How cam HEI and MS2 controll advance??

[turbogrill]

Hi,

I have been googling and googling but I can't understand how you can set the timing curve using a HEI timing module?

You still have a dizzy and only 1 coil right?

The only time there is a spark is when the rotor hits the contact pads that leads to the spark plug. And this is fixed? (Except mechanical advance and such).

[Matt Cramer]

The rotor is in contact with the terminal for enough crank degrees to permit firing the coil at more than one crank angle.

[slow_hemi6]

1. the rotor is never in contact with the caps contductor, there is always a gap.
2. Rotor tips are on average 25 crank degrees wide.
With regards to HEI it is called a next cylinder ignition system. http://www.msextra.com/doc/ms1extra/Diz ... Next_1.htm

[turbogrill]

The rotor is in contact with the terminal for enough crank degrees to permit firing the coil at more than one crank angle.

1. the rotor is never in contact with the caps contductor, there is always a gap.
2. Rotor tips are on average 25 crank degrees wide.
With regards to HEI it is called a next cylinder ignition system. http://www.msextra.com/doc/ms1extra/Diz ... Next_1.htm

Thanks! That makes perfectly sense! Been thinking about this for a while

I am looking into adding MS to my 280zx NA, both fuel and spark.
Currently doing research about how MS2 vs Ms3 vs MicroS, temp sensor, MAP vs MAF and how to get crank position information from the engine.

This forum in combination with all the documentation seems like a very valuable resource.

[Six_Shooter]

Thanks slow_hemi for pointing out that the rotor never actually conntacts the cap... I see how people might think that, but it's better to point out that they never do, well, never should contact. lol

Anyway, regarding the actual application at hand. As someone who has installed EFI on an L28, using an HEI module triggered from a 280Z dizzy, just skip it and go to DIS. I only used the dizzy for a brief period when I didn't have time to set up the DIS conversion. DIS was much smoother, at idle and through the power band, and felt like it just made more power because of that. The spark is potentially stronger using DIS over dizzy since there are few gaps to jump and the dwell time can be longer creating a (potentially) hotter spark. Using the 36-1 wheels that are popular will give you a good start for input signal (engine position) and then a number of different coil layouts can be used, from COP to dual tower wasted spark coils.

As far as using the HEI 7 or 8 pin modules, it will work and give you plenty of adjustment for spark advance. It's a quick and dirty way to get MS (or other EFI systems) controlling spark.

You could also do direct coil control from the MS, by feeding the VR signal into the MS directly and then have the MS control the coil.

FWIW, I'm using an 8 pin HEI module on my T-bucket currently since I originally wired it for a Delco (GM) ECM and it required the use of a stock GM dizzy/ICM to work. I'm leaning towards going to either direct coil control but keeping the dizzy or moving to wasted spark DIS.