Shaft-mounted rocker arms are usually reserved for the high-stress environment of an all-out racing engine-whether it's for drag racing or some other competitive motorsport. Most of us late-model Mustang 5.0 enthusiasts have been limited to either a bolt-on pedestal-mount rocker arm or a stud-mount arm for a more high-performance application.
Now the scene has changed with the introduction of these Jesel shaft-mounted rocker arms, which are a considerable upgrade from stud-mount rockers. By eliminating studs, guide plates, poly locks, and stud girdles, the entire valvetrain setup is greatly simplified, and the durability and precision of the company's Winston Cup shaft rockers is also significant. There's also the benefit of better-maintained valve lash, reduced valveguide wear, and fewer required valve jobs on the cylinder heads at rebuild time.
These shaft-mount rockers will fit several types of heads, including stock 5.0, any FRPP aluminum GT-40, cast-iron GT-40P (the ones in our '93 coupe subject car), Brodix ST 5.0 Track 1, Edelbrock 7716 Victor Jr., World Products Windsor Jr./Sr, Roush 180/200, and most other aftermarket Ford heads that use typical pedestal- or stud-mount rocker arms. Available ratios include 1.5, 1.6, and 1.7:1. Let's look at the installation procedure.
Our subject car is a '93 LX,...
Our subject car is a '93 LX, which has a stock short-block and a '93 Cobra intake manifold. In between are cast-iron GT-40P cylinder heads that were developed in the mid-'90s for V8 Explorers. The Jesel rockers are an ideal update for a street-driven car such as this one.
The Jesel Sportsman Series...
The Jesel Sportsman Series shaft-mounted rocker arms come assembled in pairs ready to install. The rocker stands shown above bolt onto the cylinder heads. All required hardware and instructions are also included, shown at right. The completeness and high quality of these components is evident throughout.
The upper intake needs to...
The upper intake needs to be removed to access the valve covers. Begin by disconnecting the battery and removing the air-inlet tube that connects to the throttle body. You'll need to unplug the mass air meter, unbolt the mass air meter mounting bracket from the strut tower, and loosen the clamps at either end of the tube to free it from the throttle body and air-cleaner box.
Getting the upper off is pretty...
Getting the upper off is pretty easy. You'll need to unplug several connectors, including the throttle position sensor (TPS), the EGR, the idle-air controller, and the vent tube that connects the EGR spacer to the oil-filler neck. Once you remove the six bolts that secure the upper to the lower and unplug the hoses underneath the upper that connect to the PCV and vacuum-distribution tree mounted on the firewall, the upper is ready to come off.
Unbolt the six bolts that...
Unbolt the six bolts that hold the valve cover in place, and it lifts right off the cylinder head.
Next, remove the rockers by...
Next, remove the rockers by unbolting each from the cylinder head.
With the rockers removed,...
With the rockers removed, the Jesel rocker stand drops into place on the cylinder head.
When installing the Jesel...
When installing the Jesel bits, all the bolt threads need to be coated with motor oil, since Jesel calls for all "torque specs with oil." While the photos show the bolts being installed and seated with a ratchet, final tightening of all bolts should be done with a torque wrench.
The rocker stands are held...
The rocker stands are held in place with low-head Torx bolts-eight for each one.
Secure each bolt down before...
Secure each bolt down before torqing the bolts to spec.
Once the rocker-stand bolts...
Once the rocker-stand bolts are in position, torque each bolt to 70 ft-lb with a torque wrench. Start at the middle of the stand and move outward in a fan-like pattern. Depending on your cylinder heads, Jesel includes two sizes of rocker-stand bolts to fit your application. These iron GT-40P heads used the smaller of the two.
Here's the rocker stand bolted...
Here's the rocker stand bolted in place on the cylinder head, ready to accept the rocker arms.
The rocker-arm pairs set right...
The rocker-arm pairs set right into place on the rocker stand.
On the outside of each rocker...
On the outside of each rocker arm, the shaft is held in place with a 5/16x1 1/4-inch Torx bolt. Torque these bolts to 28 ft-lb. Again, don't forget to first put oil on the bolt threads.
Between each rocker pair,...
Between each rocker pair, a 3/8x1 1/4-inch low-head Torx bolt is used. These bolts should be torqued to 50 ft-lb.
We set the rockers with "zero"...
We set the rockers with "zero" lash. That means tighten the rocker nut down so there's no up or down play in the pushrod. From there, tighten the nut an additional half-turn. Then secure in place with the Allen-head set screw. This should be done with the piston at top dead center (TDC) so the lifter is on the base-circle part of the cam lobe. The engine then needs to be rotated (either with a socket and breaker bar on the crank pulley or by bumping the starter) each time you move to another cylinder so that each cylinder is at TDC.
Here are the rockers installed...
Here are the rockers installed on the passenger-side cylinder head in all their glory. The driver side of the engine is next. This super-tough setup is burly enough for any street-driven car we could imagine. Note the low-head Torx bolts between each pair of rockers compared to the other type of bolt on the outside of each pair.
With the rockers in place,...
With the rockers in place, we tested the fitment of the car's stock valve covers. Although the arms are tail-profiled for better clearance than we expected, there still should be some work done to get the stock valve covers to fit. If you desire, this would be a good time to switch to a taller valve cover. Otherwise the stock covers should work with the info provided in the next photo and caption.
The baffle is already removed...
The baffle is already removed from this passenger-side cover (with the oil-filler neck). To allow the Jesel rockers to fit, this mounting area where the baffle bolts to the cover will need to be ground down for the front pair of rockers to clear. The driver-side cover seemed to fit with no mods. For extra clearance, you can also use a second set of valve-cover gaskets along with longer valve-cover bolts, which would help provide the required room.
Also included with the Jesel...
Also included with the Jesel rockers is a checking pushrod to use if you're changing cylinder heads, cams, or anything else that might require the use of different length pushrods. The four-piece kit allows for almost any length pushrod available.
Yet more examples of the completeness...
Yet more examples of the completeness of the Jesel kit are its Torx driver sockets-both T50 and T45 sizes for all the Torx bolts needed to install the system. The sockets are 3/8-inch-drive, so you'll need a 1/2-inch to 3/8-inch adapter to use them with a 1/2-inch-drive torque wrench.