Plug Interpretation

fxp

Well-known member
The Falcon was running hot the last few days. It's been nice and warm for Sydney (around 30 deg C) in September but not so warm that the car should be overheating. It was also running a bit down on power. Then yesterday the missus tried to start the car and got nothing. I had today off and checked it over and it seems the main culprit was the points. Zero gap when I took the cap off - so that explains why it wouldn't start and probably a fair bit as to why it was gutless and hot. I reset the gap, timing, idle and mixture and the thing seems to be running much much better. It accelerates nicely, idles nice and smooth and doesn't strain at speed, but it's still just the tiniest bit over temp. :?

I also pulled the plugs at the same time for a look see. I'd topped the oil recently and it was a bit over the full mark, but just a tiny bit so I didn't worry at the time, but when the car stopped I figured they may have been fouled. I'm no expert on reading plugs so I took some photos to get some more experienced opinions. What are the plugs telling me and what do I need to do to improve how it runs?

(I didn't take a photo of Plug 1 before I cleaned it but it looked similar to Plug 2).
Plug 2
Plug 3
Plug 4
Plug 5
Plug 6

cheers and thanks in advance.
 
2 is pretty good. 3 and four show typical slight richness. 5 is maybe slightly hot (otherwise perfect IMO), and six rather more hot, to the point of detriment.

The auburn hue is from MMT, an additive in some fuels and products like Nulon Octane Booster. That colour isn't anything to worry about.
 
Cheers Addo.

Why aren't you on site somewhere mate?

So all looking pretty much in the ballpark? So long as I keep my ignition in good order the heat issue with 6 should be sweet?

I struggled to keep the car cool last summer but that was with a tired engine and when I knew less about the ignition system and it's needs. The last thing I want is to have to be sitting on the side of the road with the hood up this summer.
 
You might try a cooler running plug for #6. I'm wondering whether cooling can be improved back there, too. Possibly either more direct water to the block rear, or to the head rear.

Work - clients have a new baby (2½ weeks old) plus two others under four - so I'm putting in long afternoons while they get themselves sorted out. Otherwise the littlies get underfoot or miss their beauty sleep :roll: .
 
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