The 70 GS has had an ongoing problem- the points get pitted/ burned up within a hundred or so miles. The car starts to run like doo doo. When I take the points out, they are pitted/ burned on one side. Each time the problem seems to be pitting on the non fixed side. Once I file them down and reinstall, the car runs like a champ again. Ive swapped coils, put in new condensers, contact sets. I checked the voltage to the coil. its only 5v. I cant seem to find any logical reason other than the condensers are just made out of spec. Im getting tired of trying to figure this out. i hate to do it, but I think Im going to bite the bullet and swap it over the the Crane Xr-1 setup with the rev limiter. I feel like Im giving up but Im not sure what else to do. Any advice before I begrudginly give in to technology?
I would start looking at the distributor shaft and the lobes to see if it doesn't have a slight wobble or maybe was ground wrong causing the points to open unevenly.
It has to be an out of spec ignition coil or over voltage. 5v sounds low, which shouldn't cause that issue. What is the voltage of the electrical system at 2500rpm?
Jason, Be sure that the coil has correct polarity. Be sure that the ground strap from the points plate to distrubutor body is in place and tight. If the coil is correct application it would seem to be incorrect condensor spec as you said. Double check engine ground straps to body or firewall. TexasJohn55
Is the original resistor wire still there? If you run a full 12 volts to the points, they will burn up.
Hey Jason, if you stop leaving the key on when you and your bride are out parking, that won't happen...the radio still works in the acc position, you know.:Brow:
Resistance wire is there. its actually a new M&H engine harness I put in when I bought the car 9 years ago. Just looked at them today after work. Brand new Standard Blue streak points with less than 150 miles and the non fixed contact has a small pit in it. I filed them down and the car runs good again. Im interested in getting a microfarad reading on the capacitor thats in there, but i dont know what the factory spec should be. Without something to compare it to, the reading is useless. ---------- Post added at 07:18 PM ---------- Previous post was at 07:16 PM ---------- Nah, the consolette and shifter gets in the way. i wouldnt want to disturb the synchromesh. We use the convertible for that. Cant beat a bench seat and a column shifter!
The shorting switch in the starter solenoid bypasses the resistance wire while cranking only. Maybe it is sticking at times and giving you battery voltage to the coil for long periods of time. Can you swap in another starter or solenoid?
I did the deed. I ordered the Crane XR-1 kit. It felt so.......wrong. ordered it from Summit so I should get it in a couple of days
5V sounds like close to the bottom of the voltage needed for good fire. You might look at how much current is flowing while the car is running. An electrician buddy may be able to help with that. I see you got a new ignition. But I know that you always want to know root cause. I suspect a high-resistance connection. You can make a limited check of the capacitor with a multimeter. Again, an electrician bud may be able to help.
The instant your points open, the current immediately starts looking for a path. If your capacitor (across the points) doesn't temporarily absorb the current, your points will instantly arc over. A couple instants later, the point gap is wider, the cap is charged, and the current goes to a plug instead. Make sure the cap is good, and the ballast resistor too as mentioned. I left that whole bunch of problems behind, with an HEI. Bruce Roe
...and another one bites the dust. I feel your pain. I have been re-converting cars back to points for 20+ years, and the only thing I can guess is a bad condenser ground, which only happens when a uniset is replaced with separate components and the condenser ground strap is gone. My Cadillac has 5.5 VDC+ running voltage, so 5 VDC seems fine (but below spec for sure) to me.
The deed is done. I converted the GS over to the Crane XR-i ignition. I have to begrudgingly admit it does run a little better
How was the install? I have a miss that only occurs when my engine is real hot. I've been thinking about using the Crane XR-1. Sick of points.
In two cars now, Ive used a Crane Xri The last car, JW rebuilt a distributor and curved it for me with the XRi. This car, I put a Crane XRi in myself, it was easy. I actually got a rebuilt distributor from Autozone for $35 and added the Crane kit to it. So everything was new including coil and plug wires. Install is easy, zero setup, and I found starting and running was a noticeably better. In both cases I removed a big cap HEI, they just dont work well with the GS air cleaner, and I like the stock look better. And a built in rev-limiter (which I recently had to increase after my first trip to the track :TU
Install took 15 minutes. Very easy. Just remember to adjust the rev limiter. Its set to 4k rpm. Im not sure its going to fix your miss. The miss might be in the carb. Could be a lean miss when hot. You can try richening up the mixture with propane to see if it goes away. If it does, you have your answer.
