Re: IML: 56 Ignition Problem

[randalpark@xxxxxxx]

Burned points can also result from touching the contact surfaces with 
your fingers. Any oil or lube from the rubbing block will also burn 
them prematurely. Clean the surfaces thoroughly if in doubt, especially 
if buying NOS parts from someplace. Who knows how many times they have 
been out of the box and handles by some lunck head before selling them 
to you.

They can LOOK pretty bad and still work. Could you poor performance be 
due to them being improperly gapped? The setting is .015 - .018 and 
they both need to be the same. That can be tricky on the dual point 
distributor. They have to be gapped separately and only when each set 
is fully planted on a ridge at the rubbing block.

Normal point life is about 15,000 miles. Once you have done it a few 
times it isn't too bad. On '55 and '56 it is easier to remove the 
distributor since you then have control over the position of the point 
sets in relation to the rubbing block. Accuracy is imperative. Also, 
with the distributor mounted on the back of the motor at 15 years old I 
had no trouble crawling around under there, but at 55, its not easy. 
Just mark everything so you know where it should be when your done, and 
crank the engine over in the meantime.

Paul W.

-----Original Message-----
From: a292@xxxxxxx
To: mailing-list@xxxxxxxxxxxxxxxx
Sent: Tue, 6 Feb 2007 4:52 PM
Subject: Re: IML: 56 Ignition Problem

The ballast resistor is there to limit current. The voltage drop is 
simply a side effect of the limited current that the ballast allows to 
pass through. It's the limited current that prolongs the life of the 
points.

Any resistor will show the same voltage on both sides until a load is 
applied. It's sort of like if you connect a garden hose with a spray 
nozzle on the end to a spigot. You can hold the spray nozzle open and 
turn the spigot on until there is just a trickle of water coming out of 
the nozzle. The pressure in the hose is very low. Now turn the spigot 
off and the pressure in the hose will build up until it matches the 
pressure in the pipe supplying the spigot. Turn the nozzle back on and 
the pressure in the hose rapidly drops again. A similar thing is 
happening with the voltage in your ignition system except that it 
happens almost instantaneously. A big difference in the ignition system 
is that unlike the garden hose which will briefly allow a large 
quantity of water through the nozzle, the ballast will not allow a 
large flow of current to pass through. I'm not very good at explaining 
it and that's not the greatest analogy but I hope it makes since.

In any case I would try a different condenser. I have had a bad 
condenser in the past and the engine would still run but not very well 
and it causes a LOT of excessive arcing across the points when they 
open which will fry them in short order. Also the output voltage of the 
coil will be very low which is why the engine will run so roughly. The 
job of the condenser is to allow the magnetic field in the coil to 
collapse in a controlled manner. It allows the voltage in the primary 
windings to rapidly but not instantaneously fall. It's this collapsing 
of the voltage and hence the magnetic field which produces the high 
voltage in the secondary windings to fire the plugs.

Have a good day
Brad

On Feb 6, 2007, at 5:17 PM, Jeff Cantor wrote:

> Brad,
>
> Thanks for the suggestion although it has me puzzled. I was under the 
> impression that when electrical systems went from 6V to 12V in the > 
mid-50s, the ignition systems were kept at around 6V to avoid having > 
to beef up the points. If there is still supposed to be 12V across > 
open points, then you're going to have much greater arching across > 
those points as they close hence the damage that I've observed. > 
Wouldn't 6V across those open points produce less arching and > 
therefore less damage?
> Jeff
> '56 Sedan
> Trenton, NJ


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