anti pump up lifters are they really needed?

[HPaddict]

first of all hi to everyone what a great site. finally i can ask mr david vizard questions ive wanted to ask for years. anyway this is my question, anti pump up lifters? are they really needed or are they just a modern day snake oil. the way i see it is the stiffest lifter possible with the right valve spring to control valvetrain motion would be the ideal choice yes?. if the valvetrain is set up properly why would you need an anti pump up lifter, surely a lifter wont pump up if there is no float in the valvetrain, are they just a gimik? or a bandaid fix for wrong valve spring choice. thanks guys.

[Cammer]

The term "anti pump up" is the key to explaining why this type of lifter was introduced.

When you rev your hydraulic lifter equipped car to its maximum, valve springs can lose control of the valvetrain. A regular hydraulic lifter pumps up at this time as it treats this as lash. This creates a little longer lifter and when valve tries to close the lifter holds it off its seat causing a loss in power.

An "anti pump up lifter" is a fast leaking, fast collapsing lifter used in the above scenario to allow valve to close properly. Anti pump up lifters can cause a loss in valve control and lift with subsequent power losses!

The keys to a healthy hydraulic lifter valvetrain are proper selection, installation, and maintenance of parts. Use the best valve springs and check them regularly for damage and spring pressure.

Do not assume a hydraulic lifter valvetrain to be a "no" maintenance valvetrain!
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In racing classes where hydraulic lifters are required, racers may employ a restricted movement lifter. This type of hydraulic lifter provides just enough movement to satisfy technical inspectors while allowing higher RPMs.

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[Dusty]

HPaddict,
First check out our crate oil article theres alot of good info on hydraulic lifters. We are currently working towards a valvetrain combination that is sensibly priced and can turn near 8000rpm stay tuned

[HPaddict]

exactly what i thought, i think they are a sales gimik personaly. i am a big fan of hydraulic cams especially on street motors i believe they can easily match a solid cam for performance up to certain point for sure. im in perth australia. i work at a well respected performance shop as an engine builder, i see so many people get sucked in by different gimiks and fads all the time, you guys probably see the same thing i guess. its very frustrating trying convince people they dont actually need certain things or have been given the wrong information. i also believe you can loose a certain amount of the cam profile due to a fast collapsing lifter. and as for pump up, any lifter will pump up if there is valve float even anti pump ups if they are set wrong, but an anti pump up will just stabilize quicker. as far as i know a anti pump up should be set a about only 0.002 preload which is really the reason why they might extend rev range compared to a standard lifter. if a stiffer lifter is set to the same preload of 0.002 it will do exactly the same thing and also deliver more of the cams profile as a bonus. i am amazed how many so called performance specialists dont truly understand the way hydraulic lifters actually work. anti pump ups should really be called a fast bleed lifter as they dont stop pump up they just stabilize quicker. at the end of the day theres no substitute for the right valve spring. i get sick of hearing hydraulics suck just put a solid cam in it.

[Cammer]

The huge epidemic of problems with solid lifter cams could be another good reason to consider a hydraulic lifter camshaft!

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[big block fiero]

David vizard has provided more hydraulic lifter performance information than any other source in his book, chevrolet smallblock v-8 camshafts and valvetrains.

In very brief summary david has recommended adjusting the valves so the lifters are just about collapsed (wich for years others have reccomended adjusting the lifters so they are topped out). Because of this it becomes more important for the lifter to not pump-up. Other dynamics pertaining to leakdown ratings and there effect on performance is also covered. Lots of out of the box type original thinking here.

Lots of good information in this book that I would consider A must read. You could order this book new thru an ebay book seller and have it in A week. To this day I still page thru it occationally even tho I've read it several times.

[big block fiero]

David vizard, I have a 500 ci cadillac engine in my fiero that is the very first such engine to succesfully have the variable displacement v-8/6/4 feature. The mechanizm that turns the valves on and off does so wile the lifters are riding the base circle. there is almost .015 movement in the mechanizm that is nessesary to unlock a shutter. The hydrolic lifter does'nt steal this .015 clearence because there is a secondary spring inside the mechanizm that is of a bit less pressure then the seated pressure of the conventional valve spring. I am having a cam cut with a .012 base circle runout variation so the lifter can steal this .012 then preload the mechanizm before the cam ramp arrives so I can regain some lift that was lost by the mechanizm and prevent valve bounce. Do you know, are there cams ground this way for variable displacement applications such as mine that I could look to for validation of my concept for increased rpm and horsepower?

This multi-purpose engine is a performance with economy sleeper with the engine hidden and the car appearing stock. This valvetrain has roller rockers with stud support tie bars that are hidden and fit under stock valvecovers. Power is delivered thru a switch pitch turbo 425 so the car can sound like a stock 4 cylinder then switch to an 8 cylinder with stall converter.

Matt kneen mpls, mn.

[randy]

I also have that book by David and i thought he said to adjust the lifter say .005 thousands into the hydraulic adjustment.

[HPaddict]

Originally Posted by big block fiero

David vizard has provided more hydraulic lifter performance information than any other source in his book, chevrolet smallblock v-8 camshafts and valvetrains.

In very brief summary david has recommended adjusting the valves so the lifters are just about collapsed (wich for years others have reccomended adjusting the lifters so they are topped out). Because of this it becomes more important for the lifter to not pump-up. Other dynamics pertaining to leakdown ratings and there effect on performance is also covered. Lots of out of the box type original thinking here.

Lots of good information in this book that I would consider A must read. You could order this book new thru an ebay book seller and have it in A week. To this day I still page thru it occationally even tho I've read it several times.

yep thanks ive had that book for at least 5 years now i still dig it back out here and there and read it again. brilliant book.

[big block fiero]

Originally Posted by randy

I also have that book by David and i thought he said to adjust the lifter say .005 thousands into the hydraulic adjustment.

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.