C2- 67 timing idle question? -I give up!

[Joe L.]

Re: C2- 67 timing idle question? -I give up!

Glen----

Yes, it goes on the "turned up" end.

[Patrick H.]

Re: PS

Glenn,

Pertronix has put out 3 different systems so far, and I would say that some are less apt to cause a problem than others. So, in a way, saying that you have a Pertronix unit could mean one of 3 things.

Currently I have their latest one, the Ignitor II, in my 71 and it works fine. I did, however, have the distributor recurved and fully sorted using points (as noted above) before I installed the Pertronix.

I would agree with Joe that you may want to swap back to points and see if your problem still exists. In addition, if you remove the distributor to have it checked on a distributor machine, many of the older machinies can't trigger your Pertronix so you'll have to use points anyway.

Patrick

[Wayne W.]

Re: C2- 67 timing idle question? -I give up!

I have never used one of those units, never saw the point. GET IT. The original points are good enough for me. But I would investigate where the trigger is in relation to the rotor position. I dont know whether that thing fires when the pickup closes or opens the gap. But if it is firing just as the distributor rotor is in the wrong position say half way in between or something, then it could jump to the wrong post as the advance moves.

[Glenn Ochs]

Re: PS

Patrick...I couldn't tell you what version of Pertronix I am saddled with. It was on the car when I got it. I do feel it has something to do with the condition I am experiencing. I am definately going to remove it and see what happens. Can anyone tell me the process required to go back to a points system or is it fairly obvious? My main concern is the resistor block connections.
Thank you everyone for your guidence and direction. I will keep you posted as this thing unfolds. Glenn

[Glenn Ochs]

Re: C2- 67 timing idle question? -I give up!

Wayne... Good point! (I get it). I plan to remove the Pertronix system, it seems "pointless" to keep it any longer. I'll keep you posted on what happens.

[William C.]

Re: C2- 67 timing idle question? -I give up!

This sure sounds like a case of "boy racer" springs on the distributor affecting the ability to set base timing accurately due to the centrifugal advance coming into play while setting base timing. There seems to be no other mechanical explanation for the timing change. That said, the PG cars are more sensitive to a camshaft change (stalling) if the cam was "upgraded" during the rebuild. S I would look into both areas.

[James F.]

[Mark G.]

[Duke W.]

Re: PS

I don't see the point of installing an electronic ignition in these cars. One of their advantages is no black boxes that can fail and leave you stranded like a modern car. Points are typically good for 30K miles and should be checked about every 10K for dwell and resistance. Given that most vintage Corvettes don't see much annual mileage accumulation, this would not be more than once a year.

A dial back timing light is the easiest way to measure the centrifugal curve. Add a Mighty Vac or similar tool and you can easily measure the vacuum advance curve.

Duke

[John H.]

Re: "Boy racer" springs - Bill

Sounds like the centrifugal advance is starting way too early. Remove the rotor, then either tie the weights down with a rubber band or remove them entirely, re-install the rotor, and check initial timing, and set it. Then remove the rotor, remove the rubber band (or re-install the weights and springs), re-install the rotor, fire it up, and check the initial timing again. If it has increased, someone has played with the springs and the centrifugal curve is coming in too early.

Best bet (unless you have a dial-back timing light, an assortment of springs, and some time to experiment), is to yank the distributor and take it to a shop with a Sun distributor machine and have them set it up with the correct curve; takes about 30 minutes.

[Glenn Ochs]

Ignition replacement help

Hi Duke.... I have spent a little time this AM removing the Pertronix ignition and starting to put the point ignition back in. I am putting in a uni-point system (delco) and the U505 Delco coil. My problem right now is being sure I hook the wiring up correctly using the resistor block. I also don't remember where I should be connecting the red/black wires inside the distributor(old age matter). The Pertronix connectors aren't the ones I recall.

I have the dial-back timing light, if I ever get back to running I'll dig into that one then. I don't have a dwell meter, does anything else do that for me? Please help. Thanks again. Glenn

[Duke W.]

Re: Ignition replacement help

Set new points at .019" gap, .016" for used points.

A tach dwell meter is handy to have to both check dwell angle and idle speed, since the in-car tach is not necessarily accurate at idle speed. My tach dwell meter is probably 30 years old, and I don't even know if they are sold anymore, but if they are, I recommend you buy one.

I'm not familiar with Pertronics wiring and have no idea if your wiring was modified in any way. OE has two pink wires in the vicinity of the ballast - one originates at the ignition switch and the other routes to the pos. side of the coil. The wire from the igntion switch is the system voltage source for the igntion system, and the ballast limits current. Which wire goes to which end is a matter of convenience and available wire length. A resistor is not polarity sensitive.

Make sure the black ground wire soldered to the breaker plate is properly grounded to a vacuum advance can mounting screw and the dist. housing is grounded to the engine, but given your problems, removing and disassebling the distributor for a complete inspection and blueprinting would be a good idea.

Refer to the CSM wiring diagram and be sure you have it wired correctly using continutity testing.

Duke

[Glenn Ochs]

Re: Ignition replacement help

Thanks Duke:...I think I have almost original wiring,based on your post. My current concern is where does the black wire from the Uni-point spring (points)go to? Negative side of the coil? The wiring diagram I have is no good to address this.

There was 2 Pertronix wires in the distributor when I got there today,one to the neg/coil and one to the lower connector of the ballast resistor. I don't think I need two(memory again). Glenn

[Duke W.]

Re: Ignition replacement help

The black wire that connects to the uniset routes to the negative coil terminal, but I suggest you verify this with a continuity check and make sure the wire is sound especially where it exits the distributor. Twist and turn it with the ohmmeter connected to make sure it does not go intermittently open.

If you look at the wiring diagram in your CSM you should see that the 12V power source from the ignition routes in series to the ballast to the positive coil terminal, then from the negative coil terminal to the points and grounds via the breaker plate wire to the vacuum can attaching screw, and then grounds to the engine via the distributor mounting and clamp.

Make sure this circuit has continutity all the way through including the ground circuit from the points to the engine.

Duke

[Glenn Ochs]

UPDATE - UPDATE - UPDATE

Well what do you know! It works. I finally got the ignition back to a points/condensor system from the Pertronix. And it works very well. I now have a very nice idle in gear with the vacuum advance connected. This was impossible with the pertronix. The timing goes from 6 to 14 degrees when you connect the advance. Seem smore normal opposed to the 25 degree jump with the pertronix. Still have to set the points,(just eyeballed them) but it is running just great.

Special thanks to Duke for following this thread and guiding me through the whole process. Sure feels good to have this behind me. Might keep this baby(car) afterall. Glenn