Centrifugal advance 45d distributor

Hi all
I have just brought a stealth programable ignition for my landy from accuspark.co.uk
It has a seven point RPM/degree for the advance and seven point for dwell.
I have got a copy of the 25d centrifugal advance settings but need them for the 45d. I can use the standard settings that come with it but they are not much good. The cam in my distributor is 20 degrees, so I guess the max RPM degree would be 20 degrees at 4250.
Any help would be great.

Thanks
Kev

kevin1970 said:

Hi all
I have just brought a stealth programable ignition for my landy from accuspark.co.uk
It has a seven point RPM/degree for the advance and seven point for dwell.
I have got a copy of the 25d centrifugal advance settings but need them for the 45d. I can use the standard settings that come with it but they are not much good. The cam in my distributor is 20 degrees, so I guess the max RPM degree would be 20 degrees at 4250.
Any help would be great.

Thanks
Kev

Click to expand...

What is max mechanical advance for engine? e That will be your maximum and its prob between 30 and 36 at poss 4000rpm (average engine)

Putting a cam in it (performance) means that you will need more advance lower down the rev range and at idle to stop the lumpiness.

This means that you will have to set the timing more advanced at idle and then hold back the mechanical advance as the revs rise so as not to over advance higher up.

The max advance stays the same and it is just before the engine pinks under load and is different slightly for every engine.

Its complicated and the manufacturers figures are just a guide

I got confused with dizzy cam and engine cam

Do you mean that dizzy advances twenty degrees static, that's not right cause if you double it then its 40 degrees advance when running which is way too much

More likely 10 and that gives 20 deg of advance plus 10/15 static giving 35 or there abouts which would be about correct at 4000

You need to test engine for maximum advance, advance it till it pinks under load at say 3000 plus

Then you need to test for pinking under load at 2000/2500

Then you can set up the idle, vac advance helps idle by advancing ign to allow for inefficient running at low revs

I used to have to do it by modifying the dizzy, changing springs and filing bits off or bending stops etc but it should be easy to do it electronically

Ahah that sound a bit better. What is confusing me is the 20degrees on the dizzy cam.
As I understand it every thing on the dizzy is double for the crank, like you say 40 degrees is way to much. I think I will start the curve with 6 degrees at 800 RPM at crank and 35 degrees at 4250 RPM crank and see how she goes.
I will let you know what I come up with.

Ps thanks

Kev

kevin1970 said:

Ahah that sound a bit better. What is confusing me is the 20degrees on the dizzy cam.
As I understand it every thing on the dizzy is double for the crank, like you say 40 degrees is way to much. I think I will start the curve with 6 degrees at 800 RPM at crank and 35 degrees at 4250 RPM crank and see how she goes.
I will let you know what I come up with.

Ps thanks

Kev

Click to expand...

Maybe a bit more at idle, see how it goes, just what is best for the engine, as long as it doesn't pink under load then the engine wants as much advance as you can give it

thank you. i give it a go.