I have just set the timing on my 1986 Nova SR so that with the timing light set to 0degrees the notch on the pulley and the pointer line up! Is this correct or do I need to advance/retard the timing for unleaded petrol or for small power gains! There are stickers all over the car saying that it will run on unleaded or 4 star so the valve seats are obviously OK!! If adjusting, how many degrees do I set the timing light at?!
You'll need to connect your timing light back up and wait for the engine to warm up to normal operating temp.
Then the mark (which you should of painted white) on the cranckshaft pulley should be aligned with the notch.
You now need to loosen your distributer and twist it until the with mark on the cranckshaft pulley is approx 10 degrees before the notch which it was previously aligned (10 degrees before top dead center (BTDC)).
You should notice good power gains now.
Don't forget to tighten up your dissy.
When the notch and the pointer are aligned, that is 10 degrees BTDC.
Advancing it so the mark on the crank pulley is 10 degrees before the pointer (towards the back of the car), will mean 20 degrees of advance at idle. This will be of more harm than good on a standard engine