[Quicksilver]

Need more info. Weird that 2 different starters are doing the same thing. I'm going to assume that they are using separate solenoids during the tests.

Try turning on the headlights with the garage door closed to see if the beam dims when you try to crank it. If the starter is trying to spin the engine you should see a noticeable dimming of the lights. If it dims a lot it is producing a lot of "work" so something should happen. (or the battery is 99% dead)

Sounds like you have done some sort of engine or transmission work. The engine could be jammed so it won't rotate.

Another good test is to unbolt the starter but leave it attached to the wires. Make sure the wires/cables are VERY well insulated. Try cranking it. That will tell you if the cars wiring is capable of spinning it. NOTE! If the positive starter cable touches any metal you will get a short that looks like an explosion! Oh, and the starter is going to jerk pretty good when it is spun.

Don't try cranking for very long because things can melt down very fast in the starting circuit.

Wayne