* Engine condition: Worn components, carbon buildup, and other factors will affect the ideal timing.
* Fuel type: The type of gasoline used can influence the best timing.
* Altitude: Higher altitudes require adjustments.
* Modifications: Any engine modifications (intake, exhaust, etc.) will change the ideal timing.
Instead of a specific number, the correct timing is found by using a timing light and following the procedure outlined in your owner's manual or a reputable repair manual specific to your vehicle. The manual will tell you how to set the timing to the specified degrees before top dead center (BTDC) at idle. This usually involves finding the timing mark on the harmonic balancer, adjusting the distributor, and verifying with the timing light.
A general starting point might be around 0 to 10 degrees BTDC, but this is just a guess. Do not rely on this number. You *must* consult your owner's manual or a repair manual for the proper procedure and specifications for your specific vehicle. Incorrect timing can damage your engine.
If you don't have a repair manual, consider purchasing one (Haynes and Chilton are common brands) or searching online for a digital version for your specific year and engine. A qualified mechanic can also properly set the timing for you.
