coil resistor smoking

[RootesRacer]

PIcked up a dizzy cap and quizzed the parts-house guy.

Parts guy believes that no resistor is needed for the 25D dizzy.

I put on a coil he recommended as matched to a 25D, and
put on my old 25D dizzy, engine starts again, but timing
is way way off.

I had been using a new 45D dizzy, but parts guy said that the 45D
model needs a 6 volt coil and a resistor (not the 12 volt coil I had
been using.)

I hope you'all who understand this can get it straightened out .. .

Allan

Better change your parts guy...

The distributor has NOTHING to do with if you use a ballast resistor or not.
It has ONLY to do with the coil, and sometimes to do with the electronics box (if applicable).

I can assure you the 45D distributor was used on many cars with 12v systems. In fact, I dont thing the D45
was even designed when 6v systems were in use.

Low resistance coils need the ballast which acts as a current limit at lower RPMs when the coil saturates due to excess dwell time.

Sometimes, the engine will stop with the points totally closed, and if this happens, the coil will be turned on continuously. I mention this becuase you should never leave the ignition on with the engine not running (with points) or the coil and ballast will get very very hot, likely damaging both as well as welding the points closed.

 

[puff4]

How is the ballast bypass switched, is it a contact on the solenoid (as on the tiger)?

There's a wire from the starter solenoid (the starter wire connection side) to the coil directly. There is a special terminal for this on the bottom of the solenoid. Via this connection, when the solenoid is engaged and the starter is running, power also flows directly to the + side of the coil.

The wire is white with a green tracer and has Lucar connectors on both ends, covered with clear vinyl sleeves (which usually turn opaque yellow/brown over time). On LHD cars it is routed from the solenoid, up under the lip at the top of the engine bay's aft bulkhead (firewall), then down the right-hand support strut to the coil. The wire has a black sleeve on it for most of it's length and is held in place against the bulkhead flange with two or three small clips which slide onto the flange.

I couldn't find a pic of a real Lucas solenoid, but here's a replacement showing the tab on the starter wire terminal which could be used for the direct wire to the coil (the original solenoid should have two connections like the smaller independent one on the left (which is for the ign. switch), and it would be directly opposite on the other side of the solenoid and would be therefore hidden in this photo):

And here's a pic of an un-restored Alpine engine compartment, showing the wire and clips:

 

[puff4]

Oh, and you're right - it is NOT shown on any of the wiring diagrams (S1 thru V). Here's a color version of the diagram for a SV, and it's not there either (with thanks to Martt Ollman)...

 

[SIVAllan]

Better change your parts guy...

haha, can't do that. He got me going again, by luck or by design .

Allan

 

[SIVAllan]

...

To test for proper ballasting, try unplugging the ballast and you'll find - if it's correctly wired - that the car will start (while in 'start' mode) but then quit as soon as you release the switch (while in 'run' mode).

I guess my SIV has incorrect ballasting, as it makes no difference for running the engine.

It cranks and appears to run no differently, whether the ballast is hooked up or omitted.

I understand that the current is routed so as to step up cranking power while protecting normal operations.

What is the "penalty" for the coil or other parts, if a ballast is omitted ..??

There must be a good number of Alpines with the original wiring harness, so likely wiring has not changed.

But perhaps the parts have changed somehow from the past, solenoid, coil .. ??

Thanks!

Allan

 

[Tom H]

Allan, you are saying (in your original post) that the ballast resistor was smoking and yet in your most recent post it seems to not even be wired into the coil circuit, since disconnecting it had no effect.

If these are the facts then my guess is that the ballast was somehow wired so that one end is connected to 12 V and the other end is shorted to ground. This would explain the smoking- getting the full 12 V, instead of about half the 12 V.

There is no change in the "harness" whether a ballast resistor is used or not. Same harness. Only difference is: with no ballast the white wire (from the ignition switch) goes directly to the coil - as shown in the schematic. But with a ballast resistor installed the white wire goes to one end of the ballast resistor - located close to the coil so the same harness works. Then an extra short white wire goes from the ballast resistor to the coil.

And then there is an extra wire, not part of any harness, as described and photo'd by Kevin, covered with a vinyl sleeve, (black in my car ) that goes from the solenoid (small terminal) to the coil. This is the bypass circuit.

The penalty is that if the coil is designed for a ballast resistor and the resistor is omitted, you will likely overheat the coil, as it will get twice the voltage it should. And the high voltage output will be twice as big as it should be. That might also explain the burned distributor cap - too much high voltage!

Tom

 

[64beam]

Hi Allan,

Unless you want your Alpine original, you could remove the Ballast resistor completely and go to a 3 ohms coil (as was previously mentioned I believe). That way there is one less component to worry about. It is not just the coil you need to worry about if you have no ballast resistor. If you rely on the coil resistance only in the circuit, the current drawn in the circuitjumps by 2.5 times (approx. 4 up to 10Amps). Starting to get to the stage where that Lucas smoke will escape .

Regards, Robin.

 

[sunbby]

There is no change in the "harness" whether a ballast resistor is used or not. Same harness. Only difference is: with no ballast the white wire (from the ignition switch) goes directly to the coil - as shown in the schematic. But with a ballast resistor installed the white wire goes to one end of the ballast resistor - located close to the coil so the same harness works. Then an extra short white wire goes from the ballast resistor to the coil.

And then there is an extra wire, not part of any harness, as described and photo'd by Kevin, covered with a vinyl sleeve, (black in my car ) that goes from the solenoid (small terminal) to the coil. This is the bypass circuit.
Tom

The starter solenoid to coil wire is white with a green stripe on my car, as is the short ballast resistor to coil wire.

Here's a picture:

To bypass/eliminate the resistor you would remove both white-green wires and connect the white wire directly to the coil. As previously stated, you MUST have a 3 ohm coil to do this, otherwise you run the risk of overheating and ruining the coil among other things.

Allan, when you "omitted" the ballast resistor did you move the white wire or merely disconnect it? I think puff4 wanted you to disconnect it and leave it disconnected. This way the white-green wire will supply the coil while cranking the starter, but as soon as you stop cranking (as when the engine starts) the coil should stop getting power and the engine will stop.

 

[SIVAllan]

Thanks everyone.

I'm going to get the car this afternoon and will look at the wiring. All I can say at this point is that two wires from "somewhere" ran to the ballast, now run to the coil.

I will also call the parts guy to see if the Lucas coil he recommended for use wilthout a ballast has the right ohms for that...

Gotta run for now...

Allan