66 corvette 427/425 with TI No Spark

[John L.]

THERE IS NO SPARK AT ANY OF THE CYLINDERS !!!!!!

66 corvette 427/425 with TI no spark. Checked coil Primary resistance got .35 ohms Secondary got 11900 ohms. With key on at plus side of coil got 3.4 Volts. Battery reading 12.6 V.

Note - installed new antenna switch over the weekend. Went to cruise Saturday and it was very hot. Car when first parked was dead probably due to heat. Jiggled firewall connector - same. Let it cool for about 1/2 hour and started right up. Drove home around 9:30, put car in garage, would not start next morning. I did not think car was running very well on drive home. Yesterday I jumped it with my Honda thinking maybe it was the battery -- same no spark. -- Help

I do seem to have spark at the coil high tension tower. Maybe bad coil wire or rotor or cap ??????

[Donald H.]

Re: 66 corvette 427/425 with TI No Spark

A friend with a similar car, 66 425HP, has had a similar nagging problem for months. He could drive the car for 10 or so minutes, then it would just die. In the past he was able to restart the car soon after it died.

He had changed the TI module (now using the K&N solid state), carburetor, and at least one coil.

I went to help him this past Monday. He had borrowed an NOS TI coil so we swapped coils. We took the car for a drive around his neighborhood, very hot day at 90+ degrees. After just a little more than 10 minutes, we were turning around in a cul-d-sac and the car just died. Would not restart even after waiting a few minutes. We pulled the coil wire at the distributor and got no spark.

He also has a new GM Licensed reproduction coil and a Pertronix Flame-thrower coil. A friend of his has been using the Flame-thrower for years on a TI ignition. We installed the Flame-thrower and drove the car around for 25 or so minutes. It ran find, so we are hoping it was the coil. By the way, we shot the coil with an IR got and it was over 180 degrees.

We tested the NOS coil when we got back to his house and it test good, about .40 ohms on the primary side and 11k or so on the secondary. I don't know anything about electronics, but it appears a coil can break down and still test good, or it had cooled off enough in 20 minutes to reset. But it was still very warm, almost to warn to hold.

[John L.]

Re: 66 corvette 427/425 with TI No Spark

Well problem solved - could not really find a problem - everything tested to spec. Removed and cleaned dist cap, wires and rotor. Tried it again and had spark. Of course the recently rebuilt carb was overflowing really bad. Put another carb on the car, primed it and it started fine. Now just have to adjust the idle mixture and speed and should be good to go.