A neighbor has a 1987 420 SEL with a problem. She heard a tapping noise on start up and decided to drive her other car. She asked me to have a look which I just did. When I popped the hood I noticed a hole in the drivers side cam cover. Against my better judgement but out of curiosity I started it up. It started quickly and it did tap pretty good but it ran decent for the short time I ran it. I know something in the timing let loose BUT it runs too good for me to believe that it crunched the valves, in fact I've never seen one run after jumping time. I believe the chain is slapping making the noise and hole in the cam cover but it has not jumped time, yet. I have done nothing more than stated here. She said she's not going to fix it and has offered it to me very cheap. You think it would run so well, with excellent oil pressure during the 20 seconds that I ran it, if the timing jumped? I was thinking of buying it, replacing whatever broke [guide/rail/?], new chain, cam cover and driving it.