Cranking ignition timing

[Number 7]

Is there a typical setting that will ensure quick starting? I'm running an early MoTeC ecu that doesn't have a separate cranking setting, on a 4.3 BV RV8, 214 cam and approx. 10:1 CR. Following a full rebuild, I've adjusted the map at 0 load and 0 rpm from 16 BTDC to 10 BTDC and at 0 load and 500 rpm from 14 BTDC to 10 BTDC. This has made it quicker to start, rather than seeming to labour a bit on the starter. Idle is set to 1K rpm, and because of the interpolation, I didn't want to adjust any sites above 500 rpm. Any thought please?

[sidecar]

I run a progammable MSD ignition system, I would have to hook up my laptop to it to read the setting that I programmed into it. from memory I am running quite a lot of ignition advance at idle, possibly 20 degrees, at an RPM below 500 I have retarded the ignition as much as the system would allow, again from memory I think that it was something around 12 degrees. Basically you may as well run very little advance from say 0 to 500 RPM (maybe 5-10 degrees) then ramp up the advance from 500 to 750 RPM to the figure that you wish to run at idle. Your idle is 1000 RPM, I'd hold the idle timing figure to say 1050 -1100 RPM, then start ramping in the timing as the revs rise in the same way that an old bob weight system would work. Your timing curve would have a flat step from 750 to 1100 RPM which is the plateau where your engine idles. Your starter motor will be very happy with this setup!

Having said all that I am not familiar with your setup, I have assumed that it is possible to do all of the above with your system.

AJMHO!

[stevieturbo]

Is there a typical setting that will ensure quick starting? I'm running an early MoTeC ecu that doesn't have a separate cranking setting, on a 4.3 BV RV8, 214 cam and approx. 10:1 CR. Following a full rebuild, I've adjusted the map at 0 load and 0 rpm from 16 BTDC to 10 BTDC and at 0 load and 500 rpm from 14 BTDC to 10 BTDC. This has made it quicker to start, rather than seeming to labour a bit on the starter. Idle is set to 1K rpm, and because of the interpolation, I didn't want to adjust any sites above 500 rpm. Any thought please?

It's unlikely timing is the cause of any starting problems, more likely fuel and air.

[sidecar]

Having a lot of advanced timing dialed in at idle can make the engine harder to start because the starter motor finds it hard to crank the engine over. Old Tiger Months used to have a retard setting to allow the bloke to swing the prop for the same reasons.