SBC wiring questions that haven't been answered through "search"

You are referring to an internal resistor coil. The ballast resistor is not there because it was a 6V conversion. Many, MANY 12V point ignition systems used a ballast resistor to keep the points from arcing and burning. They even carried over to electronic ignition systems for a number of years.

 

So if I am starting with an empty engine bay, how would I know if I needed ballast resistor or not?

 

If you already have a coil, you'll need to do a primary winding resistance check (Ohm test) to see if it has an internal resistor. Again, these are primarily from later electronic ignitions. If you don't have a coil and are running points ignition, I would use the external ballast resistor. This allows you to run full battery voltage when cranking for easier starting.

 

Yeah, I'm running points ignition and have a new Accel Super Coil hooked up to it. Their site has a CYA clause as to whether or not you should use a ballast resistor....

 

They still make those yellow plastic lunchboxes?? LOL

In general, if you have points, you want the resistor separate so you can have the full voltage cranking lead to the coil.

So, you got it pretty well figgered out now, Ross?

 

I like this drawing for it's simplicity and the way it breaks up the wiring into systems. This is all that any car needs. People like to panic over wiring. If you take it one system at a time it really is pretty easy.

The wire for the choke can be connected to any terminal that is hot with the key on and dead when the key is off. A simple test light can tell you what you need to know. If you chose to use a terminal on the ballast resistor make sure it's the full 12V side and not the reduced voltage (distributor) side.

If you have an alternator then the charging portion of this diagram will change but the rest is the same.

The diagram that you started with looks like it came from a Motors Manual.

When you get this done you will understand your car and it's systems much better and if you do ever have a problem you won't need an 800 number to talk to a tech.

The terminal block that you showed will need jumpers if you want to use one hot feed feeding several connections. They make little metal clips that bridge the dividers between the terminals and connect adjoining terminals so that one hot wire will feed more than one device. They are much cleaner looking than a bunch of short jumper wires tying the terminals together.

Hang in there. It will all work out. Everyone trying to help learned this way.

 

HAA...yeah, I kinda wish it were one of the lunchbox ones, those looked cool. This one is brand new and looks like the Pertronix Flamethrower ones.

OK......so I *finally* got it figured out after a good night's rest. There are two variations of the old school diagram and I've reposted them below:


NOTICE how there are two wires coming off of "4" on the regulator, making a loop TO the switch ACC and back via IGN. I'm not sure why that loop is there or what its function is exactly.






In the one that I made below, I used another diagram that looked exactly the same, but only had ONE line coming from "4" on the regulator going to the switch IGN. You won't see the old school switch drawn, because I replaced it with a drawing of how my switch is configured. However, how I drew the line coming from "4" is exactly how it was drawn originally. Notice there is NO loop back from IGN back to "4" from the switch.









Once I noticed the difference, I thought "hell, why don't I try moving the one wire I have currently coming from the regulator at "4" and taking it to the switch ACC instead? Figured the worst that could happen is that it would blow up and I'd die a shrapnel death Once I did that, it works fine! Is the second part of the loop through the idiot light just to show you if current is still flowing? I used a volt meter when I had the line from "4" going to switch IGN, and it was still getting current even when the switch was OFF. That's why I wasn't able to shut it down once I cranked it.

I have no idea why I didn't notice that before. You'd figure a grown man could figure out where 4 wires go, with a map, in less than 2 days

 

Not at all true. There are many different 12v coils made today with totally different resistance values depending on application. We, PerTronix, make 12v coils that have .32, .45, .5, .6, 1.5, and 3.0 ohm primary resistance!
Ballast resistors are still necessary and recommended for points systems.

 

I've run several 12-volt coils with ignition point type PDC breakers and never had a problem with the coil overheating. All my Harleys use 12-volt coils without ballast and I converted my 64 T-bird with the worn out transistorized ignition to a 12-volt coil and its been running like a top for 10-years with no ballast.The 6-volt systems don't need a ballast resistor either since a coil won't overheat with a 6-volt electrical carrier. As far as what causes breaker points to burn up, that can be blamed on a bad condenser or a mismatch condenser/capacitor for the system used. Granted though most 12-volt carrier systems do require the voltage be dropped to near 6-volts to control coil temperature and regulate against voltage/current spikes.

 

My point was that for a temporary system, like was originally described at the begining of this thread, you may not need to worry about a ballast resistor at all. To just run a car in and out of the shop for a few minutes and what not. For a long term system with a 1.5 Ohm primary coil then by all means use a ballast resistor of 1 to 1.5 Ohm for the coil's longevity. Simple as that.

 

NOW that I have the basic wiring figured out, I hooked up a tach so I could dial in the carb idle. Since it was a cold start, I cranked it, let it run for a few, and opened up the choke to make sure that the gauge was working properly. I topped out at 2500rpm. I held it there for about 20 seconds or so, then I notice some wisps of smoke coming from the back of the voltage regulator. WTH? The case of it was a little warm when I shut it down, and it restarted fine after that. It doesn't smoke when it's idling around 500rpm or even up to 1000rpm. So far I haven't been able to duplicate it. Any ideas? A short perhaps? I have a couple of grounds attached to one of the mount screws on the regulator, but that's what one of the manufacturer diagrams specified.