Spark Plug Question

[yogi]

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

[fanaudical]

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).

[T77911S]

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

[stlrj]

Originally Posted by yogi

Hello I know our manual says to change our spark plugs every 30,000 miles or every 2 years.

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

[John W.]

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

[ChrisHoover]

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

[911obgyn]

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.

[r lane]

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

[Marc Bixen]

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.

[RedCoupe]

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.

[yogi]

I want to thank everyone for the replies.

[chrismorse]

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

[manbridge 74]

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

[r lane]

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.