173k will be getting tired engine wise! So budget for that, speaking personally corrados need a lot if work to make them reliable! Mines having a new engine built at the moment, but as said, it's investment for the future. Club Chairman
I can guarantee if your engine has done over 80k your exhaust valve guides will need replacing. Your best off doing valve guides and seals, headgasket and skim. Job done. Talking about 500 quid for a head overhaul and will fix around 75% of oil consumption / blue smoke issues. Club Chairman
Sounds like you need whip head off and check. If it's running really rich you could have washed your bores and scored them, could also explain metallic fragments, I can't imagine that they would be off your cams though I'm afraid! Have you done a compression test or leak down test? Club Chairman
Yeah as above, the later heads had some slight improvements for oil flow for chains but doesn't really offer any improvements but fully inter changeable, I've just had a new head built for my new block and have had the cover skimmed to match. As long as to swap cam sprockets etc.. Shouldn't matter if single or double top chain Club Chairman
Quite common to leak there to be honest.... Did you torque up the head bolts in the right order / sequence? Another thought is that the head could be warped if it's over heated (worst case scenario but always advisable to give)it a sk Club Chairman