When to use dielectric grease?

[Shaun @ Tru6]

Here's what I know:

When installing Clewett plug wires, directions say to use dielectric grease at all connections.

Dielectric grease is not conductive.

I'm OK with the hot spark going through the wires/connectors/plugs and the non-conductivity of the grease nullifed if that's the right way to put it. But I've rebuilt my 69E engine electrical panel with various fuses and relays and want to maintain the best e- connections as possible.

What I don't know:
Should I use a light coat of dielectric grease on all terminals to keep corrosion at bay? Will it affect conductivity?

[89911]

It keeps out dirt and moisture that lead to corrosion and lack of conductivity. A great place to use it is the connections in the tailight and turn signal lens that seem to always get moisture in them or anywhere else where moisture is involved.

[Gearbox]

The purpose of dieletric is to minimize corrosion on metal electrical contacts. And yes, it doesn't conduct electricity by itself. But the product is a very thin non oxidizing grease that is meant not to interfere with the circut. In other words, it "squishes" away from the two points to allow the circut to make contact, and to protect the surrounding metal from corosion. I use it on every contact on the car and fuses with no problems, so have at it. Good luck.

[cgarr]

Interesting that you post this now, I just got my 72 out of the barn after 2 years and used the grease on all the electrical connections, especially the grounds, for some reason these German cars are very sensitive to ground issues. All was in perfect order. Another good product in a spray is made by CAIG Labs, www.CAIG.com its Deoxit D5, cleans, lubes and protects electrical connections.

[RWebb]

An Excellence article {Jim Pasha?} said to use it to keep the rubber boots from getting heat-'welded' to the plug insulators.

My real question is when would you use a conducting 'lubricant' rather than a dielectric grease. Jim Sims posted once on a related query but I didn't understand his answer. It was related to whether the metal contacts move or not (e.g. wiping action, as in a switch).

[Jim Sims]

Good electrical contact is made when the surface oxides (corrosion) and dirt are either "wiped" away by sliding action or "pushed through" by the clamping load pushing the contact surfaces together. When a plug/socket combination (for a example a relay into it's base) is assembled the pins and socket receptacle contacts "wipe" against each other, a "Faston" type connector does the same thing as you plug the two parts together, as do most electrical "mechanical connections" with a few exceptions such as mercury switches. These same actions wipe away the dielectric grease so it doesn't interfere with the passage of electrical current. The same principle also applies to sliding contacts - the sliding or wiping action removes the surface oxides and grease except immediately under the contact point or patch.
It is important to understand that unless they are specially designed, most electrical "mechanical" connections make electrical contact at only a single, small "patch" or at most three small "patches". The point of the dielectric grease is to keep the air and water out of these patches so surface oxides and other corrosion doesn't occur. The reason for the mechanical cleaning during maintenance of brass, copper and copper alloy contacts that have been in service is to remove surface oxides and dirt that may be too thick or too well adhered for the joint assembly forces (i.e. the sliding or pushing together) to wipe away or penetrate.
If the contacts are plated with noble metals such as gold, rhodium, etc. or silver, mechanical cleaning should not be used as these surfaces either do not corrode significantly or in the case of silver the silver oxide is nearly as electrically conductive as metallic silver.
I can not think of a place on a 911 where one would want to use an "electrically conductive" grease for electrical reasons.
I use dielectric grease for nearly all electrical connections on my 911 with the exception of points and distributor rotor and spark plug threads. I use a very, very small amount of anti-seize compound on my spark plug threads; it is very important not to get this anti-seize compound on the spark plug ceramic insulator or the spark plug boot and wire. There are differences of opinion about using anti-seize on the spark plug threads but I believe the conclusions that it interferes with electrical grounding or joint thermal conductivity are false.

[RWebb]

Thanks Jim.

Here is the item I was talking about. It feels greasy but I prob. should not have assumed it was a 'grease.'

It is called NOALOX, "Anti-Oxident Joint Compound"

http://www.idealindustries.com/IDEAL-EZ/products.nsf/ItemMasterLookup/
p30-024?OpenDocument

Summary of claims for it:
reduces corrosion of similar and dissimilar metals joining together to make an electrical connection; primarily used for Aluminum cable, but also commonly used on copper
____________________________________

- Do you see any value in it? I went to our local elec. store looking for dielectric grease and the guy told me to use this...

[Jim Sims]

Noalox appears to be a dielectric grease with zinc particles in it; the greasy carrier is probably silicone grease. It will likely work fine for most electrical contacts. I would take care using it on high voltage applications like ignition spark plugs/wires as the zinc particles may promote tracking (shorting) if the grease gets on the spark plug insulators or on the outside of the wires or boots. The silicone grease NAPA sells ("Sylglide"?) works fine as a dielectric grease.

[RoninLB]

i use Graphite-50 on my spark plugs

http://www.loctite.com/int_henkel/loctite_us/index.cfm?&pageid=114&layout=3



the can info refers it to being used w/sparkplugs. Loctite copper, silver, etc make no mention of being suitable for spark plugs.


that's all i know besides figuring that even simple multiplex systems are suceptable to problems w/ improper dielectric.

[Shaun @ Tru6]

thanks everyone for all the great info. going to AutoZone today.

[dshepp806]

I went with Pete Zimmerman's recc on spark plug installs..on a few threads..no antiseize here. It's probably ok to use but EVER so sparingly and AT the right place. Lithium for me....?

[scottb]

I'm reviving this thread to ask a question --

I'm rebuilding an old starter solenoid. Once I get everything cleaned up, would I be doing any harm if I smeared a thin layer of dielectric grease on the various electric contacts?

Thanks!

[Shaun @ Tru6]

Based on the above, I'd say it's a good plan.

When my E goes back together, every terminal outside the cabin will get a film of grease.

[azasadny]

I use dielectric grease very sparingly on any electrical connections (fuses, relays, bulbs, wire connectors, etc...)

[azasadny]

Originally Posted by cgarr

Interesting that you post this now, I just got my 72 out of the barn after 2 years and used the grease on all the electrical connections, especially the grounds, for some reason these German cars are very sensitive to ground issues. All was in perfect order. Another good product in a spray is made by CAIG Labs, www.CAIG.com its Deoxit D5, cleans, lubes and protects electrical connections.

Craig,
Nice bug!!

[burgermeister]

NoAlOx is used when attaching aluminum wire (like the one coming into the fuse box of your home) to said fuse box, or anywhere else connections are made with aluminum wire, which should not be too many places outside of a fuse box these days. I used it when replacing my main breaker box, and for the one in the shop too. Without it, the aluminum could oxidize and eventually the connection may get warm, or hot, or start a fire and burn the place down...

cgarr & azasadny - Slugbug, no Slugbugs Back!!! (NICE BUG!)

I used to work at "Recycled Bugs" in Auburn Hills for a summer...parts for convertibles were always marked up 50%, even if it was the same part as a non-convertible...

[RWebb]

thx burg...