I'm currently running Autolite copper (cheap) #25's in my 77 Ford F150. Problem is, every 2-3 months, truck starts missing and running like crap and one or two plugs get fouled. Ends up being the back ones on both driver and passenger side. Damn passenger side one is a biotch to get to. Also sometimes some of the others will foul.

Here's the question. Should I go up in heat range for this motor (remember, it's a 400 and is the original/old motor) for the plugs? Any other tips to make these last just a little longer?

I'm pretty sure warming the motor up for 5-10 min. on a winter cold day isn't great for the plugs either, but I do drive about 25 min.to work, so the trips aren't short.

Thanks-

 

They used to make an adaptor that was to stop oil fouling, it was basically an extension you put on the plug, Check at the auto parts store and find an old parts man. It will work till you get the engine fixed.

 

Sounds like the valve guide seals.

Do a compression check, if compression checks out good, it just needs new seals.

 

I have an extra 460 laying around that has a set of those in it. Never have fired it up to see how bad it smokes.

 

 

Do you guys have pictures of EVERYTHING??????

 

Better off fixing the problem rather than throwing on a half baked bandaid. You are depending on the truck to get to work and put food on the table.

 

They used to sell these plugs call fires in oil by Aldor thru JC whitney, You might still find the right one on ebay. The company Aldor is not around anymore. I used them, mine wiere 14mm thread width. They worked great. It was always the same piston that would misfire. The one on the driver side close to the battery #4 piston. Mine is a V6. I found a plug just as good or better at Advance auto made by Bosch. It has 4 prongs/electrodes and had a hot heat signature and last a long time. Mine lasted over a year before I had to replace it again. They cost about $5 each. Ask for Bosch and make sure it has the 4 electrodes as it just keeps on going. When it went bad I took it out and it just looked a bit oily. I good spark plug cleaner or air blow out might make it work again.
Great plugs.

 

WOW a 13 year old post

Being the last 2 plugs I would check the drain back holes to make sure they were open and valve seals as said.
I would also go up a heat range or 2 till I could get this fixed and yes you could run them adapters if you can find them now days.
Dave ----

 

I used those in 3 cylinders in a 390 that was in my 1964 Mercury Montclair YEARS ago.
It did take longer for the plugs to foul but they still fouled.
I carried a spark plug wrench and a wire brush to clean them off when the did.
That was one tired old 390.