8 replies to this topic

[Spannermanal]

Hi, can anyone tell me what timing setting I should be aiming for with a stobe light? I briefly checked last night and it was off the timing marks but seemed to be running ok. (Turning dizzy til engine revs stop rising and then drop by 250)

[jaydee]

What are you going to time in, a MD266 camshaft or a dizzy?

[Spannermanal]

Sorry, should have been more specific! The cam has been timed in already. This is the ignition timing. Thanks

[jaydee]

Ah ok What distributor are you using?

[Wil_h]

If you are running a standard dizzy then all you can do is set it to the book then advance and retard it to find the point that the car drives the best.

with a dizzy it will always be a case of 'the lease worst position' i.e. where it is about right for as much of the rev range as possible.

[Spannermanal]

I'm using my old 850 45D4, which I know is going to be out on the advance curve, but have been told that it shouldn't make that much difference(?) The Haynes manual for a 1100 said about 16 degrees stroboscopic, but this had the engine running very lumpy. When I adjusted it so it ran OK and then checked with the light, it was off the timing marks completely. At this stage vacuum advance is not attached anyway. I was considering getting a non vacuum dizzy, but not sure how that affects driveability on a mild road car.

Incidentally, I am at the beginning of setting this up and assume that I should set ignition timing before going on to adjust the carbs which are twin 1.25" HS2. I also have a 295 head and LCB manifold if this has any implication - which I wouldn't have thought would for ignition timing.

[jaydee]

I'd set the timing at maximum advance and not the idle advance. I'd try 30° at 4000 rpm, and see how it goes.

[MiniLandy]

Doing it by the book won't really help you that much, just tweek it until it feels best.

The only way to adjust it to perfection is to have it setup on a rolling road and the dizzy recurved, or do the DIY equivalent which is mappable ignition and a wideband lambda sensor.

[Wil_h]

I'm using my old 850 45D4, which I know is going to be out on the advance curve, but have been told that it shouldn't make that much difference(?) The Haynes manual for a 1100 said about 16 degrees stroboscopic, but this had the engine running very lumpy. When I adjusted it so it ran OK and then checked with the light, it was off the timing marks completely. At this stage vacuum advance is not attached anyway. I was considering getting a non vacuum dizzy, but not sure how that affects driveability on a mild road car.

Incidentally, I am at the beginning of setting this up and assume that I should set ignition timing before going on to adjust the carbs which are twin 1.25" HS2. I also have a 295 head and LCB manifold if this has any implication - which I wouldn't have thought would for ignition timing.

You should keep the vac advance, it's the only way the car can adjust the timing againat load. Dizzys are cr@p in all cases, but whover told you it wouldn't make any differance were either saying:
1) That all dizzys are rubbish and whatever one you fit it'll never be right, or
2) They had no real understanding of how the correct advance curve transform the performance of a car.

As above, forget the tickover, concentrate on whct it;s doing when it matters. Set to 30 deg at 4k (with vac disconnected) re-connect vac advance and try it.

As for what to do first, it's all a bit of one, then a bit of the other, but getting the basic timing somewhere close will make sorting the fuelling easier.

As has been said above try 30 deg at