Detonation after distributor cap install.

[dvw]

Well, the car is still detonating which was my original problem. So that hasn't gone away, despite everything checking out. I'm going to toss in the old spark plugs just to see what happens. I'm honestly tired of messing with it, for a while.

If I find the solution (it's going to be something ridiculously simple, of course) I'll post back.

Everyone: Thanks for all the help!

How much ignition timing does it have now? If it never detonated before and it does now it has more timing now than it did.
Doug

 

[kaj750]

Pull out a little timing

I have it where it was. Could just swapping out bad wires create a situation where I need to reduce timing further? I have no problem, giving it a shot, of course.

How much ignition timing does it have now? If it never detonated before and it does now it has more timing now than it did.
Doug

You would think. I'll finish swapping the spark plugs tomorrow and see what happens. The plugs in there now are NGK, cross-referenced from a catalog. Confirmed by physically being no different than the autolite plugs that came out before. Throwing in another set of 58s. At this point, the spark plugs are the only, actual change from before.

 

[1 Wild R/T]

Like I stated back in post 24...

Your old cap was junk... I've seen caps like that before where the engine ran like crap... Adding timing made the engine run better... Putting a new cap on means you need to pull timing out in order to run right...

So there's actually a pretty good chance that cap was bad when you bought the car... The erosion of the plastic around the center electrode didn't happen overnight...

 

[Geoff 2]

Another possibility for the detonation.

The dist will have an internal centrifugal curve that advances the timing. Done with weights & springs. Spring could have stretched or come off, allowing timing to advance more than it should.

 

[Some Car Guy]

Set total to 34. I’d do that before changing plugs. NGK 5s are what you want.

 

[Geoff 2]

The total timing may not be the problem. It is how quickly it gets there....see post #64.

 

[Some Car Guy]

The total timing may not be the problem. It is how quickly it gets there....see post #64.

Since we don’t know what his timing is at, getting the total under control is first priority. If he’s pinging at 34, then we can get into the curve.

 

[LowBikeMike]

Under what conditions does it detonate? Normal driving, heavy acceleration? I run a Unilite and get detonation in 4th gear mid to full throttle or heavy load.