Rocker Arm Adjustments (walk me through this like I am a child)

whats wrong with rednecks?

Adjusting Hydraulic Lifters for Proper Preload

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 spin the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the pushrod, you are at "Zero Lash". Turn the adjusting nut down one half to one full turn from that point. Lock the adjuster into position. 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.

DissFigured said:

wasn't sure of my issues (engine tapping) replaced header gasket. Went through 20 other issues. It is rocker arms. I know because I ran the engine w/ the valve cover off (Any thoughts on getting oil out of the driveway) and tightened the rocker arms until the tapping stopped. I did this totally un-scientifically just tightening until tapping stops. I want to do it the right way so here is where I need a step by step walk through.

Correct me if I am wrong:
1. remove all spark plugs so I can easily turn engine by hand
2. start w/ cylinder 1 finger in hole cranking till pressure or screw driver in hole until TDC

3. If Exhaust lifter is up, then I am at TDC of exhaust stroke, so tighten exhaust rocker arm just til I can't turn the rod free hand, then 1/4 - 1/2 turn more

If Intake lifter is up, then I am at TDC of intake stroke, so tighten intake rocker arm just til I can't turn it free hand, then 1/4 turn more

4. Repeat for all other cylinders.

Am I missing anything?

Click to expand...

Yea, at TDC on the exhaust stroke, the exhaust valve is just closing and the intake is opening. In other words, both are open to some degree, the exhaust is just closing at the top of the stroke and the intake is opening, so the piston will draw the F/A mixture into the cylinder on it's way down. When it's reached the bottom of the stroke, that's when the intake valve closes. Then the piston starts back up, compressing the mixture, & at TDC of this stroke, that's when both valves are fully closed and the lifters are on the base circle of the cam. That's when you want to adjust the preload on hydraulics and the lash on a solid cam. If you have the 70-up 4 bolt harmonic balancer, there are 4 bosses that the pulley bolts screw into, one of these will be lined up close to the timing pointer. After adjusting each cylinder in it's turn of the firing order, rotate the crank 1/4 turn before doing the next. I use the balancer bolt bosses lined up with the pointer as a reference in turning the crank. Two complete turns of the crank equals one complete cycle in the firing order.

If you mark your distributor base (not cap, 'cause you will remove it) where the #1 spark wire is located, then, after removing the cap, the pointer will be pointing in the vicinity of #1 when you are at TDC compression stroke on that cylinder. The pointer will not point directly at #1 because you will have some spark advance - it will be pointing just past #1 when your TDC mark lines up with your timing pointer. Anyway, this will keep you from mixing up TDC exhaust stroke with TDC compression stroke (the latter being what you want).