Does rotating distributor clockwise advance or retard ingnition?
 

I have been experiencing bad detonation at +4K rpm heavy accel only.
I have change fuel 98 octane (France) and cleaned the lower plugs which had some carbon deposits and were abit brown on the top of electrode ????
I added some octane booster- still nothing.
Then loosened the bolt that holds the main distributer and rotated it a small amount clockwise.
The detonation stopped but it seems less 'perky' at lower revs??
Also revs seem lower at idle.
What damage can I do here if it is advanced/retarded.
The original postion was marked by mechanic and used to be good at this setting.
- So what has happened?
Did my Carbs go out of sync? tune?
Or should I have car retuned at new setting?
Will try to seek out a garage here in Normandy tomorrow.
Any advice appreciated
Ben

Don't they have timing lights in France?

Stephan

If you have 98 octane there is no need for octane-booster. With high octane, the combustion is earlier. 92-94 octane is sufficient. Decide which one you want to use and have the timing set accordingly with a stroboscope (Timing light) At the same time, set the mixture. Just turning the distributor blindly is no good. Follow the correct procedure for a tune-up. Good luck.

To retard the timing you rotate the dist in the same direction as the rotor turns. It sounds like you did retard the timing if the idle slowed down and is less perky. And it stopped the detonation. I would play around with it some more until you get it to run good and not detonate. It sounds like you are close

98 is RON - equates to ~93 or 94 in the US.

Thanks for the help, unfortunately i am in the 'sticks' here in Normandy where the nearest garage is an hour away but i just found out they do not work on old Porsche's :(.
I believe the nearest garage who can help may be in Paris :(.
I will try and rotate the dizzy, until I get a balance of non detonation and rev fluctuation.
I wish i had time to sort this before the car left UK.
I may return it to the UK for a more major service in a few months as the car wil have to go into storage in a few days for a few months.
But not before a visit to Le Mans Today :D
- Question still troubles me is why the mixture/timing changed????

will take lots of pics in Le Mans!
Rgds Ben

Hey Ben

why not static time the dizzy, huh..........Ron