Timing questions

[esprit s2]

Car is running reasonable nicely now but there are some hesitation issues that remain.

when I use the strobe light on the timing marks I notice the following:

At idle when engine is up to temp the mark on the crankshaft pulley is on the 10degree mark

when gentle throttle is applied the timing mark retards to the tdc mark and with further throttle it eventually goes to, where I think, it should.

any ideas?

[rjwooll]

Hi Paul,

I'm not familiar with the vacuum ignition system on the Elite except that it is vacuum retard, not advance (I think), and will retard the ignition by up to 8 degrees under full vacuum. On some cars, the vacuum take-off port is underneath the edge of the throttle butterfly, which means that it is blocked off at idle. If this is the case on the Lotus engines, then it may explain your symptoms, as a slight opening of the throttle would allow vacuum to be sent to the distributor, and this would retard the ignition by a few degrees causing the timing to move towards TDC, then as vacuum decreases under wider throttle openings, the retard effect is reduced as you observe.

Do you think this makes sense?

Richard

 

[esprit s2]

Makes perfect sense! Thanks again.