Not too familiar with them, TBH - I think my MK1 Escort may have had one, but it was one car where I never had cause to dismantle the engine :-) My old truck just has timing gears (which are prone to stripping, it seems)
I'm out of touch there - I remember 30k being common for cam belt changes, but that was on vehicles that would be getting on for 20 years old now (how time flies!)
I'm not sure why the Stag ones had such a short life - there wasn't really anything inherently oddball about the design. The hydraulic chain tensioners were prone to wearing out, though. I suspect it may just have been that the oil pressure wasn't particularly good on that engine, even from new, so the engineers hedged their bets and specified a low replacement interval.
Yeah, I'm not even sure what the basis was of using the Dolomite engine, unless it was purely a way to get an initial green-light (i.e. they convinced someone it'd be easy to throw two together and get a V8)
The Stag isn't a particularly wide car though, so maybe they thought there wasn't the space to have the pump and dizzy off to one side rather than in the middle.
Sure, but I think it was a marketing thing - they always wanted it to be a V8, even though the prototype used a six... wish I had some of my documentation here to confirm that, though!
Oil passageways weren't anything special, the oil pump wasn't that good, and factory quality control was such that a lot of engines shipped with a boat-load of casting sand still kicking around in the engine - which promptly found any way it could to clog things up.
IIRC the later cars got a better rad, but I don't recall if they did anything to improve the water pump now...
cheers
Jules