but my money says that when the chain was rolled in, a guide wasn't used. What happens then is the chain jumps at the right cam. The next time it jumps whicle rolling in will cause the valves to contact the pistons. That is why, on almost every t-chain DIY response you read you see the suggestion to roll the crank over two complete rotations (a complete cycle). If the cam timing is off you won't be able to make 2 rotations by hand AND if you don't do 2 rotations by hand you won't know if the cam timing is off (and if you did everything right and didn't have the chain jump, 2 rotations will be smooth and easy).
Now, have they looked at the left bank? That is the side that usually eats it when a chain goes.
I would argue the labor involved and the bent valve(s) are the shops bill, I would also suggest doing a complete valve job of the rest while the car is apart (your bill).
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
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