Exhaust Manifold

[stonefox]

I was trouble shooting my lack of heat that was and nows is not coming through my Kodiak III tonight when I noticed that the exhaust manifold closest to the bulkhead (#4 ?) was not quite cherry red compared to the others but consideribly red when looking at it in the dark.Is this normal? There was over a 100 degree F difference between the front and rear manifolds.
Back to the original problem.Since rebuilding my Kodiak unit last winter it was producing adaquit to good heat .Today I seemed to have lost all flow through heater.Pulled off supply to heater ,no flow at idle ,as soon as I increase the hand throttle I got flow.I assume this is waterpump speed related ? I have not yet checked the return flow because I dont want to dump AF on my newly discovered cherry red manifold ,hence paragraph above. My gut tells me of a blockage in the heater core or plumbing.Does it sound like I'm shakining the right tree. What has me concerned is the return from the heater enters the head right above the aledged hot manifold.Truck didnt have a heater before nor was it used during the summer.Anyway ,enough rambling on my end .You folks have any thoughts. Thanks Sean

[stonefox]

So I've solved the AF flow problem - malfunctioning selector valve.
But , I'm still curious if the exhaust manifold should get hot enough to turn red in the dark run at a high throttle.

[siii8873]

Sean,
these things are a blast eh? I thought the flow was the other way through heater. Exits engine above#4 and returns to front.
Not that this answeres your question. Blocked fluid passage in block? How does the #4 plug look compared to other three, compression difference?

[73series88]

your manifold gets red hot
i actually dont know. never noticed if it was red
aaron

[bpj911]

I can't imagine running it hard enough to be red but I could be wrong. I have seen one on an old WC allis red before but the timing was way off

[Sputnicker]

Sounds like it could be a fuel mixture problem, perhaps caused by an intake manifold leak. I don't think they would glow unless they are too lean and if only part of the manifold is glowing, it suggests a local vacuum leak. If the carburetor was causing the lean condition, they would all be glowing about the same. Start by checking your spark plug closest to the glow and see if it looks too lean. If you don't know what to look for, I'm sure a google search would yield some good photos of what to look for. Don't risk burning the valves with a too-lean condition.