No Limit Mfg 12 Valve Cummins Roller Rocker Valvetrain

Cummins 12V Roller Rocker Arm Kit
Add durability and performance to your valve train with No Limit's roller rocker kit for 12v Cummins engines.

Corrected Rocker Arm Geometry reduces the amount the roller tip travels across the valve tip, and translates the camshaft motion more accurately. This also reduces valve tip and valve guide wear.

Bushed aluminum rocker arm bodies provide light wieght performance with wear protection. Bushings are burnished for ulitmate roundness, and strength.

Increased ratios to add valve lift. We stock 1.7 , 1.75, and 1.8. Custom ratios are available upon request.

Pressurized oiling to the rocker arm shaft, and pushrod.

One Piece Billet Aluminum Valve cover with o-ring seal, and 2 fill or breather holes.

Pressurized oiling spray bar to oil the roller tip and valve springs. Spray bar includes metering jets to put the right amount oil were it counts, with out overloading the valve train with too much oil.

Precision V Block style stand with a snap tight shaft fitment. The shaft and stand provide multiple clamping points increaseing shaft and stand rigidity. This reduces shaft deflection, and negative harmonics in rocker arm system. Produces even more accurate camshaft translation, and valtrain durability.

4340 coated and hardened rocker shaft for high durability, and smooth performance. Coatings protect the shaft, and rocker arm from material transfer that caused friction, and damage.
Increased ratios to add valve lift. We stock 1.7 , 1.75, and 1.8. Custom ratios are available upon request.

14mm Head Stud Option

Intallation of Cummins 12V roller Rocker Arms.

12 valve roller rocker arm kit only fits the 5.9 12V Cummins cylinder head.

Requires 20 longer head studs. ( Call No Limit MFG or ask your dealer for information about head studs.)

Place subplate on cylinder head. Make sure subplate is sitting flat on valve cover surfaces.  Assemble rocker arms , stand and shafts onto subplate. Make sure the rocker arms and shafts are lubricated with assembly grease or oil to protect during engine start up. Align subplate and rocker arms over valve stems. Now torque head to engine block with appropriate head studs.  Roll the engine over by hand, and check valve lash. During this also check that rocker arm and valve tip alignment are correct. Once lash has been set. You can turn the engine over but do not start. Check to make sure oil is geting the rocker arm shaft. You should see oil squirting out of the the back of the rocker arm. Once you have oil to the shafts, assemble the valve cover. You will need to attach an .250 oil line from an oil port off of your engine block to the fitting in the top of your cover. You must do this or you will cause damage to your rocker arms and valves. Once you have the oil line installed make sure the oil line is getting oil to the cover. Once that is confirmed. You can start your engine.