When to change plugs

[ugltrk]

1996 Ranger Supercab W/ 86,000 book says to change @ 30,000
also states 100,000 tuneup, pulled one from each side to check condition
both looks good, the step at the tip is still good, no burn/deposits.
Also some models I'm told use different #s on right/left side (wanted to check that), same #s both sides(why different #s)

purchased in 1998 w/ 8,000 mi.
mobil 1 5/30 very little consumption no add between changes
MPG...19/21 local..24/26 hwy
3.0 5 speed

 

[Wicked_Sludge]

which book are you looking at? the owners manual?

most ford vehicles have a reccomended plug service life of 100,000 miles...yours should be no different.

ive never heard of people using different plugs (or did you mean different service intervals?) for different sides of the motor. the only reason i can think of that someone would try this is because your truck is waste spark and half of your plugs will wear the electrodes down faster than the other half. but at any rate, change all the plugs with the same numbers at the same time, dont mix and match. make sure you use a double platinum plug or else you'll be changing them again in no time.

 

[ugltrk]

WS,
Maybe the different plug # was the double plug engine...The small maintainance schedule book that comes with the vehicle is where I got the info, where it states @ 5,000 mi, change oil/filter, lube this, and that,etc states at 30,000, 60,000 change plugs.
I had thought I would change them @ 100,000, using AWSF32PP Motorcraft, which is what is in there from the factory.

Thanks for the reply, great forum BTW...Bill

 

[Wicked_Sludge]

the 3.0 isnt a double plug engine. the only ranger engines that ever had 2 plugs per cylinder were the 4 bangers starting in '89.

if the plugs look fine and the gap isnt way out, then i'd let them slide till 100k. my '93 had the original plugs in it when i got it at 94k and when i pulled them to inspect, they were just about due. using factory replacement plugs is an excellent idea...this way you know you have the proper heat range in there.

 

[hades]

The book you were reading confused you as I see it. Well I hope Wicked_Sludge here has helped you be enlightened.

__________________
Ford Parts Online Blog

 

[fixizin]

Yes, the OEM plugs ARE differing part #'s on the left bank vs. the right bank; the reason for this is the dual-phase ignition, and the high cost of platinum, i.e. on one bank the spark jumps from center electrode to GND electrode, and on the other bank from GND to center electrode... the platinum only goes on the "landing" side, where the pitting would occur absent platinum.

IIRC, the Motorcraft REPLACEMENT plugs simply coat both electrodes with Pt, to avoid confusion by DIYers... at the factory there's no confusion, and they save a few pennies.

Very good explanation in this thread:

http://www.therangerstation.com/forums/showthread.php?t=19381&highlight=ignition&page=2


Back on topic: If you're still getting 24-26 on the hwy, I'd let it slide, unless you've set aside time and gumption to dive into other maintenance anyway. (Auto tranny guys are reluctant to believe I get 25MPG hwy w/ the 5-spd stick... lol.)