repeated condenser failure

[MarshallGTi]

ok, i'm on my 4th or 5th condenser in 2 months, what could be the problem? is there something else i need to check thats maybe feeding too much voltage to the condenser? could it be the weird looking resistor thing by the coil? i set my timing statically, will getting it done properly sort it out? i really wanna take it to KKK but not if i'm gonna be swapping condensers on the side of the road...

[IMPI]

my 74 Passat same problem
I replaced the coil and no more problem i laso deleted the resistor thingy and used the wire going into the resistor as the positive on the coil
Armand

[MarshallGTi]

its eaten condensers regardless of coil (2 different coils, each destroyed 2 condensers)

is that resistor not important? or should i maybe try a Citi coil that has the resistor built in?

[vader]

If its still blowing condensers then chainging coils in my opinion would not solve the problem.
Have you measured the voltage to the condenser.
Have you checked all the earth points?
Have you tried swopping the dizzy with another one? Your problem might lie here.
Try by passing the "resistor thing". Post a pic of it and we can see if we can identify it.

[IMPI]

Resistor coils work in the following manner. The 12v feed from the ignition is fed through a resistor to what is in effect a 7volt or thereabouts coil. the other wire to the coil is fed from the same lead as the one energising the solenoid on the starter. so that when the starter is operating there is 12 v at the coil thus giving a fat temporary spark during start up if this lead is made permanent the coil overheats and fails. since the one lead only gives temporary power it can be disconnected and if the resistor is by passed there should be 12v at the coil when the ignition is switched on. Lots of so called cheap coils are actually resistor coils and it is very difficult to find any good quality ignition parts. I would go for the whole lot at once Bosch or Huco coil, bosh points and condensor (the ones in the red and blue boxes are also ok) and a set of new leads include a rotor and cap if your budget allows and I am sure the problem will dissapear
Armand

[MarshallGTi]

the resistor thing i'm refering to is the white rectangular bit next to the coil.
earth strap was next on my list to check.
dont have a spare dizzy and a new one was put in the car when i bought it.

if i understand right, voltage at the coil should be say 7 to 9 volts with just ignition, and only up to 12v when cranking? IIRC i measured around 11v with just ignition, could be mistaken tho.

[retrovan]

Dump the resistor, that is the resistor that sum guys use when changing the car from 6volt to 12 volt, and not having to change the coil.
If you have a 12 volt coil, get ride of the resistor, the voltage after the resistor is to low for the coil, and putting a big load on the condenser, that is why the condenser keeps going, could coincidentally also be that you have a box of condensers, BUT the resistor is not helping the issue much.

If you need to change the coil, go to Diesel Electric, get a Bosch coil, not cheap, but you only have to buy once.

Herman

[Tony Z]

Dump the resistor, that is the resistor that sum guys use when changing the car from 6volt to 12 volt, and not having to change the coil.
If you have a 12 volt coil, get ride of the resistor, the voltage after the resistor is to low for the coil, and putting a big load on the condenser, that is why the condenser keeps going, could coincidentally also be that you have a box of condensers, BUT the resistor is not helping the issue much.

If you need to change the coil, go to Diesel Electric, get a Bosch coil, not cheap, but you only have to buy once.

Herman

Not entirely accurate there squire.
Some coils need the resistor, as Empi said, the resistor is bypassed during startup and during normal operation it uses approx 9V.
Mostly however, points type coils have the resistor built in and thus the external resistor isnt needed. Maybe you could double check that you dont have an external resistor on a coil that already has the build in resistor? As Herman points out, too low a voltage (double resistors) will burn out the condenser.
BTW, condenser is short for condensator which is the German word for Capacitor... so if you thought it is something fancy, think again. But the size is important, too big and it wont charge properly, too small and it wont store enough charge....

Putting a non-resistor type coil or a coil with too little resistance will burn out things quickly, especially the points as too much current will now travel thru them.

[MarshallGTi]

so how do i find out if my coils have the internal resistor or not?

and if i take the resistor out, i would connect the 2 wires together hey? what then of the 3rd wire? it sits between the + side of the resistor and a solenoid looking thing on the carb...

[Tony Z]

from http://www.wikihow.com/Check-an-Ignitio ... gen-Beetle


Use an Ohmmeter to test the coil

Remove all the wires taken off the terminals of the coil attach the positive and negative, red and black, wires of the meter to first the terminal 15 (positive) and 1 (negative) that are stamped on the coil.
A reading of at least 3 - 4.5 ohms, indicates a good coil.
A bad coil will show a higher reading then 3 - 4.5 ohms.
Place the red or black lead from the meter to the center of the coil (secondary post), and to either one of the terminals, 1 or 15 on the coil.
A reading of 9,500 - 10,000 Ohms, sometimes less, indicates a good coil.
A reading of 11,000 Ohms or more, or a reading of zero indicates a bad coil.

[MarshallGTi]

but how would those readings show me if the coil has an internal resistor (so i can remove the external) or if it has no resistor (meaning i need to leave mine in place)?

on all 3 coils i have, the readings are there or thereabout...

[Tony Z]

if you have the internal resister you should read about 4 ohms across the primary windings
if you have no internal resistor, you will read 2 ohms or lower

[MarshallGTi]

excellent... guess i'm getting rid of the resistor this weekend then...

[Ron&Gill]

A condenser is indeed only a capacitor. However, low voltage to a capacitor does not equal high amps, and therefore low voltage is no danger to it. It just doesn't do what it is supposed to, but it doesn't die.

[retrovan]

Why does a Capacitor /Condenser die.

It is made from two thin strips of metallic sheeting, normally aluminium.
These are sandwiched between layers of insulation, normally wax paper.
At the canter the leads are connected, normally mechanical, with spot welding.
These sheets are then rolled up from one side, so that the leads come off in the centre, top.
The connection is not a massive thing, and is normally kept as thin as possible to not make bumps in the rolled up sheets.
So as you have DC going through, you have a high resistance in the joint, and if the voltage is low, you can have the joint going open circuit.
That is why you get a cap, that is near top of the voltage scale rather then the bottom of its voltage scale.
That is why the cap will always give on low voltage, and /or when you start the car. It will not start with the starter, but will take strait away when pushed.
To fix it when broken, you dent the outer can, this puts pressure on the rolled up sheets inside, and this applies mechanical pressure on the connection joint.
Now the cap works again.
And normally keep on working, as this pressure stays there, and will not brake down.\
So the morel of the story, if you have a dented beat-up cap, keep it, it will most probably out last the car.

OMO
Herman