Hitting the Redline. Is it bad?
 

I recall hearing people say this. Since I drive granny style daily, I should try to rev the engine high, like at redline once in a while. It helps to break up some of the carbon deposits, etc, etc.



True or false?



If true, should it be done with no engine load, like in N?



I also read that over-reving can be bad for an engine. Like it can bend valves. One would also say, how can that be? Engine have electronic cut-offs. And yet, there are guys that miss a shift (like 6th to 3rd, instead of 5th) that would cause the engine to over-rev.



Educate me.



TIA.

It won't hurt anything, but it was definitely more helpful for engine cleaning in the era of (compared to today) poor quality oil, piston rings, and carburetors. Unless you already had a problem, hitting the redline every once in a while only means you will experience the rev limiter once in a while.

Hitting the redline/rev limiter isn't going to give you any problems. Sometimes I will ride it for several seconds when doing autocross.

if u downshift like that even with no fuel of spark the engine is still gonna rev to like 9-12krpm...

theres a video online of an integra diong an endo because he put it back into 1st instead of 3rd, needless to say it was toast!



edit: if redlining did damage those guys with crotch rockets wouldnt redline in neutral all the time

The video is epic, but it is not what is being discussed. WAY back in the day, you would occasionally want to bake the crap off your intake valves by running your engine at high speed. This is not the same as grabbing 1st at redline.