the 85 will be a 617.

the vac pumps sometimes fail and the part jams the timing chain and breaks it.

i had this happen to my 82 300td. damage was as described above. i went ahead and did the bottom end while at it. today i might not do that. the bottom ends are very robust and there was a good chance i wasted a couple or so thousand doing it.

so the vac pump if not replaced can damage a well maintianed engine.

i have not heard of breaking a cam chain any other way i dont think on a 617.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.