Datsun A15 coil - need resistor or no?

[rbastedo]

I've got a bit of a Frankensteins Monster thing going on here with an A15 in an MG Midget.

The previous owner did some custom wiring.

 

I put in a new coil a few weeks ago, trying to isolate a misfire condition.

I specified I wanted a coil for a 1980 Datsun 210 with A15 motor.

 

The other day I happened to feel the harness while the car was running and it was HOT.

I started taking it apart and found a white wire with a cloth covering that was the really hot one.

It connected to my ignition wire, the white one to the coil.

I cut it loose and no longer had the heating up of the wiring harness problem and my misfire got a little better though it's not gone.

 

Did that engine / electrical system / coil require a resistor?

Is there anything else the wire from the coil to the ignition switch should be connected to?

There is another white wire that is spliced in but I haven't had time to trace it yet, this splice was made about 6 inches out on the engine side of the firewall.

[metalmonkey47]

Yup, they did have a ballast resistor in place in the B310's with A15. Not sure what the resistance is though.

[ggzilla]

USA models never used a ballast resistor. Some or all Canada models did.

The coil should be used with the original type distributor, a high energy electronic igntion. If you have the 'matchbox' (black box) distributor that's the one.

 

> Is there anything else the wire from the coil to the ignition switch should be connected to?

That depends on your Morris, doesn't it? In a Datsun 210 or Datsun 310 yes that's the IGN circuit and there are lots of things on it.

 

Also keep in mind that coil w/o resistor uses a lot more amperage than coil w/resistor. Is the Morris wiring big enough to handle that much current?

[rbastedo]

I've been making some changes and where ever possible have been using heavier gauge wiring than stock.

I was an electrician in another life, long long ago...

[banzai510(hainz)]

I would add a ballast in series with the coil.

 

Matchbox ignitions are like .7 ohm coils

[ggzilla]

Yes, it won't hurt to use the ballast resistor. Plugs gapped at 0.035 will be fine.

[rbastedo]

I have this kind of distributor:

 

[banzai510(hainz)]

the coil determines the current amount. since you have a 210 EI coil for that year I assume its EI. so there are close to .7 ohms so 12volts divide by .7 = 17amp going thru the key swtcih and wires.

 

 

Point require alot less as this prevent the points from buring up but they use a point coil which is higher resiaitance and a ballast also.

 

 

IF This was me hear , if you have a HOT START wire(bypasses the ballast during START), You could run the Matchbox like a point set up and use a bigger ballast resistor like a 2 to 2.5 ohm inseries with your coil(.7 ohm) you have. This would drop it around 4 amps.

 

#1)so +12volt wire to the ballast then to the plus side coil.

#2)Hot START is 12 volt during START , hooks right to the +side coil. Mosre or less you should have 2 wires at the coil. When Key switches back to ON it would go back to #1