Valvetrain Woes

[Gripenfelter]

Picture it...
You have your pedal to the metal and you're coming up fast on that magic 6000 rpm redline in second gear. You jab the clutch and keep your foot planted and slam it into first gear again. OOPS!!

Your motor pukes out all kinds of noise like its gargling nuts and bolts and you have a dead motor.

What happened here is that by shifting back into first gear, you have mechanically forced the engine to rev well above 7000 rpm. No electronic rev limiter can save you now.

Because the stock springs are relatively weak, when compared to aftermarket ones, they are unable to keep the lifters in contact with the camshaft leaving the valves open (valve float) when the piston comes slamming back upward into them.

What follows is bent valves, bent pushrods, possibly broken valve springs and damaged pistons.

Some people try to add hardened pushrods to solve the bent pushrod problem. GM designed the pushrod to be a sort of "fuseable link". So it would bend if over revved. If it didn't bend it would do more damage to the valves and pistons which now how to take the majority of the stress from the impact.

By adding stiffer valve springs, which resist float upto rpm levels as high 6500 rpm and beyond in some cases, you can decrease the chance of engine damage on a blown shift and at the same time keep building compression (horsepower) right past the redline thus expanding the power band of the motor.

Just some mindless babble that went through my head.
*burp*