Hi Energy vs Pro Magnum HFT lifters

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chrgdrt

chrgdrt

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The Pro magnum are totted as allowing more rpm's/less susceptible to pump up. Does anyone have any experience switch from the Hi-Energys to Pro mag lifters?
I'm currently running the Hi-Energys and it's getting into valve float/pump up around 6150~6200. I plan on checking springs first but I'm wondering if a switch in lifters would be beneficial?

any thoughts or opinions?

Thanks,
Gary.
 
There are 2 lifters Crane currently offers - one is the high rpm type, one is a variable duration type. What camshaft do you have? Do you have the part number of what you have? The "Hi Energy" line of cams should have the anti-pump up already so changing to Comps really isn't a change other than brand name.
I would first make sure that the spring pressures, pushrods, and overall valvetrain geometry are good before you replace them. Valve float is caused by a variety of things from lack of spring pressure to harmonics to lifter bore clearance.
 
Gotcha - I got my brands crossed...lol. Same basic idea tho: the standard recommended lifters for most are not anti-pump up design. The Pro Magnums are the anti-pump up that would be recommended for a larger and/or faster rate of lift Comp. With them you need the adjustable rockers but they should add rpm over the 822s depending on the rest of the combo. Both are very sensitive to lifter preload too - so that's something to check too - you may be losing rpm by not having enough preload on the 822 lifter.
 
I have a Q in @ Comp to see what they say the RPM range is, the specs are aprox 250 @ 50 with 508 lift on the intake and 525 ex. i do have adj rockers. I want to say I set the preload @ 1 turn, So i'm in the ball park but that is something I will ck and document when i ck the springs.
 
Depending on the rockers, one turn may only be .010-.020" and you can safely run preload up to .050+. So you might want to experiment with that while you're playing around with it.
 
You can try running the lifters with zero preload to see if that helps reduce/eliminate the valve float. That should tell you if the lifters are pumping up at higher rpm's or if its the springs.
 
Rockers are indy's 360-R4-4SR, 1.5's with 3/8"x 24 adjusters which work out to .040"/full turn. checked my notes, set at 1.5 turns so thats about.060" preload, probobly should back them off some.
 
Anti pump up lifters are a myth, destined to part you straight from your cash. How can a lifter "pump up" if there is no clearance in the valve train? Think about it... If they are pumping up, then you have another problem..
 
Bakerlite said:
Anti pump up lifters are a myth, destined to part you straight from your cash. How can a lifter "pump up" if there is no clearance in the valve train? Think about it... If they are pumping up, then you have another problem..
Click to expand...

To a point. A less pre loaded plunger, pops that snap ring right out. A reason for the internal C clips. Rhoad's do both ends well,I don't agree.


www.compcams.com/.../COMP4-115.pdf
Adjustment specs. Moper is close...
 
A bigger C clip does not make a lifter " anti pump up". It's a safety feature incase the lifter starts to pump up. They have bigger bleed down holes designed to be used on an engine that "may pump up" ie, class racing where you are limited in valve spring choice.. The whole idea is to keep the valve train stable so pumping up does not happen in the first place. Rhoads is a bleed down lifter, not an "anti pump up". All so called "anti pump ups" are bleed down. In fact it relies on pumping up to make it work at high RPM.. and I don't know a sole who uses them.
 
Crane has just introduced a hydraulic lifter with the tighteset of tollerances to work above 8000 rpm on some applications. It's not an anti pump up... that should tell you something :)
 
Bakerlite said:
A bigger C clip does not make a lifter " anti pump up". It's a safety feature incase the lifter starts to pump up. They have bigger bleed down holes designed to be used on an engine that "may pump up" ie, class racing where you are limited in valve spring choice.. The whole idea is to keep the valve train stable so pumping up does not happen in the first place. Rhoads is a bleed down lifter, not an "anti pump up". All so called "anti pump ups" are bleed down. In fact it relies on pumping up to make it work at high RPM.. and I don't know a sole who uses them.
Click to expand...

Study harder.The snap ring,replaces the weenie wire clip,that pops out,when valve float hits.... Rhoads do extend the rpm band,used correctly. Had valve float,Chev rat238/248@ 050,112 lobe centers. Peaked 5900-6000. Stuffed the Rhoad's in for drive ability purposes. It pulled higher,than the Crane" anti pump up's" I pulled out. They work better,on small block mopar.Take some time,read the link I left. Have a Merry Christmas....
 
Of coarse they will (may) pull more manifold vac, they are reducing your duration and lift as they bleed down. The fact that you say the wire clip or C clip as I mentioned in my previous post can pop as a result of valve float , proves my point. You don't fix valve float by replacing the lifters unless you put lighter ones in there and reduce the mass acting on the weaker valve spring. And you don't need anti pump ups if you have a stable valve train.
Have a nice Xmas too.
 
We agree,from two different points,two different ways of communicating.I'm good.
 
Bakerlite said:
You don't fix valve float by replacing the lifters unless you put lighter ones in there and reduce the mass acting on the weaker valve spring. And you don't need anti pump ups if you have a stable valve train.
Have a nice Xmas too.
Click to expand...


I am planning on checking spring pressure first, and replacing if they're not up to spec. Just a thought while I'm in there is there any benefit to also swapping lifters.

the original question, "Does anyone have any experience switch from the Hi-Energys to Pro mag lifters?"

BTW they are 2 grams lighter also.

Merry Christmas to All!
 
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