Just want to be sure I did this right. Lifters are fully pumped up and what I did was put the push rod checker in at 7.300" and torqued the rocker to 22ftlbs and then adjusted the pushrod checker with my finger till their was zero lash. I took everything off and I came up with 12.5 turns so that leaves it at 7.425". My quistion is do I leave it at that or do I add the preload for the ls7 lifters I was going to go with a .075" preload because I have a set of 7.500" pushrods already or do I get a set of 7.425". I ask because I read snd hear so many different things like find zero lash and leave or find zero lash and then count the turns and that's the preload or with stock rocker ratio you dont need preload and so on. Well im not really sure what do to because at 7.500" I get about 1.5 turns till torqued which means the preload of .075" is good. With the 7.425 I get less then 3/4 of a turn which means I need longer for the preload but that means that I have zero lash and just torque it. What do you guys recommend the 7.425" zero lash and 3/4 turn till torque or the 7.500" with .075 preload and about 1.5 turns till torqued?

 

Rocker bolt torque really makes no difference to this, but it's eeeeezy to get right, so why not. There's nothing about them that "crushes", "distorts", or anything else, such that some variation from the "nominal" value will affect anything dimensionally. It's all metal to metal. Once they're "tight", no dimensions change. You can't leave em loose to "adjust" anything, or worry about "how many turns to torque", or any of that crap; you tighten em until they're properly tight, which for that size hardware is about 22 ft-lbs (actually, 30 N-m, since they're metric bolts and 22 ft-lbs is merely the approximate value when converted from metric to imperial). IOW, you treat em exactly the same as any other bolt that size.

Personally I don't like the "method" of counting turns on the rocker bolt to "measure" anything. Just seems kinda crude, at best. Esp when you have an adj PR in your hand. That "alternative" is for people who don't have the tools. You don't need it. Ignore it.

LS7 want about .080" of preload. If your adj PR produces zero lash at 7.425" then 7.50" PRs will give you .075". Close enough for gummint work, for sure.

 

that's kinda what I assumed I just never really understood why some people say you need to count turn with a checker and some don't I get it's a crude way of doing things but at the same time it's very confusing. My whole things of why I ask is because when I built another engine awhile back I got my zero lash snd added the preload and ended up with 7.575 pushrods which caused the engine to run like crap because it was to much and kept the valves slightly opened. So now I'm kind of paranoid to add preload to things lol. But at 7.500 with the push rod checker I didn't notice any movement with the valves like on the previous engine. So maybe I added wrong or simply didn't know what I was doing this was years ago.

 

The proper way is to measure the pushrod checker with a set of accurate dial/vernier calipers, or a 7"-8" outside micrometer. I was a Tool and Diemaker for 43 years, and my personal set of mikes went from 0"-6", so most people won't have an outside micrometer that large. Get an accurate reading, let's say you use a 0"-8" dial caliper, and get 7.425", as you say. Some PR companies measure differently than tip to tip. Call the manufacturer of whatever brand PRs you have, give them your measurements, and they'll tell you what you need. However, it sounds like you're past this stage. Unless the PR checker is graduated, there's no reason to count turns. That's why you use a checker in the first place, to get away from the BS of counting turns of the checker, rocker bolt, etc. It's also a dead nuts measurement (+-.002, at MOST!). Best of luck to you........

 

8" calipers from Horrible Fright are $32.
The differing methods of measuring, gauge length vs end to end length is approx .015". Not enough to make or break preload.
Most basic LS builds fall between 7.375 and 7.425". But we always check to be sure.
Counting turns is simply confusing......

 

Love that Horrible Fright, Ron!!!!

 

Also I can tell you that no matter how many times you check, and what push rods you put in, you can EXPECT that an after market cam will be MUCH NOISIER than a factory cam.. No way around it. I have tried the cam on base circle, find zero lash, and then count turns until you reach 22 lb. ft. of torque and usually can get them all within 1.4 to 1.75 turns... does not matter as the engine runs fine but you have the sewing machine sound. I once chased that sewing machine sound and ended up ordering, installing, and trying 4 different lengths of push rods to no resolution of the sound. I have a set of 7.3, 7.350, 7.389 (factory length as measured with a caliper), 7.4, and 7.425" push rods. I settled on the factory length after checking all 16 rockers with the cam on the base circle and ALL of them falling in the aforementioned 1.4-1.75 turns range... Yes, it still makes the sewing machine sound... but... you get used to it.. and headers just make it louder-but also drown out some of the noise with a better sound of exhaust.

 

How to properly measure

 

This is a great article that covers all sorts of questions about measuring and preload


https://gwatneyperformance.com/lifte...ont-hurt-will/

 

Ok thanks guys for the answers I'm just afraid to add preload after finding lash because last time I did it it pushed the valves to far open causing issues with the engine. But it's possible I didn't do it right.

 

If what this guy is showing in this video is correct, it is contrary to what I have read everywhere else, and seen on Youtube..... If 1 full turn is .079" then essentially from ZERO lash, you would be at a pre-load of .079" at 1 turn. I've heard and read-but DO NOT KNOW IT TO BE TRUE-that with factory GM lifters you want your pre-load to be about one half of total lifter plunger travel. I've heard and read that GM lifters supposedly have .180" total internal travel. If any of this is accurate then it would mean that you would want about .090" lifter pre-load if I understand this correctly. However, I've read on this site and other places that you should shoot for about .070" lifter pre-load. If that is the case, and based on seeing the video above, we should technically be shooting for 1 full turn from ZERO lash, with the lifter on the base circle of that lobe... Maybe that's why I can't get these things to run quietly. I've been shooting for 1.5 and usually fall on, or just on either side of that.. and wind up with the sewing machine sound. My last engine I tried MULTIPLE push rods (and have several Comp Cams sets for sale if anyone is looking?) trying to get to the magical 1.5 turns and found that the factory length put me closest to that target. Now... based on that video.. I'm thinking I could actually try to get closer to just 1 full turn which would mean a shorter push-rod. Luckily I have a brand new set of Comps here in 7.350" length. How much you wanna bet I change all 16 push rods to get closer to 1 turn from ZERO lash and it will still sound like a Singer on steroids? Who has some virtual beer to put me up to this? Please note I'm not standing behind anything I posted here. NONE of this is my opinion-just what I've read and heard. I'm as confused as ever.

 

I just went and read this entire thread; https://gwatneyperformance.com/lifte...ont-hurt-will/
and towards the bottom they are indicating that as little as 3/4 of a turn will suffice for lifter pre-load.... Hmm... makes me wonder if I've just been using the wrong length push rods and setting them up for too much pre-load all this time. I may have to try the 3/4 to 1 turn method on my next build... as luck would have it, I will be building a .030" over 6.0L next week... I'll go for minimal pre-load and see if I can get it a little quieter. Worse case I have to change them out after its installed in the vehicle.

 

So from what I'm gathering I'm not the only one confused by any of this lol. How can some say don't worry about the turns and some say do. Some say find zero lash and leave it some say fond zero lash and then add the preload. Kinda confusing tbh. So again do I go with the 7 425" or the 7.500" since I would need preload. But then again maybe that guys cam is a stock cam and ours being over .600 lift gives it a different reading. And with the 7.425" that gives me 3/4 of a turn which would put close to the preload so id need 7.450" but everything contradicts itself. I think I'm gonna stick with the 7.500 which is 1.5 turns ish. Which is what everything I read said and even my engine builder said to do. But then again what did everyone else do

 

How about just tighten the rocker arm to hand tight, find zero lash, measure the OA length of that and add your lifters desired preload? I do not care how much preload you'll get by turning the bolt 360° when the end goal is to have the proper preload on the lifter of choice once the bolt has reached 22 ft lbs of torque.

 

Anyone that has built engines, especially performance engines, sure as Hell isn't gonna guess, and take the extra time, by counting turns. Pushrod checkers are basically an inside micrometer. They're dead nuts accurate, and they're a lot faster than counting bolt turns. Put the lifter on the base circle, screw the checker in a ways that you know is too short, install the checker, tighten the rocker. Then turn the checker until it stops against the rocker cup. Remove the rocker, remove the checker, and measure it. Whatever the checker measures is zero lash. Add to that length whatever preload you need to run. It really is that simple!! Some of the advice in these threads about counting bolt turns.......Doing all this unnecessary counting bolt turns, it makes setting up a hydraulic valvetrain harder than setting up a solid valvetrain, which totally defeats the purpose of running a hydraulic lifter in the first place!!! I can't understand how people can drop 10-15k, or MORE, into an engine, then refuse to drop $25 for a pushrod checker!!!!

 

exactly what you said is what my machine shop said. I do have an adjustable pushrod checker from comp cams that I used before. The reason I posted this is because what you said among a few others is exactly what my assumption was. But people said that the way I was doing was wrong and that I need to do turns and stuff which defeated everything my machine shop told me to do that what was my general understanding. So I ended up falling down this rabbit hole of youtube and forums and confused myself. Because what I don't want to do is have 10k into an engine and have the proper tools but wrong pushrods because nobody has a clear answer. So I think I'll just put the 7.500 which assuming is the correct way to do things gives me .075" preload.

 

Please note I highlighted the important part of your post...... what exactly IS the proper pre-load on the lifter...? From reading it varies depending on what type of lifter you have. If you can answer that question, then you will have provided information that NO ONE ELSE seems to know FOR SURE. I'm not being antagonistic..I'm not being argumentative... I just want to know WHAT THE PROPER PRELOAD SHOULD BE!!!!!! Your opinion may be the same, or may vary from what everyone else is saying... so how do we really know what the right pre-load is? That is the conundrum. I can tell you that 1.5 turns in from zero lash with LS7 lifters will produce an engine that runs just fine with a sloppy stage 2 cam.. though it will have sewing machine, whirring, valve train noise-it will run just fine!

 

Okay... lets delve a little deeper into this since you seem to think it's just SOOOO EASY with a push rod length checker... I have in my possession a factory GM push rod that I cut into two pieces, drilled and threaded the cut ends of both pieces, put a piece of all thread between them with 2 jam nuts so that i have made my own adjustable length pushrod... using that to find Zero lash means SQUAT... Yes, I extended that adjustable push rod to find me ZERO lash. Yes, I then added .080" for pre-load. Yes, I then ordered push rods based on that measurement... You know what? STILL got the sewing machine sound... Yes, the engine runs perfectly fine! But when sitting next to a building such as a drive through restaurant you can still hear all 16 of those little lifters just whirring away.. You can hear what sounds like springs slamming valves back into the head on the closing events. So... It's not that we don't want to "spend $25 for a pushrod checker".. Please.. we want it FACTUALLY correct and to date there are so many differing opinions as to how to set this up, and how much pre-load is acceptable with whatever lifter you are running.. TOO MANY VARIABLES! There is NO single answer! If it were as easy as just using the push rod length checker life would be a dream.. But that's not reality.

 

YES! I think you should use the 7.500" pushrods if they give you the .075" pre-load! The only thing I'd caution you against... is being upset if you have the sewing machine sound when done... I think this sound comes from the way the after-market cam ramps are cut... The factory cams are designed to have really soft closing events IN MY OPINION to avoid excess valve train noise. The after-market cams, in order to have that higher lift, and longer duration, and still have the proper timing events have to utilize more aggressive ramps.. I believe (but could be really wrong) that is why the after-market cams are much noisier than factory cams. The after-market cams are just so much more aggressive in their opening and closing events because they have to accomplish these high lifts, and longer durations, within a limited window of degrees. It is because of that limited window of degrees of cam rotation that the ramps have to be made so much more aggressive and therefore we get the excess noise. I've built 5 engines so far this year all with after market cams to include Texas Speed cams, and Comp Cams, and even a china knock-off cam-ALL OF THEM ARE NOISIER than factory cams. All of them being in the .600" lift area with duration #'s in the 228-240 range. This is with shooting for 1.5 turns from zero lash to find pushrod length. Almost all of them ended up using factory length push rods except one that had milled heads and .040" head gaskets.

and before I forget.. I really enjoy everyone sharing what they know, or what they believe to be true... I hope that everyone that has experience with this that comes across this thread will share their experiences. somewhere within all the personal experience(s) we will find the best way to set this stuff up. For me, today, I learned that maybe 1.5 turns is not the optimal way to do this. I will start using the 3/4 to 1 turn from this point forward until I can factually state it's either better, or worse, and adjust from there. I'm really excited now to build this next engine next week to see how how much noise, or lack of noise, this next 6.0 makes.

 

sounds about right I mean honestly it's a 421 so I doubt I'd head the ticking over the exhaust anyway lol i just wanted to be sure that I wouldn't have issues with the valves being stuck open again like before. Although it would be nice to have a proper and legit way to do this rather then have several opinions all of which hardly anyone will agree with. But I guess if the ticking noise is the common theme then I guess no one is wrong then.