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Discussion Starter #1
Been doing some reading on Glow Plugs and most know that they will not last forever and when one lives in the cold of Alaska, while it has not been like in the 60's or 70's it is still cold, this winter has been harder and it looks like mine are in need of replacement.
There are two types, single coil and dual coil glow plugs. For 347k I have been using single and it time for the third set of glow plugs. This is a 2000 E350
So my question to all that stop by... Which plugs? Single or Dual coil??????
 

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Motorcraft/Beau ZD-11's only.

Some have been able to use Welmans but I would stick with factory for the glow plugs.
 
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I'll second bugman's recommendation. Too many "stuck glowplug" threads over the years for anything other than ZD-11's. Cheers!
 

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Discussion Starter #4
But if they are not any larger , just built different.
Here is what I am looking at from the seller
And here in Alaska even in the summer for about a month the plugs might not be needed, but about 9-10 months we are using because of temps below 50

"
What is a "dual coil" glow plug?

Dual Coil Glow plugs, as their name implies, have two heating elements instead of just one. The addition of an extra coil allows the glow plug to have a "self-regulating" feature. In the past, glow plug design was a balancing act. If resistance was low, the plug would get very hot quickly, but would burn out. If resistance was high, the glow plug would heat up slowly, and not get very hot, but last virtually forever. Dual coil designs have what is called a "positive temperature coefficient" – the hotter the glow plug gets, the higher its resistance goes. This allows the glow plug to get very hot quickly for faster starts, but gives extended life at the same time.

"
 

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I'd go with the ZD-11's as well. I think I'm on my third set, and only the ones that were in the replacement engine were burnt out (I forgot to have them changed out when the engine was sitting on the shop floor. :() The first set was changed when I upgraded injectors, and they all tested good. Just did that because I was already in there.
 

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Discussion Starter #6
I see that we are still causing trouble...
Ok,
Let me ask this, the ZD-11's, because they have been round and really no one has tried the dual coil?
I know that there are two styles of O rings in my business, one at a x cost and the other at xx cost because of chemicals.. the second is to last longer but in reality it comes in at about the same over all cost.

So could the dual coil be like this? a set of 8 at about 80.00 and that is a bit more than what a set of Fords would cost, but if I would be changing them out in another 150k miles... ?
 

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Have you actually NEEDED to change yours out in that 347K miles? Or were you just doing it for peace of mind (kind of like I did on the first change)?
The engine I put in had 129k on it and 6 of 8 GP's were bad, but that was over 100k miles ago and the ones in the truck are still good.
 

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Discussion Starter #8
She needs to have a engine block heater on to get oil temps to 50 and she starts right up, under the 50 and it will turn over and then if and when it starts there is a White Cloud............ big time....
 

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The big question on the plugs is will they come out of the head without a fight after they burn out?

That has always been the question with aftermarket ones. All it would take would be for one to make you pull the head off of the engine for you to forget about them. I'm not saying that will happen but usually when a owner comes on here and says that they have a stuck glow plug it is usually a aftermarket one.

But like I said, a old owner on the forum here with a IDI has used Welman glow plugs with no problems and I believe that they were dual coil plugs. The only problem is that he hasn't been around for a couple of years in order to ask him if he ever did have any problems with them.
 

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Discussion Starter #10
That is why I am asking the questions. But even stock plugs or Ford can have the same challenges?
 

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Now for my background, I am a fire investigator, and as such we have to learn a lot of stuff about a lot of stuff. One of those topics is electricity and resistance. From the manufacturers quote above... "If resistance was low, the plug would get very hot quickly, but would burn out. If resistance was high, the glow plug would heat up slowly, and not get very hot, but last virtually forever. Dual coil designs have what is called a "positive temperature coefficient" – the hotter the glow plug gets, the higher its resistance goes. " I'm calling this snake oil because resistance and heat ALWAYS do this. They are forever in tandem. Heat goes up, resistance goes up, resistance goes up, heat goes up. This how thermo-couples work, as well as a myriad other electronic heating or heat detecting devices, and is a major culprit in accidental fire causes. When a manufacturer lies to sound smart, I tend not to trust anything else they say. Maybe there is a benefit to the "dual coil technology," I dunno. But the ZD-11s lasted me 210K, came out of the heads without a hitch, and are now replaced with the same thing. Sounds like your experience with them is as good as mine, so if it ain't broke...
 

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Discussion Starter #12
Now this I understand, sounds like I should go with standard plugs for this, Gasket and wires and new plugs should do the trick.
 
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While you're in there, you should measure your injector armature clearance. If you haven't done any work on them you can do a shim kit to make them last a little longer. There is a sticky in the engine forum
 

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Discussion Starter #14
Should be good there, this set was installed at 197k, so they should be?
But will run it by the shop, I do not have the tools or a shop to do this and I would rather spend the time on water treatment rebuilds.
 
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