anti pump up lifters are they really needed?

[rookie]

Originally Posted by big block fiero

That is what most everyone else has said for years but check your book again, hes saying .005 from being completely collapsed (solid) so the lifter cant loose lift or bounce when it closes because of aireated oil. There is alot more to this subject that is in the book. I would say more but I dont want to cheepen the full content of whats in the book by only telling part of the story, or out of context that may lead to misinformation. You dont have to have A chevy to appreciate this book as this information is applicable to all engines.

I too own and read most everything David has written and you are correct about adjusting the lifters to the bottom of the lifter and not the top.
Keep in mind as he says in his info, pay close attention to what you are doing, this is for extra power and will shorten the life of the cam in some cases.
Some lifters will not oil at all adjusted this way and don't forget push rod length difference.

The super stock guys shim their hyd.roller lifters to only give about .020 of hyd. before they go solid, I guess you could do this on flat tappet, but not sure.
I wonder if any lifter manuf. are making some thing like this for racing?

[randy]

I went back and read the book David wrote on camshafts and on page 82
he writes however, a stock off the shelf lifter can be made, in effect, an anti-pump up lifter. By adjusting the valve lash so that it's only say .005 into the hydraulic adjustment, the lifter is restricted from pumping up by more than a like amount. What he doesnt say is that with a good lifter and a bad valvetrain adjust at the .005 adjustment, but with a bad lifter and a good valvetrain u adust towards the bottom of the adjustment. I remember reading once in a issue of muscle mustangs and fast fords where on a ford build up he says ford lifters were prone to collapsing and he used washers to shim them so the didn't have the travel to collapse.

[big block fiero]

I see what your saying randy about adjustments designed to solve a problem and for this book to be complete that information is in there, but I believe david vizard is suggesting that if your building your motor to perform its best and you are selecting your parts for this purpose then he prefers bottoming the lifters out and has seen gains on the dyno to support this suggestion.

Maybe david does or doesnt prefer this method any more and so Ill ask, david vizard "do you still prefer this method"?

[DavidVizard-GFN]

If I am using a hyd. roller for the street I almost allways adjust toward the bottom. If it's a question of maximing power then I will restrict plunger travel to 10 -15 thousandths and adjust with a small amount of lash say 2 thousandths. Have been up to 7800 rpm that way.
DV

Originally Posted by big block fiero

I see what your saying randy about adjustments designed to solve a problem and for this book to be complete that information is in there, but I believe david vizard is suggesting that if your building your motor to perform its best and you are selecting your parts for this purpose then he prefers bottoming the lifters out and has seen gains on the dyno to support this suggestion.

Maybe david does or doesnt prefer this method any more and so Ill ask, david vizard "do you still prefer this method"?