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C2H5OH
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Discussion Starter #1 (Edited)
There is good reason when I say to stick with Motorcraft or Autolite spark plugs, and here is why:


Autolite XP5364







Bosch Platinum +2 4315








NGK Iridium IX TRX5IX 7397





Looks like one just doesn't fit quite right eh.
I'll order some more and test fit them and be back.



zetec master spark plug list

First, this list includes plugs that are either 25mm (.984") reach or 1" (25.4mm)reach, be sure to check which you are thinking of buying.

I still have to get proper info on heat ranges, which vary by manufacturer, and link them in.

List is a work in progress just like the pictures.

List can be viewed here --> http://spreadsheets.google.com/ccc?key=pvM_S91qF4IgOFFYKeZdQMg


To be continued ...
 
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C2H5OH
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Discussion Starter #3
Use the first photos as reference.

The Bosch would work as far as reach, but their quality is lacking IMO.
 

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Focus "Sleeper"
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The ZEX spark plugs are too short too. Not to mention they are disgustingly expensive. Didnt know then that the motorcraft coppers were the best I could get, and about 1/3 the price. Car ran like crap with the zex plugs. Thought they would be better cause they made my nitrous kit and i figured if anyone knew about nitrous, it would be them. Nope. Not the case.
 

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^Maybe they did that so the heat of the plug wouldn't cause any detonation. Instead of keeping the plug cold they just put it so far away from the cylinder it wouldn't detonate. Lol.
 

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i previously ran with the bosch plugs and cyl. #1 and cyl. #4 would misfire. i ran into a guy at advance and he told me that autolite is the way to go with fords. my engine runs alot better now plus they are quite a bit cheaper.

p.s. - my eninge sometimes misfires tho, not as much as when i ran the bosch plugs tho. i dont have any clue as to why #1 and #4 misfire tho. i have changed plugs, wires, and fuel filter. the only thing left that i know of is: ignition and fuel pump.

anybody have any pointers?
 

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C2H5OH
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Discussion Starter #8
Bad coil would be a good bet.
 

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NGK Iridium plugs are great too
 

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the Motorcraft coppers look to be longer than the autolites. and i love the coppers there is a difference.
 

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The reason why the NGK plug doesn't fit correctly is because it is the wrong plug for the application. NGK LTR5IX-11 4344 is listed as the plug for the zetec.

one key aspect of this part number is the "L" which denotes the reach of the plug (~25-26mm).
 

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C2H5OH
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Discussion Starter #13
^^I know that, but if you go on O'reilly web site and look by application they are listed for the zetec. No clue why. I had told them this 2 years ago and they have yet to believe me. Maybe some photographic evidence will make them change it.

I'm just buying plugs that parts systems have listed for our cars, not necessarily what is correct.
 

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[cool] Here is the difference between short vs long plugs

http://www.carcraft.com/howto/ccrp_0703_picking_the_right_plug_for_power/index.html

Thread reach does vary, but the two most common flavors are the short 0.460-inch and the longer 0.750-inch versions. The longer thread reach is generally used most often with aluminum heads, while the shorter versions are used with iron heads.
Most Gen III GM V-8 and some Ford engines use tapered-seat plugs with an in-between 0.0708-inch thread reach. If you use slightly longer 0.750-inch thread-reach plugs, a portion of the threads will protrude into the chambers and cause all kinds of grief and possible pre-ignition problems. This is why the right spark-plug application is so important.

So for fords, shorter is better since the only picture of the plugs not inside the chamber is the NGK. If you didn't get good performance from the NGK's then you should check the gapping, too wide and you will actually slow down the car.
 

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C2H5OH
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Discussion Starter #15
Hey great you can read. Thank you for displaying that. Now find me something application specific or better yet find the people who have had good luck with NGK or Bosch vs those that run Autolite or Motorcraft. You will find quite quickly that you are wrong. Trust me i love NGK with a passion, but they do not make the proper reach for the zetec.

and you want the plug in the chamber. I'm not sure how you figure you wouldn't. The goal is to expose the largest amount of spark to the largest area of air/fuel mixture to induce the burn.
 

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in australia ford specifies the zetec with ngk iridiums (or so my mechanic tells me). thats what i had put in last service and the car runs absolutely fine. been 6 months now and i've never had a misfire or anything. my mech says ordinary (non iridiums) work fine but i would need to change them much more often.
 

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and you want the plug in the chamber. I'm not sure how you figure you wouldn't. The goal is to expose the largest amount of spark to the largest area of air/fuel mixture to induce the burn.

If you read the article, it states that having the plug too far in the chamber can be counter-productive. Besides do you know what happens in the cylinder when the spark ignites the fuel/air mixture? A "bubble" of combustion occurs that is formed as the gasoline burns in excess oxygen. That means that as the reaction spreads, it spreads evenly across the cylinder wall causing the piston to move. This also means that you want to minimize the amount of plug sticking out into the chamber because the heat from the reaction can actually ruin a plug.

Here is a nice demonstration from pulstar of what happens when your plug sparks http://www.pulstar.com/ignition-velocity.html
 

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anti svt
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well here is an equation we can all understand. my focus: ngk - car ran like crap, Motorcraft - car runs awesome. the only thing i use ngk in are my sled and dirt bike and they run great with them just not the focus
 

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has anybody heard anything good about the autolite copper's?

do they compete with the motorcraft's?
 

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in australia ford specifies the zetec with ngk iridiums (or so my mechanic tells me). thats what i had put in last service and the car runs absolutely fine. been 6 months now and i've never had a misfire or anything. my mech says ordinary (non iridiums) work fine but i would need to change them much more often.
Fords never come with anything but Motorcraft plugs in them from the factory.... I think your mechanic wanted to sell you a set of expensive plugs.
 
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