The Stovebolt Site Forums The Shop Area Engine Shop Myth Busters

I am dying to try this experiment, but my old 4400 truck is scattered all over creation. Could
someone with a 216/235 or whatever pull the
condenser wire off the points, start it and see
what happens. I believe it will run fine, but the points will fail prematurely. I think the only way the poor old condenser can take the rap
for all the starting and running problems is if
it shorts to the case internally. This would be
the same as shorting the points to ground. I am a "show me" kind of guy. What thinks Ye!

Stuart.

With out the condenser the motor should not run at all the condenser helps the coil biuld up voltage to fire the plugs, with out it not enought voltage to fir the plugs.

super250six

super250six,
Are you sure! If you have some spare time, why don't you try it...let me know what happens! I will even buy you a brand new set of points and condenser just for the effort! What say ye!!


Stuart.

If you ever had a shot condenser, you know that one of the smallest, cheapest parts at the whole car can leave you in the middle of nowhere.

It will not run with a shot/without condenser, bin there done that.

Even with my electronoc ignition, that uses the points only as a trgigger and uses verrrrrry low current on the points I need a condenser.

Frank

I've had a condenser fail, both in my tractor and in a 1966 Chev bellaire. Trust me, you're lucky to get a few random pops out the exhaust.

fredstev,
I wonder if a FAILED condenser would exhibit the same problems as NO condenser? What would happen if my brand new good condenser broke the wire going to the points, and the wire just dangled without touching anything.


Stuart.

I just tried this on the bench. NO condenser results in a very weak spark.

reo_guy,
Very interesting. Was the weak spark at
the POINTS or did you have a coil/plug setup
so you could watch the plug intensity. What does it do WITH the condenser hooked up on the same system? Can you see a noticable difference?


Stuart.

I had a complete setup: distributor, coil, and one spark plulg gapped at ~0.045". Without a condensor, the spark at the plug was very weak. With the condensor, the spark was fine. The amount of arcing at the points wasn't noticeably different with or without the condensor.

It will not run!!!! At least mine will not. Test proceedure
1.Started the truck with condensor hooked up. Runs
2.Disconnected condensor wire. Wouldn't even fire.
3. Connected condensor wire. Fired right up.
So myth stands. No condensor no Run.

reo + Oehm,

Thank you very much. So I guess it isn't a myth. This was my thinking on the experiment: The condenser is actually a capacitor, which "stores" an electrical charge. As the coil saturates, the points open, the electrical field in the coil collapses across the secondary winding producing the high voltage to fire across the gap of the plug. The points are just a switch in the primary circuit and as they open , because the system is DC, a large arc will develope between them. This uncontrolled arc is what BURNS the points. The condenser (capacitor) grabs this spike of voltage, stores it and bleeds it off to ground...thus saving the
points.

This is how I figured the system worked..so if the condenser is removed, why doesn't it still work? It seems like it should, just with more arcing & sparking in the points area.

I wonder what part of the equation I don't understand...so as they say on TV, the myth stands.

Thanks again to reo and Oehm for taking the time to try this...do I owe you a set of points?

Stuart.

Reducing back EMF by the use of a cap on the primary gives more energy to the secondary.

Baldy,
In simple terms, does this mean the
condenser slows bleed off to ground of the primary which strenghens the secondary voltage?


Stuart.

It gives a path to ground when the points first open which reduces point arcing and causes the field to collapse sooner.

It gives a path to ground when the points first open which reduces point arcing and causes the field to collapse sooner.

The condenser diverts current to ground when the points first open which reduces arcing and causes the field to collapse more quickly.