What causes a burnt exhaust valve???

[dbtk2]

I am tearing apart my 3.1 for my topend swap and I noticed that on one cylinder the exhaust valve is burnt. I have heard numerous times what that means, but can someone remind me what it is and what I can do to prevent it from happening again?

Thanks,

Shawn

[montessgtp]

I heard a lean condition can cause a burnt valve But im not 100% sure

[Juglenaut]

Higher heat combustion that normal.

Lean condition. worn lifters, pushrods, cam or a combination of all of them at that cylinder (rare). Worn valve train in that cylinder can change the way fuel burns.

most common is a lean condition.