Leathermag, The part that bugs me is do they not check their marks after changing and tensioning the chain or belt? Or do they know it is off after a quick check and just leave it? If that is the case it is just plain stupid or almost criminal if being paid for. .Tha engine is never going to run right unless there is enough adjustment to cover it. Usually there is not. Spun the crank pulley and belt drive cog after 200 thousand on my volkswagen the other day. For a second thought the crankshaft broke when I found the belt tight and not turning. There was just about the crudest engineered form of keyway engagement. It was just a stamped raised portion on the aluminum cog. It looks like the metal was just displaced from either side and bunched up. Of course it was wiped out pretty bad and soft aluminium as well. Just took a few minutes to drill for an interference fit pin and shape it to the keyway contour plus press it in. Usually german engineering is better. If it had spun out at speed rather than at morning startup I would have been looking for a new head at least. At low rotational speeds the hydralic valve lifters seem able to give enough to eliminate bent valves or other damage. The adjustable mechanical lifters do not have that much if any slop so inspect your chain guides periodically on your old 123s. If they fail by wearing out and the chain gets involved you will probably wish you had.