Bill --

I know that others on the BB are more knowledgeable about this than I am. Hopefully one will jump in and correct my mistakes.

My '86 245 does NOT have a crank sensor, but my '90 240 DOES have one.

Of your cars, I suspect that the two '87s do NOT have the computer controlled ignition (and thus require ign timing adjustments by turning the distributor). But the '89, '91, '93, and '95 very likely DO have computer controlled ignition (look for the sensor to confirm yes or no).

Haynes manual 97020 (240 series, '76 thru '93), section 1-16 (Ignition Timing) says, "1976 through 1988 models -- check and adjust every 15,000 miles or 12 months..." I interpret that to mean starting with the '89 model, we cannot adjust timing.

"...if a car has the crank sensor, for the most part, is the small amount of adjustment in the distributor not utilized..."

That seems correct -- turning the distributor will NOT alter ignition timing in a car having a crank sensor.
--
Don Foster (near Cape Cod, MA)