curious about valve lash setting/check

-
oldmusclelover

oldmusclelover

Well-Known Member
Joined
Nov 23, 2017
Messages
203
Reaction score
64
Location
mid west
hello all, been reading, and reading, but haven't found an answer to my curiosity. my apologizes if this has been answered: when setting valve lash, I have read many tricks of the trade. what I am wondering is, should the rocker have 'approximately' the same distance from the valve stem when you work the tappet with the hex key after setting? or will the oil pressure make the difference when the engine runs? while on the subject, should you feel resistance when applying the 1/4, 1/2 (or whatever your preference may be) turn of 'load' after you feel resistance on the push rod? or should it turn freely? some say resistance, some say the push rod to stop spinning before you start to put load on the lifter, have even read putting oil on your fingers to tell when you have the 'enough' resistance to start applying the recommended load turn, then tighten the nut. but I haven't read anywhere if there is a 'check' per gap when rocking. I understand the hex key and nut will have different gaps (hence the adjustment). thank you all for your knowledge, I spend waaaaay too much time on the computer when I start reading on this site, and love every minute of it! thanks all, Jack
 
yellow rose said:
If it's a hydraulic you can use an 1/8 of a turn to 1 full turn and the engine won't know the difference.
Click to expand...
Wow.. I thought for sure you would suggest solid lifter because he's losing horsepower with the hydraulics...
Possibly too much medication lately?....
 
I am totally lost. Hydraulic? Solids? Hydraulic with adjustable rockers? Briggs and Stratton?
 
I've read the OP's question numerous times and I cannot grasp what he's asking.
 
yellow rose said:
If it's a hydraulic you can use an 1/8 of a turn to 1 full turn and the engine won't know the difference.
Click to expand...
appreciate that yellow rose, if there isn't a 'check' for the setting, is there a good way to know when you have gotten to "the sweat spot" before adding the load? I was adjusting this afternoon and it seemed to me to be going further and further before the push rod would stop spinning. could I have been doing something wrong? holding too tight? and yes, hydraulic lifters. one other point, engine hasn't run in a couple weeks, would that have any effect?
 
RustyRatRod said:
I've read the OP's question numerous times and I cannot grasp what he's asking.
Click to expand...
sorry Rusty, probably put too much info, but trying to get enough to explain. just wondering if there is a check AFTER setting the load. I could still rock the arm into the lifter with ease (using the hex key), and had about a quarter inch between the valve stem and rocker arm. does that make sense, I hope?
 
I've always "been told" that you "want" the lifter about in the middle of it's travel with valves closed. "This might vary" from lifter brand to lifter brand, or, LOL with the incredible deck/ head precision to which these girls are born, from one lifter position to another. Bear in mind that thousands of these were built WITH NON ADJUSTABLE lifters, and ran many many miles, some quite hi performance LOL
 
oldmusclelover said:
sorry Rusty, probably put too much info, but trying to get enough to explain. just wondering if there is a check AFTER setting the load. I could still rock the arm into the lifter with ease (using the hex key), and had about a quarter inch between the valve stem and rocker arm. does that make sense, I hope?
Click to expand...
You had 1/4" air gap between the rocker arm and the valve tip??
 
oldmusclelover said:
sorry Rusty, probably put too much info, but trying to get enough to explain. just wondering if there is a check AFTER setting the load. I could still rock the arm into the lifter with ease (using the hex key), and had about a quarter inch between the valve stem and rocker arm. does that make sense, I hope?
Click to expand...

Now we're onto somethin. That's perfectly normal. Get the camshaft lobe of the rocker you're adjusting on the base circle of the lobe (valve COMPLETELY closed) adjust the rocker so that it has zero lash and no preload, then 1/4-1/2 turn down and lock it down. Then move to the next and repeat.

This is how I do it. Others use a heavier adjustment such as 3/4-1 full turn and I've even seen some people use 2 full turns. I prefer a lighter touch.

Lastly, I do the rockers ONE at a time right down the line, rather than IOEC or "whatever the hell that is" because once again, it's easier FOR ME. I mean, how big a hurry are we really in here? lol That method has always served me well.
 
Last edited:
Ah, apparently adjustable hydraulics. Makes more sense now. Thanks Rusty.
 
312P4452989.jpeg

I've always went by this chart and it served me well...
 
oldmusclelover said:
thanks j par, I did use this chart. do you set your rockers by 'tension' on the push rod, or do you keep turning the hex key until the push rod stops spinning completely? and how light of a touch is needed?
Click to expand...
I would do exactly like rusty said I'm sorry I'm not supposed to mention his username but I have solid lifters..
 
Have adjusted Chevy hydraulic lifters and we got them to the Bass Circle and would turn them down till you felt tension. I would kind of spin the pushrod back and forth between my fingers and when it would come down and you could feel it start to stop that would be what I would consider my starting point and then crank it down x amount from there...
 
j par said:
Have adjusted Chevy hydraulic lifters and we got them to the Bass Circle and would turn them down till you felt tension. I would kind of spin the pushrod back and forth between my fingers and when it would come down and you could feel it start to stop that would be what I would consider my starting point and then crank it down x amount from there...
Click to expand...
so there isn't much tension when cranking down to 'x' amount?
 
the reason I asked, is that I set them with 'feeling tension' on the push rod, then went through again setting them with 'stopping the push rod from spinning' and it was quite a noticeable difference to where they were set.
 
Get the cam to its base circle using whatever method you want, MP decal, degrees or logical crank rotation looking at the opposite rocker. Spin the pushrod, and start cranking down the adjuster-you'll feel it drag when it touches the pushrod. From there, add your preload, or subtract lash on a mechanical. The TPI on an adjuster is 20 so 1 turn more is about .050 and fractions there of. Thats about in the middle of the preload range. The cup in a hydraulic rocker can compress .00x before its check valve closes and it becomes 'solid' That where the preload comes in. It gets the piston past its spring pressure into the check valve.
 
You must log in or register to reply here.
-

Back
Top