Spark Plug Question
 

Hello I know our manual says to change our spark plugs every 30,000 miles or every 2 years. New cars today can go 100,000 miles before they need new spark plugs. So the question is do we need to change them every 2 years? I'm asking because I haven't even put 10,000 miles on them. Can they last 3, 4 or 5 years if it takes us that long to put 30,000 miles on them? Thanks

Others will chime in with more info, but I think that really depends on how "clean" your engine is running. Today's cars are running near stoichiometric air/fuel ratios almost constantly - my old 911 with CIS sure isn't. I swapped plugs in November and was surprised how much better it ran (only 15k miles on those plugs, too).

i don't worry about a time frame.

as said.
new cars burn more efficiently.
also the plug type can help.
but run copper plus in your car. nothing fancy

No reason to replace them if your engine runs as clean as the newer ones.

In Wayne’s book he recommends every 15,000 miles. As stated above age doesn’t really matter.

Can you just give them a good cleaning and reinstall? Why replace if the electrodes are in good shape?

The gap changes as the electrode wears. I noticed the NGKspark plugs wear faster than Bosch, I check the gap at least when I do a valve adjustment.

My main concern with plugs staying in place for extended time, is the action between steel and Aluminum. So pull them, inspect and reuse them if thy pass, with a smidgen of Antisiez

Stay away from anti-seize on spark plugs, we use a dab of wheel bearing grease. The metal, copper or aluminum, in the anti-seize can short out the spark plug. Also, use the lubricant sparingly.

I believe anti-seize can only short out a spark plug if some is smeared on the porcelain. Shouldn't be a problem if the anti-seize paste is confined to a little bit on the threads. Also, I worry about grease carbonizing on the threads closest to the combustion chamber.

I want to thank everyone for the replies.

Pulled spark threads on Datsun
 

Many moons ago I pulled some threads on a hot rod Datsun work truck and really don’t want to repeat with the 911.

Is there a high temp dielectric grease that might avoid this problem, while not interfering with the full grounding of the plug.
chris

Yes, but Datsun cylinder heads were made of compressed cheese. Avoiding unnecessary goops where possible is good practice.

Just for the record, I have been putting anti-seiz on sparkplug threads for as long as I can remember, and I have had my shop for 48 years. Every customer car, my cars, my 2 track motors, and have never experienced an issue because of that. I mean very LITTLE is applied. I do know that chasing down a problem, the wrong suspect can be blamed. Most of us work in a bit of a bubble and don't have the resources to do repetitive tests and we frequently will have conflicting results from what seems to be someone else's identical process. Pelican has provided a forum to help expand the bubble and I am grateful for it.