Opinion On Adjusting Rockers Cold Or Hot

[Dandeluxe]

WENT FOR A 300 MILE CRUISE A COUPLE OF WEEKS AGO AND MY TRUCK STARTED MISSING. SO WHEN I GOT IT HOME I NOTICED A STRANGE NOISE UNDER THE VALVE COVER NO. 4 CYLINDER HAD A BENT PUSHROD AND THE ROCKER HAD SLID OFF THE SPRING. I CANT REMEMBER HOW I USED TO DO IT?WHEN I PUT MY NEW PUSHROD IN WHAT IS BEST? SET THE NEW PUSHROD COLD OR HOT AND RUNNING. NOTE IT IS A 350 SMALLBLOCK. IM TOLD COLD. TO BUMP IT AROUND UNTIL THE 2 VALVES ARE CLOSED AND THEN SNUG DOWN THE ROCKER AND FEEL THE PUSHROD WITH MY TWO FINGERS AND LET IT SPIN SLIGHTLY THEN 1 FULL TURN WITH THE RATCHET. HOW WOULD YOU DO IT. I KNOW RUNNING AND HOT IS A BIG MESS. THANKS, DAN

[72 CustomCamper]

I always roughly set them cold, then fire it up and do the final adjustment hot while running...

Chuck

[bpmcgee]

Dan,

I've asked a bunch of mechanics this question. Half of them scoff at the ones who set it while it's running, saying they're a bunch of no-talent junior-mechanics who don't know a wrench from a wench.

The other half laugh at the ones who set it while it's NOT running saying they're a bunch of no-talent junior mechanics who don't know all the tricks.

In the end, I had to set mine while it was off, because my roller tips were too quiet to set the other way.

Brian

[beau396]

I have done it both ways. If you know that the lifter you are setting the lash for is on the baseline of the cam (lowest lift point) then tighten the nut until you feel resistance on the push rod while you spin it then go 1/2 to 3/4 more and I have never had to do a follow up adjustment. I usually do it twice to make sure the preload is right. However there really is not any reason that you can't do it while it is hot, other then the possible oily mess. Just tighten until it stops making noise and go another 1/2-3/4 turn.

[mikep]

I'm with the first crowd .

When you set the valve you have to make sure that its on the heel of the cam. If your just setting it with the valve closed you might or might not be on the heel of the cam. With hydraulics the plunger will compress a bit when your not running SOMETIMES and throw your valve adjustments out of wack. Theres a good write up on the compcams website of how to figure out where the heel of the cam is when setting the valves. It doesnt really matter with hydraulics if you do it hot or cold to answer the question. This whole debate is why I like to set hydraulics before I even put the manifold on so I can actually see the lifter plunger move . Then I set the valve adjusters with a dial indicator for .040" compression of the plunger. Its an old F*rd non adjustable valve train habit that works well with chevies too.

[Longhorn Man]

I do mine running...but that is from a lack of tallen in all reality.
If I find somethign that works...I stick with it.
Who cares if you make a mess on your engine...just another reason to go to the coin opp and wash your truck....right?

[7T1BURB]

"Running and hot is a big mess"....here's a thought. I just finished adjusting the valves on the newly rebuilt 307 in the BURB yesterday. I have an old valve cover that I cut out a 1" strip across the top of the cover. After initially adjusting valves COLD during the rebuild, I fired it up and did a proper break-in. Shut it down, changed oil and filter and installed the "modifed" valve cover with gasket...fired it up again and eliminated most of the oil flying all over while adjusting the valves HOT (3/4 turn down after proper valve seating). I've used this modified valve cover a number of times on engine rebuilds and it works well. Just a thought.....hope this helps!

[JimKshortstep4x4]

I set the valves cold initially and then run it for a recheck. I use a cut off valve cover and deflectors to reduce the oil problems.

When it is running, I loosen the valves until I get ticking, tighten to just eliminate the ticking and then turn 1/4 turn tight.

I just don't feel comfortable with the cold setting alone and I like the confirmation of checking when it is warm and running.

I also believe that Murphy was an optimist!

Jim

[mikep]

my biggest problem with the adjusting while its running deal ( besides the oil mess . hi pressure and volume pumps make the valve cover trick useless. tried it. still got oil everywhere ) is that with cams with a lot of duration and free flowing exhaust youve got so much low rpm lope that its almost impossible to hear ticking of the lifters. Years of working in heavy industry added to years of shooting off howitzers in the Army havent left my hearing so nimble. Thats why I started setting valves with the engine not running. Especially with the dial indicator method . There is nothing more accurate. Set it and forget it.

[old Rusty C10]

ive always done it hot running... thats the way i learned and its the way i taught my kid lol

[lngbed71]

Cold for me, but wouldn't go a full turn after zero-lash. Usually 1/4 turn does the trick. Like Mikep says "set it and forget it"

[Kid]

cold for me too. Never had a problem.

[crazy longhorn]

I adjust them cold during assembly,no problems. if i do any adusting after run in, I do it Hot, with the eng running(that feels easier & faster to me). I use a set of "windowed" covers, & dont have any problems with any oil mess......as long as the eng is idling. Buzz the throttle one time, & that hy vol pump will oil the truck, garage wall, & anything else in the way! I set the plunger 1/2 turn preload(by comp cams reccomendation), but have run them as loose as 1/8 turn on a high winder, with hyd cam. Either way works, just a matter of preferance.......crazyL

[68speedalert]

I like to adjust valves like I like my beer..............cold.


Steve

[bigjimzlll]

I adjust mine cold...the lash is .003 greater cold then hot. oh wait...you mean hydrolic lifters...then which ever way floats your boat..pretty hard to mess it up either way

[Dandeluxe]

THANKS TO ALL YOU GUYS FOR YOUR INPUT I AM GOIN WITH THE COLD METHOD, SET IT AND FORGET IT .