You need a special tool to compress the shims and a pick tool to pull them out.
The shims have a tolerence between the cam and the shim. With engine at TDC#1 you can check the clearence on #1 intake and exhaust. There is a procedure in the Haynes manual or the factory service manual.
You can check the clearence yourself, but if you do not have the special tool and a supply of various shims (thickness), it would be tough, or time consuming at best.
Assuming they got the wrong shim on, you would have to measure each intake and exhaust clearance, the thickness of each shim and compare to the factory specs, then put the proper shim in the proper place.
I would insist they do it, since from what I've read it wasn't making valve train noise until after they installed new seals.
Tuesday, January 30th, 2007 AT 2:00 PM