Valve float or lifter pump up first?
Thread Starter
Melting Slicks
Joined: Mar 2001
Posts: 2,372
Likes: 51
From: New Milford CT
Valve float or lifter pump up first?
What happens on a 2002 Z06? Assuming no rev-limiter at all? What does the engine feel or sound like when this happens?
I know it will make a big bang when it blows-up! I mean when it first starts to happen, before damage occurs? Which happens first, float or pump-up?
On my early gen 1 small blocks and many others, the engine just sort of stopped reving and pulling at some high rpm point but did not ever break anything.
I know it will make a big bang when it blows-up! I mean when it first starts to happen, before damage occurs? Which happens first, float or pump-up?
On my early gen 1 small blocks and many others, the engine just sort of stopped reving and pulling at some high rpm point but did not ever break anything.
Drifting
Joined: Jul 2002
Posts: 1,613
Likes: 0
From: Spring Tx
Re: Valve float or lifter pump up first? (CJS)
Which came first the chicken or the egg? Lifter pump up can occur without doing major damage, but if the lifters are pumping up, you are getting some degree of valve float. The damage occurs when the physical amount of lifter pump up causes the valves to make contact with the pistons.
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: Valve float or lifter pump up first? (CJS)
Lost is correct.
Usually valve float occurs and the lifters "pump up" at that time to take the slack out of the valve train.
"Interference engines" typically are verrrryyy unforgiving of this event.
Usually valve float occurs and the lifters "pump up" at that time to take the slack out of the valve train.
"Interference engines" typically are verrrryyy unforgiving of this event.
