i know this is a topic thats been gone over and over and over but since theres no search i'll post it... simple question i know.

 

Logic would tell me that it would be running too rich... however there are a couple other things to look at as well...

1) Make sure the Cat isn't plugged up.

2) I had a v6 firebird before that had too much timing advance, and this caused glowing exhaust manifolds.

How good is the car on acceleration?

 

Glowing=lean

 

Check the plugs. Bad or incomplete combustion will cause them to look dark almost black. Lean combustion with make them look very white, spotted (common to detonation), or very shiny brown also known as glazed. Rich conditions almost never result in a hot manifold unless you have an exhaust leak. Retarded timing will give the appearance of a rich condition with a hot header, because the fuel will continue to combust in the header. In the back of every haynes manuel they have pictures of plugs with the associated combustion condition printed next to them.

Once you learn to read plugs, tuning an engine is easy.

 

Lean......

 

Unburnt fuel reigniting in the primaries/manifolds/pipes.

Usual cause, too much fuel.

Rich.

Retarded timing.

Unburned fuel reignites in the primaries/manifolds/pipes.

Effect..

Rich.

Severely advanced timing could be as well, but would be noticed by "pinging".

Lean mixtures cause high combustion chamber temps. In order to carry that much heat through the exhaust to cause it to glow, my HO would be something will melt...spark plugs, then primaries.

Ofcourse you could have mechanical issues such as poor seating valves, allowing unspent fuel to reignites as well as poor ignition issues causing imcomplete combustion.

 

 

89 rs ive been expriencing the same problem . Is your engine carb or fi please give all the details may help both of us.

 

k.. thought it was lean.. was just wonderin, its a problem i had with my nova a year or two back when i was jettin the carb

 

Lean lean lean

 

check your cat......
it might be that it is clogged. if so replace it.. also did you advance your timing if so, retard it.

then the best way that i know of to check weather is lean or rich is to check your plugs.
rich- black, olly and looks like they were dipped in used motor oil

lean- they are clean and brown whitish color.


the jetting in the carb is what will cause this, jetting is very important. pull the plugs and see if shes rich or lean. if u don't know post a pic. i think from what i'm seeing and reading that she is a little on the rich side, but thats bnot your only problem, check your cat and/or muffler/s

 

Oh boy, looks like we have a discussion in the making

I've given specific examples of why a rich mixture causes the "glow"...

Now instead of head slaps I'd like someone who just says "Lean=Glow" to explain to me why that is?

I'd be interested to learn new things.

 

car has no cats, i just couldnt remember if going to smaller jets or larger jets fixed the problem but i think i used larger ones...

 

Retarded timing allows the fuel to finish/continue to burn in the headers.....nothing to do with being Rich...just the valves are opening at the wrong time......as for the head-slapping, This is another age old argument....if the search feature was working , you could see what I mean.....Now are these headers glowing during the day ? Or do you just notice it at night.
As for the cat, look under your car at night after a road trip...cant miss it if its bad.
You said it yourself...a lean condition causes high temps in the combustion chamber...now will the opening of the valves cool the temps enough not to heat up the headers?
I learn new stuff all the time on this board...and I stick my foot in my mouth also...alot. But, I also go out of my way to help the people on this board if I think I have a solution...
No flaming here, Its just funny sometimes to see the wide variety of responses a person can get.........

 

NO CATS ALLOWED!

 

put a match to a pair of Summit brand Shorty Headers and watch them glow....ALOT of variables here.

 

its not always the lean burn that can make them glow it is because the eng. is lean and it is not burning all the fuel and the rest is going to the header and finishes its burn kinda like a rich con. but,(the fuel is spread out so far that it burns really long) I have played with a few 350 chevys with headers and while tunning the carb you can get them lean where the header glows red hot like you just took the torch to them. I don't know if they miss under load because I never was stupid enough to try that.

 

Lol, did you read my response? Under retarded timing I specifically mentioned "Effect"...not as running rich, but the same "effect" as running rich.

In "effect" the unburnt fuel that passes out of the exhaust is reignited by the hot primaries.

And as far as the valve events occur, ignition timing does not affect valve events. You can rotate the distribuitor 360*'s, and the valves still maintain their exact same relationship to the crank spinning.

As far as myself saying lean causes high combustioon chamber temps, you may have missed my point.

The valve opening doesn't cause it to cool, but the exhaust flowing out of the head causes it to cool immediately. As soon as the exhaust exits the head, it will begin to cool. The "cooler" air (versus combustion chamber temperature) will be colder ( less hot) than the combustion chamber temp.

Now try to imagine if you have enough heat to make metal glow red at one specific point...say a primary tube on a header...and you now have a cooling effect..say from exhaust gases..running through the primary tube...how hard/impossible would it be to make the entire tube glow without melting the tube at the entry point(at the exhaust port)?

Do you see what I'm getting at?

In order to maintain a constant of heat to make a pipe/tube glow red for a long length you'd have to have some catalyst along the length of the tube (fuel comes to mind ) or what would occur, you'd have a melt down at the begging of the point of heat.

Ever use a torch? If so, apply heat to something .065 or so, about 20 inches long, and try to make the entire length glow red without melting anything.

 

I kinda undersatnd what you're saying, but you seem rto be contradicting yourself.

You mention "lean burn", but then say "not burning all the fuel".

Not burning all the fuel cannot be a "lean" condition...if the condition is lean, then that means there is not enough fuel...so there won't be any "extra" fuel to ignite.

 

Myself as well, I'm not trying to start a war, just exporess what I know. I rarely come here to ask for help, and more times than not I try to give sound advice...tyhat said, I also try to learn from the post's read, to help me in anything I might encounter.

My point to asking those who say a lean condition causes this, is to explain why....not just say it.

We all know lean mixure cause high combustion chamber temps...not an issue. But high combustion chamber temps do not cause the exhaust to glow...this is two separate animals.

I will say this, yes, if the exhaust tubes are short enough, you can make them glow...I'll toss this in...those of you who have ever
used a chainsaw, will know you you run it wide open and adjust the highspeed jet until the exahuast start to glow, the richen it up...but this pipe is only about an inch long. Let it run to long like that and it's ring and bearing time for your two-stroke.

 

i think it rich and ur timing is to advanced this will cause gas to be exiting the headsinto the headers, and then igtiniting, the reason ther fuel mixture wasn't burned properly is because the timing to to far advaced.
my .02

 

...oh Sorry! LOL.....
I know timing has nothing to do with the valves.... But it has ALOT to do with when the plug fires...in relationship to when the valves are open or seated....You are missing My point...I'm saying........we are all a little right..........later dooooods!!!

http://auto.howstuffworks.com/engine.htm Check out the GIF.....