small block chevy valve adjustment
I need to know how to adjust the valves on an early 70's chevy 350 engine. I have seen it done but never did it myself.
There are dozens of tutorials on adjusting valves. The one I cite is from Crane Cams:
Firing Order: 1-8-4-3-6-5-7-2
Distributor rotates CW.
Remember the valves go: E I I E E I I E
Adjusting Hydraulic Lifters for Proper Preload
EO/IC Method (Exhaust Opening/Intake Closing)
In order to adjust the preload, the lifter must be properly located on the base circle or "Heel" of the lobe.
At this position the valve is closed and there is no lift taking place. You will need to watch the movement of the valves to determine which lifter is properly positioned for adjusting.
1. Remove the valve covers, and pick a cylinder that you are going to set the preload on.
2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake rocker arm. (Why? Because when the exhaust valve is just beginning to open, the intake lifter will be on the base circle of the lobe, the correct position for adjusting the intake.)
3. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. (If you are installing brand new lifters they will be in the neutral position when they come in the box.)
4. Now, jiggle the push rod up and down while tightening the adjustment nut until you hear and feel the clearance has been removed. This is “zero lash”. Turn the adjusting nut down one half to one full turn from that point. Lock the adjuster into position if using polylocks. The intake is now adjusted properly.
5. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close.When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.
6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.
Thank you for your input. It is now time for me to put your knowledge to use. We shall see if I can handle this or not. Thanks again.
do we assume u've installed a new cam and lifters?? if so do the preadj as cobalt listed... run the engine to break in the cam then re-adj while running... after break in.... engine at idle, loosen rocker till clicking, slowly tighten till click stops then in 1/4 turns, tighen another 1/2 turn... move to the next lifter till done... it would be nice to have a old valve cover u can drill the holes in, so u can keep the squarting oil at min...
Here's one that I wrote for the wiki....
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