Engine Making Metal - Suggestions?

[reecewallace]

Looking for suggestions on what to do here:

I just put a new Skytech starter on my O300-A because the old pull-style one was making grinding noises then subsequently stopped engaging the gear in the accessory case all together.

When I pulled the old starter off, the teeth on the starters gear drive were chewed and worn, and clearly putting some metal into the engine. Fortunately, the drive gear it mates with in the accessory case was fine.

Anyway, I changed the oil afterwards and to no surprise, I found a bunch of steel in the filter—very likely from the old starter grinding. At the recommendation of my mechanic, I flew 5 hours then cut the new filter open to check it again for metal. Once again, however, it had more steel in it than we'd like to see.

I'm concerned the steel is coming from somewhere else and not just from the old starter. However, there could be residual metal circulating in the engine from the old starter which wasn't completely flushed out at the last oil change and filter, presenting itself as new metal every time I cut the filter.

My mechanic bore scoped the engine in multiple spots and from what he could see, there was nothing visibly wrong (can't see entire engine) other than some wear on the left mag drive gear in the engine.

Is there anyway to clean out the engine to see if it's actually making new metal? What are my options?

1450 SMOH in 1984
350 hours STOH (6-new Millenium cylinders 2012)
Compressions: 74/80, 76/80, 76/80, 70/80, 76/80, 74/80
Oil burn good (1/4qt per 5 hours)
All temps/pressures good
Runs great

[GAHorn]

I’m afraid you’re facing everyones’ worst fears….and you’re into a highly speculative area… but if it were mine, I’d first pull the oil-pressure relief valve for internal inspection (it’s at the end of the lubrication-circuit…if metal is there..it’s everywhere)…… and if none found there……the front oil-gallery plugs to inspect for metal particles ….and of course, the accessory-case and sump. (and that is where the oil pump is also.)

But if it’s bad news. I would expect (in the minimum) to require a new mag gear and, to be thorough…. all the gears should probably be inspected and re-certified….which means you may as well plan a full overhaul/rebuild/major-repair. (No pun intended, but everything revolves around the main crankshaft-gear and if it’s damaged the entire gear-train and engine is at risk.)

It’s not going to make you feel better…but the best chance to have avoided all this (IMO) is when the starter began to fail…. instead of operating the engine the accessory case should have been opened up at that time (by removing the generator/starter, mags and screens) for inspection …prior to further operation. By operating the engine after the starter failed has likely sent metal throughout the engine. I’m deeply sorry this has occurred.

If it comes to this, You might consider finding a used engine out of a salvage yard that still has time remaining on it.

The GOOD news is…the filter is the FIRST thing after the oil pump…so if the pump picked up steel…it would be filtered before heading out anywhere else.

[c170b53]

Good info from George and I’ll just add my thoughts : I’ll guess that the plastic dam provided by Skytech was used to cut the dowel off when the starter was replaced and the metal is just from the old starter gear. The filter should do its job and eventually the metal should be captured or become entrapped in the sludge within the engine.
But if the metal is new metal production, most likely from the lifter faces.

That’s not good.
So, continue to fly and monitor the metal capture and either ; if it goes down, you win. If it remains somewhat the same, you can count on a ruined crankshaft and a complete overhaul (which you are likely close to carrying out anyway). Most of the engine parts affected by the metal will be tossed anyway, the crank is the biggie.
When crossing the strait, I would ; not go direct but put as many rocks below me as I could, add a few more thousand feet than normal and I would be wearing my life preserver.

[GAHorn]

I’m hoping my earlier comments are over-blown and that Jim is correct. (With the comment your mechanic found the mag gear damaged…..I may have misunderstood the description of how much the old starter gear had disintegrated. I hope that is the case….that I misunderstood.)

Jims comments are very insightful.

[reecewallace]

Good info from George and I’ll just add my thoughts : I’ll guess that the plastic dam provided by Skytech was used to cut the dowel off when the starter was replaced and the metal is just from the old starter gear. The filter should do its job and eventually the metal should be captured or become entrapped in the sludge within the engine.
But if the metal is new metal production, most likely from the lifter faces.

F0DCD2C3-6296-4DFC-A243-6D698499FDA8.jpeg

That’s not good.
So, continue to fly and monitor the metal capture and either ; if it goes down, you win. If it remains somewhat the same, you can count on a ruined crankshaft and a complete overhaul (which you are likely close to carrying out anyway). Most of the engine parts affected by the metal will be tossed anyway, the crank is the biggie.
When crossing the strait, I would ; not go direct but put as many rocks below me as I could, add a few more thousand feet than normal and I would be wearing my life preserver.

Correct, I did not get any metal inside the case when use the plastic Skytech dam.

Good idea about flying over the water. I'll make sure to fly it high with my jacket on once I bring it back to the island. Going to call Okanagan Aero Engine and get their thoughts.

[reecewallace]

I’m hoping my earlier comments are over-blown and that Jim is correct. (With the comment your mechanic found the mag gear damaged…..I may have misunderstood the description of how much the old starter gear had disintegrated. I hope that is the case….that I misunderstood.)

Jims comments are very insightful.

Your insights are helpful. My mechanic is going to inspect the engine further, and remove then check all the areas you mentioned for further metal.

Pulling out the oil pan should show if there's a bunch of metal sitting in there too.

[c170b53]

Pulling the pan would be a pain, it’s alot of work. Then you may not like your pan when you have it in your hands. Maybe go through the aft drain plug with a flexible pipe cleaner (followed with a magnet) if you must but you’ll be disturbing the 38 year old sludge which might be beneficial in trapping errant particles.
Tough spot to be in, anything you touch likely will need attention and some of the stuff is, as we know, expensive. I’d try to get as much money out of it whilst monitoring the metal but it is risk analysis situation.

[reecewallace]

Pulling the pan would be a pain, it’s alot of work. Then you may not like your pan when you have it in your hands. Maybe go through the aft drain plug with a flexible pipe cleaner (followed with a magnet) if you must but you’ll be disturbing the 38 year old sludge which might be beneficial in trapping errant particles.
Tough spot to be in, anything you touch likely will need attention and some of the stuff is, as we know, expensive. I’d try to get as much money out of it whilst monitoring the metal but it is risk analysis situation.

I went through the aft drain plug with a magnet and cloth, and did find some metal unfortunately.

When I asked my mechanic if it's safe to keep flying, he replied, "I don't see why not". I'm not sure how I feel about his words...As you know, I fly a lot across the Strait (for those who don't know, it's 30 miles of open ocean) and a reliable engine is key in a single.

My AME's suggestion was to fly another 10 hours, cut the new filter open, and see if it's still making metal. But again, it could be residual metal circulating from the starter. I suppose less metal in the filter every time I cut it would mean it's from the starter.

I spoke with a couple overhaul shops today, and the price to dismantle the engine and clean everything is around $15K. At that point, may as well go for an overhaul.

I did have a thought though—

Send engine in for overhaul and perhaps reuse my cylinders? They're in great shape, not too old, and low hours. This could significantly cut the overhaul price down if they're still usable. That said, the longer I fly it with metal circulating the more damage will be done. Plus, it could be a failing cam or lifters like you said, and the starter metal is just a red herring.

[c170b53]

Thought the same about your cylinders, a bottom end repair and time continued, as its non commercial going past TBO would not be an issue. As for 15K, I think they know that’s the tipping point, once its apart it will be more to put it back together, especially if there’s a requirement to replace major components.
Just guessing but I imagine 30K was the quote for Fred to do an overhaul or was it more ?

[GAHorn]

Reece, did you take pics of what you found with a magnet in the sump? Can you quantify it for our general education?

If it were mine, I’d pull the suction oil screen and the oil filter adaptor (I’m presuming you have the spin-on filter adaptor by FM Enterprises or such) and clean out the bottom of the accy-case/sump area as good as possible to see just how much is in there …as well as to simply get that stuff out.

Flying the airplane overhead your field on the island for an hour or so isn’t disqualifying.

And then check that filter again.

However…. it is already a 1400+ hour lower end in your engine and practically new cylinders. If metal hasn’t got to your cyls then I’d certainly be happy to reuse them. Pull the two forward rocker-covers (5&6) and see if any metal in them. (I’m thinking that is a low possibility since the oil that gets up there must first go thru the lifters and pushrods…but if metal is up there….it’s probably best to plan on a complete overhaul including repair/rebuild of the cylinders.)

Take pics.

[reecewallace]

Thought the same about your cylinders, a bottom end repair and time continued, as its non commercial going past TBO would not be an issue. As for 15K, I think they know that’s the tipping point, once its apart it will be more to put it back together, especially if there’s a requirement to replace major components.
Just guessing but I imagine 30K was the quote for Fred to do an overhaul or was it more ?

Overhaul was quoting between $34-35K CAD at Okanagan Aero, and $39K at Aero Recip. They told me the price changes daily just like the USD

[reecewallace]

Reece, did you take pics of what you found with a magnet in the sump? Can you quantify it for our general education?

If it were mine, I’d pull the suction oil screen and the oil filter adaptor (I’m presuming you have the spin-on filter adaptor by FM Enterprises or such) and clean out the bottom of the accy-case/sump area as good as possible to see just how much is in there …as well as to simply get that stuff out.

Flying the airplane overhead your field on the island for an hour or so isn’t disqualifying.

And then check that filter again.

However…. it is already a 1400+ hour lower end in your engine and practically new cylinders. If metal hasn’t got to your cyls then I’d certainly be happy to reuse them. Pull the two forward rocker-covers (5&6) and see if any metal in them. (I’m thinking that is a low possibility since the oil that gets up there must first go thru the lifters and pushrods…but if metal is up there….it’s probably best to plan on a complete overhaul including repair/rebuild of the cylinders.)

Take pics.

I did not take photos of what I found in the sump and filter adapter holes. It was a small amount of metal on a magnet compared to what I found in the filter.

Let me give this photo some context.

This metal is from the second oil filter we cut open after finding metal in the first one—it contains only 5 hours of flight time. The first oil filter had about 4x as much metal, but had 50 hours on it.

My mechanic's technique is cut the filter open, visually inspect, then rinse the filter off in a bucket of brake cleaner, then run a magnet through the bucket. This ensures all metal particles are removed from the filter, visible, and can be picked up with the magnet.

Right before I found the metal, I replaced the rocker head gaskets, and did not see any metal in the rocker assemblies.

My plan is to clean it all out as best as I can, do a full oil change, fly it, then check again. My mechanic said he can instruct me to remove the oil pan within 3/4 hours, saving some me $

[c170b53]

I like your fly it a bit and see plan.
Cleaning as best as you can without disassembly, run it say two hours, check the filter to set up a comparison base then monitor over several filter changes, hours over material collected should tell you where you’re going.

[n2582d]

Reece,
Sounds like you are getting good advice from experienced AMT's. Reading the latest AOPA Pilot magazine (February 2022, pg. 97) brought your situation to mind. The article referred to Lycoming Mandatory Servicer Bulletin 480F "Metallic Solids Identification After Oil Servicing, and Associated Corrective Action." In my opinion that bulletin is equally applicable to Continental engines.

As far as flying over the strait, I see that the water temperature is around 7º C. That gives you 30-60 minutes until exhaustion or unconsciousness and 1-3 hours survival time ... assuming orcas aren't around. I'd think about wearing a gumby suit if beyond gliding distance of land. Scuba divers use inflatable safety "sausages". Very lightweight and compact -- might be something to consider if you are frequently flying over water.

[voorheesh]

It might be a good idea to keep that airplane within gliding distance of an airport or safe landing area until you figure this out. Flying over water given what you know or suspect sounds dangerous. I think flying it to get more information is ok but be careful. Good luck and hope it works out for the best.