HI
DOES ANYONE HAVE THE IGNITION TIMING SETTING FOR A STD 1098, 1967, FITTED WITH UNLEADED HEAD.
REGARDS
ALAN
IGNITION TIMING UNLEADED HEAD
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The 'unleaded' head makes no difference to the timing. You need to get the engine running and up to full temperature - then swing the dizzy very slightly from side to side until you get the very best/smoothest idling. I should say - it's wise first to make sure the vacuum advance mechanism is working - by sucking the pipe and watching to see the dizzy base-plate move back and forth. If not working - get a new one - urgently! Then - take the car for a good run up a hill - listen for any trace of 'pinking' when you put your foot down on the hill. If pinking - retard very slightly - if no pinking, advance slightly and try again until you get a touch of pinking - then retard it very slightly. That's it - the timing is now optimised for your vehicle as best it can be with that dizzy.
If the idling is now not perfect - you may have to chose between good idling and ideal running - but you MUST NOT have anything more than the very slightest tinkle of pinking just as you put your foot down - sustained pinking is a big NO NO!
Ideally - the dizzy curve is probably needing re-mapped - to suit unleaded fuel (not the head) - but the difference in overall performance will be slight.
There is an excellent (but quite expensive) electronic dizzy - known as '123' - which has a number of built-in selectable advance curves, so you can get the ideal setting for your engine at all engine speeds and loads - however this is really only going to be justified on a modified engine.
The Mini lads get great success (they claim) using the Megajolt ignition system - which completely eliminates the dizzy - and provides fully mappable ignition timing via your lap-top. They particularly claim excellent torque and driveability even when using cams with wide timing and high lifts. Again - it's not cheap, although some of it can be 'home-brewed' and the rest obtained from the scrap-yard. if I had the time - I would be giving it a go!
Oh - and if you want a starting point for the above - go for 5 degrees before TDC and work from there - don't just blindly set the timing and assume it is correct for your engine !
If the idling is now not perfect - you may have to chose between good idling and ideal running - but you MUST NOT have anything more than the very slightest tinkle of pinking just as you put your foot down - sustained pinking is a big NO NO!
Ideally - the dizzy curve is probably needing re-mapped - to suit unleaded fuel (not the head) - but the difference in overall performance will be slight.
There is an excellent (but quite expensive) electronic dizzy - known as '123' - which has a number of built-in selectable advance curves, so you can get the ideal setting for your engine at all engine speeds and loads - however this is really only going to be justified on a modified engine.
The Mini lads get great success (they claim) using the Megajolt ignition system - which completely eliminates the dizzy - and provides fully mappable ignition timing via your lap-top. They particularly claim excellent torque and driveability even when using cams with wide timing and high lifts. Again - it's not cheap, although some of it can be 'home-brewed' and the rest obtained from the scrap-yard. if I had the time - I would be giving it a go!
Oh - and if you want a starting point for the above - go for 5 degrees before TDC and work from there - don't just blindly set the timing and assume it is correct for your engine !
