LT1-LT4 Modifications 1993-97 Gen II Small Block V8

valve adjustment

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Old 06-27-2013 | 06:34 PM
  #41  
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Cleaning new lifters should be the first order of business before you oil them up for installation. It's always been that way. That packing goop has to be removed.
Old 06-28-2013 | 01:06 AM
  #42  
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Originally Posted by leadfoot4
Bingo!!!
Well said!!

Bingo
, i caught two bad mouths with one post. Hey lead, lets hear u explain why adjusting the rocker by noise is more accurate than roller with your fingers. I have adjusted hydraulic lifters for years and yes learned the hard way that rolling p-rod until it drags a little is the best way. It takes nearly the same effort so can u explain why is using your ears so much better? Do you have something to share or are u just a dead beat bad mouth trying to look good by getting on the bandwagon?
Oh by the way your friends understanding of lifter preload is *** backwards. 3/4 turn compresses the lifter cup more reducing lifter piston travel and provides more lift than smaller preload like your 1/4 turn which makes the lifter piston travel farther reducing vlv lift. Yes 3/4 turn preload will make more rpm and hp than 1/4. So your bad mouthing friend already BS clam for 7k rpm with 1/4 turn instead of 3/4 is as retarded as it gets.

But at least u have friends with the same amount of expertise,
cardo
Old 06-28-2013 | 05:41 AM
  #43  
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Shoot me for my honesty and i won't quote anyone here so i can't be accused of bashing anyone. But i have never been able to compress the p-rod cup by hand. I just tried this again a few weeks ago with my used roller lifters and using my entire body weight all i did was put a dent in the wood block i was pushing against.
The only time i was able to reassemble a hyd lifter and compress the cup enough to get the retainer in was with a flat tappet lifter and used the vise jaws to force the cup down with a substitute for the p-rod.
I just don't know why i keep reading posts where someone says they get the cup to compress trying to find zero lash. So i look in my Chevy Power Manual to see what GM performance says and nothing is mentioned 'bout filling up or pumping up the lifter - just find the zero lash by rolling the p-rod until some drag is felt.
So in my opinion if your expecting p-rod cup to move before u reach zero lash it ain't gonna happen. And i'll just leave it at that as my opinion - unless some bad mouth wants me to defend my statements. But i'm reading several here are asking these questions so u cantake it or leave it thats from my experience - and it may help someone here.

cardo
Old 06-28-2013 | 07:22 AM
  #44  
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Originally Posted by cardo0
It takes nearly the same effort so can u explain why is using your ears so much better?
A)Because it has worked for me for the last 45 years;

B) Because I'm not running monthly "tutorials" on this forum, trying to "educate" everyone on how to adjust hydraulic lifters.
Old 06-28-2013 | 08:51 AM
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so I gotta ask..........lets say you use the "engine running" method.....how do you get an accurate measurement on the amount of lash on the lifter?
Old 06-28-2013 | 11:39 AM
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Originally Posted by quik95lt1
so I gotta ask..........lets say you use the "engine running" method.....how do you get an accurate measurement on the amount of lash on the lifter?
Well, assuming that you agree that a given number of turns on the adjusting nut is an acceptable reference, you start with getting a "rough" adjustment by getting the car on #1 TDC, and set the 8 rockers that are on the base circle of the cam (obviously engine off). I don't know, right off the top of my head which ones you do, beyond #1 int. and ext. but it's listed in the shop manual. I move the pushrod up and down until the movement stops, then go 1 turn of the adjustment nut. Do this to the 8 rockers, then turn the engine over 1 full revolution clockwise, as viewed from the front of the engine, then do the remaining 8 rockers.

Start the car, let it reach operating temperature, then just go around to all 16 rockers in turn, loosening the adjusting nut SLOWLY, until you just hear the lifter click a little then tighten it back until the noise stops. That's zero lash. Add another 1/4, 1/2, or full turn, as you see fit.
Old 06-28-2013 | 12:36 PM
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What ever method is used, if you know what you are doing then every one of them will work just fine for adjusting a hyd. roller setup, again, only if you know what you are doing. If you follow one of the many proven, well established, been around for decades methods and, something gets messed up, blame yourself. Blame the tool behind the tool. Those who make this a huge deal and nit picking what steps are best, especially for the average LT1 setups that have been run for years now are compensating for their ignorance.
Old 06-28-2013 | 12:43 PM
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Tighter lash = more bottom end , reduced lift and duration. Looser lash = more top end , increased lift and duration. Dang man give it up.
Old 06-28-2013 | 01:17 PM
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where do you guys come up with some of this stuff..........with hyd lifters you have two things that can bite you in the *** in either direction.........you can bottom out or experience "pump up" of the lifter.......in dedicated low mileage drag race applications very tight lash is ok (aka leaving about .020 ish of travel in the plunger to the bottom) the idea being that as the valvetrain speed increases and forces become higher the pluger bottoms out and acts as a solid lifter basically.....problem being they don't last long like this..........the other issue being pump up this is masked by using very little preload.....pump up is encountered when the valve train experiences slack due to high rpm unloading of spring pressure on the valve aka "valve float".....at this point the oil pressure pushes the lifter pistion all the way up and can hang the valve open for a split second which will kill high rpm power......this is espically seen with aggressive HR cams which have become VERY popular lately........thusly the "loose is fast" idea can work if the cam is too aggressive and the valvetrain weight and pressure isn't enough to support the rpm.....the extra lifter travel allows the valve to not hang open thusly it makes more top end power.............then the other half of guys say tight is fast.....aka the bottom out method.....which again does work but beats up parts......in a perfvect world .070-.080 preload on say an ls7 lifter will put you dead center which with a properly designed cam and valvetrain works perfectly to make power and last a long time........

thusly........the engine running method works great for dads farm truck or the family minivan.....for a performance application its about as dated as a bag phone.......set your lash so its center of your lifter travel with the engine not running and end of story...if you have a float issue you can try and back them off a bit to help but all it is is a bandaid on a bullet wound.....

now with a solid roller cam the whole lash thing has a lot more promise to it horsepower wise but that's antoher thread

Last edited by quik95lt1; 06-28-2013 at 01:23 PM.
Old 06-28-2013 | 01:39 PM
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Originally Posted by quik95lt1
thusly........the engine running method works great for dads farm truck or the family minivan.....for a performance application its about as dated as a bag phone.......set your lash so its center of your lifter travel with the engine not running and end of story...if you have a float issue you can try and back them off a bit to help but all it is is a bandaid on a bullet wound.....
An opinion or..... ?
Old 06-28-2013 | 01:50 PM
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Originally Posted by SS RRR
An opinion or..... ?
that its dated? yes I suppose its an opinion.....but I really cant see how its not more accurate than guess where your lash is with the motor running
Old 06-28-2013 | 01:55 PM
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I dunno. Before stating if doing the running method with later, more aggressive ramp rates is a bad thing I'd like to see more info on how.
Old 06-28-2013 | 02:02 PM
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Originally Posted by quik95lt1
where do you guys come up with some of this stuff..........with hyd lifters you have two things that can bite you in the *** .......set your lash so its center of your lifter travel with the engine not running and end of story...if you have a float issue you can try and back them off a bit to help but all it is is a bandaid on a bullet wound.....

now with a solid roller cam the whole lash thing has a lot more promise to it horsepower wise but that's antoher thread
How do you suggest you find this 0.070"-0.080" of preload, with the lifter in the engine, and the intake manifold in place?







( don't tell me, roll the pushrod in your fingers until you feel drag, and that is "zero lash". Then turn the adjusting nut down 0.075", whatever that equates to in "turns"...)
Old 06-28-2013 | 02:07 PM
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Thread count/per rotation on the rocker stud, sir. That will give you an exact measurement. Again the Comp R thread comes to mind. People were saying they were adjusting their rockers to "1/8 turn past a **** hair..." and that is the wrong way to go about it.
Old 06-28-2013 | 02:07 PM
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Originally Posted by leadfoot4
How do you suggest you find this 0.070"-0.080" of preload, with the lifter in the engine, and the intake manifold in place?







( don't tell me, roll the pushrod in your fingers until you feel drag, and that is "zero lash". Then turn the adjusting nut down 0.075", whatever that equates to in "turns"...)
with the intake on you've got two options 1 tighten the poly until the lifter is completely collapsed and work backwards with your turns or lightly turn the poly until you feel it contact the rocker then make your turns from there.......5-10 thou either way isn't gonna make or break the day in a street application obviously im just stating what is actually happening when people are saying loose vs. tight is better
Old 06-28-2013 | 05:42 PM
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Originally Posted by quik95lt1
....5-10 thou either way isn't gonna make or break the day in a street application obviously im just stating what is actually happening when people are saying loose vs. tight is better

I hear you!


Originally Posted by SS RRR
Thread count/per rotation on the rocker stud, sir. That will give you an exact measurement. Again the Comp R thread comes to mind. People were saying they were adjusting their rockers to "1/8 turn past a **** hair..." and that is the wrong way to go about it.
I know what you mean, BUT the sheet that Comp provided with their lifters specified 1/8 turn beyond "zero lash". I even e-mailed Comp (twice, in fact), and that's what they told me...seriously!
Old 06-28-2013 | 06:10 PM
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Originally Posted by leadfoot4
I know what you mean, BUT the sheet that Comp provided with their lifters specified 1/8 turn beyond "zero lash". I even e-mailed Comp (twice, in fact), and that's what they told me...seriously!
Which lifters? My Comp R's specifically state something like .06 to .08" past lash?
Old 06-29-2013 | 02:30 AM
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Originally Posted by quik95lt1
where do you guys come up with some of this stuff..........with hyd lifters you have two things that can bite you in the *** in either direction.........you can bottom out or experience "pump up" of the lifter.......in dedicated low mileage drag race applications very tight lash is ok (aka leaving about .020 ish of travel in the plunger to the bottom) the idea being that as the valvetrain speed increases and forces become higher the pluger bottoms out and acts as a solid lifter basically.....problem being they don't last long like this..........the other issue being pump up this is masked by using very little preload.....pump up is encountered when the valve train experiences slack due to high rpm unloading of spring pressure on the valve aka "valve float".....at this point the oil pressure pushes the lifter pistion all the way up and can hang the valve open for a split second which will kill high rpm power......this is espically seen with aggressive HR cams which have become VERY popular lately........thusly the "loose is fast" idea can work if the cam is too aggressive and the valvetrain weight and pressure isn't enough to support the rpm.....the extra lifter travel allows the valve to not hang open thusly it makes more top end power.............then the other half of guys say tight is fast.....aka the bottom out method.....which again does work but beats up parts......in a perfvect world .070-.080 preload on say an ls7 lifter will put you dead center which with a properly designed cam and valvetrain works perfectly to make power and last a long time........

thusly........the engine running method works great for dads farm truck or the family minivan.....for a performance application its about as dated as a bag phone.......set your lash so its center of your lifter travel with the engine not running and end of story...if you have a float issue you can try and back them off a bit to help but all it is is a bandaid on a bullet wound.....

now with a solid roller cam the whole lash thing has a lot more promise to it horsepower wise but that's antoher thread

Nice explaination though i believe the problem with too little lash/preload is the lifter loses lift due to the increased internal piston travel until the oil cavity is filled and cannot bleed down fast enough causing the lifter to act as a solid holding the vlv open when it should be seated. And i don't have a Spintron test machine with time elapse photography to prove this so i had to learn it from the publishing experts - may it flame the part time experts here or not.
But regardless thx for your input and it was nice to read someone that actually shared thier experience and insight. No personal attacks either.

cardo
Old 06-29-2013 | 02:37 AM
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Originally Posted by leadfoot4
How do you suggest you find this 0.070"-0.080" of preload, with the lifter in the engine, and the intake manifold in place?

( don't tell me, roll the pushrod in your fingers until you feel drag, and that is "zero lash". Then turn the adjusting nut down 0.075", whatever that equates to in "turns"...)
U would have to read a book to see how the pros adjust within 0.010" preload - worth over 10 hp D. Vizard says. And yes i have never done that trick and wouldn't think of explaining what i read with the juvenile mentalities on this forum. So if u really want to know how its done u will have to read a book - start with David Vizard.

cardo

Last edited by cardo0; 06-29-2013 at 02:44 AM. Reason: spelling
Old 06-29-2013 | 02:40 AM
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Originally Posted by SS RRR
Thread count/per rotation on the rocker stud, sir. That will give you an exact measurement. Again the Comp R thread comes to mind. People were saying they were adjusting their rockers to "1/8 turn past a **** hair..." and that is the wrong way to go about it.
Not even close but i will drop a hint: the pros use feeler gauges to set the hyd lifter preload.

cardo

Last edited by cardo0; 06-29-2013 at 02:41 AM. Reason: typo


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