Is a ballist resistor needed on a stock points distributor. I'm putting a 63- 401 nailhead in my T coupe and the buick it came out of had one. I know it drops the current to the coil but is it necessary. If so one one kinow the ohms needed.
It's been a long time since I messed with those, I converted all my points cars over to the Petronix electronic insert to replace the points but kept the resistors. I recall reading somewhere they reduced the current to the coil after the car was started. Years ago I ran a mallory dual points set up w/o the resister and an oil filled coil with no problems. But it wouldn't hurt to keep it.
The ballast resistor is there to help prevent the points from burning. Usually, an OEM won't throw stuff on a car that's unnecessary.............
Yes it's necessary. Just buy one for the same year and model Buick the engine and coil came out of. You don't need to know the ohms....
On my Pontiac I ended up using a Dodge truck one, about 1.5 ohms from the local farm store. It drops me down to roughly 7V when running. I also have it wired so it gets bypassed using the R terminal on the starter when cranking to get full 12 volts when starting. The wire from the R terminal goes to the coil side of the resistor.
Man its been awhile but here goes...Hit your coil with an ohm meter...pos. to neg....1.5 ohm +use a resistor if it reads 3.0 ohms or more it is internally resisted. Don't buy anything that is .o6 ohms like flamethrower II coil ! They are for capacitive discharge units like pertronics II or III but wont work on the basic Pertronics unit. The advice about the R terminal above is worthy, some old ign switches provide NO current to the coil when in the crank position...cranks but wont start. wire from starter will power up the coil while it is energized. Experience is a lousey teacher...you get the test first....lesson later !