Wrecked82

How many miles should a set of spark plugs last. Standard copper core and platinum. Not going to invest in iridium.

Yes, I know, will get a lot of posts that spark plugs are cheap and "I change them every year". Yeah, yeah, I know. I don't care to do unnecessary maintenance, no matter how cheap. If something doesn't need changing out, you are doing it only for your self-gratification - pun intended.

Sayfoo

I believe that a spark plug is good as long as the electrodes are in good shape. Went to change mine on my 69 at 10k miles and they looked so good that I just checked the gap and left them in. I don't see anything that will break down other then the electrodes. They are basically just a electrical conductor and a insolator.
I think that the old leaded gas is what used to eat up the old plugs and I'm not seeing it with unleaded. Same with the exhaust system. Even mild steel parts don't rust out as fast.
If you're burning oil or getting other deposits, then, yea, do it.
I always buy the cheap, on sale standard plugs for $1-$1.50ea. I even got a set of Autolites free a few years ago with the mail in rebates.

zwede

I usually replace standard plugs after 15K-20K miles.

Mod75

I usually go 5-7 years on a tune up, then i just replace wires, cap,rotor,plugs. Last year i rebuilt the dist.

10,000-15,000 miles and i just replace everything.

PeteZO6

I have 139,000 miles on my F250 pickup with a big block 460. Original spark plugs. Runs great, still same gas mileage as when new. Why change them?

Pete

WHITE 1974

I would think every 12,000 for copper and maybe 18,000 for platinum,provided the car is otherwise kept in good tune.

7T1vette

Or, spend $5-7 per plug and get 100,000+ miles on a set of iridium NGK plugs. I have a van that went 108,000 flawless miles with the original NGK iridium plugs. When I pulled them out [just because I thought they should be changed after that many miles], they looked like new....no corrosion, no pitting, no tip erosion....NOTHING. So, what did I replace them with???? Autolites? Noooo. AC Delcos? Noooo.

I'd be a complete fool not to put the same product back in--wouldn't I? And that's what I'll stick in my '71 when it needs them.

my 76 ray

Since you don't want to do unnecessary maintenance with Sayfoo.

alswagg

We change carbureted engines plugs every 3 to 4 seasons. EFI 5 to 6 seasons. These cars are rarely run and have poor ignitions and fuel systems. I would not go by miles but as time or seasons. Al

SIXFOOTER

My 2000 Z71 pickup has 260K miles on it and factory plugs

gcusmano74

Yeah, well, that is a fuel injected, electronic ignition, computer controlled engine. Quite a bit different than a 40 year old Chevy small block bolted under a carburetor.....

PeteZO6

While what you say is certainly true, a spark plug is still a spark plug, unless you're in the UK, then it is a sparking plug.

When lead was taken out of gasoline, the major cause of spark plug deposits went away. I'm not saying don't change the plugs, but as long as the engine runs well, doesn't miss, and gas mileage doesn't go down the toilet, there isn't much reason to change the spark plugs. OTOH, if it runs crappy, changing plugs can't hurt, and may well help.

Pete