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Just got done installing TSP's LS7 roller rockers onto my LLSR setup, and finally got valve lash into a good range after days working with ".001 shims.
Every time I let it warm up though, I check each header with a laser thermometer. Cylinder 4 seems to be about 100* lower than the rest. I pulled all the plugs (brand new TR7IXs last week). I'm terrible at reading plugs. Can anyone gather any pertinent information from these before I just play off the temperature difference in cylinder 4 and start ripping on it?
Plugs are arranged in the photos (2-4-6-8) (1-3-5-7).
Last image is plugs 4 (left) and 5 (right).
I can't provide much insight - but I can tell you that the cylinder (4) is definitely firing.
Cylinder 3 - have you measured the temperature on this one?
3 and 4 are running richer? By the looks of it, they're the only ones that have any kind of browning on their porcelain body. A cylinder running richer, will have cooler exhaust temperatures. Why they'd be running richer than the rest, I have no idea. Could be a myriad of reasons.
The white porcelains on the rest of the plugs have always had me confused. I posted a similar question months ago - but it's hard to get answers on this. Anyway, I figured they'd all have some level of browning, even without mileage. I figured if the cylinders are firing, they'd brown the porcelain.
3 and 4 are running richer? By the looks of it, they're the only ones that have any kind of browning on their porcelain body. A cylinder running richer, will have cooler exhaust temperatures. Why they'd be running richer than the rest, I have no idea. Could be a myriad of reasons.
The white porcelains on the rest of the plugs have always had me confused. I posted a similar question months ago - but it's hard to get answers on this. Anyway, I figured they'd all have some level of browning, even without mileage. I figured if the cylinders are firing, they'd brown the porcelain.
I'll totally buy this. 3 and 4 are richer than all the others. Richer mixture is a cooler mixture.
Doesn't surprise me that nearly new plugs, running at stoich, are still nice and bright white.
I can't provide much insight - but I can tell you that the cylinder (4) is definitely firing.
Cylinder 3 - have you measured the temperature on this one?
3 and 4 are running richer? By the looks of it, they're the only ones that have any kind of browning on their porcelain body. A cylinder running richer, will have cooler exhaust temperatures. Why they'd be running richer than the rest, I have no idea. Could be a myriad of reasons.
The white porcelains on the rest of the plugs have always had me confused. I posted a similar question months ago - but it's hard to get answers on this. Anyway, I figured they'd all have some level of browning, even without mileage. I figured if the cylinders are firing, they'd brown the porcelain.
Cylinder 3 is running around the same as the rest. I did notice the browning on 3 and 4 as well. I'll actually drive the car for a few minutes later tonight rather than just let it idle in the driveway. Will update results afterwards to see if the plugs/temps are a bit more exaggerated.
No idea why they'd all be this different with literally zero miles on them. Only change since the car was running great before was OEM to TSP roller rockers and new pushrods. Old rockers were practically leaving the valve tip and having a groove worn into them due to the lift
They look OK. The heat range is good. The heat band is on the bend, so the plug is not too hot or too cold. The mixture is a little rich. There is a carbon ring on the plug body. Fouling is good, and most importantly, the porcelain isn't speckled. Dark speckles indicate carbon deposits leaving the piston crown from detonation. Silvery speckles are from aluminum, bah!
"I'll actually drive the car for a few minutes later tonight rather than just let it idle in the driveway. "
Reading plugs that have not had a load on them, is not accurate.
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Help Reading Plugs 
