I need to adjust my valves, but my Haynes manual is not very clear on how to do this. My idle is very lopey and sounds aweful. My book mentions adjusting them at TDC, but doesnt specify how far to rotate the crank to get to the next valve.

Also after finding zero lash for the rocker arms, on an '85 how much more do you tighten them? I've heard 1/2, 3/4, and even a whole turn.

 

The way I do it is pretty simple and works EVERY time (when done right!)

1. install rocker arms loosely and make sure the hydraulic lifters are not collapsed (may need to wait for the lifter to spring up)
2. find TDC cylinder 1 (it does not matter if its compression or exhaust TDC)
3. tighten all rockers to zero lash. (half of the valves should be closed, so the eight rocker arms on the closed valves will have a lot of slack)
4. rotate engine 1 turn (i.e. 360 degrees)
5. There should be half of the rockers (eight rockers) now loose that you did not tighten in step 3 b/c their corresponding valves were open some amount and are now closed. adjust those rockers to zero lash. The eight with their valves closed in step 3 should be tight b/c their corresponding valve should be open some amount.
6. Now tighten EVERY rocker arm nut 1/2 turn (and then lock them if you are using locking adjusting nuts - found on all good roller rocker arms)

All should be good then!

A simple recap would be:
1. loosen rocker arms
2. find cylinder #1 TDC
3. Adjust rocker arms to zero lash.
4. rotate engine 360 degrees
5. adjust rockers that are not at zero lash to zero lash.
6. tighten all rocker nuts 1/2 turn.

 

main thing is you DON'T want to over tighten, I usually go from 1/2-3/4, BUT, I like to be able to take the push rods and be able to rotate them, If I can't rotate them I'll back off a little. After I'm done I'll just set the valve covers back on, start the engine and listen to it before I install the covers permanently.

 

you can run the engine without the covers??? wont that get oil everywhere? i've been putting it all back together with each adjustment.

 

That is simpler than any other than I've heard before. That ought to work fine on a stock or mild cam, where making sure you are near the center of the base circle isn't important. There really wouldn't be any need to find TDC for #1 or any other cylinder. Adjust 'em where it sits, then rotate the engine 360° and do it again. That is just too simple to be true. It might not hurt to turn the engine 90° to 135° a couple of more times just to look for any stragglers.

RACE ON!!!

 

It can get messy..but that's the way I've always done it, years ago I bought some clips that went on the rockers and they kept the oil from getting all over, but we adjusted alot of valves while the engine was running. I just would rather clean up a little mess than permanently attach the valve covers just to hear I needed to readjust a loose lifter.

Re-read what I said, I just set the valve covers on..then start the engine. All sound good, then I bolt them down.

 

The biggest problems people have in setting the preload in hydraulic lifers, is properly locating zero lash. Spinning the push rod until it won't spin any more or gets really difficult, can present problems. Some lifters, even in the same set, can have different strength plunger springs, making the resistance to push rod twirling different for different valves. Especially for the novice, I recommend jiggling the push rod up and down, between the lifter plunger and the rocker arm until the movement JUST stops. It is an awkward motion to make, but it is much more sure than twirling.

Yes, the engine can be run without rocker covers. It is best if you have some "rocker stoppers" or another means of controlling the oil. Regardless, it will be messy. Especially if you are looking for the bare minimum, or no preload, zero lash is most accurately pin pointed by ear, on a running engine.

RACE ON!!!

 

What can happen if you overtighten?

 

Death to the cam lobes, possibly bent push rods, worst case other than losing a cam...losing the engine.

 

But long before that, any valve that is over tightened, won't close, and the engine will run like garbage. You will correct the problem before it can cause that kind of trouble.

RACE ON!!!

 

This is what I do, wiggle it up and down to their is no wiggle-travel, then go 1/2 turn

 

If i have a ticking sound from the rockers, (which ive heard on another Chevy V8 before too) what should i do? Mine being an LT1 can i still do things in a simular fashion to what is desribed here? I have Crane Cams gold 1.6:1 RRs on my engine.

 

Theoretically, once the lifter is preloaded, the amount of preload can only affect the distance the lifter plunger can travel to determine how far the valve can be held off of the valve seat during lifter pump up. And, of course, the amount of wear, before another adjustment becomes necessary. As a practical matter some forum members have reported limited success, quieting the valve train by altering the amount of preload. Good luck.

RACE ON!!!

 

THe pushrod can still spin even with some preload on it.

 

The way I was taught goes like this(You'll get it right every time):

1. Turn the motor by hand till the rocker your working on opens fully

2. Now continue to turn the motor till the rocker fully closes- Give it a little more of a turn to make sure you are on the flatest part of the cam- then remove the the stock rocker(if your changing to 1.6's) if not loosen the rocker till the push rod just spins then tighten till it is just snug

3. Then take your wrench and give it 3/4 a turn; now your ready to move on

4.Now do the next one in line( you can start at the drivers side front and work your way back) follow the same procedure above

You are adjusting one at a time and although this might take a little longer you wont go wrong. You'll get it right every time. You'll actually become a qualified rocker adjuster after a couple then as you continue with the rest and you get to the other side and get half way through you will have reached the level of EXPERT rocker adjuster! Imagine that an expert at something!

Thanks,Matt

 

If it were that easy, we wouldn't have bi monthly threads asking about adjusting the valves and the problems people have, doing it correctly. If you want to take that amount of time to make sure each valve, in turn, is on the base circle of the camshaft, once the valve is at fill lift, as you describe, rotate the engine a full 360°.

"(You'll get it right every time):". The problem comes at "loosen the rocker till the push rod just spins then tighten till it is just snug". If you have read the preceding posts, you would be aware that not all lifters require the same effort to spin the push rod after zero lash has been achieved. Obviously, you can do it, and get it right, every time. So can I, but that doesn't do the first timer a whole lot of good.

RACE ON!!!

 

not good for race, but best for street --set em while its idleing...pull one rocker cover off, put on oil deflectors (cheap at any auto parts store-one package for one head is all you need) or old cover chopped open , or wear nothing at all if you like smoking exhaust manifolds for a few days...idle engine and go down the line, loosen each adjuster till you note large increase in ''clacking'' noise, tighten till noise JUST drops off, go to next rocker,etc...stop engine, go down line and tighten each adjuster 1/2 turn if a couple hundred extra rpm is important, 1 full turn if you hope you'll never see it again, 3/4 turn for half-fast guys like me...close up and do the other side.

 

That doesnt work, thats why things got screwed up, I never turned the engine and just tightened them up like you said.

I followed these directions to the tee, but now the engine wont even start. I'm seriously considering just letting the vette sit in the garage for good. I've taken the thing apart like 20 times and it still wont run. Why does it have to be so touchy anyway. I've never had a valve problem with any other vehicle.

 

I don't think CFI-EFI was telling you to do it that way, from my reading of his post, it sounds to me like he didn't think it would work. I've never heard of this method, not sure if it would work or not, but I don't think so.(Not saying it doesn't work, I've never tried it, so I can't really comment on it). There are as many different ways of doing this as there are people doing it. The directions given on Cranse site were correct, but you can usually get away with doing both valves on one cylinder when that cylinder is at TDC on the firing stroke. To be sure your doing it on the base circle of the cam for each cylinder, I wouldn't try to do more than one cylinder at a time, especially if your not real experencied at it. Pull both valve covers off, and the distributor cap. Crank the engine around (manually) till #1 exhaust valve opens and closes, then #1 Intake valve wil open and close, right about now the timing mark will be coming up on 0 degrees on the timing marks and the dist. rotor will be pointing at the #1 wire position on the cap (It's helpful to take a sharpie and mark exactly where each cap terminal is on the body of the dist. since the cap has to be off to see the rotor). This is TDC of the firing stroke of #1 Cylinder. You can now adjust these two valves. As far as the actual adjustment, thats kinda tricky if you don't know exactly what your feeling for, this " Started it up and immediately threw code 14 and 15 which doesnt make sense. The coolant is fine. When it runs, its about 400-500 rpms and sounds very lopey like its cammed or something. It will stay running though." definitly sounds like they were too tight, this " For some reason they dont want to stay at zero lash. I started it up and it sounds a LOT better. Rpms are in the normal range of 600-700rpms and dont fluctuate much. However, I noticed a tapping sound that sped up with the engine." was a whole lot closer, they were just a little loose, hence the tapping noise. At this point you should have just used a screwdriver to the ear to figure out which one was making the noise, then tightened it in 1/4 turn increments till it stopped, then added the extra 1/2 to 3/4 turn to preload the lifter. Now your all out of wack from the sound of it, so just back them off until they have a little play in them, use the jiggle method recommended earlier " This is what I do, wiggle it up and down to their is no wiggle-travel, then go 1/2 turn". This should get you really close if not dead on., then rotate the engine 90 degrees clockwise and you can adjust the next one in the firing order (1,8,4,3,6,5,7,2), after doing all eight like this, you can start the car with the Valve covers off, (the deflectors help somewhat, but if you have or can get an old plain steel valve cover, cut the top out leaving just the sides and gasket rail, the cut it in half long ways, you will have the perfect tool to use with the rocker clips (which, by the way, only work with stock type rockers, not roller rockers). You have to cut it in half to clear the clips, other wise they just get knocked off by the upper portion of the V/C. The clips block the oil squirting out of the rockers, and the V/C parts keep the oil draining out of the head from spilling over the V/C gasket rail onto the exhaust. If any of them click after this, use the aforementioned screwdriver trick to isolate which ones and tighten as above. If you make the above V/C tool and get the clips, you can also just start the engine once you've done the preleminary adjustment and then loosen each one 1/4 to 1/2 turn at a time until they start to click (the engine may not run real well when loosening if you go to fast due to the excess clearance), then SLOWLY (it definitly won't run well while your tightening them due to the fact that the lifter has pumped up to max. and the valve won't seat until that excess oil has 30 or so seconds to bleed out) turn them back down until their quiet, then add the extra 1/2 to 3/4 turn. Hope this helps, I'm going to be away from the computer for the weekend, but I'll PM you my number if you need further clairification.

 

It sounds as if somewhere I ticked you off! If so I appologize! When I was doing mine this was what was suggested by many a member as well as others. I think we are all aware that all threads are not the same and not every adjustment will be the same. If you want it done your way perhaps you can meet with the member and help him do the adjustment on site. I was just giving a suggestion that was a technique handed to me and now is a technique that I WILL CONTINUE TO USE. It worked great and it can be done as well by a first time individual. If a person wants to do a correct adjustment then they can pull valve covers and do it with the motor running! If you do not want me to suggest this way anymore then let me know!

Thanks,Matt