Ballast resistor or not?

[anthonym]

This post/entry is summarised here https://www.caterhamlotus7.club/blogs/entry/1052-bdr-wiring-ballast-resistors-and-types-lucas-43d-distributor-blanking-plate-pertronix-electronic-ignition-and-coil-covertly-damaged-dizzy-cap-no-spark/

 

I'm told that when a ballast resistor is in use in the ignition system, it will (must) be included in the ignition circuit. The example to buy that I find https://advancedautomotives.com/lumenition-megaspark-2-ignition-coil-with-ballast-resistor-points-systems-ms2-4739-p.asp

here the image on that page: 

 

and in other images it looks like the ballast-resistor can be expected to be nearby like in this image: 

 

I know nothing about the Version numbers except mine is 2.

All straight forward enough so far. 

Does my car have a ballast resistor? Yes but it is fitted to the master (cut off)  switch and does not appear to be in the ignition circuit, it looks like the following image which seems to be in place for what I always thought was their purpose which is to protect the system (components) from destructive jolts from the alternator (for example when it is switched off by turning the cutout switch.)

 

So here's the thing; I cannot find any other ballast resistor, despite spending unpleasant time under the dash, videoing all that, taking many photos, no ballast-resistors. 

In which case why is my coil a Megaspark 2 (for use with a ballast resistor)? OR is the one on the master switch in some way used in the ignition circuit?

The problem is I have no spark and I am trying to figure out why. The coil primary coil resistance is 1.7 

I suppose what I would really like to understand is if there is no ballast resistor present in my ignition circuit, then there isn't one and the one on the master switch cannot be serving that purpose - in which case i have the wrong type of coil fitted. 

Does anyone understand these things? 

Anthony

 

 

 

 

Edited August 1 by anthonym
Link to end conclusion/solution

[Jonathan Kay]

6 minutes ago, anthonym said:

Yes but it is fitted to the master (cut off)  switch and does not appear to be in the ignition circuit, it looks like the following image which seems to be in place for what I always thought was their purpose which is to protect the system (components) from destructive jolts from the alternator (for example when it is switched off by turning the cutout switch.)

Isn't that discussed in another thread?

Jonathan

[anthonym]

Just now, Jonathan Kay said:

Isn't that discussed in another thread?

Jonathan

 

I am lost in that thread and need to start over.

[Jonathan Kay]

5 minutes ago, anthonym said:

I suppose what I would really like to understand is if there is no ballast resistor present in my ignition circuit, then there isn't one and the one on the master switch cannot be serving that purpose - in which case i have the wrong type of coil fitted. 

Please could you list all of the components in your current (!) ignition system. 

And do you want to keep it as close to that as possible?

Thanks

Jonathan

[anthonym]

coil, distributor, electronic igniter, ht leads, plugs - however my post is asking for assistance in understanding what would amount to an answer to your question.

I wish to remain close to the original - so I so not want the modern coil per plug solution.

[Jonathan Kay]

Just now, anthonym said:

coil, distributor, electronic igniter, ht leads, plugs

Thanks.

And the details of the coil and distributor and "electronic igniter".

Jonathan

[anthonym]

Lucas 43 D.

Powerflex Igniter.

Megaspark 2 for use with ballast resistor.

[Miker7]

What voltage do you get at the coil? If you get 9v ish you've got the ballast resistor somewhere in the circuit. If you get 12v you haven't and that is potentially one of your problems? If you have 12v for a quick test, disconnect the ballast resistor from your FIA switch and put that inline to the coil and try again measuring voltages and starting the engine (just don't switch off the car with the engine running via the FIA switch until the resistor is back in its place).

Related question, when did you last charge your battery / what voltage does it show currently? I'm wondering why this is a problem now if you've changed nothing and perhaps the car just about managed to start with a battery in a good condition & now its a little flatter.

[Jonathan Kay]

1 minute ago, Miker7 said:

Related question, when did you last charge your battery / what voltage does it show currently? I'm wondering why this is a problem now if you've changed nothing and perhaps the car just about managed to start with a battery in a good condition & now its a little flatter.

Wise words. If you're using the car's battery as part of the diagnostic testing it's vital to know that it's up the job. I'd measure the minimum voltage during cranking as well as the unloaded voltage.

Jonathan

[anthonym]

I'll go disconnect the ballast resistor and report back

[anthonym]

I'm updating this "live" so it is under construction/ now complete.

NOTHING DISCONNECTED

Battery Voltage 12.75 volts 

Coil Primary resistance 1.7 ohms

Secondary coil reads 6.0 on the 200k setting - whatever that is?

COIL DISCONNECTED

Coil Primary resistance 1.7 ohms

Secondary coil reads NOTHING PRESUMABLY BECAUSE THERE IS NO EARTH

COIL CONNECTED TO IGNITION WIRES 

Same as above

BALLAST RESISTOR DISCONNECTED

Same as above

Finished - any more tests?

So I need to know the correct primary resistance for a Megaspark 2 coil..did,'t someonme provide a test doc in the previous two struggles?

Edited July 29 by anthonym

[anthonym]

Ok so if I understand correctly iiuc I have a coil requiring a ballast resistor and no ballast resistor; which leads to burnout of either or both igniter and coil

At 1.7 ohms the coil seems ok, which leaves the igniter suspect but not tested, though absence of a spark may be a clue.

Edited July 29 by anthonym

[anthonym]

So I got my coil off (harder than it sounds) and it says:

=========================================================

MegaSpark 2 

High performance coil for use with contact breakers 

MUST be used with 1.5 ohm ballast resistor www.autocar-electrical.co.uk

=========================================================

Whether contact breakers includes electronic replacement I have yet to clarify. 

Edited July 29 by anthonym

[anthonym]

OK SO MY LATEST guess is the coil is ok for now and the igniter is goosed.

edit: so these electronic igniters seem to have a requirement of x volts (for example 3 volts) and this needs to be matched by the coil; against that some say they can work with any coil. This info does not seem to be particularly apparent when ordering (I've seen nothing at all). The only safe method seems to be to buy a matched coil from the same supplier when ordering the igniter - which is what I did with the order due to arrive tomorrow. However I was not being clever, merely desperate.

Edited July 29 by anthonym
Typo

[OldAndrewE]

With the coil disconnected and the ignition on what voltage do you get between the white coil supply wires and a known earth?

[anthonym]

Just a sec…12.44 volts

When cranking 9.44 volts

using earth to battery negative

master switch ballast resistor still disconnected

Edit: battery has been fine and last charged two days ago, 2amp charge slowly. Driving it uphill across the drive and into the garage on the starter alone (old trick not recommended!) and it wasn’t then dead impressed me: hence the charge up. 
 

all this was after trying to bump start it at various speeds / gears down a mile or two of steep hill while rolling home from the start failure point.

Edited July 29 by anthonym

[OldAndrewE]

That tells me you do not have an ignition ballast resistor, it will be in series with the coil supply .  If you are getting 12.44 volts then there is no resistor in series.  The one associated with the FIA switch is nothing to do with it.  It will not be just a case of adding the ballast resistor to the coil, you will also need the system to supply full battery voltage to the coil when cranking

[anthonym]

Brilliant. Thank you. 
So tomorrow I can fit my non ballast resistor coil and associated igniter. If they are delivered.
 

I am terrified of then finding I still have no spark. I am laughing here, a sort of laugh of terror. 🙂

Thanks again; your confident response is exactly what I needed. 
 

Regards Anthony. 

Edited July 29 by anthonym

[OldAndrewE]

Fingers crossed for a good outcome Anthony

[anthonym]

I’ll say Andrew. Watch this space, literally.

[Miker7]

The drop from 12.4v to 9v is exactly what the ballast resistor is there to circumvent & ensure the coil gets enough electricity to generate big fat sparks to start the engine.

If you've downloaded the escort manual suggested previously, page 271 describes with pictures exactly how the ballast resistor / coil works. I previously said 9v (it was a number picked to make the point), turns out with the original Escort its actually 6v.

Page 276 onwards describes some tests for the ignition system, which carries on over a number of pages - except this is for a traditional points based system, not the electronic trigger you have. However i'd expect some of the tests are still valid, for example, page 291 describes testing the coil. I'd suggest testing the coil prior to fitting so you know what 'good' is at the start. This means if something fails you can double check the coil hasn't broken. 

Page 294 lists the technical data which i've pasted below. Depending on the country making the part depends on the values. 

If you still want more info, this is a link to the A Series mini (what i grew up tinkering with) which uses the same principles (Lucas got everywhere). Choosing a Coil - Project A-Series (weebly.com)

 

[anthonym]

Yes have escort pdf will read, bit later. Non ballast resistor kit just arrived so will fit and see if we get a spark. 
 

Since the space frame level rebuild excluding engine it seems I am replacing all the ancillary engine components  such as the overflow system, the DS pump, the sump pan and now the ignition system, though not yet the dizzy itself where I am wondering … but that’s another thread (vacuum advance or not)

Great idea to test the coil first.

thanks mike 

 

Edited July 30 by anthonym

[Jonathan Kay]

18 hours ago, anthonym said:

Just a sec…12.44 volts

When cranking 9.44 volts

using earth to battery negative

This post is not about the ballast resistor, but about the condition of the battery.

Is your Seven positive earth or negative earth? I'm not sure where you put the meter probes, but assuming that those are battery voltages:

The usual rule of thumb is that the minimum voltage during cranking should be greater than 10.5 V. (And the transient minimum will probably be lower than that registered by ordinary multimeters.) Below that electronic bits can drop out with a range of interesting consequences. 

But you don't have an ECU and I can't predict what effect that low voltage will have on your ignition set-up.

I'd rig something that doesn't drop that low for future tests: a better battery, or jumping with fat leads off another vehicle with the revs up, or maybe a jump start pack although I've never played with one in this context.

Jonathan

[anthonym]

I've used a jump start pack to the same results all round.

This post IS about a ballast resistor. Edit: as discussed above.

Edited July 30 by anthonym

[Golf Juliet Tango]

22 hours ago, anthonym said:

I am lost in that thread and need to start over.

I understand that. TechTalk threads over a few pages long have two faults: finding the response needed and the loss of focus. Compact and concise, well focused threads are considerably more helpful (excellent titles help)