Typically, you do a valve adjustment on a hot engine but it can be done cold *if* you determine your cold valve adjustment figure.
You need a set of flat feeler gauges of thicknesses bracketing your valve adjustment number. Do not use round wire gauges of the type used to gap plugs. Use two gauges, one .001 thicker than the adjustment and one .001 thinner. For instance, if you're setting your valves at .030-in., you need a .029 and a .031 gauge.
The adjustment is checked by pushing the flat gauge between the valve stem end and the rocker arm tip.
Start with #1 cylinder. Turn the engine by hand until the the #1 intake valve just starts to close. Adjust the exhaust valve to the proper valve lash figure. Turn the engine by hand until the #1 exhaust just starts to open. Adjust the intake to the proper valve lash figure.
Repeat this procedure to all seven remaining cylinders. Firing order is not important. I usually work down the left side of the engine then do the right side.
During the adjustment procedure, adjust each rocker nut so the gauge that is .001 too large either will not fit or fit with great difficulty and so the gauge that is .001 too small fits very easy.
You can do the valves cold, if you perform a one-time test. Warm the engine operating temperature. Adjust both valves of #1 cyl. to the proper valve lash figure. Let the engine cool overnight then measure the lash at both valves on #1. Record the cold figure and, in the future, use that to adjust your valves with the engine cold. In many cases, the difference between hot and cold will be .001 or .002.
As with many maintenance operations, different methods may be employed to achieve the same result. Adjusting solid lifters is one of those tasks that has developed a number of those different methods over the years. Hib has provided us with a method that will accomplish this task and ensure positive results. I would like to submit the following additional methods, while making no claim as to which method is the "best" -
1. Hot and Running. This method is probably the fastest, but can be the messiest.
-Remove 1 valve cover and start motor.
-While getting drenched in hot oil, adjust all valves on that side of engine.
-Shut off motor, replace valve cover and remove valve cover on other side - restart motor.
-Again, while getting drenched in hot oil, adjust all valves on that side of engine.
-Seek medical attention for the burns, move vehicle and call a hazmat team to come clean up the spill....
There are a great many (who said geezers..?) people who have used this method for years and swear by it. I met one in the emergency room the other day. He claimed that valves do not get shoved trough piston tops and feeler gauges do not get holes punched in them. He suggested removing both valve covers and running the engine at redline for 10 minutes to remove all that pesky hot oil... Variations on this method include the purchase of oil deflector clips which are fastened to each rocker arm to prevent oil from flying all over the place and the fabrication of a valve cover with the upper part removed to permit access while preventing excess oil loss. This method is great fun and can be used at parties to entertain your guests.
2. Single rotation. This method is similar to the method that Hib described except that half of the valves are adjusted with the engine at top dead center and the other half are adjusted after rotating the engine one rotation. With the engine hot, off and valve covers removed;
-Rotate engine until timing mark on the harmonic balancer lines up with the 0 mark on the timing cover tab. With the engine at the number one firing position the following valves may be adjusted: Exhaust 1-3-4-8, Intake 1-2-5-7.
-Rotate engine one revolution until timing mark on the harmonic balancer lines up with 0 mark on the timing cover tab. With the engine at the number six firing position the following valves may be adjusted: Exhaust 2-5-6-7, Intake 3-4-6-8. I have never tried this method, doesn't seem like the lifters would be in the right position on the cam lobe...
3. Double rotation. Similar to the Single rotation method except that, well,... you rotate the engine twice. Four valves are adjusted per turn. With engine at normal operating temperature and #1 piston @ top dead center:
-Remove valve covers.
-Adjust intake valves 2 & 7, exhaust 4 & 8.
-Rotate engine 180 degrees.
-Adjust intake valves 1 & 8, exhaust 3 & 6.
-Rotate engine 180 degrees.
-Adjust intake valves 3 & 4, exhaust 5 & 7.
-Rotate engine 180 degrees.
-Adjust intake valves 5 & 6, exhaust 1 & 2.
-Install valve covers.
-I made up all these names moments ago - I don't care if you don't like them... oh and you're welcome.
-Regardless of method used, the idea is to measure the lash when the lifter is on the heel of the cam lobe at normal operating temperature.
-I concur with Hib's suggestion to use two feeler gauges for each measurement, makes sense and I will have to try that - but you may also like to try a "go-no go" style feeler gauge. Each feeler's tip is shaved to the correct tolerance from a .001" - .002" larger feeler - so you can slide it in and feel when it hits the larger portion of the gauge - I bought mine at Napa. About a hundred dollars, definitely a hundred dollars.
-As Hib mentions, many folks prefer to work cold. In order to determine cold clearances they make adjustments hot, allow the engine to cool for an extended period (like overnight), then measure and record the cold clearances for future use. A close cold lash setting can be obtained by following these general guidelines; with iron block and iron heads, add .002", with iron block and aluminum heads, subtract .006", with both aluminum block and heads, subtract .012". If it gets too cold, you can always wear a jacket.
-I really didn't meet someone in the emergency room the other day expounding the virtues of adjusting valves with the engine hot and running - I made that up too. Now I'm going straight to hell for sure.
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
Since you are going to hell anyway can I give you a list of my old friends to look up?
I think I have tried every one of these methods for adjusting valves. I only did the hot/running a few times before I figured out that this is stupid. Got out my Corvette shop manual and, wouldn't you know, there was a better way. Imagine a 16 year old actually reading how to do something.
I use the single rotation meathod on hydraulics regularly. Hasn't failed me yet. I prefer to be more accurate on solids, though, using the Hib method. However, if your solid lifter car is used a lot and you are often adjusting the valves, you will develope a feel for the right amount of drag on the feeler guage and only use one guage.
The rocker nuts also get looser with use and if they are old I would suggest new nuts to better hold the adjustment. Better yet, if you have enough clearance under your rocker covers, is to install the rocker nuts with the locking set screw in the middle. Then you know they will stay where you put them