I have an 89 560SL engine 107.967 gas. My question to the forum is this; At what point of the crankshft rotation should the camshaft timing marks line up with the slots on the cam towers. I have heard everything from 5 to 12 degrees BTDC. My engine is currently set at 0 TDC, this after a timing change change. I am thinking that I may be 1 tooth off. Good compression, but the ignition timing has to be set at 25 degrees advanced inorder for the engine to run reasonably well. Seems like I am getting a loss of power and using way too much fuel.