Hi from the other side of the pond!
i have a 1999 E350 V8 Triton and i am just about to replace the original plug with a set of NGK TR51X . the only problem i have is i don't know the gap size?
could you guys pleas help a clueless Brit
Cheers Tony

 

Hi Tony!

I just posted the other day my bad luck with NGK, fast wear and they have broken just below the hex on me too many times.

I now use only Champion or Ford/Motorcraft.

But gap I think is .054

 

You might want to use the highly recommended and often cited MotorCraft or Autolite plugs as OEM spec'd for that motor. There are just too many instances of other brand plugs being more problematic than beneficial.

Your gap should be 0.054".

Edit:
Whoops Tony---PST beat me to this! Heed the advice of those who've already "been there, done that" on plugs!

 

You don't need a gap with these.... E3 Spark Plugs They have been tested to improve fuel economy by 10-15 % too ...I believe BOSCH makes a similar style.....

 

One of the reason I have changed is that she's running on LPG. The NGK one are iridium and the champion ones are copper. As LPG runs hotter than petrol I'm thinking the NGK could be the best option. But as its the first time I've ran a LPG vehicle I'm not sure.
Cheers Tony

 

Tony you might want to post this in the Modular V8 forums too----since its LPG there might be a fleet manager or mechanic already familiar with alternative fuels. Link: Modular V8 (4.6L, 5.4L) - Ford Truck Enthusiasts Forums

I assumed it was petrol (gasoline to us Yanks! )---perhaps you'll find a real-world user over in the engine specific forums.

Welcome to the FTE forums BTW!