Yeah it was definitely in the housing the right way. Just to confirm, the picture you refer to shows the old piston lying down in the extended position you suggest?
I ended up stripping everything down again. When I first took the cam cover off the chain was loose, but I think that was because I'd already removed the tensioner, but to double check I hadn't buggered the timing up I put the tensioner back in, rotated the crank to TDC on cyl.4 and used the cam locking tool to confirm the timing was still ok -it was (phew!).
After fitting the tensioner In both extended (confirmed timing), not extended - pressing on the rail to activate tensioner (confirmed timing again) the noise is still the same 🙁
I'd swear it's the chain rattling - I put my ear right by the sprocket end of the cam cover and the noise is definitely coming from that end. I'd say it's a bit noisier on tick over than pre cam swap and there's this horrendous rattle in a very narrow rev range just below 3000rpm. :cry:
I guess the only thing left to do is fit the whole cam chain kit. dunno..
Does any experienced person fancy fitting a kit to a VX220, preferably some one close to Brum? I'd do it myself, but this is no fun anymore and I'm prepared to pay well....