08-09-2022, 06:22 PM
I use a bog standard manual dizzy on my car, its in very good condition with decent gears and no spindle slop.
I hardly ever have to change the timing between road use sprinting or hillclimbing.
My engine works between 2000 rpm and 6500 rpm on the same amount of advance.
I recently had my car on a rolling road to get the SU set up and changing the timing made no difference to the power output !
Unless it was retarded too much.
The tuner said its down to the fact that side valve engines have such low compression.
My engine made 28 BHP after the needle and spring were modified.
Most Austin engines are in a low state of tune and usually operate between 800 Rpm and 4000 Rpm so should not need much adjustment of the timing.
I always though the vacuum take off retarded the ignition when the throttle was closed on tickover and the bob weights advanced it as the revs increase.
If you open the throttle you get less vacuum.
Those with vacuum wipers will know this.
I hardly ever have to change the timing between road use sprinting or hillclimbing.
My engine works between 2000 rpm and 6500 rpm on the same amount of advance.
I recently had my car on a rolling road to get the SU set up and changing the timing made no difference to the power output !
Unless it was retarded too much.
The tuner said its down to the fact that side valve engines have such low compression.
My engine made 28 BHP after the needle and spring were modified.
Most Austin engines are in a low state of tune and usually operate between 800 Rpm and 4000 Rpm so should not need much adjustment of the timing.
I always though the vacuum take off retarded the ignition when the throttle was closed on tickover and the bob weights advanced it as the revs increase.
If you open the throttle you get less vacuum.
Those with vacuum wipers will know this.