So here's the conclusion to the saga:
New tensioner worked itself loose (well, failed because the bolt was still tight) which of course allowed the timing belt to slip behind one idler and the entire thing incinerated itself. Pistons contacted valves, lifters did their job and broke. Since the valves all felt good I got lifters and timing parts and put it all back together again. Runs like a champ. The lifters worked / failed as designed.
Lessons learned:
1. I'm pretty sure the tensioner that failed was economy aftermarket parts...I can't remember. But I know I didn't get it from IDParts. Get your parts from IDParts. Don't even bother looking elsewhere you'll regret it.
2. Getting the intake cover back on is not easy. The manual suggests using a couple long studs, definitely do this. It took me 3 tries to get the thing dropped perfectly straight on and not pop a lifter out of place. Super aggravating.
3. This is not a job for the weak of heart or low of patience. Getting all the crap out of the way, esp the wiring, is a PITA.
4. All in all, this is a well designed engine and it's designed to be worked on. Daimler just mounted too much stuff around it.
I've been running Mobil 1 European Formula 0w-40 as long as I can remember, and there was absolutely no build-up on the top of the head and the cams looked perfect. Happy about that.
