First plug change.

[yellow rose]

Gettin' there...next set of plugs. BKR6E, one step colder than the last, still a standard .035 gap. 100 miles of street driving, with 4 "passes" on the secret country dragstrip right before I pulled them. No clean-cuts at the top or anything but I'm getting a good glimpse..


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Richest one
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Leanest one. Yeah I broke it..
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I'm getting plating color change on 1-2 threads so the engine's liking the heat range. NGK's read heat a little different but it's easier to see in person.
I bumped the IAB's way up to see what a big swing would do, went .078s, and it leaned things out but took power and response with it, after re-adjusting the base settings.

When you took that big swing, did you maybe add a little fuel through the T slot restricters? Sometimes when you get one circuit right, it changes another circuit, if that makes sense. You may also have needed to open the power valve sooner, but that should be set by your cruise vacuum and shouldn’t change one you get it set.

So, before pulling the blocks to change anything internally I wanted to test one more thing and went to .070 IABs and .031 MABs, BUT closed my secondary T-slots up just a quarter turn from .020 and bumped the idle timing to 24 to get the RPM back to 850. Now at 24 intial, up from 22 and my total is actually only 32. I reported it at 34 last time but I put a timing tape on my shiny balancer (Romac) and now I'm seeing things more accurately..
The T-slots come down to the same level on this (4-corner) carb, and I remember back in the day BG recommended setting them all the same, then later they said "close the rear slots for engines that idle under 1000 rpm, open them square if idling above 1000..." then later changed again....so apparently even they weren't sure lol.
Since I'm dealing with the primaries mostly for now anyway, I got thinkin' maybe the rear slots are just bleeding extra un-needed fuel during the transition period...seems to have leaned me out without losing the ability to push the *** end into the next lane at 30 mph LOL. I know, but the kids love it

I'm liking the idle and cruise now but it's a bit lean under power as you can see.

It looks to me like you can drop a couple of numbers on the primary main jets to clean up the cruise a bit, but you’ll probably be lean in transition and/or WOT. You can address the transition with your T slot restricters and WOT with the PVCR’s.

In addition to the plugs, the gauge says 13.1/ 60mph cruise. 13.8-14.0/40 mph cruise, which is where this car spends most of it's time. I know it's modern unleaded, so it doesn't color up quite as fast but I'd like to see a little more at the bottom. Now I may go back to that 10.5 PV and see how she flies.
Oh....my ford buddy gave me some Champion plugs out of his stash, a mix of 12 and 10 heat range and I'm gonna compare the results to these NGKs. I prefer the NGK but Champs are a little easier to read sometimes, I think..

 

[yellow rose]

And check this out. When I'm cruising along and I floor it, trans kicks down and the car rockets on down the road...and the A/F drops to 11.7-12.0 and stays down there. But, from a slow creep or stop if I nail it and go through the gears manually (taking care not to blow the tires off too bad at the bottom end) the gauge runs steady in the 13.7-14 range all the way to pucker-and-lift. What's up with that? Gearing/load related? I figure WOT is WOT as long as things have a chance to stabilize, but the two situations are producing different readouts....
It absolutely hauls balls shifting manually at WOT but the plugs seem to correlate more to the high 13's on the gauge than the 'stomp from a cruise' numbers.

I don’t even have a good guess for this. My WAG (Wild Assed Guess) is without knowing throttle position you may (and by “May” I’m just straight guessing but it’s all I’ve got!) be in a slightly different throttle position, which can affect the 02 reading.

It doesn’t take much of a change in throttle position to change what the carb “sees” as far as load, road speed and such.

I was going to buy an 02 sensor, but I decided to just buy a data logger so I can use a TPS and log and download what’s happening at any road speed, throttle opening, RPM...all that stuff.

Again, that’s my WAG.

 

[beanhead]

Okay thanks, maybe I have it wrong on the heat range. I had it in my head that two threads max was desirable on an NGK, which is what I have even though it's tough to see in the pics. Either way I'm putting in these Champions for the next round of tuning and I'm mixing stock and colder plugs (because they were free!)
As far as the mixtures, I'm thinkin I'll bump the PV back up first, then adjust jets and/or PVCRs to get it happy. And I'll maybe have to adjust the transition again like YR said but maybe I'll get lucky and it'll stay put. (--yeah right). Anyway thanks for the input, I'll report back..

 

[fishmens67]

I'd go 1 step hotter on the plug

 

[512Stroker]

They look cold to me too, but not lean to me though. It looks like it’s rich on the transfer slots or he may be able to drop the primary main jet a couple of numbers and then open up the power valve channel restricters if it’s lean at WOT.


Many years ago, I read an NGK article, or maybe it was in the catalog or something, but it said for heat range you want 2-3 threads showing color.

Champions I don’t go much over 1 thread. The playing on the two plugs are different, but, IIRC in the end they both end up running at the same heat load. So either Champion uses a higher temp plating than NGK, or NGK uses a lower temp plating.

However that works. It’s damn sure confusing. Just looked at a set of AC plugs yesterday, and they look really nice, but I have no idea what plating they use, so I’ll use them and see what they look like.

I hear ya YR
But look at the second batch of plugs and then look at his text where the OP talks about his AFR readings IMO those readings look lean. I normally dont go by electronic AFR measurements, as being an old Engineering dept dyno Tech I do know how off they can be if not calibrated properly.
Well If he knocks a hole in it we'll know.
I hate living on the edge, there's no place to sit. LOL

 

[beanhead]

I hear ya YR
But look at the second batch of plugs and then look at his text where the OP talks about his AFR readings IMO those readings look lean. I normally dont go by electronic AFR measurements, as being an old Engineering dept dyno Tech I do know how off they can be if not calibrated properly.
Well If he knocks a hole in it we'll know.
I hate living on the edge, there's no place to sit. LOL

Thanks. I agree, however it's the mid/upper rpm area that I want to richen up. The idle/off idle I'm good with, I don't mind running on the lean side down low as long as the power's still there. But yes I think it does want more moving up especially at WOT. Honestly after my full blasts and seeing the plugs I'm very happy to see or hear zero signs of detonation!
And I'm for sure not living or dying by the gauge numbers, just seeing how it's readings match the plugs. Fun stuff!

 

[yellow rose]

I hear ya YR
But look at the second batch of plugs and then look at his text where the OP talks about his AFR readings IMO those readings look lean. I normally dont go by electronic AFR measurements, as being an old Engineering dept dyno Tech I do know how off they can be if not calibrated properly.
Well If he knocks a hole in it we'll know.
I hate living on the edge, there's no place to sit. LOL

Yeah, I went back and looked at the numbers and I agree. Looking at the plug it looks a touch rich, but the numbers say it’s lean. I’m all for NOT knocking a hole in anything, so better safe than sorry. I hate killing parts.