Condenser question

[grandpa Love]

We bought out an estate,old fella had worked on cubs,A, super A ,C Farmalls and N series, hundred series Fords. We now own a couple dozen condensers. ( And points) Question about condensers, some are IH , some are Ford. What is the difference? Other than slight size? Will the ford work in an IH distributor? If they fit. Why or why not?

 

[Janicholson]

We bought out an estate,old fella had worked on cubs,A, super A ,C Farmalls and N series, hundred series Fords. We now own a couple dozen condensers. ( And points) Question about condensers, some are IH , some are Ford. What is the difference? Other than slight size? Will the ford work in an IH distributor? If they fit. Why or why not?

The condenser is designed/engineered to dampen the spark across the points when they open. This limits point contact erosion/pitting. The condenser also allows the magnetic collapse of the coil, on discharge into the plugs, to pulse back and forth (ring) Study Kettering ignition. The actual Microfarad rating, and peak voltage the dielectric is capable of are similar across most common applications. A very wrong condenser will run poorly or cause points to have pits on one side and peaks on the other as they wear. Using them is just fine. If abnormal point wear is noted, stop. (reading up on the physics of capacitors is appropriate (modern name for condensers) Jim

 

[oldproudvet]

We bought out an estate,old fella had worked on cubs,A, super A ,C Farmalls and N series, hundred series Fords. We now own a couple dozen condensers. ( And points) Question about condensers, some are IH , some are Ford. What is the difference? Other than slight size? Will the ford work in an IH distributor? If they fit. Why or why not?

Keep the old condensers, as stated they will work unless they're way out of range. Much higher quality then you can buy today. Anything new is a fit-all Chinese piece of crap........... Larry

 

[Russ from MN]

I was told once long ago never to change a condenser as long as it's working, the impedance of the condenser needs to match the coil, and if you buy a new one you really don't know, unless you have an accurate way to test them. There isn't anything to wear out, but the heat might break them down eventually. Good to have spares though, for troubleshooting, I read that the new ones aren't very good!

 

[grandpa Love]

Keep the old condensers, as stated they will work unless they're way out of range. Much higher quality then you can buy today. Anything new is a fit-all Chinese piece of crap........... Larry

Thoroughly disagree....not all "Chinese crap". Brand new points from Napa have been fine. They are made in Mexico. But tractor supply condensers have been fine ,too ..who knows where they come from. In today's global economy,I find a positive attitude helps. Maybe you just wish them to be bad and so they are!. I hope they are good and therefore they are.. my Chinese phone, computer,and a million other products are good

 

[Janicholson]

The condenser is designed/engineered to dampen the spark across the points when they open. This limits point contact erosion/pitting. The condenser also allows the magnetic collapse of the coil, on discharge into the plugs, to pulse back and forth (ring) Study Kettering ignition. The actual Microfarad rating, and peak voltage the dielectric is capable of are similar across most common applications. A very wrong condenser will run poorly or cause points to have pits on one side and peaks on the other as they wear. Using them is just fine. If abnormal point wear is noted, stop. (reading up on the physics of capacitors is appropriate (modern name for condensers) Jim

Quality can still be found, but one pays correctly for it. The capacitor that has poor dielectric material, and bad environmental seals will fail quickly or not work from the beginning. Jim

 

[grandpa Love]

I was told once long ago never to change a condenser as long as it's working, the impedance of the condenser needs to match the coil, and if you buy a new one you really don't know, unless you have an accurate way to test them. There isn't anything to wear out, but the heat might break them down eventually. Good to have spares though, for troubleshooting, I read that the new ones aren't very good!

Urban legend....new one are good 99.99% of the time

 

[Janicholson]

Urban legend....new one are good 99.99% of the time

I believe the assessment of the point gap and running of the engine should be used as a judge of whether to replace or keep a condenser. I rarely change them. Jim

 

[timcasbolt]

The problem with condensers (other than not having a way to check them) is that if it's no good it will ruin an expensive set of points.

 

[JMOR]

The problem with condensers (other than not having a way to check them) is that if it's no good it will ruin an expensive set of points.

Depends on how the condenser is bad......if open, not likely to damage points, as most engines will not run without or with an open condenser.

 

[wore out]

We bought out an estate,old fella had worked on cubs,A, super A ,C Farmalls and N series, hundred series Fords. We now own a couple dozen condensers. ( And points) Question about condensers, some are IH , some are Ford. What is the difference? Other than slight size? Will the ford work in an IH distributor? If they fit. Why or why not?

Capacitor testers that will thoroughly evaluate a capacitor are EXPENSIVE, but many reasonable priced DMM's have a capacitor test function that will display the microfarad capacity value of your new condensers.

You could check them out and mark the results on the boxes and see just how much the capacity varies over your "stash".

IIRC, some of the IH Blue Ribbon repair manuals give the capacitance value for a given application, and old paper "hard copy" parts reference manuals for brands such as Standard Ignition, NAPA, etc. have some required mfd. values listed for at least some of their applications, they can sometimes be found reasonably on ebay,

By matching what you have to what is required for a given application you would know which ones you could "sub" without issues.

The above info is for a (+) ground systems, reverse the (+) and (-) signs if evaluating the points in a (-) ground system.

Source: John Deere "FOS-20" Chapter 6-Ignition Circuits. (FOS = Fundamentals of Service, a series of John Deere training manuals.)

 

[Russ from MN]

Urban legend....new one are good 99.99% of the time

Your probably right, you work with them quite often. I think the last set of points I worked on was probably 30 years ago, when I tuned up our IH 340 utility. The only thing we have now with points is a 48 Farmall C, and it runs fine. The old saying, if it isn't broke, don't fix it!

 

[old]

Urban legend....new one are good 99.99% of the time

You may have good luck with new ones but in the past 10 years the few I have tried to replace with new ones where bad right out of the box so I have not replaced a condenser in over 10 years due to so many being bad

 

[Texasmark]

The points close to allow the coil to fill with energy. For any given system that's called the "dwell" and can be measured with a dwell meter. When the rotating distributor shaft has come to the proper position, the cam on the shaft opens the points.

Coils are inductive devices and they don't immediately stop current flow. By the design physics, the opening of the points attempts to stop the charging current from flowing. V across the inductor = L (inductance of the coil) x di/dt. If dt goes to 0, with points opening, V across the coil tries to go to infinity. The rate of rise and value of that voltage spike depends on the coil design. At some point the voltage across the points is of sufficient magnitude to arc over. This arc over is what moves material from one contact to the other in the points circuit.

Putting a capacitor of the proper value across the points resonates with the coil and allows a path for the coil current to continue to flow as it charges the capacitor and they resonate until all the energy stored in the coil is dissipated in circuit resistance or in the spark plug gap This limits the magnitude of the voltage across the coil as it discharges, with the secondary firing the plugs. The capacitor microfarad value is selected to slow the "rate of rise" of voltage and resultant maximum value across the points to something below the arcing rate/value as the coil stored energy decays dumping its charge into the spark gap.

Therefore, your optimum value depends upon the inductance value of the coil and the width of the point gap. With a handful of suspect capacitors, its a crap shoot as to how far you can miss the optimum value and not have your points weld.......moving material from one side to the other as "wore out"'s illustration indicated.
That's the way I see it.

 

[Geo-TH,In]

We bought out an estate,old fella had worked on cubs,A, super A ,C Farmalls and N series, hundred series Fords. We now own a couple dozen condensers. ( And points) Question about condensers, some are IH , some are Ford. What is the difference? Other than slight size? Will the ford work in an IH distributor? If they fit. Why or why not?

GP
You need a meter that can measure capacitance, microfarads, MFDs
The red meter on the left will do the trick. I'm guessing most ignition capacitors are close to the same value.

 

[Texasmark]

GP
You need a meter that can measure capacitance, microfarads, MFDs
The red meter on the left will do the trick. I'm guessing most ignition capacitors are close to the same value. View attachment 67817

I would say it depends on the selected spark plug. What Joule value stored in the coil (1/2 L x I exp.2) is required to be consumed to light off a combustion chamber on different machines with different specs and resultant different plugs especially when you compare the huge plugs of yesteryear vs current production with half or less the mass, to ignite, and combustion pressures from yesteryear, over the years, and today's clean air environment. If all the same, with the battery voltage the same, which is hasn't been, then the Joules stored in the coil resonating with the same capacitor would satisfy the point protection process.....but going to betcha that's not the case.

 

[grandpa Love]

We bought out an estate,old fella had worked on cubs,A, super A ,C Farmalls and N series, hundred series Fords. We now own a couple dozen condensers. ( And points) Question about condensers, some are IH , some are Ford. What is the difference? Other than slight size? Will the ford work in an IH distributor? If they fit. Why or why not?

SO.....will the Ford work in the IH???

 

[JMOR]

Examples:
Ford 8N =0.29 to 0.32 microFarads
Ford NAA =0.21 to 0.25 microFarads

The radio noise suppression caps look just like the points caps, but one that I measured was 55.0 microFarads. Just for fun and education, the tractor ran with this large cap across the points!

 

[old]

SO.....will the Ford work in the IH???

Maybe maybe not due to the fact consenders are not rated like the Capacitors are hard to say since you don't know the MDF rating

 

[JMOR]

SO.....will the Ford work in the IH???

My experiment posted about 20 minutes ago, says it will almost certainly run. Will it be exactly right for best point life, I don't know.