Fried points

[Jim L.]

Re: Fried points

From a static energy viewpoint, the energy the points dissipate is V**2/R. That equates to the voltage impressed across them (squared) divided by their intrinsic contact resistance.

From a kinetic energy viewpoint, the energy the points dissipate is I**2xR. That equates to the current flowing through them (squared) times their intrinsic contact resistance.

Both calculations that you suggest will yield the POWER dissipated at the Ohmic junction of the points and both numbers will have the same value. They are simply two different means by which one can arrive at the same answer.

Neither calculation will yield any measure of ENERGY since the points are incapable of energy storage.

From an electrical engineering point of view (I are one),.....

I are one also.

Jim

[John D.]

Re: Fried points

What would cause points to get fried after a very short time (minutes) ?What should be checked? This is a dual point in a fuelie if that matters. Mike

Michael, I read all the posts below even though the equations were beyond my feeble mind. You didn't say anything about the components you are using in your car. All I know is that you have a 58-60 FI. Since an original 107 coil is extremely rare I might then assume you are running a repro 107.? What ballast resistor are you using? Do you know the specs on it? Whose points are you using. Are they NOS, Delco made in Mexico, NAPA, Standard, (same as NAPA)
What about the condenser. A few years ago we tested 50 NOS condensers. Only 14 were good and some of those were border line.
Has your distributor been run on a good Sun or Allen, etc distributor machine? Has your coil been tested?
Do you have the coil wires on correctly?. Ballast resistor wired correctly?
Is it a repro ballast resistor? What number is the part. D1110 or D1111 or ??? An 091 and an 107 are both really hot coils. Don't know if it's the voltage or the amps or whatever. But they really throw out a lot of juice.
The 107 originated in the old days in heavy equipement. Off road equipment. Bulldosers, school buses, old trucks. Dale Pearman taught me that 30 years ago. Course I never found an old poc equipment to steal one from.
Start anew if you have to. Go to NAPA and ask for CS 786 or CS 786P points. Get the matching condenser. If you need the number holler as it's in my shop. Check the ground wire on your distributor. Make sure it's not shorting out. Put on a known good original Delco coil. Or buy a good one from NAPA. Check the ohms resistance on the ballast resistor like Duke, etal said. Check the wiring. Good luck. Let us know what solved this issue.

Be careful. A buddy of mine had to do his 57 FI engine compartment over after the coil blew up. Luckily he didn't get hurt except for his wallet. John

[Duke W.]

Re: Fried points

That's not the correct point number for dual point distributors, except for the '62 dual window type that used the same point set as single point distributors.

I don't know the number off hand for the point set used in earlier dual point distributors, but I believe it was the same set as used in the contemporaneous inline six.

Duke

[Bill C.]

Re: Fried points

Thanks for all the clarifications guys, I now have a headache and remember why I quit electronics school, it to, gave me headaches!

[Michael K.]

Re: Fried points

Wow! Thats a lot of info to digest. Thanks to all of you for the advise posted. I will re-read it all a few times and then get busy checking it all out making sure I am using compatable parts. I will try and post the results when found. John, I will let you know if I need that # from you.
Thanks again.
Mike

[Jim L.]

Re: Fried points

That's not the correct point number for dual point distributors, except for the '62 dual window type that used the same point set as single point distributors.

If Michael's car is a '58-'60 fuelie, the CS786 is the correct point set for his application . CS786 is also correct for the '62 dual point distributors and most other Chebby applications between '57 and '74, except those using the 891 distributor and '57 fuelies.
Jim

[Timothy B.]

Re: Fried points

Another argument for the breakerless ignition.. I too have points but it seems like alot to go through when new technology works better and so easy to install and change back..

[Duke W.]

Re: Fried points

Redesigning the system is not the proper way to correct a problem, but all too often this approach is used.

Duke

[Richard T.]

Re: Fried points

Gee I remember when I bought a set of points at my local auto parts store, the point set came with a new rotor and a resister. Problem solved? However that was when the parts were made in the U.S.A.

[David D.]

Re: Fried points

Wow, double E squared power! This group is indeed powerful. Great reading. I'm afraid to look at what's on my 60.

[Stewart A.]

Re: Fried points

I might go get another tinny my head is hurting after that.
And I'm not going to re read it I'll end up with a migraine.