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  #31 (permalink)  
Old 06-23-2010, 11:25 AM
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1.21 giga-watts???!!!!
 
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Geez, why not just run a solid cam?

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  #32 (permalink)  
Old 06-23-2010, 12:00 PM
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R U aware of all the street driven solid roller problems?

I don't care to rebuild my roller lifters 2X per year.

BBP
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  #33 (permalink)  
Old 06-23-2010, 06:14 PM
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1.21 giga-watts???!!!!
 
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No, I am not aware of those or any other problems. When I built my engine, I planned it out, spent the money where it needed to be spent, saved it on things I could, and built a 400 HP 350 that gives me no trouble at all. Maybe it helps to avoid cockamamy ideas like the one the thread is about. But that's just me.
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  #34 (permalink)  
Old 06-23-2010, 06:41 PM
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Why are you not wanting to adjust the lifters the "normal" way? Because if you think this is going to net you 20 extra HP with the Lunati 50156 232/242@.050 cam you have, I can say w/o hesitation that IMO it will not.
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Old 06-23-2010, 07:29 PM
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I don't know about others but in my case:
- that's what I have, and I have a few aftermarket ones sitting in boxes to choose from in addition to having an OEM one in every car that I own
- in the case of my project car right now I'm on a "figuring out what I can get out of the stock setup" kick right now.
- solid roller conversions are $$$ and the heads that I'm using won't easily play nice with appropriate valve springs
- to some extent I'm playing "what if" with my questions to learn more about the dynamics of the situation.
- The car I have that a solid roller cam would be the most appropriate in also has a setup that makes it a real project to get the passenger side valve covers off which will make even annual rocker adjustments a pain

otherwise no reason... I'm not afraid of them or anything...
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  #36 (permalink)  
Old 06-23-2010, 08:29 PM
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Quote:
Originally Posted by Silverback
I don't know about others but in my case:
- that's what I have...
I'm a little confused by this post- what question are you asking, or what question are you answering? The thread is buff Bills, AFAIK, and any questions or answers are to HIS- not your- posts, unless your question was quoted by the respondent.

This is why we like the posts to remain unhijacked for the most part- it cuts WAY down on the confusion and cross-talk.

If you have specific questions pertaining to your engine, I'd suggest you start a new thread where your question will get the attention it deserves.

Quote:
Originally Posted by Silverback
Just throwing out reasons why someone might not want to "adjust the lifters the "normal" way."

Not hijacking the thread, I just feel that the discussion would be more useful to everyone if we had a clear explanation what happens at both ends of the adjustment range, since it sounds like a lot of the conversation appears to center around misconceptions of how hydraulic lifters work, and like I said, I'm not sure that I'm 100% clear there.
Thanks for the explanation, SB.

Last edited by cobalt327; 06-24-2010 at 05:51 AM.
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  #37 (permalink)  
Old 06-23-2010, 09:43 PM
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Does anyone have a copy of this book? I have read a few of Vizards books and don't recall anything like this or what he says about it. I used to have a collection of books like his and they all seemed to never get returned when I "borrowed" them out to people.

I would like to see a scan of the actual article because a lot of this isn't making any sense to me.

BTW Buffalo, what "street driven roller problems" are you referring too? Lots of roller engines out there built by the factory these days and they aren't having problems I know of...never heard of any aftermarket problems either.
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  #38 (permalink)  
Old 06-23-2010, 10:15 PM
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Just throwing out reasons why someone might not want to "adjust the lifters the "normal" way."

Not hijacking the thread, I just feel that the discussion would be more useful to everyone if we had a clear explanation what happens at both ends of the adjustment range, since it sounds like a lot of the conversation appears to center around misconceptions of how hydraulic lifters work, and like I said, I'm not sure that I'm 100% clear there.
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Old 06-23-2010, 11:09 PM
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I copied this:

"Design:
A hydraulic lifter is an assembly of an outer body into which is placed an inner piston/plunger sub-assembly, and an inner spring that holds the piston/plunger assembly up against a retainer on the top of the lifter which forms a cavity below the piston/plunger and the inside bottom of the lifter body.

The inner piston/plunger assembly is made of the piston/plunger part which is hollow and has an oil entry hole in its side, a top called the socket where the push rod rides, under the socket is a flat disk inertia valve, at the bottom end is a check valve sub-assembly that contains a check valve which can be of a ball or disk design retained against a hole in the bottom of the piston/plunger body with a light spring and a retention cup that holds these pieces to the bottom of the piston/plunger.

The top of the lifter outer body is machined for an inner retention device that keeps the inner piston/plunger assembly from coming out. This device is a either a wire bail or a Circlip. Inside the bottom of the lifter body is a spring that lightly presses the piston up against the retention device at the top.

Operation:
Engine oil under operating pressure is fed into the lifter from a hole in the side of the outer body. This oil passes into the hollow piston/plunger where it goes in two directions: one, past the inertia valve under the socket to feed the pushrod, rocker, and valve spring with oil; the other past the bottom check valve to fill a chamber under the piston/plunger assembly pushing it up toward the retainer thus removing all clearance lash in the valve train. Engine oil pressure is not high enough to overcome the spring pressure keeping the valve closed, but is sufficient to remove the lash. When adjusting the rocker nut, the valve spring is strong enough to overcome engine oil pressure to allow the push rod to press the inner piston/plunger into the lifter’s body. Excessive downward adjustment will at the extreme press the check valve assembly into the bottom of the outer body damaging it. The adjustment is nothing more than depressing the piston/plunger
an amount about equal to the heat caused expansion of the engine and its parts, it should be about the amount that a solid lifter clearance is set to as all you want is the lifter to operate where the piston/plunger does not pump up against the retainer with an exception I’ll talk about later, nor so much “clearance” that lost motion in valve train becomes enough to hold the valve open when the piston/plunger pumps up to remove excess clearance due to valve train deflections and spring harmonics.

When the cam lobe starts to push the lifter against the valve spring, the plunger sinks ever so slightly too where inertia plus the light retention spring closes the check valve trapping oil in the cavity below the piston/plunger and the inside bottom of the lifter body and closes the disk valve that controls oil flow into the pushrod. This hydraulically locks the inner piston/plunger to the outer lifter body. Continued rotation of the lobe then pushes the lifter to where it actuates the valve train to open and close the valve. This is one place where a small amount of lost motion occurs as the inner piston must initially move fractionally slower than the outer body. This is done by allowing a tiny amount of oil to leak out while the lifter is rising on the lobe’s ramp.

When the lifter comes off the closing side of the ramp, the loss of valve spring pressure allows the internal high pressure trapped oil to push the check valve open as well as the disk valve to the push rod and escape. Oil then flows to the rocker mechanism and into the lower cavity till the cycle repeats on the opening ramp. If during this part of the cycle a “clearance” appears due to bending of the push rod, rocker stud, or floating or sticking of the valve; the plunger under engine oil pressure will react to close any clearance until it meets with valve spring pressure. If these events occur the piston/plunger will position itself higher than its initial adjusted position. If the next cycle of the lobe gets to the lifter before it can bleed the excess oil out from the force of the valve spring pushing backwards on the piston/plunger assembly; the base point of the piston/plunger will start that much taller as it hydraulically locks itself for the
next opening cycle. Then when the lifter comes off the lobe, the valve will be held off its seat, unless the lifter has enough cycle time to bleed the excess oil out of the lower cavity. This is pump up, it occurs because something in the valve train has put either a clearance by deflecting under load, a loss of valve control from spring surge, or a momentary time lapse against function as in a sticking valve. By adjusting the plunger/piston lower in the lifter body, you increase the hydraulic lash, which at pump up will increase the amount of distance the valve will be positioned above its seat. This, also, increases the time and number of RPMs that must be reduced in which it would take the lifter to bleed down to recover from a pump up situation. So to a very large extent, the lifter’s ability to hold the initial zero lash adjustment is dependant upon when the check and disk valves close and how tightly they close.

The response time and amount of a lifter’s ability to track with the cam profile is directly related to how radical that lobe profile is and the amount of valve spring pressure that pushes on it. All hydraulics have some amount of “leak” down and a response time to recover that on the back side of the cam. There are lifters such as the Rhoads' that have more leak down than would a production lifter in a grocery getter engine. Crane and Comp also utilize fast leak down lifters to the same purposes which is to obtain a faster recovery from a pump-up situation and to build in an amount of RPM dependant variable cam timing. The latter is used on hot cams which tend to kill bottom end torque where a reduction of duration and lift at lower RPMs tends to bring the torque curve peak to a lower RPM and to hold that peak over a boarder rev range which provides more low speed power without resorting to high stall converters and or stiffer rear end gearing.
But the down side is these lifters tend to tick at low RPMs where the downward movement of the piston/plunger does not have time to recover to zero lash on the cam heel because of the designed in leak rate. But as RPMs come up, the plunger runs out of time on the lobe to sink as much as at low revs, so the lifter nearly returns to its adjusted zero lash state by its normal operating process of viewing the high leak down as a distance of lash to be taken up. But these type lifters always leak the piston/plunger a bit more than the OEM type so they will extend the operating rev range before pumping up, but always at the cost of a tiny bit of duration and lift at the valve against the theoretical events commanded by the cam. This is where a solid lifter always carries an advantage.

As I said back at the first paragraph of the Operation section, there is a situation where you can push a hydraulic to function more like a solid. If the piston/plunger retention device is a Circlip instead of a wire bail, it is possible to adjust the lash so it is just at zero lash with the engine hot to where the piston/plunger assembly is just touching the retaining Circlip. This will prevent the lifter from pumping up to where it holds the valve off the seat as it takes up lash that develops from deflecting parts and spring surges. However, this can put a lot of load on the retention device which is why Circlips are recommended over wire bails. But bear in mind that a failure of the retention device will result in a messy, if not destructive, situation.

Bogie"
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  #40 (permalink)  
Old 06-24-2010, 07:51 AM
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1.21 giga-watts???!!!!
 
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Buy Isky solid roller lifters or don't run solid rollers on the street if you don't want to rebuild. Simple solution.
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  #41 (permalink)  
Old 06-24-2010, 09:11 AM
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Excellent, where in that paragraph does it recommend bottoming the lifter to act as a solid?

I don't see it.
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  #42 (permalink)  
Old 06-24-2010, 11:31 AM
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Nowhere, different source of hydro lifter info for Silverback & others.

Do a google search of this site:

street solid roller problem site:hotrodders.com

I get 338 hits

Do a google search:

street solid roller problem

I get 87,200 hits

BBP

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  #43 (permalink)  
Old 06-24-2010, 11:42 AM
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Do a google search on David Vizard

I get 141,000 hits

His books are just full of "cockamamy ideas" NOT

BBP
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  #44 (permalink)  
Old 06-24-2010, 12:10 PM
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So what- google "bad ideas" and I get 99,900,000 hits. Means nothing.
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Old 06-24-2010, 12:26 PM
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"There are some people who, if they don't already know, you can't tell 'em."....Yogi Berra

I'm done with this
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