Electrics when starting

[sholdowa]

yuh

ballast resistor just drops down the 12v feed so you dont burn your points out real quick

No you've missed the point. When running, the alternator develops about 13.8V, and the ballast resistor drops this to run a coil designed for an 8V feed. When starting, the 200+Amp load on the battery drops the voltage that the battery can deliver to about 8V, so shorting the ballast resistor provides the correct voltage to the coil to deliver a decent spark to start then engine while cranking.

If you run a non-ballasted feed to an 8V coil, then the HT voltage will be way too high, and the arc generated between the points will soon burn them out.

[forced]

As above but if you run 12v all the time to an 8v coil it will run too hot too and be more likely to burn out if you left the ignition on with the motor not running.

If you're rewiring the car, i'd have thought it a lot easier to start with a stock loom rather than doing it from scratch.

If you had a haynes manual or similar then you'd have the wiring diagram.

A nice easy upgrade would be to use an igniter from a later model car (to give a better spark) along with a balast resistor which would be best bought from a place like pick a part.

Steve

[Yowzer]

There should be an electronic ignition module ya can steal from something, like a chrysler jobbie or similar, and run an electronic dizzy instead.

eg.

Simple as really, just need a dizzy that fits your engine.

[peteretep]

As above but if you run 12v all the time to an 8v coil it will run too hot too and be more likely to burn out if you left the ignition on with the motor not running.

If you're rewiring the car, i'd have thought it a lot easier to start with a stock loom rather than doing it from scratch.

If you had a haynes manual or similar then you'd have the wiring diagram.

A nice easy upgrade would be to use an igniter from a later model car (to give a better spark) along with a balast resistor which would be best bought from a place like pick a part.

Steve

i will be using parts of the original loom, but i want to rewire it to bring it up to new spec, as well as future proof it in case i ever decide to use a computer or add any other things, surely having to add a single ballast resistor to a new loom wouldnt justify using most of the old loom? plus i want to be able to say ive done it

I have several versions of the old loom and its fairly crap, because there were different drawing standards back in 1968 it makes for hard reading, and alot of back and forth between pages

I currently have a bosch gt40r, is this not as good as an igniter from a late model car? possibly the difference would be that at high rpm it could get maximum spark still??

[forced]

Still use your coil, an igniter is just another name for an electronic ignition amplifier. So the points drive the igniter and the igniter drives the coil.There's only a small current through the points then and generally the igniter has the dwell extension built into it so you get a bettter spark even at high revs. Once you've got one of those then it's easier to fit a rev limiter if needed. Another thing to be aware of is that when points wear and need resetting, the gap gets smaller rather than bigger because it's the rubbing block that actually wears down, not the points themselves.

Steve

[lowlancer]

That setup Yowzer shows still has a ballast resistor does it not? They're just used cos the system is designed to run on less than 13.8V cos the starter theives like 4V when cranking.

[Ke36]

yuh

ballast resistor just drops down the 12v feed so you dont burn your points out real quick

No you've missed the point. When running, the alternator develops about 13.8V, and the ballast resistor drops this to run a coil designed for an 8V feed. When starting, the 200+Amp load on the battery drops the voltage that the battery can deliver to about 8V, so shorting the ballast resistor provides the correct voltage to the coil to deliver a decent spark to start then engine while cranking.

If you run a non-ballasted feed to an 8V coil, then the HT voltage will be way too high, and the arc generated between the points will soon burn them out.

is that not what i said?

[peteretep]

Still use your coil, an igniter is just another name for an electronic ignition amplifier. So the points drive the igniter and the igniter drives the coil.There's only a small current through the points then and generally the igniter has the dwell extension built into it so you get a bettter spark even at high revs. Once you've got one of those then it's easier to fit a rev limiter if needed. Another thing to be aware of is that when points wear and need resetting, the gap gets smaller rather than bigger because it's the rubbing block that actually wears down, not the points themselves.

Steve

im not educated on late model ignition systems, is there a website or something that could explain to me how an igniter works? i cant seem to find much on the net about them

[Yowzer]

It basically does the same job as the points, only electronically. The dizzy gives the igniter a signal pulse, the igniter breaks the circuit to the coil and induces the spark. Don't have to worry bout dwell angles and shit wearing out as it's all solid state electrics.

Or something near enough to that anyway. Correct me if I'm wrong

[edit]

http://www.jetav8r.com/Vision/Ignition/CDI.html

That has a nice chunk of info

[Yowzer]

That setup Yowzer shows still has a ballast resistor does it not? They're just used cos the system is designed to run on less than 13.8V cos the starter theives like 4V when cranking.

Yup yup.

Could run a higher volt coil and lose the resistor altogether, but then ya won't get the advantage of the higher voltage on cranking.

Although I never plugged the starter wire in anyway and have never had a problem when cranking (but then the plugs are still next to new, will most likely make a difference when they wear out a bit)

[peteretep]

ok so whats an igniter that i would use? does it not need an ecu?

[Yowzer]

Nah it's all self contained. I'd say all the basic transistor igniters are pretty much the same so there should be a few to pick from.

I think all the late 70's chryslers use the same type and they are piss easy to wire, I'd say ford would have something similar, (or maybe lucas )

[peteretep]

can you point to some on trademe at the moment?

[Raizer]

http://www.trademe.co.nz/Trade-Me-Motor ... 313882.htm

http://www.trademe.co.nz/Trade-Me-Motor ... 982292.htm

[forced]

Last one I bought was $8 from pick a part.That included the connector & end of the loom. Stock factory parts FTW. Personally I wouldn't go near MSD stuff, it's too old, too expensive, too big, too unreliable & outdated.

Steve

[Yowzer]

Still gotta be better than points though

[sholdowa]

I have several versions of the old loom and its fairly crap, because there were different drawing standards back in 1968 it makes for hard reading, and alot of back and forth between pages

This and the fact that the loom - especially the insulation - is 40+ years old is why I've decided to make a new one from scratch. I'm also upgrading the ignition on my pinto to all electronic - megajolt and no distributor at all - at the same time. This'll be a major voyage of discovery for me as well, so I expect to be regretting my decision on a regular basis.

[peteretep]

Last one I bought was $8 from pick a part.That included the connector & end of the loom. Stock factory parts FTW. Personally I wouldn't go near MSD stuff, it's too old, too expensive, too big, too unreliable & outdated.

Steve

for my escort, what type of cars would i look for at pickapart, i can go there this afternoon and have a look around, just need to know what type of car im looking for

[sentra]

you got to be joking using points to switch an electronic module

[Brock-Lee]

Why, it does seem a little like polishing a turd but will help the points perform better. You take all the load off them and allow them to last longer and shit. Jaycar does a kit for pretty cheap that might be worth looking at toooooo.

Yar