[maytag]

Originally Posted by Gilles

BY, how difficult would be to measure distance between the top of the piston and the plug? Could this help to ensure that you don't have a slightly bent rod?

Thanks Gilles. A piston-stop is easy enough to build and use to check piston height, but a simple compression test will tell most of that story.

Thanks, everyone, for your responses here. I wasn't looking to start down a road of paranoia-induced "what-if" scenarios, haha. I just didn't want to start breathing a sigh of relief that I'd dodged a bullet, simply because the motor turns without making weird noises, without first checking to see if there are other COMMON breakage-points that I should be looking at.

It sounds to me like the typical AOS failure "catastrophe" happens at relatively high RPM's, where the energy in the rotating / reciprocating assembly is enough to break lots of things when that piston comes to a sudden hydraulically-locked stop. I think I avoided this. I think what I'm seeing is that after I shut off the motor, the oil continued to run (because of gravity) into the cylinder whose intake valve was open. Then when I hit the starter again, there was enough oil in that cylinder that it made a short attempt to compress, then locked. But the starter shouldn't provide enough energy (force) to break anything internally (other than, perhaps, the starter, haha).

SO:
Yes, I'm going to peek inside the cylinders with a borescope.... because I bought one and want to use it, haha. I'm considering a deeper sump & baffle, so if I do that, I'll also poke around with the borescope on that side. And Yes, I'll probably do a compression check, because all the plugs are out and the motor just clicked 150k miles: I'd like to see what we're dealing with. But then I'm going to clean it all up, button it back up, get it good-n-hot to burn out as much of the oil as I can, and hope I'm not looking at replacing o2 sensors, or other.

As for the AOS: I'm not entirely convinced that it's bad. I'm running on the working theory that this is all related to the spin, and I simply overwhelmed the AOS. I'm going to purchase a manometer, so I can check it once it's back together. In the meantime: I'm going to go trace-out the pathway of the AOS vent & drain, and look for a place to intercept and add a catch-can of sorts, that can give me a warning if it starts getting accumulation, but won't immediately dump it into the motor. Again: what a STUPID design this AOS is. Tell me again how brilliant the Porsche engineers are?

Thanks again everyone.