I'm doing a spring tune up on my 69 442 w/455.

I swapped the spark plugs out, first time since I bought her (2020).

I provided a pic, just wanted to see if anyone had any input on how to read them, if they are fine or if I'm running lean/rich.

Thanks for any input.

 

they look old
you need to read fresh plugs

 

Quite (possible) likely you're adding an octane booster which often demonstrates the color you're witnessing.

 

Look again, the electrodes aren't worn at all. I can't say that I've ever seen brown deposits like that. And I assume these are platinum or something, not regular metal electrodes.

 

If i make out the numbers right they are Bosch WR9FP platinum plugs. Never used them myself. Start fresh with some AC Delco's.

 

Sooo your saying wrong plugs, is issue ?
Looks like old **** built up.

 

Specifically, it's the MMT (Methylcyclopentadienylmanganesetricarbonyl) additive used in high octane booster solvents which creates the discoloration. The Internet is replete with images, suggestions, ratios, etc. using MMT. What someone does w/ their own engine is their own decision. If you have a street engine there's really no need for any octane booster, IMO. If you have a race engine, use race (octane) fuel. Let's face it, someone racing a race engine isn't waiting around four years to change spark plugs.

 

Really can't see what the electrode looks like at that angle. Outside of being dirty, can't tell what shape they are in. Bosch Platinum plugs should last quite some time with limited driving, if the engine was running well clean them up and re-install.

 

Actually, you can.

 

No, just an observation. The shape of the center electrode is consistent with platinum plugs. Personally I use conventional plugs because a) I'm a cheap SOB and b) I change plugs often enough that there's no reason to spend the money on platinum or iridium or any of the other exotic plugs. Keep in mind that these exotic plugs were designed to fire emissions-friendly mixtures and meet tailpipe standards after 100,000 miles without a tuneup. This is what a plug with built up crud looks like, which is not what you are seeing in the OP's photo.

 

Same here. My 79's get green & white stripe Delco R46SZ plugs. No iridium or platinum. I just changed mine yesterday and they looked eerily similar to Nova 69 442's. They are already on their way to the landfill or I'd have snapped a photo. I also changed the rotor/cap with correct NOS Delco parts. Seems like I just tuned the car up, so I looked up when I actually did the last tune, which was just before the 2021 Nationals. Man, nearly 2 years flew by. My 260 is running noticeably smoother, as I bet Nova's will too with a fresh set.

 

Yeah, I used the Bosch Platinum with pretty good success. I used to see them everywhere, haven't seen them in years. The center electrode is tiny, that is mostly the electrode cover you see. The actual electrode is the size of pin head. My go to spark plugs are NGK. I find they provide a slightly smoother idle than the Chinese AC Delco and Autolite.

 

Exactly. That's why I go after and use the green stripe made in USA plugs in the Acniter boxes. All white Delcos, no sale. The new plugs are just not as good.

 

Actually the burn color is almost perfect your jetting and air fuel ratio looks pretty good. Won't hurt to change them though.

 

All thanks for the replies. I have by using octane boost with lead additive. Maybe I’ll skip the octane boost for a while, check the plugs in a bit. I did swap in some new plugs for this season, so we’ll see how they do. Thanks again.

 

You ran the plugs for 4 years ? I don't see anything wrong with them. You could try one step hotter range, but I am not sure it would be worth the bother. Do whats been working.

 

Good call Norm a/k/a Vintage Chief!

 

I always download something like this when I change plugs. I can tell what oil-fouled plugs look like but can never remember what color means what. There are lots of different versions of this amd some are more detailed than others, but they all help.