rbastedo Posted May 20, 2011 Report Share Posted May 20, 2011 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. Quote Link to comment
metalmonkey47 Posted May 20, 2011 Report Share Posted May 20, 2011 Yup, they did have a ballast resistor in place in the B310's with A15. Not sure what the resistance is though. Quote Link to comment
ggzilla Posted May 20, 2011 Report Share Posted May 20, 2011 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? Quote Link to comment
rbastedo Posted May 20, 2011 Author Report Share Posted May 20, 2011 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... Quote Link to comment
banzai510(hainz) Posted May 20, 2011 Report Share Posted May 20, 2011 I would add a ballast in series with the coil. Matchbox ignitions are like .7 ohm coils Quote Link to comment
ggzilla Posted May 20, 2011 Report Share Posted May 20, 2011 Yes, it won't hurt to use the ballast resistor. Plugs gapped at 0.035 will be fine. Quote Link to comment
rbastedo Posted May 20, 2011 Author Report Share Posted May 20, 2011 I have this kind of distributor: Quote Link to comment
banzai510(hainz) Posted May 20, 2011 Report Share Posted May 20, 2011 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 Quote Link to comment
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