The noise lasted the full 30 seconds before I shut her down. I'm having her flat bedded to the mechanic in the am to check out tensioner and chain. It's the most unnerving sound I've ever heard from an engine. I don't even want to start it again until I get this fixed.
Thanks Bill.

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1991 560SEL (254K miles)
1980 Lincoln Mark VI - Givenchy
1979 Lincoln Mark V Collector's Series
1979 Lincoln Town Car Collector's Series
1979 Ford "Effie" Pickup (in gradual transformation to a show/street truck)
1969 Lincoln Mark III (waiting for "Overhaulin" to call)
1989 Lincoln Towncar
2001 Lexus GS300 (spousal unit's daily driver)