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[Andy B]

Who can remember how to wire them up? There's no loom just bit of wires. I've done it once ..... but old age has stepped in & I can't now remember.  :-/
I've tried a direct feed to the +ve of the coil and then connected the tail of the condensor/points to the -ve. That melted the points!!! I've got another new set & don't want to do the same to these.
Any pointers? I've had a quick Google bt can't find what I want.  :-?

[zirk]

Who can remember how to wire them up? There's no loom just bit of wires. I've done it once ..... but old age has stepped in & I can't now remember.  :-/
I've tried a direct feed to the +ve of the coil and then connected the tail of the condensor/points to the -ve. That melted the points!!! I've got another new set & don't want to do the same to these.
Any pointers? I've had a quick Google bt can't find what I want.  :-?

From memory didn't the Points short the Neg down to earth (so it fires on its release, ie goes open cct), so the Pos will go to +12v. also dont forget the Condenser (Capacitor) accross the points.

[Andy B]

Who can remember how to wire them up? There's no loom just bit of wires. I've done it once ..... but old age has stepped in & I can't now remember.  :-/
I've tried a direct feed to the +ve of the coil and then connected the tail of the condensor/points to the -ve. That melted the points!!! I've got another new set & don't want to do the same to these.
Any pointers? I've had a quick Google bt can't find what I want.  :-?

From memory didn't the Points short the Neg down to earth, so the Pos will go to +12v. also dont forget the Condenser (Capacitor) accross the points.

That's what I thought, but that's how I ended up with charcoaled points ...    

[mantahatch]

IIRC Live feed to terminal 15 on coil, wire from terminal 1 on coil to insulated side of points and condenser wire also to insulated side of points, and make sure the earth side of the points have a good earth.

Alos there are two types of poits type coils, standard 12volt coil and a ballast resisted coil which runs at 9volts.

I hope I have remembered this right.

Mike

[zirk]

Its not a 6 volt coil that needs the resistor box is it?, seem to remember Vx did that for starting purposes, ie so you get a better spark when cranking the starter?

[RobG]

This might help Andy http://books.google.co.uk/books?id=5jNS4NubpR4C&pg=PA125&lpg=PA125&dq=how+is+the+condenser+and+contact+point+wired+in+a+cars+distributor&source=bl&ots=JBWzhkjhUB&sig=jQscohu2CPG_wTlcnTzHu2ef1uE&hl=en&ei=uHbLSa2ND4qUjAeyoZzzCQ&sa=X&oi=book_result&resnum=1&ct=result#PPA125,M1

[Field Marshal Dr. Opti]

I once owned a MK1 Astra Estate.....................on a 1983Y plate..................as far as I 'am aware this was one of the last cars to be fitted with contact breakers points.

If memory serves ............I would set the "heel" of the points against the high point of the cam in the dristributor...............then set the points gap to 15 thou.............with a feeler gauge.

I would use a home made light bulb .............with croc clips .......in order to find out exactly when the points started to open.

I would line up the timing marks on the engine first ....by hand ...........as I did not have use of a strobe light.

[Andy B]

This might help Andy http://books.google.co.uk/books?id=5jNS4NubpR4C&pg=PA125&lpg=PA125&dq=how+is+the+condenser+and+contact+point+wired+in+a+cars+distributor&source=bl&ots=JBWzhkjhUB&sig=jQscohu2CPG_wTlcnTzHu2ef1uE&hl=en&ei=uHbLSa2ND4qUjAeyoZzzCQ&sa=X&oi=book_result&resnum=1&ct=result#PPA125,M1

Thanks for that Rob ..... I'm not quite surehow different mine is, but it gives me something to compare.
 

[Kevin Wood]

Many coils require a ballast resistance in the LT feed to the coil. Although this is sometimes shorted during cranking to aid starting with low battery voltages, it is actually done to give a higher impedance feed to the coil which builds the charge in the coil faster, reducing the dwell time over a coil designed for 12 volts directly.

Anyway, such coils have a very low DC resistance so will flow much too much dwell current without a resistor in series. My guess is that this is your problem. Sounds like the wiring is fine.

Sometimes the ballast resistor was built into one of the LT leads meaning it could easily be discarded unwittingly.

Kevin

[Andy B]

I once owned a MK1 Astra Estate.....................on a 1983Y plate..................as far as I 'am aware this was one of the last cars to be fitted with contact breakers points.

If memory serves ............I would set the "heel" of the points against the high point of the cam in the dristributor...............then set the points gap to 15 thou.............with a feeler gauge.

I would use a home made light bulb .............with croc clips .......in order to find out exactly when the points started to open.

I would line up the timing marks on the engine first ....by hand ...........as I did not have use of a strobe light.

I can remember the actual setting of them, having a MkIII Cortina in the dim & distant past has engrained the method in my memory.

[Andy B]

Many coils require a ballast resistance in the LT feed to the coil. Although this is sometimes shorted during cranking to aid starting with low battery voltages, it is actually done to give a higher impedance feed to the coil which builds the charge in the coil faster, reducing the dwell time over a coil designed for 12 volts directly.

Anyway, such coils have a very low DC resistance so will flow much too much dwell current without a resistor in series. My guess is that this is your problem. Sounds like the wiring is fine.

Sometimes the ballast resistor was built into one of the LT leads meaning it could easily be discarded unwittingly.

Kevin

Thanks Kev, I'll see what other coils I have. We're talikng 60's technology here though .......      

[Kevin Wood]

Use a multimeter on ohms to check the resistance between the LT + and - terminals.

I'm guessing that a 12v coil will be around the 5 ohms area give or take a bit.

If it's below 2 ohms or so it needs a ballast resistor IMHO.

Large pinch of salt required as it's a while since I've played with anything that had points.

Kevin

[Andy B]

......
Large pinch of salt required as it's a while since I've played with anything that had points.

Kevin

You and me both.
I'm sure that some on this site weren't even around when I last set points    

[unlucky alf]

i thought is was a case of 12v on starting & 9v running, some systems had a ballast built into the harness & some had it mounted on the ign coil, bought a mk2 savage [3.1] years ago as the guy was melting points all the time so sold it cheap, a couple of quid later on a ballast resistor & it was fine god i miss that car

[Marks DTM Calib]

What engine.

You should also set them based on dwell and not gap as the breaker operating cam in the dizzy will be worn.

The resistor does not do anything at all in reality for dwell....in fact it will result in the dwell needing to be longer in order to get a fully magnetised coil as you will have lowered its Q.


What the resistor will do is offer some protection for the coil under engine non-start conditions, allow a little less iron to be used and reduce the interference. It shoudl also improve spark during cranking