A variety of other procedures exist, and you may find one of these more to your liking. The means by which you work through the cylinders is strictly a matter of personal preference, and so is the amount of lifter preload. Personal preferences aside, for most engines, one-half to one additional turn after all clearance is eliminated is ideal.
With the Curtisbilt rockers, you should begin adjustment by ensuring that the pedestal is firmly positioned against the cylinder head surface and measurable clearance exists between the rocker and pushrod on one end and between the rocker and valve stem on the other. Then begin rotating the adjuster while chasing it with the lock bolt. After the lock bolt is snug, back it off a bit and rotate the adjuster again. Continue the process until all clearance is eliminated, then proceed to set preload or lash.
We installed 1.75:1 ratio rockers on the engine shown in the accompanying photos because we plan to install a performance camshaft (with about .600-inch lift) in the near future, and a 1.85:1 ratio would be a bit much. However, the higher ratio rockers represent a relatively easy means of increasing performance without taking the skinned-knuckle adventure known as a cam swap. With either type of rocker, the Curtisbilt shaft arrangement provides a significant increase in valvetrain rigidity and precision, and that's something any LSx engine can use.
| DIFFICULTY INDEX ::: | NNN |
| ANYONE'S PROJECT | no tools required | N |
| BEGINNER | basic tools | NN |
| EXPERIENCED | special tools | NNN |
| ACCOMPLISHED | special tools and outside help | NNNN |
| PROFESSIONALS ONLY | send this work out | NNNNN |
An internal snap lock holds...
An internal snap lock holds the line in place. To unlatch it, you need a special tool or a LOT of patience. You put the tool around the fuel line, push it toward the connector, and the fuel line pops off.
After the fuel line is out...
After the fuel line is out of the way, the valve cover bolts and the valve cover are removed to expose the rocker arms.
You've undoubtedly noticed...
You've undoubtedly noticed this isn't the same cylinder as is shown in the previous photos. It's posing in this photo because it's not mounted on an engine and is therefore better suited for showing close-up details. Of note is the pedestal between the rocker and head and the Allen-head retaining bolt. The pedestal seats against a rocker mounting boss (one is visible behind the valve spring on the right) and retaining bolt holds everything in place.
A 7mm wrench is used to remove...
A 7mm wrench is used to remove the bolts that hold the rockers in place. After all the bolts are completely loosened, all eight rockers can be removed by lifting theong aluminum bracket that runs beneath the rockers.
Note the gap between the pedestal...
Note the gap between the pedestal and the rocker mounting boss. Until you get the feel for the adjusting procedure, it's easy to wind up with a gap like this when you think a rocker is properly adjusted.
After all the rockers are...
After all the rockers are installed and adjusted, stand back and admire them; then double-check adjustment before re-installing the coil assemblies and covers.
Now that you have all the...
Now that you have all the rockers installed, you're ready to adjust. Just slip the supplied adjusting socket over the adjusting nut and turn it with a 15mm box wrench. Use an Allen wrench to turn the lock screw and chase the adjusting nut to make sure the pedestal is firmly seated against the mounting boss. After all clearance is removed between the rocker and pushrod, rotate the adjuster another one-half to one turn and tighten the lock screw.