Condensor stuff-discussion .......

[BUBBAS IGNITION]

Tons of condensor questions etc . I recieved a fellow "barners" condensors in the mail to test on my distributor condensor tester and thought it would make a good discussion. The condensors were NOS from years ago ( can be a problem).
Typical condensor testing consists of calibrating the tester meter and hooking up to the condensor body and output lead.
Some interesting results.

Thre test positions.

1=Leakage: Leakage will show if the condensor has a problem holding a charge, in my world the slightest amount of leakage makes the condensor defective. Should not leak any energy at all !
2= Series resistance : The condensor should show some series resistance to flow , it isnt a direct ground but for electron movement it appears to be a direct circuit. Must have resistance.
3= Capacity: Each condensor has a very specific storage capacity ( measured in micro farads or mfds) Too high and the contacts will arc , too low and the contacts will arc and engine may or may not even run.

The bubbas explanation of condensor function.

The contact points open and close allowing the magnetic field to build up and collapse creating a secondary spark to the plugs.
The electrons are considered to be little stick men called Es' Just consider the little men to be wearing a E t shirt!!!
When the contacts are closed the Es flow thru the circuit and build a magnetic field in the coil.
When the contacts began to open ( lets say .001) the Es being lazy dont want to jump the gap and take the path of least ressitance which appears to be the condensor ( series resistance) this proves to be a good move UNTIL the condensor fills with the lazy Es! ( capacity) If the capacity was like the helment flathead ford of (.48 mfds) the condensor would allow 48 Es to enter the condensor. The 49th one just couldnt get in and the 48 cant get out ( leakage). As more Es gang up in the circuit they finally decide that they have enough numbers to go back to the contacts and jump the gap.
Two issues confront them now , one the gap is no longer .001 and is wide open at .015 so its going to take many more Es to make the jump! Two just about when enough Es gather to make the jump, the contacts close allowing them all ( including the 48 in the condensor) to flow to ground! Then it starts all over again !!!!

A Note ??

Condensor are sealed at the factory in a vacuum. They MUST remain dry inside . Checking a drawer like this one has shown that only about half of these test good. They havent maintained that vacuum for year after year.
Problem two is that most new ones are the incorrect capicity for the vehicle and ignition coil being used....

 

[CP]

E-man, that is very well put. Being someone that does not understand current, the e guys makes much sense. So now im wondering.....I found an old condenser and put it on and it made the engine run great. How do i know what the capacity is? or am i safe since its working.....I get the feeling i could be only safe temporarily ? How many e-men jumping are too many? If not enough e men, i assume no strong spark at all.

 

[TerryOH]

another consideration should be heat. In service the condenser is exposed to a large temperature change. I suggest you retest the good condensers for leakage and value after you have warmed them up to about 200 degrees if the test results stay the same as ambient, the condenser is probbly good. Do you know the voltage your sun condenser is testing at, or is it variable? When the coils are rebuilt one of the rebuilders replaces the internals. I am wondering if the same value of condenser as the original is correct for a rebuilt coil??? Maybe GM could answer this question.

 

[Henry/Kokomo]

Great discussion / explanation. Thanks for posting.
Henry

 

[hotrodjeep]

Is this what I missed at the Bubba's Ignition class????
Damn, I should've gone I'd have learned alot. Maybe next time.

Jeff

 

[BUBBAS IGNITION]

another consideration should be heat. In service the condenser is exposed to a large temperature change. I suggest you retest the good condensers for leakage and value after you have warmed them up to about 200 degrees if the test results stay the same as ambient, the condenser is probbly good. Do you know the voltage your sun condenser is testing at, or is it variable? When the coils are rebuilt one of the rebuilders replaces the internals. I am wondering if the same value of condenser as the original is correct for a rebuilt coil??? Maybe GM could answer this question.

Good point on the heat issue. When a walk in customer brings in a distributor and the complaint is runs good cold and breaks up warm, i just put it in the distrubutor machine and start applying heat with a large heat gun.
Pretty common failure with some of the aftermarket rebuilds , they use the cheapest parts miney can buy......

Rebuilt coils??? Another good point !!! The stock Ford nos condensors are pretty high in the mfd rating ( .48 mfds) and the replacements are often lower (.28 mfds). You can hear these arcing on the tester and we install a .40 vertex mag condensor to fix the problem.