Contour Enthusiasts Group Archives Forums Modifications Duratec Performance What is the best spark plug to use on SVT's????

what is the best spark plug to use on SVT's or Contour? Ford Motorcraft? or NGK ? or what?

I would recommend looking at some of the other spark plug related threads.

here ya go.

Stick with Motorcraft ASWF32-PP or the Autolite double platinum analog.

If you opt for Motorcrafts, DO NOT let the dealership try and tell you that AGSF32 is the suggested replacement. This plug extends into the combustion chamber approx. 5/8" beyond the ASWF plug resulting in stumbling at high rpm's (personal experience).

Art

If the AGSF32 plugs did extend an extra 5/8 into the combustion chamber, wouldn't that bump up the compression ratio and cause possible timing issues. .02

Originally posted by 2112:

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If the AGSF32 plugs did extend an extra 5/8 into the combustion chamber, wouldn't that bump up the compression ratio and cause possible timing issues. .02

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Technically it would yield a "slightly" higher CR. (less than .1) Remember it is only a shell & electrode not a solid object.

However the bumping I would be worried about is the piston & the ground electrode. Plus the fact it disrupts the incoming air charge (flow & swirl) much more sticking that much further into it's path.

I was using the motorcraft plugs, the ones that came with the car which had maybe 20K miles on them when I had all that stuttering in my car early this year. After changing coil packs and new wires it was mostly gone. Anyway, I occasionally got a low rpm stutter/misfire from them so I decided to change the plugs back to the bosh platinum +4's I had used earlier. I had tried the +4's as a test when I had an unmodded 2.5L in the car and didn't find any benefit to them. I warrantied the plugs with Autozone (my buddy is a manager) and changed out the now 20K motorcraft plugs back to the new Bosh +4's. Idle was better and no more midrange stutters. THat has been 7 months and still good.
I learned the ford ignition system inside and out while developing that add-on module for the emanage and I can say that the plugs wires and coils are each equally important to the igniters in the pcm. The trouble is, you need an oscilloscope to see the kind of noise that is being introduced into the coil primaries and by using different plugs and wires.
My advice is to use the factory plugs (posted earlier) so that it gets as close to the orignial impedance on the igniter circuit as it was designed for.
I have put many hours with an o-scope into this ignition sytem and let me tell you that the less noise the system experiences the cleaner the individual sparks will be and the better your car will perform all through the rpm range.

warmonger

Originally posted by Art Hazebrook:

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Stick with Motorcraft ASWF32-PP or the Autolite double platinum analog.

If you opt for Motorcrafts, DO NOT let the dealership try and tell you that AGSF32 is the suggested replacement. This plug extends into the combustion chamber approx. 5/8" beyond the ASWF plug resulting in stumbling at high rpm's (personal experience).

Art

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A freind of mine is a servise advisor at a Ford dealership. I asked him if he could get me some parts including the AWSF32PP spark plugs. I told him the stock ones were crap because they were only single plat. He sent me back an e-mail saying that the plugs I need are AGSF32FM. I told him that the owners manual says to use AWSF32 and that the dual plat equivalent is AWSF32PP. He tells me that the owners manual may be incorrect because they are sometimes printed in advance and they may have changed the plugs after the printing of the manual.
I just asked him to get the plugs I want but he says that their computers are constantly updated and that his part number is correct. He asked for my VIN # and will contact Ford to find out what plugs are correct . I wonder why some dealers have one part number and some have another. It will be interesting to see what he finds out.

I put my old Motorcraft ones back in after running +4's for three years -- The Motorcraft seem to work better in my car. The power band seems to be smoother and the detonation I was experiencing as the secondaries opened seems to be gone. The +4's appeared to be in relatively good shape.

What's interesting is that the center electrode's one the plugs from the front bank are the ones that are worn -- the rears look brand new. I thought the coil pack design was supposed to wear the rears faster? Am I remembering wrong?

-Lance

Originally posted by 99tour:

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I just asked him to get the plugs I want but he says that their computers are constantly updated and that his part number is correct. He asked for my VIN # and will contact Ford to find out what plugs are correct . I wonder why some dealers have one part number and some have another. It will be interesting to see what he finds out.

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The latest Motocraft catalog (much more reliable then the dealer!) still states the use of AWSF plugs in all 99 & older 2.5L.

It only has the 3L (all years - except Jag & LS 3L's) now superceded to the AGSF style and 00-02 2.5L. (except the 00 SVT & Jags - They state AWSF22FS)

I had a lengthy post of this subject in the last few weeks if you want to search for more details.

{mini rant}
This topic only comes up like 5 times a week ( )
{/mini rant}

On the Bosch topic. Mine lasted maybe 2-3k miles. One bank was completely shot, the other well worn for such low miles.

The AWSF22FS plugs I replaced them with looked brand new (after 10k miles) when I pulled them a month ago or so.