Today , I took Kristen out for a drive in Boris now he is registerd and all was fine until we were stopped on the side of the road and he decided to stop. Checked out and no spark. Checked voltage to coil and voltage present but still no spark.Removed high tension lead from top of dizzy and earthed when Kristen cranked him over a few times and then all of a sudden I got spark??. Put back together and OK. My question, is the ignition coil on the way out or is most likely the points?. Checked over wiring and found nothing loose etc. Next question. I had a look for a coil around and most say they need a "ballast resistor" which I am sure my 72 super dosn't have.Can I still use these types or do I need one with an internal resistor.
Thanks in advance for any advice. Al

[ Edited on 6-11-2006 by CHADMYSTER ]

I would be looking at points.

Points is a variable thing. they can close up or get crap in them

Make sure they are fine first - then move to other things

Check also that the connector between points and the condensor isn't earthing on the dissy body... it should have a plastic thingy that is screwed to the dissy side to insulate it/ keep it from floating around.

:thumb

thanks

any clues regarding the ballast resistor??

The ballast resistor is used on early Fords etc...
the coil gets all the 12 volts when the starter motor is turning over, so the engine will start with full spark, but when the key is released, back to ignition on , the power then goes thru the ballast resistor to the coil, so the coil won't overheat and burn out...

so the coil gets around 10 volts or less while the starter motor is turning over...
and then gets approx 8 volts thru the ballast resistor , so if the Coil was connected all the time it would get up to >15 Volts from an alternator or Generator...
so the Coil would be really putting out some spark...
until it died....

All the VW shops sell 12 volt non resisitor Coils....

Get some spares at the next swap meet....
Coils go cheap...

Your problem could be simple like a loose condensor...
or the condensor now has a fault...
these can be intermittant...
also check the rotor button in the distributor...
these have a resistor built into the top of them, and they can burn out... also intermittantly...
or the coil...

Best of Luck

Lee Noonan - 68AutoBug --

http://community.webshots.com/user/vw68autobug 

Chadmyster,
This puzzled me a bit as well. Seems if you get a Bosch "Blue" coil (and there are 3 different types!) one of them needs a ballast resistor. I just went to a car shop and looked up the Bosch coil for a '72 volkswagen and it said "SU12" or some such. Whacked it on, no ballast resistor. BTW a ballast resistor is used to lower the input voltage into your coil. Some have an in-built resitance anyway and some specifically must be used with a ballast resistor of x.xx ohms and that's what you look for in the ballast resistor. Elsewhere people have said you can run a GT-40 bosch coil (not a GT-40R!).

Ctefeh

[ Edited on 5/11/2006 by ctefeh ]

Hi Sean,

yes, I've been running GT40 coils in air cooled VWs since the 70s...
I actually changed My GT40 for a standard coil as I intend to add an electronic ignition which still uses a coil, but the GT40s put out too much spark and also overheat...
because of the high voltages used... in the electronic ignition kit... so GT40 coils must actually induce more spark than a normal coil....
Some of the locals use the exposed type coils...
ie.. not oil filled...

cheers

Lee

so if I get bosch GT40 I should be sweet?

Chadmyster,
The GT-40 will do the job no worries, the "SU12" direct replacement was $12 cheaper from memory and plain black.
But as Lee has mentioned, don't overlook that condenser or getting the correct rotor for your distributor!

Regards
Ctefeh

thanks all

well just got home and checked points and condensor and all Ok. Looked inside distributer cap and found sprung loaded centre contact burnt off??. Does anyone know what might cause this symptom?.
Thanks AL

I don't really know what causes that Allan...
I always thought that people had taken the cap off and somehow knocked the carbon button off...

Never really heard of one actually burning off...

Is the Coil OK then??
It may have shorted out internally??
The rotor button hasn't caused it??

Lots of Questions.....:P:P:P

Lee

Al - once i had a run of that.

Tore the carbon brush clean out 3 times. New cap each time.
Finally shoved a different dizzy in there.
Whether it was the rotor had a bur on it pulling the brush out or whether it was a run of bad caps i dont know.
By the end i was putting new / old / stolen bits in to sort it.

I have ordered a coil from Mick Motors as I was after a few other bits. Will chase up a new distributer cap and rotor and see how I go. Seems funny how it all happened at once. This is longest drive it has been on since I bought it. Only 1hr or so . I thought it might have been heat related ?.

its funny We drive our cars not thinking that it all depends on that 10c piece of carbon and a tiny spring keep up on the road....

I think We all have those thoughts about the Heat Allan..

thats why i couldn't drive Mine without the engine lid open at the top... too paranoid about heat...

I hope your luck changes...

Lee