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Ballast resistor


Guest Wayne S

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Guest Wayne S

Can anyone help me as I'm really really stuck at the moment. Need to try and bypass the ballast resistor wire thats in the loom. I've indentified it as the pink wire under the glovebox joined to a yellow/white wire with a weird bullet connector.

 

BUT, I can't for the life of me work out where the other end is plus if I cut this and leave it disconnected OR connect the yellow/white wire to the thick white wire coming off the back of the ignition switch I get power from the swtich as normal but still only get 3.5 v at the coil and 1.5 when cranking the starter.

 

Where can I wire too and from or where do I cut in order to bypass this so I get a full 12 v to the coil? I have no connectors in the engine bay at all unlike the standard TR7.

 

PLease help - got no idea where to turn next :angry:

Edited by Wayne S
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Wayne,

 

If you can located the position of the white wire connection to the white/pink wire. It should be straight forward all you need is to connect onto the white wire, which should go back to the fused board supply (non fused side).

 

If you use similar size cable you will then have 12v feed on normal running position.

Edited by tr7jim
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Guest Wayne S

Hi Jim,

 

I think this is where the problem lies:

 

"If you can located the position of the white wire connection to the white/pink wire" - Part of my problem is that I can't as this doesn't seem to be in any visible section of the loom. Behind the dash perhaps? Was hoping there is an easier way to wire in a bypass...

 

"the fused board supply (non fused side)."- where is this , how do I know which wire?

Edited by Wayne S
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"If you can located the position of the white wire connection to the white/pink wire" - Part of my problem is that I can't as this doesn't seem to be in any visible section of the loom. Behind the dash perhaps? Was hoping there is an easier way to wire in a bypass...

 

"the fused board supply (non fused side)."- where is this , how do I know which wire?

 

With a ballast, you should have 8V when running, 12V when cranking. Summat wrong there.

 

Take the new 12V feed from any terminal on the fuse box, provided it's live only when the ignition's on. Ideally, make your bypass with white cable because that is ignition colour, and if you want to remind yourself what you've done, annotate the wiring diagram in your shop manual.

 

At the risk of stating the bleedin obvious, one needs a non-ballast (standard) coil with a 12V supply. If one puts 12V to a ballast coil it will cook.

 

Ivor

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With a ballast, you should have 8V when running, 12V when cranking. Summat wrong there.

 

 

 

Shouldn't it be 6 Volts running with a RV8?

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Shouldn't it be 6 Volts running with a RV8?

 

Nah, 8V. In fact, if you put a DVM on the coil+ with the ignition on but the engine static, then slowly rotate the engine by hand, you can see the voltage flipping between 12V and 8V as the points open and close.

This is another reason it can be hard to detect a ballast feed, sometimes it shows 12V blink.gif

 

Ivor

Edited by 88V8
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Nah, 8V. In fact, if you put a DVM on the coil+ with the ignition on but the engine static, then slowly rotate the engine by hand, you can see the voltage flipping between 12V and 8V as the points open and close.

This is another reason it can be hard to detect a ballast feed, sometimes it shows 12V blink.gif

 

Ivor

 

 

God I hate ignition systems. The coil listed for my Rangie is a 6 Volt Coil. :(

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God I hate ignition systems. The coil listed for my Rangie is a 6 Volt Coil. sad.gif

 

Mmmm, 77, so was that the Opus? It was an integrated system, so perhaps for that specific application the 6V coil is right. If not, it will cook, not the end of the world.

I still have the Opus setup on the Shed, as it works I haven't replaced it with the Lumenition I bought. I'll check the resistance across the coil.

 

Ivor

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Guest Wayne S

Thanks Guys,

 

Really helpful. I have managed to get a 12v feed to the coil by splicing of the big white wire under the ignition switch. Using the mallory ballast resistor supplied with new dizzy (like a TR4 one, big block with terminals on it) I'm now getting a spark so will next re-check and then try a start up! I can confirm its around 8v after the ballast resistor.

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Thanks Guys,

 

Really helpful. I have managed to get a 12v feed to the coil by splicing of the big white wire under the ignition switch. Using the mallory ballast resistor supplied with new dizzy (like a TR4 one, big block with terminals on it) I'm now getting a spark so will next re-check and then try a start up! I can confirm its around 8v after the ballast resistor.

 

Urrgh I hate electrics. Anyway, glad if we're helping.

Wayne, you mention 12V to the coil, and a ballast, so I'm a bit confused, not sure where you're aiming to go with this. unsure.gif

 

If you're running a standard coil then your white feed from the ignition switch to the coil + is all you need, you don't need a ballast.

 

If you're running a ballast coil, then the feed from the ignition goes to one side of your big white block and from the other side of the block run a white wire to the coil +. That gives you the 8V for running.

Also, you run a wire from the starter solenoid - the output side of the solenoid so it's only live while the starter is being cranked - and run that to the coil + as well. That gives you 12V for starting.

So that's two wires to the coil +, neither of which comes direct from the ignition switch.

Both those wires can be normal ignition thickness.

 

If you can't read the label on your coil to determine whether it's a ballast or not, disconnect the wires from the + and - terminals, and check the resistance across the terminals with a DVM. If you get 1.5 - 3 ohm it's a standard coil, if you get about 0.9 ohm it's a ballast coil.

 

You can run a ballast coil at 12V, but it will fry.

Equally you can run a standard coil at 8V but it will give a poor spark and the plugs may foul.

 

Your Mallory, is it a dual-point or an electronic?

 

A ballast is worthwhile with a points dizzy as it saves wear on the points and you get a fat spark for starting.

 

If you have electronic ignition, a ballast is less worthwhile as you have no points, and you get a big fat spark anyway. Unless of course you're running an electronic system that's deigned to work with a ballast, I do have a Mallory electronic dizzy but it's still in the box. Somewhere.

 

Ivor

Edited by 88V8
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Mmmm, 77, so was that the Opus? It was an integrated system, so perhaps for that specific application the 6V coil is right. If not, it will cook, not the end of the world.

I still have the Opus setup on the Shed, as it works I haven't replaced it with the Lumenition I bought. I'll check the resistance across the coil.

 

Ivor

 

 

 

No electronics..Lucas 35D8 dizzy, points and condenser. The coil specified in Haynes is a Lucas 16C6 (6 being the voltage) although I have been running the coil that Paddocks supply as the 'usual' alternative.

 

We must all go down the same routes for I also have a Mallory (dual point in my case). For this I have purchased a Pertronix Ignitor and Flame Thrower coil. Trouble is that this set up needs 12 volts all the time so not enough spark to fire up LPG on cold cranking!!! Now reinstating petrol to investigate.

 

Anyway, sounds like Wayne has made progress and I don't want to hijack any more than I have :)

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No electronics..Lucas 35D8 dizzy, points and condenser. The coil specified in Haynes is a Lucas 16C6 (6 being the voltage) although I have been running the coil that Paddocks supply as the 'usual' alternative.

...I don't want to hijack any more than I have smile.gif

 

Quite right, very bad hijacking, although it is a directly related topic.

The 16C6 is designed to run with its dedicated ballast resistor. Perhaps Paddocks have supplied you with another type of ballast coil.

If you fit a 12V coil and are still running it through the ballast (which you will be unless you have bypassed it) then as you have found you will get a feeble spark, and plug fouling or bad starting.

 

Like Wayne, you either need a 12V coil with direct feed, or, preferably, a ballast coil with ballast feed.

 

The Flamethrower is a 12V high-output coil. However, if you want more than the standard voltage at the spark plugs, you need to open up the spark plug gap. This will force the coil to accumulate a higher voltage, because it takes a higher voltage to jump a larger gap. With the standard gap you will just get the standard voltage at the plugs. The coil will not build up any higher voltage than it has to in order to jump to earth.

You may need to experiment, gradually opening the gaps. If the gap is too large you will get misfiring at higher revs as the coil simply will not be able to build up the necessary high voltage during the dwell time.

The downside of high voltage is that the rotor arm and dizzie cap will now be carrying up to 40,000V which they were not designed for.

 

Now I don't know about the Ignitor, I have Optronic in my TR, and had the same on the previous Landy and will have on The Shed if the Opus ever conks out, but if your Ignitor will run with a ballast coil then I think that would be the better option. Especially for starting.

 

Ivor

Edited by 88V8
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