Hello all, first post and “OH” need advice. Bought a 03 C180 with 71.000 on the clock no initial bad sounds, faults,drives well and has the MERCEDES renowned badge on the bonnet, and got it for a good price, what more could you want. 1000 miles later a misfire, checked it all found nothing, then wouldn’t start, towed it to a merc specialized garage. They checked it out and told me timing CHAIN stretched,” what”. Had them fit a new chain and tensioner as they said that not all cam chain faults cause damage to the cam timing. £500 later still wouldn’t start, chain had jumped 2 teeth on inlet cam and one tooth on exhaust cam. Took it stripped top end all inlet valves bent all exhaust need grinding in, replaced inlet valves and guides, inspected piston heads, no deformation. Rebuilt engine with the help of a cam timing jig tool. Started, ran perfectly 10 months 1200 miles then engine management light and a knocking tapping sound from back of engine. Took to a known mechanics who used an inspection camera and told me that No 4 piston was scrapping the bore, was caused by valve hitting crown. So engine needs to come out then rebore and oversize pistons, on a Merc, pardon. Any help and ideas? Anyone removed an engine? Where would you recommend for engine work. Sorry for first post, but it takes a bit of believing.