one header tube glowing red?!?

[4x4orbust]

i was checking fluids on the truck before another snow storm tonight (Yesssir!)  and noticed that one of my header tubes was glowing red.   the #6 cylinder, and it is the only one doing it.  there is a spot at the head that doesnt glow (bout an inch) and then 6 or so inches are glowing.  not bright red, but a noticeable glow.   
I checked spark and it was fine.   i know the carb needs to be rebuilt, but if it was carb related, why only one cylinder?   maybe a sticking valve, or retarded timing?   

i'm lost

 any ideas what would cause this?

[Grim 82]

What does that spark plug look like?
Most likely it's in the valvetrain. Loose rocker, bent pushrod, flat spot on the cam, it's hard to say. I doubt it's your carb though, or it would affect more than just one cylinder.

[VileZambonie]

Do a compression test on that cylinder

[4x4orbust]

i did a compression test on the cylinder.   it's at 110.   here is the spark plug from #6



i pulled the plug on #4 as well and checked that one.   same, at 110.   plug from #4

[4x4orbust]

any ideas?    i'm not sure where to even start looking

[ohio hab]

Usually caused from timing to retarded, or too rich fuel mixture so the fuel is burning in the header. I would check for a bad spark plug, wire, since only in one cylinder. Make sure getting full spark to that cylinder. I since re read your post and you checked the spark, also could be a bad cam lobe. Check timing first.

[Irish_Alley]

Couple things come to mind. One you need some lotion lol. Two how old the plugs. Three did you check the compression on the other cylinders

[4x4orbust]

timing is set at 8*, set it about 2 months ago, and thats where it ran best.   plug wires are good, thats what i was checking when i found the glowing tube.  

i'll have to get my girl to look into some lotion.   shes always haggling me about my working man hands.    the spark plugs were replaced last winter.  i will be checking the other cylinders tom for compression.

[Irish_Alley]

Some times working with metal if it’s thin, rusty or has resistance it will get hotter than a thicker or clean surface. That could explain the tube but for the plug idk. About the lotion lol my wife is in charge of that, I can’t remember what type it is but it works well

[VileZambonie]

Did you check for vacuum leaks? Do you have a cylinder leakage gauge? What thermostat are you running? What # spark plugs do you have?

[4x4orbust]

i found one vac. leak, inside the cab somewhere.   I disconnected the hose running into the cab and capped it off.  (not sure what it even does?!)
i do not have a cylinder leak kit, but am trying to find one locally.  i am running a 180* thermostat. not sure on the # spark plugs, i know they are champions though.


edit:  also figured out i don't know how to check compression, so those numbers are not accurate. will try to do it the right way tom.

[Grim 82]

The hose running into the cab is for the HVAC system, controlling the direction of air flow for the floor, defrost, etc.
It could also be an intake leak right by that cylinder.

[beastie_3]

It puts the lotion on its skin...

[VileZambonie]

lol

[Irish_Alley]

Lmao