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[1984diplomat]

It's me again I have to do a final tune in with my new carb and everything I read is telling me how to tune the orange box distubeter but nothing tells me how it works.

How does the orange box distubter work I might have an eaiser time tuning if I know how it works, I am sure the Box has more function than just to look pretty.
Thanks gents.

[Dippy.org]

[Casey]

It's me again I have to do a final tune in with my new carb and everything I read is telling me how to tune the orange box distubeter but nothing tells me how it works.

How does the orange box distubter work I might have an eaiser time tuning if I know how it works, I am sure the Box has more function than just to look pretty.
Thanks gents.

The 'orange box' is the Ignition Control Unit, or ICU for short, and does what it's name suggests- it controls the vehicle's ignition. You can't tune nor adjust the ICU, though, as it's non-adjustable/non-tuneable. There are two other common ICUs, often referred to as "chrome" and "purple" boxes, but they are intended more for racing applications, rather than street use.

[Woodvark]

Like Casey said, you can't tune it, but here's how it works.

In simplest terms, the orange box, or ECU is a switch that turns the coil on and off.  It serves the same function previously accomplished by the breaker points.  Basically, current comes from the ignition switch to the ballast resistor, from there to the positive coil terminal, out the negative coil terminal to either the points or the electronic module. To increase voltage when cranking, another wire from the ignition switch carries current to bypass the ballast resistor.

The transistor that is visible on the outside of the ECU is controlled by the other ECU electronics as a switch to ground that opens the negative to the primary terminal of the coil as above.  The control electronics are signaled by the pickup coil and reluctor (Hall effect switch) in the distributor.  The star shaped wheel in the distributor is the reluctor.  The 8 teeth or peaks create a signal as they pass the pickup coil. As the peaks of the reluctor pass the pickup coil, a small magnetic current is created.

When the current suddenly stops in the primary side of the coil (ECU switch open), the magnetic field in the coil collapses and induces a high voltage in the secondary side.  That voltage is what makes the spark.

If you are looking for detailed information on the ECU electronics, I could only guess about the specific components and circuitry.  Taking one apart to find out is on my to do someday list.

[Lightning]

so...when people get MSD's it's to replace the orange/purple/chrome ECU's?

[1984diplomat]

So the BOX ICU has nothing to do with advancing or retarding the timing

If that is the case are their weights in these distributers to advance them at high speed or am I setting the timing up for high speed when I tune it.
I know the vacume port is to advance it at part throttle but it should lose vacume somwhere towards the top end of the RPM range.
Thanks for the other info Guys its been helpful

[Diplomatic Immunity]

so...when people get MSD's it's to replace the orange/purple/chrome ECU's?

Yes that's exactly right.  The MSD box is capable of firing the spark plug multiple times within fractions of a second, where the stock ignition boxes only fire it once.
and the MSD box can handle the voltage of more powerful aftermarket coils.

So the BOX ICU has nothing to do with advancing or retarding the timing

If that is the case are their weights in these distributers to advance them at high speed or am I setting the timing up for high speed when I tune it.
I know the vacume port is to advance it at part throttle but it should lose vacume somwhere towards the top end of the RPM range.
Thanks for the other info Guys its been helpful

Yes there are weights in  both electronic and points style distributors.  Mopar Performance sells a kit that has springs with different tension so that you can adjust the advance that way.

[willie]

is it worth getting an MSD ignition box and distributor on a 318 with eddie intake, headers, duals, 700 cfm carb, and mild cam.

[Diplomatic Immunity]

Worth is a relative value, if you plan on any future upgrades, especialy if your looking to get more snappy engine response or are worried about overrevving you engine, then yes it's well worth the one time investment. besides prices are only going to go up and what it costs today may seem like a heck of a deal by the time you get around to needing it.

[MrPhotographer06]

i've always wanted to do this... but my dad always says we'll do it and puts it off.. just like my Y-pipe exhaust i was getting last summer.. 

[Diplomatic Immunity]

Buy it and do it yourself, as long as you can follow directions on a sheet of paper there's no way you can mess it up.
I help my bud install one one his valiant and it wasn't that complicated.