Spark plug change interval ?

[pearljam724]

What’s factory spark plug change interval on these cars, 3k miles ?

 

[toolmanmike]

Probably 12 mo/12,000 miles. Yearly tune up's were a common practice.

 

[dadsbee]

Haven't pulled the plugs out of the Bird since 1990 !

 

[toolmanmike]

Haven't pulled the plugs out of the Bird since 1990 !

I have 10 year old plugs in my 66 as well but less than 10,000 miles. It probably needs a set by now.

 

[69a100]

Probably 12 mo/12,000 miles. Yearly tune up's were a common practice.

I have 10 year old plugs in my 66 as well but less than 10,000 miles. It probably needs a set by now.

I've often wondered, would it really matter any different if it was 12 years/12K miles? I think I'm working right now on 15 years/6K miles and they're still fine.

 

[toolmanmike]

I've often wondered, would it really matter any different if it was 12 years/12K miles? I think I'm working right now on 15 years/6K miles and they're still fine.

Yep, I set my choke lean and let it warm up good before driving. And when I do I beat the snot out of it. No carbon on those plugs. LOL I should pull one just to see how bad or good they are.

 

[Budnicks]

I agree with most the posts above too

depends on how clean it's running
or if it's just one or two plugs etc.

 

[Slap Stick]

Back when there was sad in the gas it was 10-12 k miles.
Now with unleaded fuel and better ignition systems, mostly, you could extend that imo.

 

[MoparLeo]

How often do you change your oil , coolant, brake fluid, differential fluid, trans fluid...Plugs are subject to wear and contamination. Depends on the condition of your engine, the tune quality, Lean/rich, ignition system performance quality, points, condenser, rotor, cap, ignition wires, coil ...
Because the old engines tended to run rich, burn oil they needed constant maintenance. The FSM ( you do have one of course ?)gave suggested intervals based on average mileage for the time. Minor tune-ups ( a bad word really) Was normally annually and was plugs, points, condenser and rotor. Oil change and blow out the air filter ( illegal now a days) fuel filter replacement. Lubrication service was 2 times a year. Bearing repacks annually, Coolant every 2 years etc... based on daily driving. Todays petroleum products are more highly refined and the additives are much better. Still the older engines seals were of a poorer quality and the clearances were much looser resulting in more blowby and oil consumption. Rich fuel mixtures resulting in more oil contamination and fuel washing the cylinder bores. Bottom line. Preventive maintenance would be based on your vehicle condition and your driving habits. If the car just sits, it will just suffer fuel , coolant, oil deterioration based mainly on water contamination caused by condensation , seperation of the chemicals and oxidation especially in the cooling system.
One of the reasons for doing this hobby on older cars is that you do a lot of hand on care of your car. Don't do it because you have to , do it because you want to and enjoy it. People think nothing of taking their new car to get an oil change and spending $50. plus. You can replace your plugs, points etc... for the same price yourself.

 

[Ranger16]

Yep, I set my choke lean and let it warm up good before driving. And when I do I beat the snot out of it. No carbon on those plugs. LOL I should pull one just to see how bad or good they are.

A little water ingestion via one of the carb vacuum ports does a good job of cleaning the combustion chambers and plug as well. Come to think of it, I'm due for a cleaning.

 

[towtruckAl]

does anyone remember k mart and others selling recond plugs basically sandblasted and regaped .

 

[OKDart]

Contamination can be removed, it takes tens of thousands of miles to erode them.
For years all I did was take a wire brush to them.

 

[odcics2]

One reason to change plugs is that they can seize up.
I did a tune up on a relatives car in the late 70s that had the original right rear plug!!
Took a breaker bar to get it out!!!
It was C body 440.

 

[pearljam724]

Today’s plugs don’t last like they used to. Even the supposed good name brands. I put 7k miles on my car in 2 years since owning it. I think that mileage is suffice to change them. I’ve had plugs fail with less than a few thousand miles on my pick up. None of these parts last today. Half of them are junk, the day you buy them.

 

[MoparLeo]

How much do spark plugs set you back ? If you take them out to check them it takes exactly the same amount of labor to put new, properly gapped plugs back in. Most all pre 80 Mopars come exclusively with copper core Champions. Back in the sixties and seventies they about a buck each. Not really any more now if you figure inflation. Since the plug wire boots are probably torn, might as well do the wires...Cap...rotor...use plenty of dielectric grease when you put it back together.

 

[pearljam724]

Haven't pulled the plugs out of the Bird since 1990 !

You gotta drive it.

 

[dadsbee]

You gotta drive it.

Which part of that have you missed???????

 

[YY1]

as needed, pending inspection

 

[Don Frelier]

My 300M had the original plugs in it when I bought it with 127,000 miles on it.
The gap was probably .080 or more.
I did a quick calculation and it came out to roughly 125 million times they had fired.
They were clean and dry.
If it runs properly, my opinion would be you should be able to go 20,000 miles on a set of plugs.
If you have a really hot ignition the gap will grow.

 

[toolmanmike]

Put in some platnum's, double platinum's or irridium's. They'll last you forever in your old car.