302 Valve Lash/Head Help

SoCalCruising said:

Hydraulic tappets?

1. Place crank at TDC, compression stroke
Firing order for 5.0 is 13726548 (verify - that's from memory)
Both valves for #1 cylinder should be fully closed at this time - check
2. If you have a drill and oil pump priming rod, pump up the lifters now (run drill motor in reverse) if not, you should disconnect the coil and spin the motor PRIOR to setting the crank at TDC
3. Place rocker on stud and run the nut down until you feel some resistance. Now, back off the nut a bit, use fingers of one hand to grasp pushrod and turn it. It should turn freely. Tighten nut by hand while spinning pushrod back and forth between two fingers. At about the same time you feel resistance in tightening the nut, you should also feel resistance to turning the pushrod. This is zero lash.
4. Use wrench to turn nut down an additional 1/2 - 3/4 turn (I use 2/3 turn, but there is no magic in that). If you have locks, hold the nut steady with wrench and tighten allen nut down to lock the nut at this position.
5. Now, turn crank 90 degrees clockwise and go to rockers for cylinder 3. Repeat 1-4.
6. Turn crank 90 degrees and go to cylinder 7. Repeat 1-4.
7. Etc. following firing order. Always verify that both valves are closed prior to adjusting each rocker.

After you have driven the car a bit, it's a good idea to take off the valve covers and repeat this process with a warmed-up engine. I just finished the second setting of my rockers and found some inconsistency in preload as the initial setting was done cold and, probably, without all lifters pumped up equally.

I think that about does it.

Click to expand...

dcstang67 said:

1. After removing the necessary accessory brackets and the valve
covers, remove all stock rocker arm parts, as none will be reused.

2. Clean the cylinder head surface where the new guide channel will
sit, and also clean the threaded rocker hold-down bolt holes.

3. Remove the pushrods, clean and reinstall them, making sure that
the pushrod is in the lifter seat. Once the pushrod is seated in the
lifter, we recommend you use a squirt can with engine oil to fill the
pushrods, one at a time, as you install each rocker arm. This
insures immediate lubrication of the rocker arm.

4. Working on one cylinder at a time, turn the engine by hand,
watching the pushrods. When both pushrods are at their lowest
point and appear to be at an equal height, you are in the correct
position to install the cylinder's rocker arms. This will occur when
the cylinder is at top-dead-center, on its compression stroke.
Since both pushrods will also be at an equal height, but not as far
down, when the cylinder is at top-dead-center on the overlap
stroke, you should rotate the engine twice to insure that you have
the pushrods at their lowest point.

5. Install one rocker arm at a time by inserting the 5/16" bolt through
the top of the rocker arm, MAKING SURE THAT THE FLAT SIDE
OF THE FULCRUM IS FACING THE BOLT HEAD. After this is
done, slide the pedestal onto the bolt with the curved area of the
saddle contacting the rounded side of the fulcrum. Next, slide the
guide channel onto the bolt with the raised edge facing up toward
the rocker arm, then loosely thread the bolt into the head, while
making sure that the pedestal is in the channel and the saddle is
in the correct location on the fulcrum. Refer to the diagrams to
insure that the rocker arms are properly seated. (To better illustrate
the correct fulcrum position, the two drawings to the right
show the fulcrum separately.) Repeat this process with the cylinder's
other rocker arm.

6. To check and adjust the lifter preload, turn the bolt by hand until
there is no clearance between the front roller and the valve stem
and the pushrod is seated in the rocker arm pushrod seat. Slowly
torque the bolt to 18-20 ft/lbs. Since you are pushing down the
plunger in the hydraulic lifter as you torque the bolt, it will probably
take a minute or two for you to get the correct setting. You
should be able to turn the bolt between 1/4 & 1 turn before you
reach the correct torque setting. This will give you the correct lifter
preload of .020" to .060". If you can turn the bolt more than one
turn to achieve the proper torque, you will have to shim the
pedestal. Two different thickness shims are provided for each
rocker arm to assist you. A thick shim represents approximately
one turn.
If you cannot turn the bolt at least 1/4 turn after first contact with
the roller and valve stem, you will have to install longer pushrods
to obtain proper hydraulic lifter preload. Pushrods are available in
different lengths, specifically for this purpose. There are many
modifications that may have been made to the engine which will
change the lifter preload, such as a valve job, different camshaft,
or different thickness head gaskets, and factory tolerances can
also affect the lifter preload on stock engines.
Note: You may find that the lifer preload is different between a
cylinder's intake and exhaust or between one side of the engine
and the other. Because of this, we recommend you check the
lifter preload on each rocker arm.

7. Repeat this process on the remaining cylinders. Make sure that
each rocker arm is properly seated and torqued into position.

8. Once completed, place a valve cover on the cylinder head, without
a gasket or bolts. Hold the valve cover in place by hand and
rotate the engine, without starting it, and make sure the rocker
arms do not contact the valve cover. If minor interference occurs,
this can often be eliminated by using a thick valve cover gasket or
by modifying the cover or its baffles. Taller, aftermarket valve covers
will also solve the problem, but make sure they will clear the
intake assembly and/or any accessory brackets. Intake manifold
to valve cover clearance can be a problem on engines with factory
fuel injection. Before installing the valve covers for the final
time, we recommend that you fill each rocker arm with engine oil
to insure lubrication during initial start up.

Click to expand...