S dizzy centrifugal advance

[970s]

Hi,
Just a stupid question, S dizzy all came out with the 10 degree centrifugal or some came with a 15 degree weight?
I had seen 2 different advance setting in the 40819 dizzy.


Al

[Spider]

The BMC and Lucas Data I have shows the 40819 as having 15 degrees of advance in the Distributor.

[Peter Laidler]

I'm of the same opinion as Spider. Maybe someone has made up one of your distributors using a 10 degree cam-stop part. But a relatively simple fix if you were pushed.

[970s]

Thanks guys, will rectify it to use.


Al

[timmy201]

The local Cooper S when brand new were noted to have ignition pinging in the review articles

I’d suggest you get the distributor tuned to suit your particular engine and the current fuel, rather than using the factory curve

[BAD942B]

The local Cooper S when brand new were noted to have ignition pinging in the review articles

I’d suggest you get the distributor tuned to suit your particular engine and the current fuel, rather than using the factory curve

Not surprised they were pinging, with 30° of crank timing + say an idle timing of a conservative 10° (although few strobes were in use at the time in the UK, possibly not so in the US) that makes 40° total when in reality they only ever needed 20° of crank timing (10° dizzy timing) + around 15° idle timing giving 35° total crank timing. Another Lucas cock up, along with the smoke from the Prince of Darkness.

[timmy201]

The local Cooper S when brand new were noted to have ignition pinging in the review articles

I’d suggest you get the distributor tuned to suit your particular engine and the current fuel, rather than using the factory curve

Not surprised they were pinging, with 30° of crank timing + say an idle timing of a conservative 10° (although few strobes were in use at the time in the UK, possibly not so in the US) that makes 40° total when in reality they only ever needed 20° of crank timing (10° dizzy timing) + around 15° idle timing giving 35° total crank timing. Another Lucas cock up, along with the smoke from the Prince of Darkness.

The quoted setting was 0-3 BTDC when set static, I guess this could have been set turning the engine over while watching the points and the timing mark

While the S timing curve and no vacuum advance may be good for a racing engine it’s less than ideal for a road car with todays fuel

[BAD942B]

The local Cooper S when brand new were noted to have ignition pinging in the review articles°

I’d suggest you get the distributor tuned to suit your particular engine and the current fuel, rather than using the factory curve

Not surprised they were pinging, with 30° of crank timing + say an idle timing of a conservative 10° (although few strobes were in use at the time in the UK, possibly not so in the US) that makes 40° total when in reality they only ever needed 20° of crank timing (10° dizzy timing) + around 15° idle timing giving 35° total crank timing. Another Lucas cock up, along with the smoke from the Prince of Darkness.

The quoted setting was 0-3 BTDC when set static, I guess this could have been set turning the engine over while watching the points and the timing mark

While the S timing curve and no vacuum advance may be good for a racing engine it’s less than ideal for a road car

I've yet to find an engine with carbs & clockwork distributor that doesn't like 10° to 15° of idle timing, set with a strobe & checked on a very good 5 gas analyser, if the timing is too far advanced the HCs go up massively likewise if too far retarded the engine sounds horrible, my old boss who was a very good tuner by ear nearly always had to much advance & a rich mixture to compensate. I guess 3° at static is most likely 10 /15° at idle.

[BAD942B]

my book 'Tuning Lucas Ignition Systems' states 14/16° at 3800 rpm dizzy, 5/7 at 800 rpm dizzy with 0/1.5 at 300 rpm dizzy, no advance below 225 dizzy rpm so at an idle speed of 800 rpm crank its most likely close to 10° crank on a strobe

[Spider]

Keep in mind too, that when they left the factory, they were timed / set for 100 Octane fuels - MKI and MKII (on the AEG163 Head) was 3 deg ATDC and MKII & MKIII (on the 12G940 Head) was 2 ATDC .

They gave a different figures for 97 Octane or 2 & 3 degrees respectively BTDC