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Spark Plugs in 1987 Ranger: Resistor or Non-Resistor?


RolandTrafton

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Hey y'all. I just got a 1987 Ford Ranger Standard Cab 4x4. It's the 2.9L V6. Figured I should give it a tuneup.

I bought (6) Motorcraft Copper Resistor Spark Plugs, but also bought (6) Motorcraft Copper Non-Resistor Spark Plugs because after a lot of googling I couldn't find a recommendation on what to use specifically in my 1987.

Also got a new Motorcraft Spark Plug Wire Set but it doesn't seem to specify use with resistor or non-resistor plugs. I figure they're universal.

The truck's in fairly good condition, but can be temperamental so I want to give it what would result in maximum performance.

So what do you guys think? Resistor or Non-Resistor?

Also any 1987 Ranger Owners out there: What kind of spark plugs do you use?
 


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19Walt93

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Resistor. Motorcraft plugs only for me.
 

franklin2

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If you do not like changing sparkplugs all the time, the next time get something with some platnium or iridium on the tip. They last much longer. Unless it burns oil and fouls the plug. Then it doesn't matter too much.
 

Dirtman

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If it has anything more electronically complicated than a clock in it you use resitor plugs. and while platinum or iridium plugs do last longer in EDIS waste spark systems they aren't really worth the cost for a standard distributor sytle ignition system in my opinion.
 

SenorNoob

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I have yet to see a resistor plug in anything except Honda 3-wheelers.
Although I just looked and see that you really have to read the specs on Motorcraft plugs to tell.

Apparently the SP419A is correct for that application.
 

Dirtman

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I have yet to see a resistor plug in anything except Honda 3-wheelers.
Think ya got that backwards...

Resistor plugs protect eletronics (computers, radios etc) so pretty much every car since the 70's uses resistor plugs. Old fashion crap with simple magneto ignitions like lawnmowers or old atvs don't have anything worth protecting so they use non resistor plugs.
 
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SenorNoob

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I think I've been using them and just didn't know it.

Honda did spec resistor plugs for the mid-80's stuff tho. FSM calls for a DR8EIX
 

RolandTrafton

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This is really enlightening. Thanks guys. SenorNoob: Where did you find the SP419A specification? I have a Chiltons Repair Manual for 83-91 Ranger/Bronco II and it says that the 1987 2.9L V6 calls for a Motorcraft AWSF-42C, but if the Owners Manual for the 1987 Ranger calls for SP419A then I might be more inclined to put those in. OCD alarm going off right now.
 

19Walt93

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Ford has changed the spark plug numbering system, I can decode the old numbers. AW means its a long reach/thread plug- about 3/4" instead of 3/8" below the seat; S means is a suppressor(resistor) plug; F means it's a tapered seat plug that doesn't use a gasket; 42 is the heat range; and the C indicates a copper core plug, P would be platinum, F is fine wire. You may find that the 2 numbers identify the same plug. Make sure to check the gap before installing them.
 

RolandTrafton

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Ahhhhhh got it. And yes, you're right 19Walt93: SP419A is indeed an AWSF-42C, so they do identify the same plug. And obviously S stands for suppressor which means resistor which means Dirtman's right: resistorless is too antiquated for my '87 Ranger. Everybody wins! And I know more about spark plugs now. Thanks guys.
 


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