Gary Lewis Posted June 28 Share Posted June 28 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? http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/waving_orig.gif 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! Link to comment Share on other sites More sharing options...
85lebaront2 Posted June 28 Share Posted June 28 I would go one range colder UR6 would be my guess. Your "header noise" could be some light detonation. Link to comment Share on other sites More sharing options...
viven44 Posted June 28 Share Posted June 28 These look Textbook good Nicer than any of the ones I've ever pulled out Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 28 Share Posted June 28 Plugs look fine to me. 🤷♂️ Remember, todays gasoline is NOT yesterday's gasoline (and not the damned MTBE that turned your plugs orange either) Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 29 Author Share Posted June 29 Plugs look fine to me. 🤷♂️ Remember, todays gasoline is NOT yesterday's gasoline (and not the damned MTBE that turned your plugs orange either) 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. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 29 Author Share Posted June 29 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. Got the UR6 plugs on order via DeWayne today. Hopefully they will be in on Monday, so I spent the day scanning in documents. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 29 Share Posted June 29 Got the UR6 plugs on order via DeWayne today. Hopefully they will be in on Monday, so I spent the day scanning in documents. 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. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 29 Share Posted June 29 ... 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 Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 29 Author Share Posted June 29 ... 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 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. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 29 Share Posted June 29 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. I use UR4's, but your EFI head is completely different than D9TE castings. Link to comment Share on other sites More sharing options...
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