retarding ignition

[Daveyboy20]

So, retarding your ignition is a way in which you can run unleaded in a leaded engine? If so, how come? surely you'd lose loads of power and also i dont see how it'd help as isnt the lead a lubricant for valve seats? Does retarding the ignition merely get rid of pinking? and if so how? question time! Cheers

[Messenjah]

unleaded petrol ha sa different octane rating so goes bang differently im not sure exactly what difference it makes but it goes bang at a different time so you need to change the ignition timing

[jimmyesh]

I'm sure 95-ron unleaded is a lower octane rating than the original 4-star stuff, hence you're correct in saying that the ignition settings on an old-skool engine will be too advanced for crappy supermarket unleaded therefore detonation can occur and hole a piston etc

 

The valve-seat thing is caused by the unleaded factor rather than the octane, as you said the lead acted as a lubricant for the valves - without it, you get valve seat recession

 

Wish I could time-warp back to the 70's!