Anti Seize on Spark Plugs? Apparently not...

[911pcars]

As others have suggested, use it sparingly. I would add, "very sparingly". You only need a little (which goes a long way) on the thread portion of the plug. As far as electrical and thermal conductivity, the gasket and seat is the main heat/current path to the engine. Keep excess anti-seize away from here and it should be fine. Dissimilar metals, under the proper conditions (like a battery), produce a galvanic reaction that can result in fusion - that is, the parts sorta become one with each other.

Minor rant:
When someone says, "I've never seen ......", perhaps one could qualify the statement by reciting the number of examples witnessed in the personal database. Being somewhat sheltered, I've never seen a lot of things, but that doesn't preclude it happening with regularity in other circles.

BTW, I have seen spark plugs frozen in aluminum heads, fwiw - but not for long after the breaker bar remove the plug and its mating threads from the head. Better minds may know, but aren't some 911 heads equipped with stainless steel spark plug thread inserts? If so, adding some anti-seize may be an honorary practice but not really needed or required.

Sherwood Lee
(as you can tell, an advocate for sparing use of A.S.)
http://members.rennlist.org/911pcars

[island911]

Originally posted by 911pcars
. . . As far as electrical and thermal conductivity, the gasket and seat is the main heat/current path to the engine. . ..

Really?
I would guess the largest thermal gradient would be closer to the tip.
As to the electrical, the head is one big wire . . .is the path of least resistance really the outside surface? And how do you know?

[Superman]

Have you had too much Starbucks, Island?

[island911]

Well it aint too much puppychow.

[Superman]

Touche'

[speeder]

Starbucks.....coming......out.....of ...nose, quit it you guys!

[9eleven]

Originally posted by 911pcars


Minor rant:
When someone says, "I've never seen ......", perhaps one could qualify the statement by reciting the number of examples witnessed in the personal database. Being somewhat sheltered, I've never seen a lot of things, but that doesn't preclude it happening with regularity in other circles.


Sherwood Lee
(as you can tell, an advocate for sparing use of A.S.)
http://members.rennlist.org/911pcars

That is so true . . . I chuckle every time I see "I've never seen . . ." written by people that own and work on one Porsche.

Unless its written by someone like John Walker, who HAS seen a lot, such statement always strikes me as being absolutely meaningless and somewhat self-absorbed.

[john walker's workshop]

i've mentioned this bulletin on several posts but most folks think they know better than the porsche engineers.

[speeder]

I had to re-read this thread looking for the "I've never seen..." remark, could not find it. Couple of "I've never had a problem(s)", including mine, so I will qualify: I have seen countless stripped, cross-threaded, etc., plugs as well as other fasteners in my lifetime of owning and working on cars, bikes, lawnmowers, etc. Just not any that I have installed, (at least not since the early '70s, when I was still shooting blanks), , but still I base my 'opinion' on this subject on what the real engineers say.

[911pcars]

"Really?
I would guess the largest thermal gradient would be closer to the tip.
As to the electrical, the head is one big wire . . .is the path of least resistance really the outside surface? And how do you know?"

Ever see a chart showing relative heat range?


Note sure what you mean by "largest thermal gradiant...", but the thermal path to the engine is through the spark plug seat. That's what I meant. There is some heat transfer at the threads but IMHO, the majority of heat transfer occurs at the seat. At least the spark plug manufacturers visualize the concept as through the seat.

As for electricity, the amount of secondary current is relatively small so this point is probably moot.

Regards,
Sherwood Lee
http://members.rennlist.org/911pcars

[Doug Zielke]

Originally posted by 911pcars

As for electricity, the amount of secondary current is relatively small so this point is probably moot.

Can't comment on the thermal dynamics issue, but I agree with Sherwood that electrical conductivity cannot be degraded (or enhanced, for that matter), by the use of anti-seize on plug threads.

[island911]

Originally posted by 911pcars
. . .Ever see a chart showing relative heat range?


Note sure what you mean by "largest thermal gradiant...", but the thermal path to the engine is through the spark plug seat. That's what I meant. . . .

Ah! Thanks, I get what you are saying.
Though *that* "heat path" is for controling the tip temperature. . . not necessarly the place where the most heat is "moving" out of the plug. (what I meant to imply by "largest thermal gradiant" )

[A Quiet Boom]

Doesn't apply directly to P-cars but aluminum heads just the same. If any of you are familiar with the term "plug cut" you'll know what I'm talking about. Plug cutting and engine is when you run the engine at full throttle such as a dragstrip and then quickly shut off the motor, roll to a stop and remove the hot plugs to "read" them. It's much more difficult to read plugs with today's gasoline than in years past but for those of us running race gas it's a quick way to check A/F ratio as well as look for signs of detontion from too much timing, boost or nitrous oxide. Anyway this procedure involves removeing the plugs from a very hot engine, usually with aluminum cylinder heads. Myself and all the other racers I know DO NOT use anti-seize or any other type of lubricant on our plugs and in fact most of us don't even use torque wrenchs to tighten them, we just tighten them by feel (1/4-1/2 turn past fingertight) I've never pulled any threads or crossthreaded etc. so I really don't see the need for this. My previous 911 engine was a 2.0 that had been barely driven for 9 years, the plugs came out just fine. Lubrication BTW can result in higher actual torque than bare threads which is why companies such as ARP recommend using assembly lube on the threads of their hardware for proper torque readings where proper torquing is essential (unlubed threads "stick" a little giving a false high torque value). FWIW