'01 Ranger 4.0L SOHC Spark Plug Gap OEM vs Denso

[benjamming]

The pickup has ~ 78k miles on it with factory plugs (nothing wrong with that). I plan on changing them along with the wires that I posted about earlier. I'm looking at the Denso iridium p/n IT16 stock # 5325. This is the correct plug per Denso's online application guide. The factory service manual calls for 0.061-0.068" gap. The Denso plugs come with 0.044" gap. Should I widen the gap on the iridium plugs to 0.061" so that they match the specs in the manual?

So, I looked at the Denso FAQ. If I'm interpreting it correctly, they say leave plug as is assuming that accidental adjustments haven't occurred. Of course, you can adjust but there doesn't seem to be a good reason to do so. What say ye? I'm thinking it's best to leave them as provided.

Also, any need for anti-seize on these plugs? Denso says to cut the torque by 50% if anti-seize is used. The FSM says 13 ft-lb (156 in-lb) which I assumeis dry since the manual doesn't say to lubricate the spark plugs with anti-seize. That would drop it down to 6.5 ft-lb (78 in-lb).

 

[Billbert]

It's best to run factory recommended gap, but you have to be EXTREMLY careful when gapping Iridium plugs because you can break the center electrode so easily.

 

[MrMeeks]

Opening the gap on the Denso plug to 061 could easily break or weaken the electrode.Use Ford rec. plug and gap.

 

[dtt004]

Hi.

You should leave the spark plug as is. Denso's spark plugs are usually "no gapping needed," and in my opinion, make some of the best iridium spark plugs on the market. I have used them with good success, along with NGK Iridum, and currently running Bosch IR Fusion (iridium/platinum) combo plugs. All are great, and so far, all of the iridiums have been gap free to reduce center electrode breakage.

You can visually compare iridium and platinum, copper, spark plugs to see how small the electrode is. The reason for this is that iridium center electrodes can create equivalent "firing" in comparison to a larger platinum or copper electrode. Combined with a higher melting point, decreased voltage requirements, higher oxidation temperature, allows the manufacturer to extend the service life of the spark plug.

Gap for your Ford is recommended with a spark plug that does not have a center electrode made out of iridium. I could be wrong, but I am sure I'm correct. I don't have a manual or experience working with Fords so if I am mistaken I apologize.

Have fun!