Carbed 4AGE dizzy issues

4AGMG
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Carbed 4AGE dizzy issues

Postby 4AGMG » Mon Mar 07, 2022 3:52 pm

I've been looking forever and cant seem to find a straight answer. I'm running an ECU-Less bigport 16v with the 3 prong distributer. I put carbs so that I would not have to use ECU for fuel, but now I can't seem to figure out how to wire the distributer. While searching it appears I will be able to run a fixed ignition with just the distributor and a coil, I'm just confused as to how to wire up the coil and distributor. Where does the negative off the coil go? do I have to ground anything on the dizzy? should I be supplying power to the dizzy?

Davegt27
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Re: Carbed 4AGE dizzy issues

Postby Davegt27 » Wed Mar 09, 2022 11:53 pm

what car/engine did the distributor come from ?

do you have a book for the car/engine/distributor ?

might help

https://www.google.com/search?q=4ac+dis ... 2gfzm1_z_M
Davegt27 Code One Racing

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jondee86
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Re: Carbed 4AGE dizzy issues

Postby jondee86 » Thu Mar 10, 2022 1:56 am

OP you are on the right track, except that you will need an igniter to fire the coil.

Every time this particular ignition question comes up I think to myself that there has
to be a simple solution. A bit of searching brings up one very simple "high energy" setup
using these Bosch components...
Bosch HEC715 high energy coil
Bosch BIM 024 ignition module

The actual details are pretty well covered in these two articles...
https://www.autospeed.com/cms/a_113193/article
http://www.dtec.net.au/Tech%20Articles/ ... ration.pdf

Image

You just use the OEM 4-tooth reluctor wheel and VR pickup as an input to the Bosch
BIM 024 which in turn sets the dwell and fires the coil. No other inputs required. The
only thing I have not been able to check out is if the BIM 024 has any kind of timing
advance curve built into the module. If it doesn't have any advance you will need to
settle on a compromise (fixed) ignition setting.

A suitable coil and ignition module can likely be found in your local wrecking yard.
Best to get a matching coil and ignition module from an OEM setup if you can to avoid
any issues with miss-matched components. A medium energy coil/igniter setup will
also work fine for carbs. High energy is mainly for turbo applications.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

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jondee86
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Re: Carbed 4AGE dizzy issues

Postby jondee86 » Fri Mar 11, 2022 9:51 pm

And if you can't find the Bosch igniter and coil at your local junkyard, there is another
possibility... the venerable 4-pin HEI igniter that was widely used on a range of older
carbed US cars, and some early EFI models. These are said to be a dime a dozen in the
junkyard, and it should be easy to pick one up with a matching coil.

Image

The deal with the coil is that it has to be capable of handling the "High Energy" output
of the HEI igniter. Use a weak coil and it will overheat and fail, so unless you like trying
to work out inductances, impedences, Ohms and henrys, just try and pick up a coil from
a vehicle with a high energy ignition system.

I have tried to highlight the important stuff on the diagram. The VR output from the
distributor has to be configured correctly. If you use this setup and it runs like crap, you
most likely just need to change the two wires over to get it running correctly. Same as
the Bosch igniter, the ignition timing is fixed, but the igniter takes care of dwell.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

4AGMG
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Re: Carbed 4AGE dizzy issues

Postby 4AGMG » Sat Apr 30, 2022 6:48 pm

Thank you a bunch for helping out with this, wish I had seen it sooner. Ended up going with a used msd 4al, works like a charm. used the hei module, the msd didn't work with it, ran it straight any everything perfect. will I run into any trouble down the line if I haven't yet or does my setup sound fine?

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jondee86
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Re: Carbed 4AGE dizzy issues

Postby jondee86 » Sat Apr 30, 2022 11:53 pm

Just discovered something that has always had me confused.... MSD call a VR trigger sensor
a "magnetic pickup". So basically if you hook your distributor up to the magnetic pickup input
on the MSD and to the coil outputs, you are good to go :) Nothing wrong with MSD and there
are about 2,638,992 of them running on cars all round the world. Drive safe !!

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.