18 replies to this topic

[miller 666]

Just fitted a 998 carb engine to a car that was running a 1275 carb. Ive finally got the thing started but i couldnt find any wiring for the coil so i just ran a 12v switched feed from the fusebox to the coil then another one to the dizzy. I have been told by a friend off here that it should be a ballasted system. And the coil is getting stupidly hot when turning over and running. Ive had a good search on here and read about having a resistor. But i couldnt get past all the deep technical writing. Im not stupid but it helps when theres just a simple wiring diagram. What is the resistor? Im sure i read it was the wire giving the 12v feed that in its self was a resistor? Can someone just put it in simple terms for me and draw me a super simple wiring diagram.

Cheers

[WiredbyWilson]

A ballast system should have an additional wire going to the coil - which ONLY supplies 12v while cranking. During running the voltage drops to 9v.

It sounds like you have wired 12v to a ballast coil - and it will burn out eventually.......... I had this problem and got round it by fitting a 12v coild with a fused 12v ignition supply.

So what colour wires have you notused when connecting the coil up? As there isn't a resitor as such - more the wire IS the resistor if that makes sense??

[miller 666]

Ive just used some red wire i had to run a fuel pump for the 12v supply. Although i was slightly confused as the coil says 12v on it?

[WiredbyWilson]

So you haven't tried using any of the original wiring for the coil then?? should be a white with yellow tracer and white with pink from memory... is normally near the oil pressure switch wiring..

My coil was getting so hot the fluid inside was dripping out of the -ve terminal. Put another new one on and all was good (after the coil just failed completely mind).

Photo might be useful to us too mate.

Edited by Wilson1330, 31 August 2009 - 05:54 PM.

[miller 666]

So you haven't tried using any of the original wiring for the coil then?? should be a white with yellow tracer and white with pink from memory... is normally near the oil pressure switch wiring..

My coil was getting so hot the fluid inside was dripping out of the -ve terminal. Put another new one on and all was good (after the coil just failed completely mind).

Photo might be useful to us too mate.

Well i bought the shell with the loom in it and i cant find any wiring for the coil, although i did find the wire for the oil pressure switch. I cant get a picture right now as the mini is kept at a mates. Another thing i will just note, when trying to get it started, we got it started and it ran, shut it off to do some checks, then it wouldnt fire and we figured out the points had moved so it wasnt making a spark even though the screw holding the points was really tight. So do i just need some "proper" wiring for it instead of just using home brew equivalent?

[WiredbyWilson]

what you have done sounds fine, as long as the feed is fused and coming from the right terminal on the fuse box.

you also need to be sure the coil is a 12v one and not a ballasted item.

from what you described it sounds very similar to what mine did, ran fine - stopped - no spark at points. might be time for a new coil?

[miller 666]

well the guy who came and had a look at my car said it was a ballasted coil... i think. Ive checked the feed on the fusebox and its a switched live so it only becomes live when the ignition is on. The coil physically says 12v on it so im unsure about that one.



Thats how i have it wired at the minute

[Penelopef1]

Hi, I have a similar problem - mini has stood for about 5 years (was running fine before). Had a mate say he would help me with the wiring then cut a load of wires out and buggered off... now I am trying to create the wiring to the coil. Have replaced the starter motor and the coil and have one wire from fuse box to + point on coil and two wires out of the dizzy - one to the - point and one to the + point on the coil....and lots of spare wires I don't know what to do with!!

I'm not getting a spark although the engine is turning over nicely.

Have I got the wiring wrong or could it be the dizzy and if so how do I check it?

Its a 12V coil inertia type. What does the solenoid do?

If anyone can help I'd appreciate it - I can add pics if necessary.

Thanks,

Jane

[miller 666]

Hi, I have a similar problem - mini has stood for about 5 years (was running fine before). Had a mate say he would help me with the wiring then cut a load of wires out and buggered off... now I am trying to create the wiring to the coil. Have replaced the starter motor and the coil and have one wire from fuse box to + point on coil and two wires out of the dizzy - one to the - point and one to the + point on the coil....and lots of spare wires I don't know what to do with!!

I'm not getting a spark although the engine is turning over nicely.

Have I got the wiring wrong or could it be the dizzy and if so how do I check it?

Its a 12V coil inertia type. What does the solenoid do?

If anyone can help I'd appreciate it - I can add pics if necessary.

Thanks,

Jane

From the haynes it suggests that the 2 wires coming from the dizzy should be, one to the coil, then one as an earth.

[Retro_10s]

Okay... remove the wires from the coil's terminals. Place the meter in "ohms" mode and measure across the coil's terminals. If your coil is for a ballast ignition it will read somewhere between 1-2 ohms. If your coil is for a standard 12v ignition system, it will measure around 3 ohms.

The test must be made with the wires removed from the coil.

[miller 666]

did this earlier retro and got 1 ohm across the coils terminals

[stormintrooper]

how odd...my ballast does the opposite....i have a 12V ballast coil....it runs at 12V and at cranking gets 9V

[bigmotherwhale]

coils do get a little hot but ushaly after starting they cool becuse they are getting switched on and off, (rather than being either on or off depending on the place where the distributor rests when the engnine stops)

the wiring diagram is correct, the distributor should connect the coil to negative through the engine block
a balasted coil is just a resistor connected in series with the coil in which case all it does is limit the current going to the coil unless the starter is engaged and it is bypassed using a relay which is connected to the solenoid of the starter, so the coil gets an extra boost of power when starting

[shorty]

how odd...my ballast does the opposite....i have a 12V ballast coil....it runs at 12V and at cranking gets 9V

thats what its meant to be doing stormin

[Retro_10s]

No - when cranking it's meant to give a full 12V to aid with starting, then drops down to 9v once the car is started.

coils do get a little hot but ushaly after starting they cool because they are getting switched on and off

This is true to some extent, but most of the cooling to the coil is from air being swallowed up by he grill into the engine bay when the car is in motion