Ignition/Timing Question

[Marc G.]

My mechanical expertise is limited so I figured I would ask the group the following question.

The idle seems to be a little rough so decided to test each spark plug wire with a timing light. When I hook the timing light up to the #1 or #4 cylinder wires I get a very inconstant flash (anywhere between <0.5 second to 20+ seconds between flashes).

All remaining (2,3,5,6,7,8) wires flash consistently with no interruptions.

I have been hesitant to replace the distributed cap and rotor due to originality but I would like to get the vehicle running smoothly.

I plan on replacing the rotor and distributor cap. Spark plugs and wires are new. Any other suggestions would be greatly appreciated.

Thanks!
Marc

67' - 327/350

[Joe L.]

Re: Ignition/Timing Question

My mechanical expertise is limited so I figured I would ask the group the following question.

The idle seems to be a little rough so decided to test each spark plug wire with a timing light. When I hook the timing light up to the #1 or #4 cylinder wires I get a very inconstant flash (anywhere between <0.5 second to 20+ seconds between flashes).

All remaining (2,3,5,6,7,8) wires flash consistently with no interruptions.

I have been hesitant to replace the distributed cap and rotor due to originality but I would like to get the vehicle running smoothly.

I plan on replacing the rotor and distributor cap. Spark plugs and wires are new. Any other suggestions would be greatly appreciated.

Thanks!
Marc

67' - 327/350

Marc------


At the very least, you should clean the distributor cap inner contacts and the rotor tip. Very careful use of a Dremel tool with a small wire brush will clean them nicely.

[Larry M.]

Re: Ignition/Timing Question

What type and brand spark plug wires are on the car?? Carbon core (as original) or solid core?? AC Delco brand or other brand??

If Delco reproduction, dated wires, were they made by Lectic Limited or others??

In addition, show year of car and engine size.

Cap and rotor may be an issue, but I would lean more toward the wires themselves, especially if old, or reproductions with carbon core. They can break down with time.

Larry

[Duke W.]

Re: Ignition/Timing Question

A dental curette is a good tool to clean the cap and rotor terminals. I get them from my hygienist. Measure wire resistance on the questionable cylinders and compare to resistance on the other cylinders. The OE carbon core type should be no more than about 5K ohms per foot. There have been many reports of problems with repro date coded wires.

The L-79 should idle at about 750 @ 14" with a correct OE or OE replacement cam with a slight lobe. Spark plugs should be AC heat range 5 or equivalent in another brand, non-resistor type preferred such as NGK B4 or Denso W14-U if you're not having the car judged. AC only offers resistor type plugs, so if you need AC for judging the R45 is the best current choice.

How does the engine perform under load?

Duke