Remove spark plug, and feel for the piston to stop moving through the hole.

If you use compressed air after removing the rocker arms, the piston will "motor" to BDC, but the valves will stay put from the air pressure. If you use 50 psi or so, you won't be able to push them down. If the intake or exhause hisses while you pressurise the cylinder, the valves are burned and you need to do a valve job.

I will probably be in Fr. Wayne over Thanksgiving, we should get together. Won't be driving the 280, alas, the heater doesn't work well enough and I don't trust the cracked block that far yet!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!