Valve Adjustment Procedure
1. Valves can be set on a hot or cold engine. A cold engine is a lot more comfortable to work on. Major camshaft manufacturers recommend setting valves cold, to avoid erroneous adjustments on lifters that may be "pumped up" If you are setting valves on a fresh engine that has not been run, everything should be well lubricated before you begin.
2. Remove both valve covers and remove the spark plugs to make the engine easier to turn over. Also, If you are setting valves on all cylinders, it is generally easier and less confusing to just loosen all of the rocker arm adjustment nuts before you begin. This also allows for all of the internal lifter plungers to return to their "home" position.
3. Using a long handled ratchet or breaker bar attached to the crank bolt, turn the engine over in the clockwise direction.
A. Starting with #1 cylinder, turn the engine over until the exhaust pushrod just begins to move up.
B. At this point, stop and adjust the intake valve on the same cylinder.
1) Tighten the rocker until you can roll the pushrod between your thumb and forefinger with the slightest bit of resistance.
2) At this point tighten between an additional quarter to half of a turn.
C. You have now adjusted the #1 intake valve. You will now want to turn the engine over while watching the same intake pushrod that you just set, it will go full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. By following this procedure, you are assured that both of the lifters are at the base circle of the cam and that there is no additional pre-load applied to them from cam lift at this point.
D. You are now able to repeat this procedure on the remaining cylinders.
4.Re-install your valve covers and your valve adjustment procedure is finished
or for a more indepth explanation/ procedure:
VALVE ADJUSTMENT PROCEDURE ... THE CORRECT Way
All the time people ask how to do this procedure, and it seems that everyone they ask gives them a different answer. Let's see if I can make this easy to understand for just about everyone. Read this entire article to understand correct valve adjustment procedures for most engines.
Introduction to Adjusting Hydraulic Lifters:
The simplest way to adjust a hydraulic or solid lifter cam whether it is a tappet or roller cam is described below. But FIRST, what you need to forget about is all that information that many individuals (and books) taught you in the past. In many cases, if interpreted wrong you could be in for more trouble than before you tried to adjust the valves yourself. Think about things that can affect your valve lash, you will need this bit of common sense before you get into this, because there are other considerations besides just putting a wrench on something and attempting to follow the cam card, or shop manual.
What type of cam are you running? (Hydraulic, Solid, Hydraulic Roller, Solid Roller, Mushroom Tappet)
Are you running aluminum heads?
Are ALL of your valvetrain parts in proper working condition?
Are your valve springs the correct ones for the camshaft and operating RPM?
What type of driving (or racing) are you going to be using the engine for?
Do you have the tools and basic knowledge required to adjust your own valves?
The last one is quite important. If after you read through this and are still a bit confused, give up and have someone else do it, or have them at least walk you through it to make sure you understand the procedure. Now, if you are wondering what can go wrong there is a quite a few bad things that can occur:
Poor running engine and low performance
Failed smog testing (if this is a smog-legal street driven vehicle)
Burnt exhaust valve(s)
Broken valvetrain components (springs, pushrods, lifters, camshaft)
Limited lifespan of valvetrain components
Excessive valve guide and seat wear
Blown up engine
Lose an important Race!
Empty Bank Account
The above list, though quite simple to understand, should scare you. It takes only a few thousandths of an inch of adjustment error to cause those problems. Now lets' get to the actual process. I am going to simplify this a bit, so if your valvetrain is somewhat different you will need to verify the correct procedure for your application.
Valve Adjustment The Quick Way:
Ok, now to the good stuff! First, view this little chart for Small and Big Block Chevy Engines that I made and see if you can understand it ... for other engines, use your firing order that matches your engine to do the same. You set up this procedure based upon "opposite" cylinders of your firing order. (see below)
Intake Valve Adjustment: ENGINE OFF!
with #1 cylinder Intake Valve at full valve lift .... Adjust #6 Intake Valve
with #8 cylinder Intake Valve at full valve lift .... Adjust #5 Intake Valve
with #4 cylinder Intake Valve at full valve lift .... Adjust #7 Intake Valve
with #3 cylinder Intake Valve at full valve lift .... Adjust #2 Intake Valve
with #6 cylinder Intake Valve at full valve lift .... Adjust #1 Intake Valve
with #5 cylinder Intake Valve at full valve lift .... Adjust #8 Intake Valve
with #7 cylinder Intake Valve at full valve lift .... Adjust #4 Intake Valve
with #2 cylinder Intake Valve at full valve lift .... Adjust #3 Intake Valve
Exhaust Valve Adjustment: ENGINE OFF!
If you have noticed, this is the same procedure as the intake valves listed above, just that you are now adjusting the exhaust valves the same way.
with #1 cylinder Exhaust Valve at full valve lift .... Adjust #6 Exhaust Valve
with #8 cylinder Exhaust Valve at full valve lift .... Adjust #5 Exhaust Valve
with #4 cylinder Exhaust Valve at full valve lift .... Adjust #7 Exhaust Valve
with #3 cylinder Exhaust Valve at full valve lift .... Adjust #2 Exhaust Valve
with #6 cylinder Exhaust Valve at full valve lift .... Adjust #1 Exhaust Valve
with #5 cylinder Exhaust Valve at full valve lift .... Adjust #8 Exhaust Valve
with #7 cylinder Exhaust Valve at full valve lift .... Adjust #4 Exhaust Valve
with #2 cylinder Exhaust Valve at full valve lift .... Adjust #3 Exhaust Valve
What about the actual adjustment procedure you ask?
Ok, let's get to the actual wrench turning ... how many of you read or were taught that with a hydraulic lifter cam you adjust it down to where there is pushrod resistance (zero lash) and then turn it down 1/2 to 3/4 turn? Well, if you did this, you more than likely have the valves not closing all the way!
The hydraulic lifter requires roughly a .030" pintle depth setting. This means that you adjust valves by the depth that the pintle in the lifter drops. Too tight and the valves do not close, too loose and they rattle and do not open properly and damage the lifter. How do you get .030"? Well, on new engines I will actually use a dial indicator and measure the depth of travel. On an engine in the car this is a bit different, and harder to do..
Now, I have two ways that I use to adjust hydraulic lifters. One uses the "clean" method with the engine off and the other is the messy way with the engine running.
Engine "OFF" Hydraulic Lifter Adjustment:
Warm the engine by running it until it gets to operating temperature (15-minutes or so). Have all your tools ready and then quickly remove the valve cover(s) and start the adjustment procedure by using the chart above. With the #1 Intake valve at FULL LIFT (this means that you spin the engine until the Intake valve on the #1 cylinder is fully open ... you can tell this by the rocker arm pushing the down until it goes no further) you can now adjust the "opposite in firing order" cylinder (see the above chart). In the small and big block Chevy engines this is the #6 cylinder. Loosen the rocker (if using roller rockers there is a Jam Nut that you must loosen with an Allen Wrench). Now, with two fingers spinning the pushrod between them to feel for resistance you easily snug the adjustment nut. When you feel resistance STOP, now you will adjust the nut down "Only" 1/8-1/2 turn. If you operate your engine a consistent high RPM, use the lighter setting (1/8 turn).
What is 1/4 turn? (see image at right)
Well, imagine the hands on a clock. You have the obvious 12:00, 3:00, 6:00, and 9:00 settings as well as the numbers in-between those. If you start with your wrench at the 12:00 position and turn it clockwise to the 6:00 position you have just made 1/2 turn. Going from 12:00 to the 3:00 position would be 1/4 turn. What is 1/4 Turn?
Now, you will do this for all the intake valves and then do the exhaust valves the same way.