My friend who is rebuilding my M42 after its epic failure, notified me that the the steel piston that used to wallow out the cast aluminum cylinder in the upper timing case has been updated. It's replaced with a plastic plunger/piston that won't cause as much wear against the more costly timing case.
So that's good to know, because the cheapest i could find a timing case was about $250. And i don't want to wear it out!
Also, I noticed that during the E36 production, the M42 block was fitted with an oil restrictor to prevent too much oil from being delivered to the head. Has anybody retrofitted one on an E30 engine?