Thanks for the info.
I tightened the chain to 0.6nm with the special tool, which is much tighter than finger tight, then put the tensioner in. Ran the car for 30 miles, rechecked timing, which was spot on.
Before repairs the timing was out by two teeth on the exhaust and one tooth on the inlet, and had probably been like that for several thousand miles.
With the crank locking pin in so the cam sprockets are effectively locked, should it be possible to rotate the cams by as much as their Vanos travel?
I take your point about the ECU re-adapting. I don't have an expensive diagnostic tool, only an obd code reader. I don't mind waiting for the ECU to re adapt if it takes five cycles or so.
when re locking the cams and crank all direction should be clockwise when setting the locks and pin in crankshaft other wise have seen people do it the other way around and get a false timing set as works against the tensioner spring of vanos springs,, also seen with engine running out of time so badly for a long period of time its destroys the cat and upstream 02 sensor as well, i tend to replace the vanos sprockets on 100k cars rules out problems later down the road FAI do a chain and vanos kit £225 ish not bad value.
below link is the best diagnostics for the money without it your totally in the dark and remember these are complicated engines ,, years ago people would not try and work on such engines like honda vtec or the mitsubushi evo engines or cosworth stuff etc,, and to be honest these prince engine are on that level so diagnostics is a big part,,
below link cheapest dealer level diagnostics https://www.ebay.co.uk/itm/2018-TCS-...frcectupt=true
there are more expensive uk sourced one's just make sure look the same vci,, good luck trying to repair it without. i've been working on this stuff for years and find it very hard to work them out with out a live data run,,