Dizzy melt down & no spark .

[Richiee722]

hi guys
I originally posted in the mech section but I started with a different problem but it's now more electrical .
I've got a 1981 westy with the 2.0 cu engine and had problems with the dizzy so after some research, decided to get rid of the hall sender setup and fit an 034 power spark svda unit.
It all went well for about 5 mins but the rotar arm melted and inside the cap looked like a candy floss machine.
I put this down to me being thick cos I had left some of the old wiring connected , doh !
With it all removed and cleaned up, all was well again for 5 mins but has now packed up again.
I've changed the coil ( correct for the dizzy ), new leads, plugs etc
The wiring is a bit butchered , but i have a ignition live at the coil but no spark ?

[itchyfeet]

a quick google states the 034 power spark svda unit connects direct to coil so the original ignition amplifier and any other original connection to the negative of the coil should have been removed.
The coil will need a ignition 12V also to the positive side but nothing other than the 034 power spark svda unit connected to the negative side of coil

What exactly did you leave in place from the old wiring? Sounds odd to me that original ignition module could cause the rotor arm to melt if left connected.

The 034 power spark svda unit must need a ground connection to body but I assume it gets that through the engine so make sure you have an earth connection to the engine by the dizzy or better still direct from dizzy body to vehicle body.

Pictures may help of wiring and dizzy area

also check the new coil is the right primary resistance specified ( 1.5 ohms or higher as I read it) most likely the problem IMO

http://www.simonbbc.com/distributors/4c ... a-bosch-vw" onclick="window.open(this.href);return false;

[Richiee722]

Hi itchy feet
Thanks for the reply
When I fitted the new dizzy I just pulled the plug out of the old one and terminated it properly.
But I left that module thing plugged in ( that wide plug thing in the corner whatever it is lol ).
And wired the dizzy red to the coil positive and black to the negative .
It ran for 5 minutes but when I turned it off it wouldn't restart . Investigation showed the black bit in the middle of the rotar arm that came with the new dizzy had melted and was all around the cap.
I talked to Simon ( I think it's brickwerks sister company ) who said I should remove that wide plug as it's connected to the coil etc. I had a new transistor Bosch coil which I checked with resistance with the multi meter and simon said it should be fine.
Started ok so thought I had cracked it.
Did about 15?miles and happened again but now couldn't get a spark any more, so emailed company to see what coil they recommended in case my Bosch coil was fried.
They recommended a Lucas low resistance coil so ordered one, fitted it yesterday but still no spark.
I don't have a separate earth from the dizzy body to the engine ?? ( neither did original dizzy I took off ).
All I have on the coil now is a black wire come from that black box next to it ( which is an ignition live ) and the 2 wires going to the dizzy .
I'll put some photos up in a bit if they will help.
If I grounded the lead from the coil to the dizzy and turned it over I was expecting big sparkie things but I just get a 1 little yellow spark when I turn the ignition on and another when I turn it off, is that correct ?

[Richiee722]

Hi itchy feet
Thanks for the reply
When I fitted the new dizzy I just pulled the plug out of the old one and terminated it properly.
But I left that module thing plugged in ( that wide plug thing in the corner whatever it is lol ).
And wired the dizzy red to the coil positive and black to the negative .
It ran for 5 minutes but when I turned it off it wouldn't restart . Investigation showed the black bit in the middle of the rotar arm that came with the new dizzy had melted and was all around the cap.
I talked to Simon ( I think it's brickwerks sister company ) who said I should remove that wide plug as it's connected to the coil etc. I had a new transistor Bosch coil which I checked with resistance with the multi meter and simon said it should be fine.
Started ok so thought I had cracked it.
Did about 15?miles and happened again but now couldn't get a spark any more, so emailed company to see what coil they recommended in case my Bosch coil was fried.
They recommended a Lucas low resistance coil so ordered one, fitted it yesterday but still no spark.
I don't have a separate earth from the dizzy body to the engine ?? ( neither did original dizzy I took off ).
All I have on the coil now is a black wire come from that black box next to it ( which is an ignition live ) and the 2 wires going to the dizzy .
I'll put some photos up in a bit if they will help.
If I grounded the lead from the coil to the dizzy and turned it over I was expecting big sparkie things but I just get a 1 little yellow spark when I turn the ignition on and another when I turn it off, is that correct ?

[itchyfeet]

check your coil again both primary and secondary resistances

your engine should have an earth, not familiar with Aircooled but this dizzy will need to earth a much larger current via the dizzy than the old one because the main coil current would have been via the seperate ignition module,
well worth adding an earth from vehicle body to dizzy body.

I woupd not ground the new dizzy negative because you don't know what harm it could do.

you may have to consider the new dizzy is knackered.

worth the pics imo, sometimes they show something that can never be seen with words

[Richiee722]

This is the rotar arm that melted .
This is the Bosch coil ( the negative form the dizzy is off in the picture).
There was also a tacho wire not shown but worked fine and a hella tachometric relay connected ( been on there a while and also works fine).
This coil was on a few months old and should of been ok with my new dizzy.
I replaced it for another new one yesterday that the company recommends to go with there power spark dizzy.
It didn't make a difference so I doubt there is anything wrong with my old coil !
So if I put the ht lead from the coil to the body work , should it spark ?
Or is that a No no ?
I will Earth the dizzy tomorrow.
But I think you're right, could be a fried dizzy

[Richiee722]

[itchyfeet]

So if I put the ht lead from the coil to the body work , should it spark ?

yes but it must be held away from the body about 1mm better to use a spark plug connected and sit the plug on earthed metal so you don't have to touch it
Also engine needs to be cranking to see a spark, it only sparks when the dizzy is turning.
be careful it does not spark to you, it will hurt alot

[Richiee722]

[Richiee722]

That's what I was doing but it doesn't spark.
It does 1 weak spark when you start cranking it over then nothing.
And when u stop cranking , it does another weak spark ?

[Richiee722]

This is the new dizzy

[itchyfeet]

check your battery voltage when cranking ( or better still charge the battery overnight anyway) if it's not been run could be very low, couple that with bad earths weak spark

one other thing to try (bearing in mind you had probs before) is to run a fresh fused 10A 12v from batt to coil as a temporary connection to rule out poor ignition wiring

[Richiee722]

Hi again
Good thinking.
I'll try running another wire tomorrow and putting an Earth on the dizzy and also charge the battery .
I'll post an update tomorrow
Thanks

[Richiee722]

Hi again
Battery charged , Earth wire added.
This might sound a bit thick lol
With regards to running a wire from the battery, do u mean to just touch iron the coil ( and see if I gets spark from the king lead ) or should I wire it to the battery and turn it over and see if there's a spark.
Probably basics I know , but I'm learning

[itchyfeet]

I mean remove the black 12V ignition positive from coil and connect a fresh fused 12V wire from the battery direcr to the positive of the coil.
this should only be done temporarily then jump in and crank
once finished the test disconnect it (as you would normally do when you take the ignition key out)

This bypasses the ignition wiring in case there is problem with it

Fault finding is all about ruling things out of the equation

You will never get a spark without turning the engine over as said before
you need a good 12V supply to coil, good earth to dizzy or engine


You can see the spark at the king lead if the lead is good
or at the spark plug leads if the cap and rotor arm are good and spark plug leads are good