im new here anyway i have a points ignition and i want to convert it to electronic using a reed switch (its what i have to work with).The voltage is 12 volt for the coil ,but the reed switch cannot switch that much current im seeking list of components to use in junction with this reed switch to cause a spark at the spark plug instead of using points any advice or ideas please?

 

Hi,
https://www.oldclassiccar.co.uk/forum/phpbb/phpBB2/viewtopic.php?t=22386

 

You need to determine the life time operations of the reed switch.
It may be less than you would like for you application.

 

Welcome to AAC.

(its what i have to work with)

Is this supposed to limit us to working with what you have? Or are you open to pursuing other means? The reed switch may very well not be fast enough to switch in the manor you wish. Plus, with every discharge of spark there's a back electromotive force (Back EMF) that will likely burn the switch out in very short order.

If we're limited to using the reed switch - this project is already over. Already a failure. Even if you use other components to do the switching, the reed can not actuate fast enough for any high RPM's (and by "high" I don't mean 8,000 RPM, 3,000 RPM may be beyond the ability of the reed switch).

 

Only found one reed switch that listed its switch rate.

Yes, that says 400Hz. That's 400 switching operations per second. Per minute that's 24,000 closures per minute. On a FOUR CYLINDER engine that's going to limit you to 6000 RPM. Hey! I'm learning here. I'm learning here. A SIX CYLINDER engine will be limited to 4,000 RPM, and a V8 will be limited to 3,000 RPM.

3,000 RPM may be beyond the ability of the reed switch

Not bad for a blind guess.

 

Aside from the issue of the reed switch operating time, which will affect the spark timing a lot before it limits the speed, there is also the reed switch operating lifetime, before it wears out. For a reed switch lifetime of 100,000 cycles, that equates to 100 minutes, for a one cylinder engine at 1000 RPM.

THAT is why you never see a reed switch triggered ignition system.
That is also the reason that many of the after market CDI and just plain switching ignition systems kept the breaker points, but reduced the power a lot.

 

You can use a couple different HEI modules with a few extra parts. This is about the easiest way to go... https://www.jalopyjournal.com/forum/threads/how-to-trigger-hei-using-stock-points-dist.978979/.

What kind of engine are you working with? There may be an electronic conversion kit out there that will simplify life

 

The whole idea is to eliminate all "mechanical" parts.
A Reed-Switch is most definitely a mechanical device, with all the problems that go with it.

You would be better-off keeping your original Points and simply installing an aftermarket Ignition-Box.

By around ~1980 every automotive-manufacturer had changed-over to all Electronic-Ignition-Systems.
This means that it is very likely that You could find a used Distributor for your Engine,
but in a later-model Car, that has an Electronic-Ignition-System that will just "drop-in-place" on your Engine.

Any type of Electronic-Distributor-Pick-up scheme will work
perfectly with around ~90% of the aftermarket Ignition-Systems available today,
whether they are Hall-Effect, Variable-Reluctance, or Optical types.

You haven't stated the Year or Manufacturer or Engine-model that You are working with.
.
.
.

 

Another question is since there are no magnets associated with points how would you trigger the reed switch in the first place?

 

ALL of the suggested schemes appear to require a replacement of the original cam that operates the breaker points. A variable reluctance pickup might work with the original cam, if the input circuit was designed for that.

 

It seems like we've scared yoshicircuit away. Or the realization his proposal is not practical and has resulted in the abandonment of the project.

 

ALL of the suggested schemes appear to require a replacement of the original cam that operates the breaker points. A variable reluctance pickup might work with the original cam, if the input circuit was designed for that.

Actually a HEI module can be triggered by points as the link in #7 shows, but a proper electronic system of some sort would be the better choice.