Spark Plug Questions

[Gary Lewis]

You'll see a parallel post entitled Exhaust Noise Questions, which was caused by noise in the headers I've recently noticed.  And that prompted me to pull the plugs today in an effort to rule out a fouled plug or an overly-rich mix.  But as you'll see, the plugs say the mix is not rich.

I'll show two pics of the plugs below, but my question is what to go back with.  These are NGK UR5's, but I recently bought UR4's to replace these, and I just discovered that these are one notch hotter than the 5's.  So I'm thinking that I don't want to go hotter give the state of these plugs - would you agree? 

The plugs on the left have been turned to show the color, which isn't all that much.  And on the right the color is turned away from the camera.  But the white is about as white as the new plugs I bought.

Comments, please!

[85lebaront2]

I would go one range colder UR6 would be my guess. Your "header noise" could be some light detonation.

[viven44]

These look Textbook good  Nicer than any of the ones I've ever pulled out

[ArdWrknTrk]

Plugs look fine to me. 🤷‍♂️

Remember, todays gasoline is NOT yesterday's gasoline (and not the damned MTBE that turned your plugs orange either)

[Gary Lewis]

Jim - Yes, the plugs look good to me.  But I wanted an opinion on whether or not to change plugs and, if so, which way.  Bill suggested colder by a notch, but I'm sure he meant not hotter like the plugs I have.

Vivek - Remember, I'm running EEC-IV EFI, which controls the AFR tightly.  And I have it tuned to give 14.7:1 AFR, not the 14.0 that most EFI units are set to.  My theory is that the 460 gives enough power at slightly leaner mix, and that gives better MPG.  But it'll still go down to ~13:1 with heavy throttle.

Bill - Ok, I'll get some UR6 plugs if I can.  But do you think the "header noise" is detrimental?  Is there a way to prevent it?  It is annoying.

[Gary Lewis]

Got the UR6 plugs on order via DeWayne today.  Hopefully they will be in on Monday, so I spent the day scanning in documents.  

[ArdWrknTrk]

When you get to UR8 they're pretty much race only plugs and very hard to get your hands on... DAMHIK!

What do you hope to achieve?
Modern fuel is NOT going to look like leaded 99 supreme from the early 70's.
If you expect that you're going to be disappointed.  

[ArdWrknTrk]

Gary Lewis wrote

... do you think the "header noise" is detrimental?  Is there a way to prevent it?  It is annoying.

Turn up that new bass speaker and fuggetaboutit

[Gary Lewis]

Can't hear the subwoofer for the noise.  But I can sure feel it!  

As for what I'm trying to achieve on the plugs, I don't want to put used plugs back in.  Most of the plugs aren't hard to get to, but #8 is a bear.

That raises the question of what plugs to go with.  I was thinking these 5's looked like they may have been slightly hot, so when Bill suggested the 6's I thought I'd give them a try.

[ArdWrknTrk]

I use UR4's, but your EFI head is completely different than D9TE castings.

[Gary Lewis]

Yes, it is.  But the spec's I've found call for UR4's for them as well, which is why I had DeWayne order them.  But clearly I shouldn't be going hotter.

[BigBrother-84]

ArdWrknTrk wrote

Gary Lewis wrote

... do you think the "header noise" is detrimental?  Is there a way to prevent it?  It is annoying.

Turn up that new bass speaker and fuggetaboutit

[mat in tn]

if you can't drown it out then you aint got enough sub!

[ArdWrknTrk]

If it doesn't pop the windshield seal you don't have enough sub.

I joke that my 8" is a sub-sub..

[mat in tn]

ahh yes . back in the 90s I could shake my eyes in my head. when I realized it was more than just shaking the mirrors I was impressed.

[ratdude747]

Just don't end up in this video!

[Gary Lewis]

Not a chance with the little 8" Kicker.  But it does everything I want.  And since it is bolted to the seat frame you get to feel it at times.

Gotta try the 1812 Overture!

[ArdWrknTrk]

Somehow I pictured Wagners Ride Of The Valkeries.  

[85lebaront2]

I used to go out for lunch before the yard shortened our lunch break from 1 hour to 30 mins and laugh at the Honduhs and similar with their subwoofers making the doors oil can. They sure sounded like tin cans with the buzzy bass.

[1986F150Six]

Gary, have you had time to install the cooler range spark plugs?