Posted by chriscase on Friday, September 02, 2005 at 8:06PM :
In Reply to: Ignition problems, and question posted by Robert Kosusnik on Friday, September 02, 2005 at 3:42PM :
When the points are closed, the juice goes to ground through the points. Do that test again with the cap off and see that the points are open. You can usually pull on a fan blade to turn the engine enough to open the points. (+) side of coil will glow brighter too with points open since most of the current won't be going to ground.
Points do wear and need to be adjusted, about evey 7-10,000 miles. It's the rubbing block that wears down, til the points don't open at all. They should open the thickness of a match book cover, about .017 inch. Re-adjust, or maybe file the points clean and then re-adjust. It's better to take the distributor out for better access, but you will need a timing light to retime it later if you do. If you want to pull the dist, ALWAYS bump the engine around til the rotor points straight ahead, put it back in with the rotor straight ahead too. That will prevent half the probs newbie tune up men have of getting it back together 180 out.
Bypassing the ballast with a wire from the + coil to the start switch will give a hotter spark when cranking. But you can only do that if you use a solenoid in the circuit, use the 'I' connection. Or if you have a foot switch starter, some have a screw connection on the side for the same wwire, but you will need a diode in the wire or thre coil will short through the starter.
It was smog laws that made Detroit finally do away with points. In 76 the Feds required that cars run clean between tuneups, so the electronic ignition became standard. Machinist type dudes can make a GM HEI dist fit, I'll do that someday to mine.