HELLO BLUEPONY!!! CAN YOU TURN THE ENGINE BY HAND??? YOU ARE WASTING EFFORT UNTIL YOU ESTABLISH THAT THERE IS NO INTERNAL FAILURE!!! AS HH SAID WITH NO PLUGS AND TIGHT BELTS YOU WILL BE ABLE TO ROTATE THE ENGINE!! SORRY about the capitals but its seems you still have not made this vital, easy test. You should be able to see the ring gear teeth with a torch and mirror as well as the motor is turned.
Good - Fast - Cheap: Pick any two.
E23 735i; E30 318i; E32 735iL (X 2 - 1 Alpine White and 1 Glacier Blue); E34 535i; E38 735iL; R50 Cooper; R55 Cooper Clubman.
E21 318i; E32 735iL; E34 535i; E38 730iL; E53 4.4i