I’m mostly a lurker and haven’t posted much. I appreciate all the knowledge shared here. I haven’t been able to find much on my specific issue, so I’ll ask the group.

At annual, a small amount of flakes were found in my O-470-R’s filter. Approximately 6 flakes, but the largest was nearly 0.15” in length. I sent the filter to AVLabs for analysis. The flakes came back as 6414/6415. Spoke to Continental and was told that alloy is found in both the crank and starter adapter shaft. Continental rep felt that the starter adapter shaft is the most likely culprit because the crank is way harder than any other metal it could rub against. Makes sense.

So, please help me understand what would be causing the starter adapter shaft to make flakes. I haven’t noticed any slipping. No backfires in the two years that I’ve owned it. It’s an old Energizer starter. Is this something that I recheck in a 10 hours, or should I be pulling the adapter right now? Sorry if that’s a really ignorant question.

Thanks in advance

Brian

I would run it another oil change and just avoid shutting down in a place that would suck to be stranded in.

Adapters are pretty cheap and swapping out a starter adapter is a pretty simple job on an O-470. Seems like cheap insurance compared to the insane costs of engine rebuilds these days?

What oil are you running? I seem to recall that running Aeroshell Plus oils (Like 100W Plus) could be a problem in Continentals with the spring style starter adapters. The Plus oils have additional friction reducing chemicals that end up burnishing the starter adapter, causing it to slip. I'd pull the adapter and have a look to see if the adapter is damaged. If it fails catastrophically you won't like what happens.

jcadwell wrote:What oil are you running? I seem to recall that running Aeroshell Plus oils (Like 100W Plus) could be a problem in Continentals with the spring style starter adapters. The Plus oils have additional friction reducing chemicals that end up burnishing the starter adapter, causing it to slip. I'd pull the adapter and have a look to see if the adapter is damaged. If it fails catastrophically you won't like what happens.

Yup. the 15W50 and any of the plus oils are really to slippery for the starter adapter. But that shouldn't cause the starter adapter shaft to chip out. Seen crazier things though. I'd pull it out and check it over and see if that's where the chips are coming from. If there isn't any chips out of the shaft, then you'll be digging deeper. Rather find that out on the ground then in the air that your crank is making chips...

Thanks everyone for your responses!

I am running Phillips 20W-50 and camguard.

I'm still struggling to understand how the shaft could be creating flakes like this, but when I described them to the Continental rep, that only further confirmed his initial thought.

What is the risk with the starter adapter shaft making flakes? If it fails, does it cause the engine to seize? Can those flakes cause other damage inside the engine?

Thanks again everyone!

I see no reason to use camguard in a Continental. If the adapter fails it will fail to start, it won't cause an engine to seize. I just replaced the adapter in my 550 last summer, same basic unit you have. $1,200 from Niagara net. I wouldn't worry about this until you keep getting more metal and the adapter starts to slip.

Bonanza Man wrote:I see no reason to use camguard in a Continental. If the adapter fails it will fail to start, it won't cause an engine to seize. I just replaced the adapter in my 550 last summer, same basic unit you have. $1,200 from Niagara net. I wouldn't worry about this until you keep getting more metal and the adapter starts to slip.

If the spring fails it wont seize, but if the shaft breaks will it still not try to lock up the engine? It's been a while since I've had one apart, so honest question. Is the shaft not directly attached to the engine via a gear? I've heard of springs breaking and failing, but I've never heard of a shaft failing.

Is the shaft not directly attached to the engine via a gear?

Yes it is and the pulley for the generator or alt is on the other end. When I switched to the 470K, a long time ago, I was trying to save some money so I had the shaft chromed back to standard by a guy in Oregon with an STC to do that. It worked for many starts for me.

Hopefully there's enough clearance between the adapter and the firewall on your plane that you can change out the adapter without having to undo the engine mounts to move the engine forward. After I broke an adapter using a fixed magnet starter on the IO520, I switched back to the original Prestolite starter and never looked back. I keep a rebuilt Prestolite on the shelf in the hangar. It's not lite, but it sure works.

Thanks everyone!

I spent some time on the phone with both Continental and Quality Aircraft yesterday. Learned a bit more. Sounds like the chips I’m experiencing are symptomatic of the old style adapter. Continental didn’t have record of which adapter was shipped with my engine. I need to pull the cowl and start exploring. Unfortunately I don’t have the room to pull the adapter without unbolting the big stuff. I’ve read about people being able to unbolt the engine, hang it, and pull it forward enough to remove the adapter… without disconnecting everything. Not sure how much that is.

Both companies stated that a broken shaft failure is extremely rare. One went as far as to say that he had only seen that once. Once in how long? I didn’t think of asking that until after I hung up. But I’m not sure I want to play those odds. The crumby thing is that I don’t think you’ll be able to tell much even after removing it. If you’re gonna remove it, you’re kinda just committing to replacing it.

CAVU wrote:Hopefully there's enough clearance between the adapter and the firewall on your plane that you can change out the adapter without having to undo the engine mounts to move the engine forward......

I had to replace my adapter about 4 years ago--
an extremely tight fit but (barely) managed to do it without unbolting the engine or mount.
I did learn a number of new cuss words though.

Luckily Kenmore Air Harbor had an overhauled one in stock so I was able to avoid more than a day or two of downtime.
I dunno / can't remember if the adapter I got is "old style" or "new style",
but FWIW both the old one & the new one are p/n 635050A4.

Also FWIW I run the p/n 646238 Energizer starter, it's heavy but works great.

I did mine on at the 180. Only has to move a few inches forward but I did have to move it. I sent mine to Bolduc Aviation in MN for overhaul. I wanted to make sure everything would fit when I put it back together. They did great work. https://www.bolducaviation.com/ .
I would not wait the last thing you need is metal floating around in the oil.
DENNY