Your thoughts on Spark Plugs...
 

Guys, what are your thoughts on spark plugs.

The reason I ask is my spark plugs are about two years old and every six months I give them a clean with a wire brush and put them back in. They look to be in perfect condition.

I was told they actually "break down" after 10,000 miles. I guess the guy meant the resistance increases or something. Fact or fiction?

Do the fancy 60,000 mile spark plugs like NGK Iridium that cost four times as much give a beter spark than a brand new ordinary plug, but just last much longer. Or would your money be beter spent buying four sets or ordinary plugs and replacing each year? So in other words is a clean plug beter than a fancy spark plug?

Bill '79SC Euro

I just use the Bosch COPPER plugs and change them once a year.* My Bosch guru mechanic friend advises against the Bosch platinums. -Chris
* When the motor is out anyway. :) My lower plugs are a huge pain to get at. (twin plug 3.4)

how hard is it to change plugs? do you have to drop the motor?

JeffW

You do noy have to drop the motor to change plugs...
The factory tool really makes it much easier if you have one.

I use a regular NGK in my 83SC and have about 30,000 miles on them... and milage and performance is great !

I use NGK and Bosch. Copper. Plugs last a long time if the environment is right (no oil, perfect air/fuel mixture). Eventually the point wear, so the gap increases. I've heard of plugs lasting many, many years and many, many miles.

Currently using BOSCH PLUS 4 Platinum plugs in my 88 Carrera with no problems.

bump

I'd skip the "fancy" plugs, unless you want to go with the K&N air filter and Cool Collar for an addiitonal 30+hp.

Seriously, I had used a couple "fancy" plugs in the past and have gone back to the $2.00 NGK with no difference in performance. I usually change them out when I do the valves but I think this is over kill sans fouling.

I believe Porsche recommends changing the plugs at 30K intervals. I know there are many 993s with 45, 50 and even 60K on the number 6 plug because its so difficult to change.

Bill,

I think the plain copper-core NGKs do a great job, and that your 4-set vs 'expensive/exotic' plug question is easily decided in favor of the 4-set annual change methodology!

It seems to me that the advertising hype for all of the 'miracle-cure' products are taking advantage of consumer's natural hesitation to have things fixed by a shop at an unknown cost ...

If you do your own tuneups, there just doesn't seem to be a need to use exotic spark plugs! And, I think many professional mechanics don't like the 'exotic' plugs ... because they get tired of arguing with customers that believe the hype, and don't believe that something else could be wrong with the beaste ... after having spent more than $100 on a set of spark plugs!

i heard the platinum plugs will last for 100,000 miles if checked and cleaned periodically.

may be good for a daily driver, but for performance i would change them more often.

Just a note about the Bosch Platinum plugs: They are very good plugs which should work nicely in newer cars, but they don't seem to work well in carbureted cars or older fuel-injected (mechanical or CIS) cars that aren't in perfect tune. The reason is that the electrode is so small that they are easily fouled by rich mixtures and oil. So, if you have a '72 E, run some decent (NGK or Bosch) copper plugs and change them at reasonable intervals. If you have a 993, run some Bosh Platinum plugs and don't change them until 2031. Okay, okay, 50K miles would be better.

Regards,
zuff

Thanks for the good advice guys.