I'm about to attempt the (after must thread research) rocker adjustment procedure. I'm sold on doing it while the engine is running. I have a thought. If I put a vacuum gauge on the brake booster line and watch its activity while I turn the rocker nuts, do you think I will be able to fine tune its idle. Im afraid I won't be able to hear any difference when Im doing this by ear. Any thoughts?

 

"I'm sold on doing it while the engine is running. "
Can get messy
I don't see why the vac reading would not work,

 

It'll work, but trust me, you will hear a definate difference.

 

Dad: I have adjusted the hyd valve lifters on GM cars for the last 40 years. Doing it while the engine is running is my preferred method. Here are some suggestions for you:

1. Go to NAPA and get a set of rocker metal clips that prevent the oil from getting outside the valve cover area. If you do not do this, you will have an oily mess. The cost of these 16 clips is about $6.
2. Loosening the rocker nuts can be done quickly.....but do it slowly to find the "zero lash" point. You will be amazed how sensitive the lifters are to being adjusted.
3. Creating a few thousands (of an inch) lash clearance will create a hellava noise in the valve system.
4. Tighten the lifter rocker nuts very slowly as the engine will tend to slow down until the lifter compensates for the tightened condition. I tighten the rocker nuts about 1/8 of a turn and let the engine settle down before I add the next 1/8 turn.
5. The FSM states that you should tighten the nuts ONE turn beyond the zero lash point. I have always used this spec. Other may disagree on the one turn.......but this is given in the FSM and it works for me
6. Don't waste your time with the vac gauge! Not needed
7. As for fine tuning the idle, do the min air or base idle adjustment. This is a simple process to do and here are instructions from the C4 Master, Gordon Killebrew: http://s76.photobucket.com/albums/j2...MinIdleSet.jpg

Bob

 

If you have replaced all the rockers, there might be a lot of noise as you do the adjustments (from rockers that are not properly set). I used the trusty mechanics stethescope on one rocker at a time and there was very little question about when the rocker transitioned from making noise to silent. I've only done this once but did learn to turn slowly. You can turn faster than the lifter can bleed down leading you to think that you have gone too far and are opening the valve.

I still remember how quiet it seemed when the last noisey rocker was adjusted. Good luck.

 

One more thing, I took off, loosened anything that was stopping the passenger side valve cover from coming off. I will have replace the coolant line, (understandable) but will I have to put the EGR tube back on. And the breather tube from the throttle body that ran into the valve cover, thats gone now. I guess my question is, will these affect the idle during adjustment ? Or just go from there ? Thanks for the replies, I battled getting the pass. valve cover off today and will get the driver side off Sunday morning.

 

Dad: You have successfully removed the most difficult side of the valve covers to remove. You should replace the EGR tube and water line to the TB (consider doing a TB by pass and clean up a busy part of the engine......look at this photo for one way to do the water line bypass: http://s76.photobucket.com/albums/j2...t=TBBypass.jpg

Be prepared to remove the alternator on the drivers side in order to get the valve cover off. It can be reinstalled before the engine is started. Make sure you remove one battery terminal before you remove the alternator.

You should plug any "open" vac lines on the plenum before you attempt to start the engine and do the valve adjustments.

Your time spent will be rewarded by having a quiet engine

 

I used to always do the valve adjustment with motor running. That was till I bought a vette. Remove parts 1-15, replace parts 4-8, start motor and adjust valves, remove parts 4-8, install parts 1-3 and 9-15 so you can put back parts 4-8 again.
Too much re and re for me
All vettes should have come with 2 piece valve covers.

 

Yes, you will hear it. If you want to fine tune use a long screwdriver to listen to the lifter.

 

I thought I was going to use the stethoscope method but it's definitely obvious the second it starts clacking. No doubt about it.

I also thought about using the clips you can buy but they won't fit on certain rockers. I didn't use them and, at least on my car, there was ZERO mess.

Oh, and good tips by Sam!

 

Went to Napa,Autozone,Oreilly and they all looked at me like I was stupid. Uh "never heard of rocker clips". I've already set the idle, TPS, IAC, so hoping this will smooth it out. Heading to the garage.

 

As long as you don't rev the engine, you won't get oil spray (don't ask me how I know this...).

What helped me was to cut some cardboard and sit it between the valve springs and the bottom lip of the head so that oil pooling there didn't spill over the edge and drain onto the exhaust.
[RICHR]

 

Here are three sets of clips offered by SUMMIT RACING. I think the Mr. Gasket style are the most common. You can click on the pic for a better view. These clips only work on the stamped steel rockers. Most roller rockers direct the oil toward the fulctim and don't squirt up and out like the stockers.

A vacuum gauge will make no difference, nor provide any different readings while setting the preload on your hydraulic lifters. The amount of preload has nothing to do with the effective duration and will not change the idle speed or idle quality, one bit. There will be no difference in the vacuum. That is the beauty of a hydraulic lifter. It is self compensating. The preload is the distance you set the plunger into the lifter body. When you set the preload, you are establishing the available room for wear compensation. That is why, unlike solid lifters, you never have to adjust the lash. A preload of 1/4 turn, a half turn, or a full turn makes no difference in how the engine runs.

RACE ON!!!

 

I think Summit has them as well but I don't think you need em in most cases.

 

I finished up this evening. Everything went well. Prep was more lenghtly than expected. Wasn't as messy as I thought. Used aluminum foil as a spill guard and it worked great, lost hardly any oil. The oil flowed from the holes, so it was pretty controllable. Went 3/4 turn once they stopped ticking. It definitely runs smoother, doesn't have that slight miss it used to. I'm happier. BUT, I did notice that #3 was noisier than all the other rockers. Using a screwdriver to listen, all sets had a "swish swish swish" sound. #3 had a definite clatter sound. Tightening it up more didn't make it quieter, so I backed it back to 3/4 turn like all the rest. It sounded deeper, it wasn't the rockers themselves. Thats where I left it, and disassembled, then reassembled, you were right Agent 86, what a pain, but I'm sure I got it right. Thanks all.

 

Good to hear you got it done. If you ever have your damper off or clear access to it, mark the circumference into 4 pies. When it comes to static adjustment, it makes it a whole lot easier.