An engine does not go off-timing all by itself. If the timing chain fails, the engine would usually be too far off to run. If someone forgot to tighten the distributor hold down, the distributor would revolve counterclockwise until it got to a point where the engine would be very low on power.
The timing on that year engine is computer controlled. It requires an engine scanner to set the timing. YOU CAN NOT USE A TIMING LIGHT.
That requires an engine scanner.
no
The timing for this engine is electronically controlled and not adjustable
The timing is set and adjusted by the Engine Control Module according to driving situations.
If you are worried about bent valves DON'T That year engine will not bend the valves when the timing chain goes bad.
rev the engine to about 2500 rpm's and turn the distributor until you find that sweet spot.
What's the mileage on the engine and what altitude are you at? check out boxwrench.com
You may have compression on any cylinder where the valves happen to be closed, but you will not have compression on all cylinders. 1991 Sable does not have a 305 engine.
4 degrees btc
looking down from (ONTOP) of the engine they are behind the water pump
they are behind the water pump looking strait down from the top of the engine