I had replaced my timing chain a few months back and all is well, but now I would like to check my timing. When I put everything back together I did it by sight by lining up the cam marks and set the #1 cylinder to TDC. Is this the correct way? I am going to use a timing light now and I don't know if it should be ATC, BTC or TDC. Does anyone know? 1991 420SEL 170K w/ new chain

Thanks

Ignition timing is controlled from the flywheel.

All you can do is make sure that the centerline of the ignition rotor aligns with the punch mark on the outer edge of the distributor housing when the engine is at TDC #1 compression stroke.

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