Foz

Hi All,

My TB/WP job continues, as I've found other issues along the way: Frayed wires, broken brittle plastic bits, broken-off bolt head, etc.

So WYAIT, I decided to change the spark plugs, since there was a bit of missing while it was cold. I pulled the boot off the farthest firewall driver's side plug, and there was 5-10cc's of oil in the chamber. Immediately I saw visions of my life flashing before me, but got onto Rennlist and saw that it was probably just valve cover o-ring seals. Next, the plug was completely fouled, with carbon spiderweb-like tendrils connecting the electrodes. The plug also felt really weird coming out, like maybe it was cross-threaded or something.

Anyway, as I'm researching the spark plug issue, I see that there is massive disagreement on the forum about copper anti-seize (which I used on all the water pump bolts, Doh! ) Now, not only do I have to worry about whether to put anti-seize on the spark plugs, I also have to consider whether I should go back and redo the water pump bolts. To concisely summarize what I've found over tens of forum threads on this issue:

An aluminum metallurgist says that copper anti-seize is basically death for steel to aluminum and should be removed immediately and completely:

https://rennlist.com/forums/5367393-post10.html

A Porsche service manager says that anti-seize is fine on spark plugs but that you should use the lower torque value specified (18 ft-lbs):

https://rennlist.com/forums/4001825-post24.html

Porsche and the spark plug makers say that you should not use anti-seize on (plated) spark plugs:

https://rennlist.com/forums/7579903-post47.html

http://www.ngksparkplugs.com/pdf/TB-...1antisieze.pdf

Permatex says that their copper anti-seize is fine for use with spark plugs in aluminum heads, and that it contains anti-corrosion inhibitors:

http://www.permatex.com/component/do...ket=automotive

As a final permutation, it seems like the plating of the bolt or spark plug is a factor too. If it is plated with nickel or zinc, then the aluminum appears to be somewhat protected from galvanic corrosion:

https://rennlist.com/forums/10001361-post26.html

Loctite's "silver grade" anti-seize (which is really aluminum flake) was specifically tested with steel-to-aluminum:

https://tds.us.henkel.com//NA/UT/HNA.../SilGAL-EN.pdf

The rest I've found is a mish-mash of hearsay that I don't know whether to believe or not: Anti-seize with aluminum in it will gall to aluminum, anti-seize with nickel in it will gall aluminum, anti-seize with graphite in it will corrode aluminum, etc. Finally, anti-seize with zinc in it (presumably the safest choice for steel-to-aluminum) has a low temperature rating: 700 F.

https://rennlist.com/forums/6458379-post8.html

I have sent an email to Roger to find out if the replacement WP bolts were stainless steel (I have a bad feeling they were). In which case, it seems like I'm going to have to go back and redo the WP, although I'm not clear on how to get the anti-seize out (brake cleaner?), and replace it with zinc-based anti-seize.

As for the spark plugs, I am leaning toward a dab of copper anti-seize and torquing them to the lower value (18 ft-lbs). I realize it doesn't agree with the vast majority of advice, but I have had too many experiences with seized bolts, and it seems like the nickel plating of the Bosch plugs should be a sufficient barrier from the steel.

Thoughts, gurus? Sorry to resurrect this topic.

EDIT: Just found out from Roger that the replacement WP bolts are galvanized zinc. So I think that I'm going to let sleeping dogs lie, and leave the copper anti-seize with the WP bolts. I have become the PO that I was warned about.

Mrmerlin

I think the bolts you get from Roger are carbon steel,
and pretty much any anti seize you use here will be better than nothing ,
as the real culprit is coolant migration into the bolt threads.

For the WP bolts I am now using the Loctite PTFE sealant,
so to prevent coolant from migrating into the bolt holes thus no corrosion,
and for the plugs silver anti seize.

danglerb

What you need is a Goo roo.

Foz

LOL. That's a good one.

Leon Speed

Spit is the best anti seize.

General consensus is silver paste for steel to aluminum and copper paste for steel to steel.

GlenL

Really? I thought it was the other way around. Still, I use Permatex silver on most everything. I asked a Permatex salesman about that and he, not unexpectedly, said it was fine.

LT Texan

+928

ROG100

Our WP bolts are zinc galvanized steel - SS would be too weak IMOO.
Any antiseize is better than NO antiseize or whatever Mr Merlin said.

SeanR

That's how I do it. And for the love of God, you don't need to coat the entire bolt with the stuff, just a small bit will work.

Bill Ball

As to spark plugs, I follow what Porsche and the plug makers recommend, as you noted - No goo.

The oil leaking past the cam cover donut seals is a nuisance. if it's only one or two and not bad, you can try one of the stop-leak oil additives that swells rubber seals. Worth a try if you don't have time to do the covers now.

Foz

Ended up using silver anti-seize on the spark plugs (Permatex 133A). Torqueing them to 18 ft-lbs was kind of nerve-racking, but it went smoothly. Two of the wells (#5 & #8) had significant oil. Blew it out for now - I'll do the valve cover seals later.

Hilton

Yes, for the threads, just a little is needed. Although for some suspension bolts the WSM specifies coating the shank with Optimoly TA (i.e. silver antiseize). (I know Sean knows this.. just mentioning it so others will think to go read the WSM when working on stuff )

Joe Twill

With spark plugs, I am more comfortable to keep track of how much the torque wrench turns after first resistance is felt. I would expect a reasonable torque reading (1/3 lower with anti seize) when a new plug is tightened 90 degrees (30 degrees used plug). This has worked well on other machines I have, I would be interested to know if it works on a 928.

The scientific problem some have with Copper anti seize, from what I can tell, is that aluminum will be eroded and deposited on the copper due to galvanic corrosion and the relative galvanic ranking of aluminum and copper. So the concern would be that the threads in an aluminum block would dissolve with copper anti- seize. When I took out the block anti freeze drain plugs in my 1979, they came out just fine...and were coated with, guess what, copper anti-seize right from the factory. Galvanic corrosion needs an electrolyte, like moisture, for it to happen. Who knows, maybe the goop in the HT keeps the moisture out. Whatever the reason was, I decided to stay with what works, and I use copper anti seize on the drain plugs.

On the original water pump bolts, I could see an occasional flicker of copper, but it did not look like copper anti seize. So I use silver anti seize instead. I think the most important thing here is the coating on the bolts. I reused my original bolts because they looked great and probably have a (black chrome?) coating that is no longer done due to enviornmental reasons. The newer bolts might be zinc, but I wonder just how thick the coatings are since these bolts seem to break alot. So again, I stayed with what works. As always, anti seize is all very confusing and conflicting for sure.

Joe
79 5spd

Fogey1

Foz did well. And thanks. For those who want to read more, here's some more. There's likely some duplication. My apologies.

https://rennlist.com/forums/928-foru...lubricant.html
Wheel Nut Lubricant

https://rennlist.com/forums/928-foru...itability.html
FYI - Anti-Seize Lubricant Suitability

https://rennlist.com/forums/928-foru...-lugs-etc.html
Special antiseize for lugs etc...

https://rennlist.com/forums/928-foru...itability.html
FYI - Anti-Seize Lubricant Suitability

COMPARISON OF ANTI-SEIZE TYPES
http://depacproducts.net/anti.html

On 4/6/09 I wrote to NeverSeez and got the answer below:
I am interested to know if there are any types of anti-seize that should not be used in some applications for reasons of galling or corrosion or otherwise.
Specifically, I am concerned about steel and aluminum alloy. For instance, steel bolts in an alloy engine block or alloy lug nuts and rims attached to steel wheel studs and rotor hats.

Your concerns are genuine. Not all anti-seize formulations are compatible with these types of applications. Actually there are only two that are currently available that would be recommended. In most cases anti-seize will contain nickel powder, which will gall aluminum & stainless threads if torqued to tight. Also, when you have dissimilar metals being joined together, you will get galvanic action which will seize the connection. So, to prevent these things from happening you should use one of these two formulations:
http://www.neverseezproducts.com/marine.htm
http://www.neverseezproducts.com/heavymetalfree.htm

will
83s 5spd

depami

Spark plug threads only require motor oil. Only remove plugs when cold, never hot. Feel is as or more important than torque wrench reading when installing spark plugs.