Dialectric grease necessary?

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i re-call when i did my tune up, i did not apply dialectric grease on my spark plugs. is there any benefits of this?
 
Apply a thin coating of dielectric grease to the porcelain and terminal of the new plug, to help prevent misfires and to make it easier to remove the boot from the plug.
 
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Originally Posted By: Billbert
Better seal (boot to plug) and much less likely to tear the spark plug boot the next time you remove a plug wire


+1
 
Originally Posted By: labman
Originally Posted By: Billbert
Better seal (boot to plug) and much less likely to tear the spark plug boot the next time you remove a plug wire


+1


+2
 
sparkplug.jpg


where do i lube? a or b?
 
What I never could get about using the dielectric greas is if you apply it to the porclean area it seems that the plug bot would wipe it off. I guess you could apply the grease to the inside of the boot and the spar plug terminal. but if it's dielectirc greas, isn't insulating electric flow if its on the terminal?
 
A is what counts, B won't hurt.

Mechanicx
The boot won't wipe enough off to prevent it from working
 
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I would recommend against using dielectric grease on the actual contacts. By definition, dielectric materials do not conduct electricity. Your plug will probably still fire, but the resistance in the connection is likely to be increased. This is not a good thing.
 
I've coated the inside of the boot, and have also coated the plug. I seem to go back to coating the inside of the boot. I never had a problem getting a spark plug boot off coating the inside of the boot. Not coating the plug or the boot can make future removal a real PITA.
 
Originally Posted By: pottymouth
I would recommend against using dielectric grease on the actual contacts. By definition, dielectric materials do not conduct electricity. Your plug will probably still fire, but the resistance in the connection is likely to be increased. This is not a good thing.


I understand your thinking. In the case of a spark plug, the metal is going to press against metal and make the film so thin that the high voltage will pass no problem.

Now for lower voltage connections, the worry seems justified. However many even fill RF connectors with that stuff, and I have not heard a resulting problem -- yet. The theory is that you are displacing air and water.

The phone company uses gel-filled connectors for reliability. That is a low voltage situation, and they are very tuned in to the best ways to make connections. http://solutions.3m.com/wps/portal/3M/en...ificationChart/
 
Originally Posted By: ryan2022
I've always used it, but I'd bet if you took it to most shops to have done, they wouldnt bother.


My mechanic replaced a bad plug wire on my Sentra. I was working on the car one day, and found a large tube of Dielectric grease by the battery. It was fun giving it back to my mechanic. He was a great guy to deal with.

I have had a tiny 1/3 oz tube for 15 years. A little goes a long way.
 
Originally Posted By: Carbon

Now for lower voltage connections, the worry seems justified


The contacts will displace the grease when you plug them together. I know a mechanic who believes that using grease on lower voltage connections makes them more reliable and reduces come-backs. I think he's right.

By the way, I've used those Scotchlok connectors to splice Cat5E cable and it works at 100mbps.
 
Originally Posted By: Carbon
Originally Posted By: pottymouth
I would recommend against using dielectric grease on the actual contacts. By definition, dielectric materials do not conduct electricity. Your plug will probably still fire, but the resistance in the connection is likely to be increased. This is not a good thing.


I understand your thinking. In the case of a spark plug, the metal is going to press against metal and make the film so thin that the high voltage will pass no problem.

Now for lower voltage connections, the worry seems justified. However many even fill RF connectors with that stuff, and I have not heard a resulting problem -- yet. The theory is that you are displacing air and water.

The phone company uses gel-filled connectors for reliability. That is a low voltage situation, and they are very tuned in to the best ways to make connections. http://solutions.3m.com/wps/portal/3M/en...ificationChart/



I have no doubt the plug will still fire. It still makes little sense to me to use a non-conductive product when conductive greases are available. You get all the benefits of protection from corrosion and the lowest possible resistance short of soldering the contacts together. Any electronic supply hous will have it, many hardware stores and there are also online sources.

Higher resistance will cause additonal heat. Not a good thing.

I know that many people use dielectric grease on everything and report no problems. OK by me, but I prefer to do things the best way possible.
 
I think the others made a good point that the terminal connecter will wipe the dielectric grease off and not harm the connecters conductance. You have to use dielectric as opposed to grease that is conductive because you don't want electricity conducting away from the terminal connection.

I always understood that you made the electrical connection then applied the dielectric grease. With plug wires you have to apply the grease first, but the terminal connector probably wipes it off. I've always applied it to inside the plug boot and have had no problems, but I always wondered about it.
 
Originally Posted By: mechanicx
I think the others made a good point that the terminal connecter will wipe the dielectric grease off and not harm the connecters conductance. You have to use dielectric as opposed to grease that is conductive because you don't want electricity conducting away from the terminal connection.

I always understood that you made the electrical connection then applied the dielectric grease. With plug wires you have to apply the grease first, but the terminal connector probably wipes it off. I've always applied it to inside the plug boot and have had no problems, but I always wondered about it.


There's really no danger of a short inside the plug boot. Naturally, conductive grease should be used sparingly. There should still be a ring of dielectric applied to the inside of the boot to luricate and seal the boot/porcelain connection. Again, it should be applied sparingly.

This debate has been going on for a long time and never quite gets resolved. Yes, the mechanics of the connection between terminals will displace the dielectric grease at the points of contact. Keep in mind that this is cold. As the connection heats up due to both current flow and engine heat, the connection gets tighter. There will be compromise between these surfaces that make upn metal expansion. I doubt it will be enough to keep the plug from firing, but it will occur.

Again, people can keep using dielectric on contacts and will pribably notice nothing bad. It's just like peple that use crimp on connectors whe n installing electronics. It will work, but is not the best way. Solder will always offer the least resistance, but most people will never notice. I just don't generally stop at good enough. Maybe that's why some projects take me so long...
 
Ford used to use some sort of white grease on low-voltage terminals like the EEC-IV (ECU connector) pins. They came from the factory that way.

Those terminals were also crimp-on terminals. Nothing wrong with a crimp-on terminal if you use a good crimp tool, which excludes just about anything that doubles as a bolt cutter and wire stripper.
 
I could be wrong (and so would be a lot of other very reliable sources) but I just don't think you'd ever want or need conductive grease on a terminal. That is what the metal conductor is for, to conduct electricity. If you put some kind of conducting material inside the boot and terminal you would be conducting voltage from the terminals. You do not want this and is why wires are covered with rubber boots in the first place.

Sometimes dielectric grease is used on the base of electronis like ignition modules, chips etc to also aid in cooling.
 
Dielectric grease prevents arcing. I used to (15 years ago) have an old IBM monochrome monitor. The flyback (which probably runs at about 10kV) started arcing. The arc actually burned a hole through the side of it. You could see it sparking and hear it crackling when the monitor was on. I applied some silicone caulk to it and that stopped the arcing. I probably could just as easily have used dielectric grease, but I didn't have any. The electrical insulating properties of dielectric grease are at least as good as silicone caulk.

Dielectric grease displaces air from the connection. Dielectric grease is actually a better insulator than air--and it also keeps water and dirt out of the connection. Air can ionize, once that happens, it conducts electricity. It becomes a very poor insulator! You could almost imagine that air is like a wall, and the voltage a battering ram. Once the voltage has gotten high enough to punch through that wall, there's a big gaping hole allowing all of the voltage in the circuit to leak through it.

Dielectric grease is a much stronger wall than air is. It does not ionize as easily as air.

I'm not sure that heatsink grease is the same as dielectric grease. Heatsink grease often has zinc oxide in it to make it conduct heat better.
 
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