087 Coil with .3 Ballast resistor

[Kent S.]

I've read several posts on the subject of coil/resistors and understand that there was a change mid-63. I have an 087 coil and the black dot .3 resistor. Will these work together without causing burned points and/or performance issues? Thanks in advance for your advice.

[Duke W.]

Re: 087 Coil with .3 Ballast resistor

All early '63 engines utilized the 0.3 ohm ballast mated with the 091 coil. When the 1.8 ohm ballast was implemented with the 250/300 HP engines, it was mated with the 087 coil. I don't know the differences in resistance values. I recall the '63 Corvette Shop manual lists values for the 091.

I can't say how the 0.3 ohm ballast with the 087 coil will perform other than the 0.3 ohm ballast with any coil will increase the change of burned points due to the higher primary current.

It happened to my 340 HP SWC back in the sixties. I would suggest using the point set with the larger contact surface... don't remember the NAPA number, but I wrote an article about it that was published in The Corvette Restorer. You can probably find it with a Web search and I know it's posted on the Corvette Forum in a thread started by me.

Duke

[Kent S.]

Re: 087 Coil with .3 Ballast resistor

Appreciate the help, Duke.

[Dick W.]

Re: 087 Coil with .3 Ballast resistor

Napa ECH CS 786

[Kent S.]

Re: 087 Coil with .3 Ballast resistor

Napa ECH CS 786

Good to know - thanks.

[John D.]

Re: 087 Coil with .3 Ballast resistor

Scroll down the bottom of the page or do an advance search of this subject. We have covered it over the years. I just read a post by Dale Pearman from 2000.
Basically a 087 coil uses a D1110 Ballast resistor.
The '091 uses a D1111 BR. The 62 dated '63 shop manual ( only one printed) states '091 BR: 1.4-1.62 Resistance-ohms.
No mention of a '087 coil or the D1110 BR that was used later in some applications.
I remember when my '63 FI car was first restored I had the wrong coil on it. I had a '087 coil with a D1111-the real deal with the cut off rounded end. I was told I was going to fry my points.
What is the ohms resistance of the D1110 BR.. I had the info but lost it. Thanks. John

[Frank D.]

Re: 087 Coil with .3 Ballast resistor

All early '63 engines utilized the 0.3 ohm ballast mated with the 091 coil. When the 1.8 ohm ballast was implemented with the 250/300 HP engines, it was mated with the 087 coil. I don't know the differences in resistance values. I recall the '63 Corvette Shop manual lists values for the 091.

I can't say how the 0.3 ohm ballast with the 087 coil will perform other than the 0.3 ohm ballast with any coil will increase the change of burned points due to the higher primary current.

It happened to my 340 HP SWC back in the sixties. I would suggest using the point set with the larger contact surface... don't remember the NAPA number, but I wrote an article about it that was published in The Corvette Restorer. You can probably find it with a Web search and I know it's posted on the Corvette Forum in a thread started by me.

Duke

Isn't there a TSB in the back of the 63/64 JG concerning this changeover ? Or am I mistaken ?

[Duke W.]

Re: 087 Coil with .3 Ballast resistor

A TSB was written by Chevrolet on the subject. I presented a photo copy to the powers that be back in 2001, but don't know if the bulletin or the requisite info is in the current version of the 63-64 JG.

Perhaps someone who has a copy can check.

Duke