Last week my '90 780T started knocking badly during a mild acceleration. The knock persisted. Seemed odd given the low miles and first rate history of the car, but realistically things can fail in the best engines. Still we decided on a staged tear down. Step one was a cam check and then a valve examination through the intake ports. All seemed OK there. Step 2 was pull the head and hope for something to fix. If not, pull the engine for rebuild. The car is just way to nice to consider anything else.
There it was, one of those little clips that are fitted to the turbo hose clamps. Probably it was in the system from a turbo swap about 7 years ago. The overlooked piece in an otherwise first rate job at a good shop (PO had it done). The clip made it past the throttle plate and into the intake and cylinder. It was being hammered into the head by the piston. Literally driven 1/4" edge-wise into the aluminum.
A little smoothing of the piston edge, a rebuilt head from the spares area of the bedroom closet, and a day of wrenching. $40 for the gaskets, plugs, coolant and sundries. Not including the rebuilt head, but that was a rainy day lay away from a couple of years ago. 780 is running better than ever, whew! And much easier to deal with a 700T than with a 240T in terms of working room and turbo mounts etc.
Now what sort of crap would I have heard from shops and dealers on this repair? I shudder to think.