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Valve Adjust with Engine Running?

53K views 14 replies 10 participants last post by  Rich-L79 
#1 ·
Hey guys!,

I am planning to adjust my valves while the engine is running, but I have never done it before. I am going to use an old valve cover that I cut the top off of so I don't get oil all over. However, I was wondering if there is any particular order they need to be adjusted in? Any help is appreciated. They are aftermarket roller/rockers and hydraulic lifters on an SBC 400, in case it matters........

Spoileddaddy
 
#2 ·
Spoiled,

Do them while the motor is off, use the "EOIC" do a search. Much better method and gets them all even. Doing them running I suspect gets the adjustmenst all over the place.
 
#4 ·
Spoiled,

Do them while the motor is off, use the "EOIC" do a search. Much better method and gets them all even. Doing them running I suspect gets the adjustmetss all over the place.
actually, with hydraulic lifters, it's better to do a final adjustment with the engine running- it takes all the variables out of the equation and gets them set right. i don't think you could do solid lifters this way, tho.
it can be done with roller rocker arms with a hydraulic cam- it's just harder to tighten each poly lock without it backing off while the engine is running unless you have one of those nifty tools.
just back each rocker arm off until it just starts to clatter, then tighten it down until it just stops clattering. you can actually feel it clatter thru the ratchet.
i always do it one side at a time- less mess that way. when all 8 valves on each bank are done, shut off the engine and give each rocker arm 1/2- 3/4 turn depending on the cam to set the preload and then put the valve cover back on and move on to the other bank.
when you are done, hook up a vacuum gauge and re-set the idle mixture screws, since it may run a bit different.
 
#3 ·
No particular order. Set your idle as low as practical for the adjustment. Besides reducing the amount of oil spurting, it'll make it easier to hear the individual valves. If you have high oil pressure, clips on the rockers might be a good idea even with the valve cover.
 
#5 ·
I have done it both ways, running is just a horible mess. Once the engine has been run and the lifters pumped up its very easy to tell where your at engine off. THe trem EOIC refferences you pick one cyinder, I just start at the front rotate the engine until
Exhaust is Opening (the EO) and adjust the intake, then rotate the engine until
Intake is Closing (the IC) and adjust the exhaust
then move to the next cylinder
 
#6 ·
Doing a running valve doesnt have to be a mess.

Do 1 bank at a time using the rocker clips or AL foil pressed/crushed/crimped over the upper ends of the rockers to stop/deflect the oil,then fold/mold some AL foil over/along the lower edge of the entire head to catch any oil that may be thorwn off the lower ends of the rockers,and also have the idle low like 550-600 rpm if possible.

I have done many running valve adj this way on sbc/bbc over the yrs with very good results.

Opp's,i just noticed you using an old cutout v-cover which is good but still use the rocker clips if there is enough clearance with the rocker cover on or use the al foilf crushed/molded over upper ends to stop or at least deflect the oil .

Scott
 
#7 ·
Thanks for the suggestions. I am going to try the Foil with the valve cover I modified. I have some of those clips a friend gave me, unfortunately they are for the stock type rockers and won't work with the Roller Rockers I have. So let's make sure I got this right: Warm engine up, loosen hold down nuts until the rockers "chatter", tighten until they stop "chatter", shut engine off, tighten an additional 1/4 to 1/2 turn, tighten the locks, then do the other side. Is that correct?


Spoileddaddy
 
#8 ·
well, mostly correct. with stock rockers and jam nuts, you can adjust each rocker and move onto the next valve and preload all 8 on that bank when they are all done- but with the poly locks you have, you need to actually put in the additional preload and tighten down the jam nut before moving on to the next valve- without the jam nut tightened up, the nut will loosen up almost immediately after removing the wrench.
it takes a little more time with the engine running, but not too much.
 
#11 ·
While I understand the EOIC method, I am absolutely behind the motor running contingent. I have twirled many a pushrod -- Fords and Chevys -- but never had a high level of confidence that I was feeling accurate preload on a shut down engine, since it involves both a spring and oil pressure inside the lifter. The way I see it, with the motor off you can't tell if the lifter has bled down and therefore if you're feeling the oil, or the spring, or both. In fact, just tightening them down must bleed some oil and every time I've done it motor off, it always feels like it can go a little tighter just a few seconds after that first twirl hits. And it probably can, since that first adjustment must force some oil out of the lifter. Thus, the very act of making that first adjustment pass on a shut down motor forces the oil out of the lifter and changes the whole equation. Plus, to me it only makes sense that the valves which were open at shutoff will be bled down more by the time you get to them since they were under pressure, while the closed valves are not. But with the motor running you've got all the valves equalized for oil pressure. Plus, you're hearing each valve tell you just what its individual preference is. I use a sliced valve cover and back off each one slowly till it clacks, then go 1/2 to 2/3 tight. I also usually end up doing each one twice to assure myself I'm right, since I'm in there anyway. It can be messy alright, but a hydraulic lifter works by oil pressure and I just don't see how static adjustment can be more accurate than when it's under operating pressure.
 
#15 ·
Unless you have entirely collapsed lifters, it doesn't matter if the lifter is pumped up or bled down, the engine off method still works fine. A hydraulic lifter at rest STILL has a spring loaded plunger which returns the top of the plunger to the top of the lifter when all lash is removed. This spring is strong enough to take up the slack in the lifter but weak enough to be over powered by the valve's valve spring. In short, when setting the valves on a non-running engine, you simply need to remove all the lash (lift the pushrod up and down to see if any lash still exists) then add your preload amount (1/4 turn, 1/2 turn, 3/4 turn, whatever you want to use).

If the amount of lash you've reached adds lash from the previous setting, the lifter will pump down to the appropriate level when the engine starts. If you've removed lash the lifter will pump up to the appropriate level.

Bottom line: the top of the plunger in a hydraulic lifter (the cup the pushrod rides in) will reach the top of the lifter when all lash is removed even with the engine off.

That said, it is just as easy, more safe and much cleaner to adjust the valves with the engine off whether it is a fresh rebuild or a previously run engine.
 
#12 ·
Twirling pushrods is a guaranteed way to get you valves too tight. IMO, the best thing to ever happen for valve adjustments is polylocks. Just get the lobe on its base circle, then just lightly run the polylock down till it stops - walla- zero lash. I always had problems adjusting with the crimped nuts, they took all the "feel out of it".

My concern with the running method is 1) it makes a mess, 2) your plunger depth may vary from lifter to lifter. Some valves and or lifters may make more noise than others in general, so you end up with different adjustments.

Heck, what if one lifter was faulty or just louder? With the running method you would just keep cranking on that nut till its quiet. Not a good way to go IMO.
 
#14 · (Edited)
I respecfully disagree,when doing a running adj on a stock to mild perf hyd flat tappet perf cam its easy to tell if you have a lifter issue,bad cam lobe,can see a bent pushrod,etc.

I have done literally 100's of running hyd flat tappet cam valve adj on motors over the past 37yrs i have been working on them(Family was in car buisness for 30yrs & i also work on cars/motors on the side too so i have a lot of experience with doing running valve adj) and it's not a bad way to go if you do it properly and take measures to stop/reduce the oil splash with rocker clips and AL foil.

But i also do the static EOIC method too for new cam installs & when rebuilding motors too.

Both the running & EOIC valve adj methods have their place,it just depends on which method better suits your needs at the time.

Scott
 
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