Tedd Thompson

If I installed a pertronix system in my 55 would my plug life be extended as it is in modern cars with electronic ignition? The thought crossed my mind today as I just started feeling a miss and realized that on the last points change I didn't change the plugs and they now have about ten or twelve thousand total miles on them, seems like short milage but it may be time......Tedd

oldcutlass

Double check your dwell and re-gap plugs if they are still in good shape. I doubt a points replacement kit will extend your plugs much.

brown7373

I drove my Cutlass 20K with a Pertronix. I just never thought about it. It did start to run a little off, and I was surprised to see it had been 20K since plugs.

droldsmorland

I run Autolites with HEI. Got 30K out of them, easy. Probably could have filed and regapped for another 30. Best plug for the money IMO.
I doubt you'll see a noticeable improvement as far as longevity in the plugs with HEI. HEI basically just eliminates point adjustment so the engine will run longer without an old school tune up....emissions thing.

TripDeuces

Plugs wear away more than wear out. The problem is with every spark a little bit of electrode get's blasted away. The sharper the edges of the ground electrode and center electrode the better. It takes far less energy to jump between the two when the edges are sharp and electricity will naturally try and find the path of least resistance whether that is a shorter distance (smaller gap) or sharp edges. Let the edges get rounded off and the gap increase and you start to play havoc with the secondary ignition as more electric energy must pass through it to jump the gap.
Filing and regapping the plugs is your best and cheapest bet. It let's everything work easier.
Autolite plugs are the hardest plugs out there and will last the longest. All these other fancy plugs with multiple electrodes and special this and that, etc. are doing nothing but supplying more sharp edges and more potential jumping off spots for the spark to jump the gap.

rustyroger

Plugs last longer in modern engines for several reasons.
Possibly the biggest factor is unleaded fuel. Remember when plugs used to get a tan coating over 10k miles or so?. That was lead and other deposits from the fuel, if you ran the plugs too long this coating could track the spark away from the electrodes.
The materials plugs are made with has improved as well, and engines run with a much more strictly controlled environment, all of which help plug life.
Ted, if you are using lead additive I doubt your plugs will last much longer than back in the day, I doubt if slightly off points will affect them much, I dare say an out of tune carburettor might have a more serious affect.


Roger.

Tedd Thompson

No additives Roger , the valves were ground for unleaded gas with the last rebuild. I was just wondering because my daily driver Honda probably has 50,000 miles on the plugs without a sputter and I'm looking to replace the ones on my 55 soon. No big deal just wondering....Tedd

Fun71

One of them being tiny, pointed electrodes made out of platinum or similar metal that is very strong (so it doesn't erode easily as TripDeuces explained) coupled with high energy ignition systems.

The combination of the above results in an ignition system that will make a spark jump the gap under almost any condition. The manufacturers have to do this to meet emission requirements for up to 100,000 miles on vehicles that the owners may not perform any maintenance on, so the spark plugs have to be capable of firing under atrocious conditions that no combustion chamber should ever be subjected to.

On our vehicles, we typically are much better than the average driver in regards to maintenance.