Ask the Editors: Do Valves Burn?
Can they really burn?
This is advice you would be wise to heed. Valve adjustment is a very important piece of regular maintenance that is often neglected by backyard mechanics to their detriment.
Generally speaking valves wear in two unique ways. They loosen up over time, often manifesting as a rattling or clanking in the top end. Or they tighten up over time. This is likely the situation your friend is warning you about.
When a piston makes contact with the valves, it pushes them into their seats. Over time this repeated pounding can drive the entire valve further into the head. When this happens the valve no longer closes all the way and when hot combustion gases escape on through, they can actually burn the edges of the valve in the process.
So in short, that is not just a slang term. A valve can indeed be burnt if it is too far out of spec. It will cost you less time and money to adjust the valve before this scenario happens.
As far as adjusting them yourself, it is indeed possible with a set of feeler gauges and a little time on google to find the spec of the valve clearances for your make and model. But if you’re in doubt, have a professional do it for you. Just be sure to get it done.
