Hydraulic roller lifter preload for more RPM's - Chevelle Tech
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post #1 of 34 (permalink) Old Aug 15th, 09, 1:25 AM Thread Starter
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Mark
 
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Hydraulic roller lifter preload for more RPM's

My combo
BBC 454
stroker crank 4.25
10.2 compression
ultradyne hydraulic roller 245/253 @ .050 650/650 lift 110 lc
850 holley DP
Team G single plain
MSD Ign.
I am wondering if anyone knows what would be the best preload for my Morel lifters for more RPM and to help prevent valve float?
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post #2 of 34 (permalink) Old Aug 15th, 09, 1:48 AM
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Re: Hydraulic roller lifter preload for more RPM's

Quote:
Originally Posted by Badrat496 View Post
My combo
BBC 454
stroker crank 4.25
10.2 compression
ultradyne hydraulic roller 245/253 @ .050 650/650 lift 110 lc
850 holley DP
Team G single plain
MSD Ign.
I am wondering if anyone knows what would be the best preload for my Morel lifters for more RPM and to help prevent valve float?
Preload does not cause valve float
Loss of valve train control does

Mike (Wolfplace)
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post #3 of 34 (permalink) Old Aug 15th, 09, 1:59 AM
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Re: Hydraulic roller lifter preload for more RPM's

Quote:
Originally Posted by Badrat496 View Post
My combo
BBC 454
stroker crank 4.25
10.2 compression
ultradyne hydraulic roller 245/253 @ .050 650/650 lift 110 lc
850 holley DP
Team G single plain
MSD Ign.
I am wondering if anyone knows what would be the best preload for my Morel lifters for more RPM and to help prevent valve float?
I like to adjust them with it running, Some engines want 1/8, 1/4, 1/2 and 1 turn

Depends on the engine

My 327 wanted less than a 1/8 turn

Now they way i get them to zero is back it up until you feel it in your hand (hand on rocker, cant explain the feel, its just a feel you learn over time) then take it until at zero lash (you can feel it) then start to preload it listening to the engine - The engine will tell you what it wants

Mike is correct that preload doesnt cause valve float
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post #4 of 34 (permalink) Old Aug 15th, 09, 2:06 AM Thread Starter
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Re: Hydraulic roller lifter preload for more RPM's

Thanks for the replys!
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post #5 of 34 (permalink) Old Aug 15th, 09, 7:39 AM
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Re: Hydraulic roller lifter preload for more RPM's

What springs are you running? Springs really make the difference.
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post #6 of 34 (permalink) Old Aug 15th, 09, 7:46 AM
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Re: Hydraulic roller lifter preload for more RPM's

One of the designers at Comp mentioned that hyd lifters are more sensitive to preload than what they would like. They are working on another hi-perf. hyd lifter that will be better.

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post #7 of 34 (permalink) Old Aug 15th, 09, 12:39 PM
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Talking Re: Hydraulic roller lifter preload for more RPM's

Quote:
Originally Posted by Wolfplace View Post
Preload does not cause valve float
Loss of valve train control does
I was wondering how long it would take for facts to enter this discussion, while its true that badly adjusted valves won,t help its the lifters loss of controlled contact with the cam lobes surface most of all that causes valve float,the more you pre-load the hydraulic lifter seat the more time it takes for the lifter to return its adjusted seat once its lost lobe contact and fully expanded its seat, to full length, you can add a rev kit and add a few hundred rpm by adding additional spring loads on the lifters but hydraulic lifters are fairly heavy compared to some of the better solid roller designs, and hydraulic lifters can,t use the same high spring loads and still work correctly and the cam lobe ramp designs are different between the two cam lobes

http://forum.grumpysperformance.com/...t=910&start=20

heres the frequent result of 6500rpm PLUS on a stock hydraulic roller lifter valve train
a few pics:




" IF YOU CAN,T SMOKE THE TIRES FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"

Last edited by GRUMPYVETTE; Aug 15th, 09 at 1:43 PM.
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post #8 of 34 (permalink) Old Aug 15th, 09, 1:15 PM
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Re: Hydraulic roller lifter preload for more RPM's

I usually aim for .080 preload on the lifter though I have not seen more or less effect rpm potential.

I run up to 200lbs seat pressure with a hyd roller on a turbo application that sees 7800rpm.

I would probably aim for around 180lbs on the seat with a hyd roller big block and try to keep it as light as possible at the valve. (use the smallest diameter spring with no damper to achieve the proper pressure, ti retainers, etc). You can run high seat pressure on a hyd roller if you use a spring that doesn't have a very high rate (say 390-425lbs/in). You do not want to run high seat pressure with a high rate spring as it will get crazy over the nose.

Run a stiff pushrod even at the expense of weight. A heavy pushrod will not effect rpm potential but a pushrod that is too weak certainly will.

Also, run a good quality rocker arm that lets you achieve proper valvetrain geometry. (pushrod length will need to be correct) but some cheapy rockers make it impossible to get the geometry correct regardless of pushrod length.

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post #9 of 34 (permalink) Old Aug 15th, 09, 1:20 PM
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Re: Hydraulic roller lifter preload for more RPM's

Let me expand
Lifter preload does not cause "valve float"
But
More preload will cause more problems if you lose control of the valvetrain for a couple of reasons
Pretty simple if you stop & give it some thought
The more preload you have the longer it will take for the lifter to recover if you lose control simply because it takes longer for the lifter to stabilize
The more preload the further the valve is going to be off the seat when the piston comes up to greet it
Hence the pictures above

Some examples
Solid lifter cam
You have say 50 thou of clearance at the valve on the intake (yes you can run it this close & closer on the intake)
It is in fact very close to 50 thou under all conditions not considering rod stretch et al
The exhaust is a whole nuther can of worms,,,

Hyd lifters
You have the same static 50 thou with say 50 thou of preload
You lose control of the valvetrain for whatever reason (usually not enough spring or the wrong spring for the parts & RPM involved)

Ok, you now just lost that 50 thou of clearance times the rocker ratio
The math says you have negative 25 thou with a 1.5 rocker & negative 85 thou with a 1.7
You now get to take your own pictures just like Paul's

So,,
Although preload doesn't cause the problem it certainly compounds it & is one of the reasons for hyd lifters with "zero lash" or running less than "recommended" preload can in some cases help
It is not that you didn't "float" the valves,,, it is just that you did not notice it as much because it may recover quicker

Or in the words of Mr. Joe Sherman,,,
Hyd lifters are for girls
No disrespect for all the ladies out there that row gears & go fast, just a "politically incorrect" comment on squishy lifters,,,, so don't shoot the messenger

Mike (Wolfplace)
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post #10 of 34 (permalink) Old Aug 15th, 09, 3:33 PM Thread Starter
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Re: Hydraulic roller lifter preload for more RPM's

The springs were an upgrade when I purched the Dart heads to handle .650 lift they are supposed to be 150 seat 400 open. I will try and set the preload less to see if this helps. I may try the beehives cause a solid roller on the street idling worries me and flat tappets seem to go flat. Thanks for all the information so far keep it coming.
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post #11 of 34 (permalink) Old Aug 15th, 09, 4:45 PM
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Re: Hydraulic roller lifter preload for more RPM's

Quote:
Originally Posted by Badrat496 View Post
they are supposed to be 150 seat 400 open.
Seems a bit on the light side, especially if you have steel retainers. I would pull one off and have it checked (make sure to measure the installed height), if it's a cheaper spring they can sometimes lose 20+lbs of seat pressure very quickly.

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post #12 of 34 (permalink) Old Aug 15th, 09, 5:32 PM
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Re: Hydraulic roller lifter preload for more RPM's

Quote:
Originally Posted by INTMD8 View Post
Seems a bit on the light side, especially if you have steel retainers. I would pull one off and have it checked (make sure to measure the installed height), if it's a cheaper spring they can sometimes lose 20+lbs of seat pressure very quickly.
=
Agreed, 150 is less than I would even consider with that cam.

Quote:
Originally Posted by Badrat496
they are supposed to be 150 seat 400 open
No offense but,,,
"supposed to be" does not really cut it, you need to check this stuff

Mike (Wolfplace)
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post #13 of 34 (permalink) Old Aug 15th, 09, 6:46 PM
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Re: Hydraulic roller lifter preload for more RPM's

Since I went to Beehives, valve train stability is significantly improved. I run 1/2 turn preload. Couple advantages to a Beehive. Spring and retainer wetight are one. Harmonics are much better. Inherent design of dual springs is friction from inner/outer rubbing together. This completely goes away.
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post #14 of 34 (permalink) Old Aug 15th, 09, 7:04 PM
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Re: Hydraulic roller lifter preload for more RPM's

HI yes the behivee fixs alot probs in bbc hyd rollers i have had em in my zz454 6200rpm no probs
victtor
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post #15 of 34 (permalink) Old Aug 15th, 09, 7:13 PM Thread Starter
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Re: Hydraulic roller lifter preload for more RPM's

Does anyone know which beehive spring would work with my cam? I know call the manufacturer but is anyone useing ones that would work and do you trust them?
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