Glowing headers

RustyRatRod said
Glowing headers is an indication of retarded timing first. With the timing being late, the fuel is still burning leaving the cylinders, because the ignition is started too late so it continues to burn. This reacts the same as a lean mixture, since all of the fuel is not burned inside the chamber. Bump the initial timing up.

Exactly Right!

barnett468 said
The only thing increasing the timing might do to your jetting is make it LEANER, and you have been told to go up on your primary jets irregardless of what you do with your timing, but do what you want.

Couldn't be more wrong!

IQ52 said
I was trying to s

I was trying to stay out of this, too many bad suggestions on where to start. I own/run a dyno, we have thermo couples in the headers we run on the dyno. During engine break in if the exhaust gas temperatures are getting to high, the first thing we do is advance the timing. It is pretty common for us to use 36 degrees total advance at 2,500 rpm. If you make it richer without advancing the timing I believe you will burn even more fuel in the headers and they will continue to glow.

Jim La Roy
La Roy Engines
Challis, Idaho

100% ABSOLUTELY RIGHT!
While it is true a lean mixture runs hotter than stoich or a richer mixture it is very unlikely to get the exhaust hot enough on its own to make it glow red. If timing were near correct it would start a lean burn inside the cylinder and have burnt the fuel out enough before the headers. What is happening is combustion still occurring in the headers. If it were that lean you'd certainly have a lean misfire condition. As for the advancing timing causing the mixture to lean out I don't buy that because the mixture (A/F ratio) is predetermined before the intake valve. Your exhaust gases will change with timing changes but not so much of what is going into the cylinder.
You may in the end for the sake of tuning have to increase the jetting but id definitely start by advancing the timing some and you'll see the headers return to normal.