Spark Plug Thread Lubrication?

[razor66]

What the recommended practice is for lubricating spark plug threads for use in aluminum cylinder heads - none, anti-seize, motor oil,..... ?

[Schurkey]

Anti-seize

[Ron Golden]

Anti-seize!!!!!! Without it the sparkplug WILL seize in the aluminum and you'll strip the threads. The same goes for all bolts screwed into aluminum.

Ron

Spelling error.

[razor66]

Anti-seize is what I used last time I changed my plugs as I just thought it would be the right thing to use as it is what I use to keep bolt threads from galling, but then I later did a web search to see if it was the correct thing to use and I found a lot of information stating that no lubrication should be used on the threads as it can lead to fouling of the plugs and improper torquing of the plugs. So, thought I would check with the experts here to get the straight scoop. Thanks for the input.

[Baprace]

Anti-sieze for spark plugs / bolts in aluminum is correct.

[wjnielsen]

I've always used motor oil.

Never had a problem pulling plugs back out, whether in iron or aluminum. And the first couple shops I worked at would see the same cars year after year, so that's a valid sampling.

If they were in there for ten years, like a thermostat housing bolt... anit-seize only. For a spark plug that's only going to be in for a year or so... 30 wt. is fine.

Oops... if you're putting platinums in a motor for someone, I s'pose you might want the anti-seize; the owner may leave plugs in for five years.

For myself, I would rather swap plugs every year on anything where they're not a bitch to get at; I think it's good to have a mechanic see the spark plugs on a regular basis. But, that's really off the topic at hand.

-Bill

[JohnnyB]

Anti-seize is what I used last time I changed my plugs as I just thought it would be the right thing to use as it is what I use to keep bolt threads from galling, but then I later did a web search to see if it was the correct thing to use and I found a lot of information stating that no lubrication should be used on the threads as it can lead to fouling of the plugs and improper torquing of the plugs. So, thought I would check with the experts here to get the straight scoop. Thanks for the input.

Id much rather be able to get a fouled plug out and a new one back in, than to rip out the threads and not be able to get any plug in. Hot aluminum with steel threads on the plug without anti-seize is a garunteed 100 percent way to seize the plug in the head over time. Don't gob it on or you will contaminate the cylinder. But carefully get it all the way around the threads. If you get too much on wipe some off. Aluminum and steel together WILL corrode together if left bare. Heat accelerates it. Anti- seize prevents or reduces it. Your choice, they are your heads.

[Fahlin Racing]

Anti-seize is what I used last time I changed my plugs as I just thought it would be the right thing to use as it is what I use to keep bolt threads from galling, but then I later did a web search to see if it was the correct thing to use and I found a lot of information stating that no lubrication should be used on the threads as it can lead to fouling of the plugs and improper torquing of the plugs. So, thought I would check with the experts here to get the straight scoop. Thanks for the input.

I remember sitting through the Permatex seminar during tech school and the rep had mentioned their anti-seize is aluminum based. In turn would (hopefully) continue to help the heat transfer to be close to correct as possible. I have not researched it extensively but that is what I remember.

[SchmidtMotorWorks]

I think it depends on how long the plugs stay in the heads and how much you tighten them.

Some people I know like to put plugs in a little more than finger tight, I have never been a fan of that.

[JohnnyB]

I think it depends on how long the plugs stay in the heads and how much you tighten them.

Some people I know like to put plugs in a little more than finger tight, I have never been a fan of that.

Agreed, But many people leave plugs in for extend period of time. How long is too long? Id hate to find the answer to that question by finding my threads still wrapped around the plug when I did get it out.

[wjnielsen]

Id much rather be able to get a fouled plug out and a new one back in, than to rip out the threads and not be able to get any plug in. Hot aluminum with steel threads on the plug without anti-seize is a garunteed 100 percent way to seize the plug in the head over time. Don't gob it on or you will contaminate the cylinder. But carefully get it all the way around the threads. If you get too much on wipe some off. Aluminum and steel together WILL corrode together if left bare. Heat accelerates it. Anti- seize prevents or reduces it. Your choice, they are your heads.

Well, here's one for ya'. Not quite fouled, but had a bunch of idling and cold starts. Don't think I can put enough load on the motor on the street to keep the plugs clean. This has had about 6 months of heat cycles on it; look at the threads and you won't see any aluminum. When I pulled it out an hour ago, it spun out easy by hand after the initial crack loose w/ wrench. Lubed w/ 30 wt.



BTW, not to derail the thread, but if anybody can discern anything about timing from the electrodes on this, please PM me or post up on a plug reading ??? thd that'll pop up here soon.

Edit: looks like the image on the post don't show the business end of the plug... got to click on the attachment. One of those days.

-Bill

[rally]

I would never use anti-seize on spark plugs period and on Aluminum heads to boot. I talked to an Autolite spark plug tech person and he told me dont use it, it causes fouling, misfire, etc. I run Aluminum heads on my drag motor. The only way i pull any plugs out is when the engine is cold, the next day. I never remove plugs to look for correct jetting, i jet for best MPH. I have removed plug #1 for TDC after a pass but will not do it only if i really have to. Save the heads and threads, remove only when cooled down or next day.

[JohnnyB]

Id much rather be able to get a fouled plug out and a new one back in, than to rip out the threads and not be able to get any plug in. Hot aluminum with steel threads on the plug without anti-seize is a garunteed 100 percent way to seize the plug in the head over time. Don't gob it on or you will contaminate the cylinder. But carefully get it all the way around the threads. If you get too much on wipe some off. Aluminum and steel together WILL corrode together if left bare. Heat accelerates it. Anti- seize prevents or reduces it. Your choice, they are your heads.

Well, here's one for ya'. Not quite fouled, but had a bunch of idling and cold starts. Don't think I can put enough load on the motor on the street to keep the plugs clean. This has had about 6 months of heat cycles on it; look at the threads and you won't see any aluminum. When I pulled it out an hour ago, it spun out easy by hand after the initial crack loose w/ wrench. Lubed w/ 30 wt.



BTW, not to derail the thread, but if anybody can discern anything about timing from the electrodes on this, please PM me or post up on a plug reading ??? thd that'll pop up here soon.

Edit: looks like the image on the post don't show the business end of the plug... got to click on the attachment. One of those days.

-Bill

I've used oil in the past too. As long as you don't over torque em, and they get pulled in and out on a regular basis, you will probably be OK. The key word is probably. However, get em really hot, slightly over torqued, and pull em while hot and maybe not soo good. Two dissimilar metals in contact with each other will corrode. Its physics. I may be wrong on the terminology but I think its called galvanic corrosion. An electrical signal is formed by the two different metals and material is transferred from one to the other. If left together long enough, it will happen. Not maybe, but for sure. How long is that time???? The oil works OK, anti-seize works better.

[MadBill]

I would never use anti-seize on spark plugs period and on Aluminum heads to boot. I talked to an Autolite spark plug tech person and he told me dont use it, it causes fouling, misfire, etc. I run Aluminum heads on my drag motor. The only way i pull any plugs out is when the engine is cold, the next day. I never remove plugs to look for correct jetting, i jet for best MPH. I have removed plug #1 for TDC after a pass but will not do it only if i really have to. Save the heads and threads, remove only when cooled down or next day.

The Autolite guy's position sounds like the cautious outlook of someone more concerned with being slagged for manufacturing a 'defective' plug than of someone interested in the long term viability of the engine. Applied sparingly anti-seize is all good.

[MadBill]

...Some people I know like to put plugs in a little more than finger tight, I have never been a fan of that.

I have a pair of plugs that were factory-installed 'finger tight'. They got so hot due to poor heat transfer in a stock TPI Firebird we were running at Road Atlanta in 1989 that the center electrodes disappeared and the porcelain softened and leaned over like The Tower of Pisa.