Superseded Motorcraft Spark Plugs Have Longer Threads

ATCzMustang

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So I ordered Motorcraft Spark Plugs for my 2001 SVT Cobra (using my VIN to get correct part) and here is what I got:


Motorcraft SP-433 AGSF32WM Platunum


When I pulled the plugs from the block to change, I noticed the plugs appear identical (overall length, size, gap) but had a much shorter cut thread length overall on the barrel shaft. The old plugs had a different part number too:


Motorcraft AWSF 32E Platunum


The plugs appear identical, but the old threads maybe go up from the bottom 1/2" until a smooth taper and the new ones go up probably a full 1" to the plug taper.


I called Ford thinking I have the wrong plugs. They confirmed the AWSF 32E plugs were the original plugs and part # for this car but were superseded by the AGSF32WM plug. Normal - parts change a lot.


I explained the concern and they checked, double checked, and triple checked that the new part was proper for my car. They transferred me to a 'specialist' and he confirmed the new plug number and said the reason for change is that plug is used in multiple cars now most likely. Since the block is tapered, the plug will go in and stop (which it did I confirmed) and some threads would stick out the top of the block. The important thing was since the block is tapered, the plug will still only go in the exact same amount and everything will be fine.


Anyone else see this, or changed to new Motorcraft plugs recently? These are supposed to be plugs for 99-04 Cobras.
 
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snakeraper11b

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The threads don't matter if you have more, or less. They are designed to be used with the earlier version and 9 thread heads. If you had a 9 thread head and an earlier style plug, then you're pissing in the wind by not using all the available threads. In our case (99-01) we're fine with either. If you look on your old plugs, you'll see a taper above the threads, just above the part that is now threaded on the news plugs. That is where the plug seats. You will not be screwing the plug down into the cylinder, I assure you haha. You're good to go.
 
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ATCzMustang

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As a quick follow up - I installed the new plugs and they work great. I was careful as the engine has aluminum heads, so hand tight plus 1/8 turn should suffice to prevent damaging the heads.
 

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