@Trucker82
@Trucker82 , Today 09:53 AM
So I read through countless threads yesterday about this subject and not one person has mentoned this happening, at least from the explanations I could surmise. I am hoping to find someone whom has encountered this phenomenon I am having and can offer a remedy.

I have 2 5.7l Gen 3 motors In my shop. One I am rebuilding and the other is getting a cam swap. The issue I am having is the EXACT same on both. The rebuild has Summit Rockers, the cam swap has Harland Sharp with the shaft bar linking the pair per cylinder. The rebuild obviously has new lifters, but the cam swap has original lifters.

Now how can I have this issue with both, yet unable to read anyone ever having this same issue....So I'll describe it now. But just to let you know so the trolls can settle down first, I have been working on cars for years, NEVER had this issue, but its obvious I have little experience with non adjustable valvetrain.

I setup my dial indicator to measure the plunger depth at 22ftlb torque, and the lifter plunger doesnt move at all. Instead the valve draws down. 1 to 7 rocker ratio means .040 lifter plunger depth will not equate to .040 valve lift. So I can't just go off how much the valve is is being lifted off the seat. This is happening on both motors, where one set of lifters is brand new and the other has 180k miles.

To further complicate the situation, I left the shop the other night to go home, with the dial indictor in position and valve off the seat. Came back to the shop 12 hours later next day and the lifter must have settled down. The dial indicator read .050 plunger depth and the valve didnt move when I loosened the bolt, the lifter plunger did. But when I tried again only the valve lifts off the seat and the lifter plunger stays solid.

So WTF.... I need to wait 12 hours on each lifter to get the proper reading of depth???? This is happning on both old and new. I know where the base circle is so don't even try to say otherwise. The Harland Sharp rockers say to lash valves while on the compression stroke. The Summit rockers I am following the age old EO-IC (exaust opening Intake closing) procedure.

I know where and how the base circle is, I know what zero lash is, I have adjusted valvetrain for 30+ years, BUT Never had issues like I am having with non adjustable valvetrain.

So my questions are:
Are guys just ignoring the 22ftlb rule and making adjustments 1/2 turn after zero lash?

IS it normal to have the lifter plunger so stiff?

Do I need to remove the valve spring and put in a valve height checker in there at the current installed height, then run through the motions of torquing to find true plunger depth? Or heaven tell me there is an easier way?

Is there a racer reading this that could tell me what he does to avoid this by using a different technique to find exact measurements of his valvetrain?

 

There is no "22 ft-lb rule". All that is, is, TIGHTEN THE FORKING ROCKER BOLT ALREADY. 22 ft-lbs = the bolt is tight and the rocker trunnion is thoroughly unequivocally unambiguously mashed against the stand plate. That is ALL. That tells you, yes, it is now fully installed.

Yes, the normal way of doing these motors is, find zero lash with an adjustable push rod, then install push rods that are [your desired preload] longer than that. It's really not that hard. Might be different for int vs exh valves, or odd bank vs even bank, or even valve by valve. But it's all pretty simple. Rocker brand is irrelevant. Find zero, add preload, done. Doesn't matter what the valve does at the moment, it'll adapt once it's running.

 

RB04av. So do you tighten rocker to 22 Flb? You werent specific on what you do. Im Still confused with your responce....what method do you use?

So are you saying after finding zero lash with an installed Pushrods checker, Are you just doing a quarter turn after zero and ignoring what torque the rocker is at? Or do you still torque to 22? Thanks for the help

 

 

OP is definitely making this more complicated than it needs to be.

 

the rocker is installed at 22 ft lbs. just delete everything you learned about any other adjustable valvetrain. the rocker is installed, or it isn't with an LS motor. the rocker bolt does nothing more. it isn't there to compress the plunger on the lifter, it holds the rocker in place. preload on the lifter is set by pushrod length.

with cam lobe on the base circle, if the pushrod is at zero lash with the rocker installed, that is your initial measurement. use a set of digital calipers and make sure the pushrod length checker does not move an iota from that zero lash measurement length, and measure with the calipers. add preload to that measurement, that's your pushrod length. i forget the difference between guage and actual length bla bla blah, but when you get your new pushrods, they need to be the measurement you found with the calipers + the preload. that's all.

that's it. you are making it too complex.

 

don't confuse using a length checker to find proper pushrod length with the rocker bolt turns method for finding preload, either.

 

Alright I like the way you put that! Thank you man! Many Blessings to you. I will do tommorrow.

 

Ya I didnt like that counting the turns method. I pretty much disregarded it.

Find Zero with rocker fully seated with Pushrods length checker, add .030 to that length for final plunger depth. Does it matter what torque reading the rocker is when seated on the pedistel?

 

you probably want more than .030 preload if you're using oem lifters. at least .060, maybe a little more depending on the oem style lifter. you want to aim for around half of the plunger travel.

22 ft lbs to seat the rocker, that's it. just make sure the cam is on the base circle when you tighten it, either when taking the measurement or actually installing the pushrod and rocker.

there is a method as well to set the wipe pattern, as well, if you do a search for it.

 

https://ls1tech.com/forums/generatio...od-length.html

 

No, not at all... just have to make sure it's all the way installed. That's it. Doesn't have to be any particular torque at all, just as long as the rocker is held onto the head where it's going to be when it's running. There's not even any tension or force on it during this process so it just doesn't matter. You could probably hold the trunnion down with your thumb and it'd be plenty close enough. All you're doing, is looking for the push rod length that takes up all the free play. Then add your desired preload to that, and buy.

.030" is not really enough preload with stock lifters such as LS7. You want something closer to .080" or so. The plunger has at least .125" of travel, and you want to take up half of that or a bit more. Other lifters of course may be different, so make sure you know what your particular ones want.

To change the wipe pattern in a stock like rocker setup you have to either shim up or grind down the rocker stands. Again, other rockers may have their own adjustment methods.

 

Thanks alot guys. I ended up shinning one side and the other side was good at stock length on the cam swap. It must have gotten a resurfaced head at one point. Otherwise there is .045 difference in pedistol height from the factory. Gotta get new Pushrods for the build. Things made a lot more sence once I got back to it and applied your help. But it still trips me out how these stock and semi stock hydrolic rollers having such a strong plunger spring. They still drop the valve on initial adjustment, but lose it after the engine is cycled a couple.

sometimes you just know too much about one thing and it blocks comprehension on a new related subject.

And other times we're just to dence to get it...

Thanks Again!