more on anti-seize

[daveismissing]

....snip..
We had a 2001 Dodge Caravan with a 3.8 engine and a little over 118,000 miles come into our automotive shop. Intermittently it was hard to start. When it did start, it ran rough, misfired, and sometimes under a load, it would even backfire through the throttle body.

We tested fuel pressure, crank and cam sensor signals and scoped both these sensors, at the same time confirming they were in sync and the timing chain was sound. After some experimentatio n, we found we could get it to act up by power-braking the engine and running the RPM between 1,500 and 2,000.

Anti-seize compound made a wreck of this 2001 Dodge Caravan.

The most challenging of these symptoms was the backfiring through the throttle body. For this to occur, combustion has to take place in a cylinder while the intake valve is open. This led us to take a close look at the spark plugs. On plug number three, we found a carbon track where the spark was jumping down the side of the plug. For this reason, we decided to pull the plugs for close inspection.

We found excessive amounts of anti-seize compound on the threads. This vehicle has a DIS ignition system, which uses the threads of the spark plugs as an electrical conductor. We later found out the owner of the vehicle installed the plugs six months earlier and used anti-seize compound. We installed new plugs and cleaned the threads in the heads, and the problem was solved.

We were still curious and confused. How could using excessive anti-seize compound cause the engine to backfire through the throttle body? We checked with three different spark plug companies to see what their ideas were on this subject. All three of them recommended against the use of anti-seize compounds.

They told us they already put a tri-valent zinc dichromate plating on the shells of their plugs to prevent the steel threads of the spark plug from seizing in the aluminum of the cylinder head. They also told us the problem with using oil or anti-seize on the plug threads is that it affects the torque setting. With aluminum heads, it is an important aspect of spark plug service these days to use your torque wrench to accurately tighten the plugs. NGK said that the concern is the threaded outer shell of the plug. If you overtighten the plug, there is a danger of stretching or even breaking the threaded portion of the plug.

They also told us that their recommended torque setting can be misread by as much as 40 percent if the threads have been greased or lubed prior to installation. The danger is not so much that the plug will break, but rather that it will be very difficult to remove the next time around.

They pointed out another problem. Many anti-seize materials come in a jar with a brush built into the top. With such an applicator, it is very easy to put too much goop on the threads. When this happens, installing the plug will effectively pump the excess material either toward the spark gap end or the spark plug wire end of the spark plug. The likely story is that it will do some of both.

Anti-seize compound is basically a mixture of grease and metal particles. Aluminum, copper, and zinc powders are commonly used. The way this works is that whenever you have two different metals, in this case the aluminum of the head and the steel of the spark plug shell, you can set up a battery action if there is an electrolyte between them. This is called a galvanic cell. What happens is that you get a transfer of metal that could cause the plug to effectively weld itself to the cylinder head. Putting the metal particles between the threads of the plug and the threads of the head gives the galvanic cell something to work on rather than the materials of either the head or the plug shell.

Anti-seize works in the same way as putting zinc on a garbage can, which is called galvanizing. It prevents rusting. The zinc sacrifices itself to the rust reaction, leaving the steel protected. The downside to anti-seize is what happens when too much of it is used. The grease and the metal particles can wind up in places where it not only doesn

[Steve Wood]

Now, that is damned interesting!  Not to mention good work on the diagnosing end

[Charlief1]

The best way to use antiseeze is to put a slight amount on the threads of one plug at a time and then put the threads of 2 plugs together. Then move the 2 of them so that you put a very light coating on both plugs. It keeps the excess to a minimum and keeps the shoulder clean so that there's no interferience (sp) with electrical contact.

Most just goop it on and throw the plugs in. The other problem is just the same as an oil drain plug. They try to crank it down so hard that there's no way it'll ever come out.

[tb3]

my powerplant instructor at school would always preach "just cause a little bit does a lotta good, doesn't mean a whole lot will do a whole lot more good"

[SuperSix]

Good info.

I have used a lot of anti-seize on my build so far - lots of stainless fasteners.. I hate getting that shit on my fingers though.

[Steve Wood]

buy a box of nitrile gloves from harbor freight, or such

[SuperSix]

buy a box of nitrile gloves from harbor freight, or such

I can't wear them for very long - I have a skin condition called dyshidrotic eczema that comes from wearing them. I guess I could wear them for a few minutes..

http://en.wikipedia.org/wiki/Dyshidrosis

I've never had it anywhere near as bad as the photos though. Gross.

[$1987 GN$]

buy a box of nitrile gloves from harbor freight, or such

I can't wear them for very long - I have a skin condition called dyshidrotic eczema that comes from wearing them. I guess I could wear them for a few minutes..

http://en.wikipedia.org/wiki/Dyshidrosis

I've never had it anywhere near as bad as the photos though. Gross.

Not with an id?

Strange as I have that condition too.

AJ___

[Charlief1]

Thank you Mark. I've been to doctors several times and they never had a clue what I had. One of the army doctors said I had jungle rot. I have noticed that my feet will break out like this after I wear steel toe boots for long periods which means I must have an alergy to nickel. It explains a lot.

[SuperSix]

Yea - I get little fluid filled bumps on my hands if I wear nitrile, or any latex/rubber/plastic gloves for any amount of time - stress can bring it out sometimes too. I must have a mild case, judging from those photos. It's irritating, but I will live. A week or so after it goes away, I have skin flaking off on my fingers..

It's like the sweat glands close or something.

[Charlief1]

I've had to bandage my feet up if it gets really bad, but I haven't had a bad break out in several years now. At least I know what it is now if I ever have a bad break out again.

[SuperSix]

I've had to bandage my feet up if it gets really bad, but I haven't had a bad break out in several years now. At least I know what it is now if I ever have a bad break out again.

Suck part is there's really no treatment for it.

[Charlief1]

What I've descovered is that if you can keep my feet dry and clean it doesn't effect me as much. I've taken my shoes off at lunch to let them get some air and wash them twice a day. My hands don't seem to be effected as much.

[daveismissing]

.. which means I must have an alergy to nickel. It explains a lot.

Money ACTUALLY burns a hole in your pocket

[daveismissing]

... if I wear nitrile, or any latex/rubber/plastic gloves for any amount of time ....

So you and KGB don't have much quality time in the bedroom?