Anti Seize on Spark Plugs? Apparently not...
 

Goes against everything I've ever done!

The Bosch plugs have some sort of coating on the threads already.
-Chris

So what's the perceived problem if you HAVE been using anti-seize on your plugs? Incorrect torque values? Gunk inside the cylinders?
regards,
jlex.

This stuff is kind of an IQ type test question.

You may have a special coating on the bosch spark plugs that are supposed to be used in 911 Porsche motors. ( I don't know)

You might lose some threads in the heads using spark plugs that are not coated with anti-seize compound due to thread seizing situations.

You don't lose threads in the heads by using spark plugs that have a little anti-seize applied to their threads.

What does it cost to repair spark plug threads in 911 Cyl heads?
( I know what I charge to do this!)

I think that the real problem is one of torque values. It also mentions cleanliness. This is a tough problem in a dirty nasty motor. Some of the byproducts, among others, of combustion is sulphuric acid and water in the combustion chamber. These help to seize the threads of the two disimilar materials of the head and plug.

Good luck,
David Duffield

Heresy! :confused:

Bruce

Humbug!!! I have been using anti-seize on my plugs since........well, ever! I used it on four Porsches over the course of many years and NEVER have I had a problem. Without it I find that its a pain to get the plugs out. The key is using a very small amount and that takes patience to apply. I use a small brush and try not to flood the threads. Carry on.....................


Bob
73.5T

Guys:
I'm with most of you. If you go deeper into Porsche's reasoning, you will ( likely) find concerns that many "anti-seize" products may contaminate downstream O2 sensors. Maybe, also...incorrect torque values. And..incorrect heat transfer characterisitcs through the threads and head.
The best compromise, IMHO, is as others have said...use it sparingly, and use O2 sensor-safe products..
---Wil Ferch

Wayne:

What prompted this thread? Did the editors find a discrepency between your book and the Porsche manuals? Just curious.


Eric
83SC

It's news to me that someone even recommended antisieze on the plug threads. I have never had a problem with the plugs sticking on any type of car. but then again I have never tightened the plugs using brute force.

It comes to those who, in the '70s, pulled a champion plug out of an aluminum head, saying "oh-$hit" with every mushy turn of the wrench. (YMMV)
As Chris says, they are coated now. I've known this for a while, but still have this need to dab just a bit of anti-seize at the threads base. (I leave the 85% toward the tip clean)

I have heard that the concern is not torque, or catalytic converters, but rather electrical conductivity.

Since my rebuild, I have not put antiseize on spark plug threads. Instead I torque them properly and change them before they get too old. Here's a tip: If you're putting new spark plugs in and you can't or don't want to use a torque wrench, tighten them until you can feel the crush washer at the base of the plug begin to collapse. Some say this is enough torque. I say continue screwing (the spark plug I mean) until you can feel that the crush washer is indeed fully crushed. This is the perfect torque.

I believe I have never seen a spark plug/head thread disaster failure that was not caused by over-torquing. I have removed plugs that apparently were installed with a long breaker bar. that's the problem.

How would you know the cause?
Maybe Jasper the Chemist can help me out here but the words "diffusion bonding" come to mind, for non-coated plugs sitting in an engine way to long.

Sure, I understand. Electro-something-or-other. And no lab was involved in testing my statement, so it may be false. But I'm not convinced it is. I have seen aluminum-head engines SPIT spark plugs out. Leaving a smooth bore. Lab or no lab, I know what happened.

On my '73T I had before college, the PO did not put anti-seize on the threads... Of course, disaster... the hex stayed in and the white insulator came out... Was it torque, heat, who knows?

From that point fwd, copper anti-seize on all plugs.

mystery solved
 

The issue indeed is conductivity, (grounding), and anti-sieze lubricant is completely unneccesary if threads are clean and torqued properly. Also never remove or install plugs when heads are scalding hot, if avoidable. I was taught to always install plugs w/ fingers only initially, (in a socket, obviously), I have NEVER had a problem w/ plugs cross-threading or siezing in any motor. :cool:

I think heat is more of an enemy than anything else. If you remove a plug from a hot aluminum head, you are asking for the threads to come out with the plug. Pulling the plugs in a hot 911 motor is asking for burned body parts, so it is not as much of a problem for skin loving 911 owners as for other cars with more accesible plugs.

Im going to continue using anti seize on my plugs. The trick is not to just glob all the threads w/anti seize, just needs a dab, then work into the threads.

my grandfather used it on the plugs in his 356, and I have used it on plugs on every engine ive ever owned.... the trick is just dont usde to much

This gives me reassurance that I have been doing is right by not using any lubricant or antiseize on my plugs and have never had any problems on air cooled or water cooled engines.

I also noticed whenever I remove an old spark plug that there always seems to be some residual oil on the threads anyway.

Joe

The bulletin applies retroactively to all Porsche models and the theory is that the anti-seize tends to act as an electrical insulator between the plug and the cylinder head. This could have detrimental effect on the firing of the spark due to the loss of a good, consistent ground connection.

Two of my three editors said "prove it" so I did. Thought it was informative...

-Wayne