Anti-pump up lifters..

[beanhead]

Hi guys n gals..with modern fast-ramp type HFT cams, at what point would you want to go to an anti-pump up type lifter (comp pro-magnum, Crane 99728 etc..)? I know they are typically noisier and the preload requirements are usually less, other than that how do they play on a B/ RB street car that only occasionally sees north of 5000 RPM? I've "heard" they even help power a tad throughout the range but I was more wondering about the 'liveability' aspects if anyone has experience with these types of lifters..thanks!

 

[INTMD8]

The only way a lifter can pump up is if you already lost valve control. (Otherwise oil pressure inside the lifter cannot overcome valve spring pressure times rocker ratio).

So no real need to meter the oil differently or limit travel within a hyd lifter.

Number one problem is insufficient valve spring pressure. Most are under sprung or not even checked. (Maybe spring spec is good but not shimmed to proper install height). Second is weak pushrods.

Before a hundred guys jump on here and say they picked up 50hp with "anti pump up" lifters I'll end it by saying this is just my opinion based on my experiences so do as you like

 

[beanhead]

Thanks, I agree that if your preload and springs are correct there really shouldn't be a need for such a lifter... Honestly in my opinion if your worried about spending a lot of time at high RPM you probably want solid anyways(or a roller I guess). I was just curious what people here might have to say, I was browsing around the 440 Source site and they show their comp anti pump-ups as being for a cam "if it will see over 5,000 RPM"... I thought that was a low number and it seemed like some BS...

 

[69b3rt]

I used these lifters for the fact of easier starting with a long duration cam. You get full cam lift at higher RPM.

 

[beanhead]

I used these lifters for the fact of easier starting with a long duration cam. You get full cam lift at higher RPM.

How much noisier than std lifters would you say they are?

 

[69b3rt]

I didn't think they were too much noisier. Not like it had solid lifters set on loose side.

 

[INTMD8]

Thanks, I agree that if your preload and springs are correct there really shouldn't be a need for such a lifter... Honestly in my opinion if your worried about spending a lot of time at high RPM you probably want solid anyways(or a roller I guess). I was just curious what people here might have to say, I was browsing around the 440 Source site and they show their comp anti pump-ups as being for a cam "if it will see over 5,000 RPM"... I thought that was a low number and it seemed like some BS...

I like hyd roller and have them in turbo LS engines at 1500hp and just under 8k rpm.

I would do solid roller if I was going for higher rpm than that