service Bulletin SB-001 still calls for the fiber gasket. Vince Bechtel at Tempest wrote this Service Bulletin will be removed shortly.
Stratus-SB-001_Rev-A-Dated-12-19-19.pdf
Mandatory Service Bulletin SB-001
(876.36 KiB) Downloaded 233 times
Screen Shot 2020-09-04 at 7.37.09 AM.png
If your adapter does not have holes for safety wire page 7 of the Installation Instructions illustrate how to drill the adapter for these holes.
Gary
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ghostflyer
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Re: Metal flakes in the C-145

Post by ghostflyer »

Having that sort of metal in the system is about normal to expect . As you said you havent cleaned that area before. Having issues with a clutch is often metal making . Personally I would check it again in 25 hours and no metal keep flying And smiling . Some engines like wine ,gets better with age and [flies] tastes better. [not the oil ] I have had brand new engines have that amount of metal In the filter after 10 hours of flying and then done some 2000 hrs before being pulled. It when you get bits and pieces with part numbers on them is when you get worried .its the non ferrous types of metal in the oil that should get your attention too . Take a sample as it comes out of the engine for a “soap” test. The laboratory will tell you what’s happening [wearing] in a engine.
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170C
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Re: Metal flakes in the C-145

Post by 170C »

So those of us with F&M filter adapters, do we also replace the fiber gasket with the crush washer? Would be interesting to see either the entire installation instructions to see if it differs from the F&M installation instructions and especially page 7 for how to put a safety wire hole in the unit.
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rschreiber
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Re: Metal flakes in the C-145

Post by rschreiber »

Thanks for the update on the Tempest filter adapter, Gary. That’s some solid intel.
Ryan
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n2582d
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Re: Metal flakes in the C-145

Post by n2582d »

You're welcome Ryan. Not entirely altruistic on my part though. I find documenting stuff like this here is a good "filing cabinet" for me to later come back to during my forever rebuild. I've found information on this filter adapter in countless threads here. It would help all of us if we could search previous threads before starting new ones on identical subjects. I'm the worst offender in this regard.

Frank, does the "Installation Instructions" link I posted above not work for you? If not, you can find it on Tempest's website -- Tempestplus.com. Regarding replacing the fiber washer with a crush gasket I would say if yours is working don't fix it but I would want to make sure that the adapter is safetied so that if it does accidentally loosen you will have an oil leak rather than a catastrophic loss of oil. Add a witness line between the sleeve and the accessory case and/or between the sleeve and the spool. Check that line on every preflight. I've counted at least ten guys on the forums here that have had issues with the adapter loosening.

I like what Jim recommends here. Has mounting the adapter so the weight of the filter is tightening the adapter helped or do some of you still have issues with the adapter leaking even with the filter around the 4-5 o'clock position?

In this thread Frank and Eric talk about interference with the alternator. I assume it is the 60 amp Ford alternator that is being referred to as I had a similar issue with mine. As you can see in the photos the three mounting holes on the alternator don't each correspond with the identical position of the webbing (if that's the right word) behind each hole. As a result, if you happen to have your alternator mounted so that the bottom mounting hole is the one hole that is offset from the web in back of it (as in the second picture below), you will end up having to remove a lot more material from the alternator than if you mount the alternator indexed in either of the other two positions.
IMG_1234 (1).jpg
IMG_1235 (1).jpg
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Gary
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