Found this on my drain plug
 

Can anyone identify these parts? They were on the magnetic drain plug at oil change. Could it be a hydraulic tensioner? Car is with updated 2.7 motor. Thanks http://forums.pelicanparts.com/uploa...1539123862.jpg

Part of a piston squirter that came apart?

Interesting. Those resemble some components of the chain tensioner, those they resemble are deep in the tensioner and couldn’t possibly escape!

The cage looks like what I see on the top of a hydraulic tensioner. I am hoping for a less involved repairhttp://forums.pelicanparts.com/uploa...1539130767.jpg

is that a round ball?
The spring... I'm not sure...
the other part looks like one of the locking tabs used on the oil pump.

All 3 pieces are the chain tensioner relief as you mentioned. I have had that cage pop out as well. It looked repairable but in the end I replaced the tensioner.

My tensioner http://forums.pelicanparts.com/uploa...1539297334.jpg

Would a failure such as this cause any particular problem? Skipped chain? I am amazed that the parts made it to the drain plug with no apparent damage.

Vinny nailed it, as you found when you pulled the chain covers and looked.

Just reassembling the parts in the tensioner will not work well. I did just that (I had dislodged the cap by ham handed prying for other purposes), but after a year or so on a track car it popped out. The cap part is just held in with the pressure from the three or whatnot bottom pieces. Since they came out, they have lost some of their tension, or perhaps the original sharpness of their edges.

Subsequently, I used a Dremel with a suitable bit to cut a groove inside the hole in the tensioner, so the ends of the cap could be spread out a bit more and had something to grip. This has held, though I haven't used the engine it is in much since then.

I am not surprised that these parts caused no damage. Elephant feet, or the nuts securing the elephant foot adjuster, from time to time get free and end up harmlessly in the sump. Not that one would be caviler about loose parts inside the engine, of course.

I checked my timing and it was in spec so did not skip a tooth.