GMH OEM ROCKER ARM FAILURES
Motoring (2017) reported "Holden will repair the 6.2-litre LS3 engine in the final 2000 or so V8 Commodores built this year following reports of engine noise and even failure in cars with as little as 50 km on the clock".
The problem has been traced to a faulty batch of inlet rocker arms causing rough idle or misfiring of the engine. Rocker arms have fractured at the nose in some instances; wreaking havoc on the valve and cylinder.
Take the bull by the horns and upgrade from your already wear inducing solid/non-roller tip OEM rockers.
Our 8mm Ultralite Pro design can be fitted in ~1 hour and at a fraction of the cost of major rebuilds associated with faulty OEM rocker arm failure. No machining required, fits under standard rocker covers.
Steer clear of cheap "fix" trunnion upgrades, which fail to address the shortcomings of OEM rocker arms.
Fit Yella Terra with confidence - Track Tested. Street Proven.
Ultralite Pro
By concentrating more mass at the fulcrum, the Ultralite Pro can withstand a much heavier spring than the Ultralitewithout compromising any oscillating weight. 10mm bolt down versions are available, in addition to the factory 8mm easyfit (EF). Intended for those who need lightweight rocker arms but insist on heavier springs!
What’s an Ultralite?
Yella Terra’s exclusive Ultralite rocker arm, shaft and pedestal system offers 50% less nose weight than the factory rocker system, the result being greater RPM potential without compromising strength or durability. The perfect low-maintenance substitute for factory rocker arms which utilise problematic cage-less bearings, solid non-roller tips and heavy steel bodies.
Yella Terra Ultralite is ideal for high revving street applications when coupled with factory/lightweight aftermarket springs. Manufactured and assembled in Australia using the highest quality materials and componentry consistent with those found in our Platinum race series.
Our wide range of true ratios allows you to achieve high lift without relying solely on your camshaft ... a trend many engine builders and racers alike are adopting to relieve the inertia on lifters and pushrods generated by aggressive and often violent ramp rates required to make big lift.
Don't fall victim to bearing/trunnion upgrades which only address half the shortcomings of OEM rockers.
Includes YT 5132 10mm valve cover spacer
Why Choose Ultralite Pro?
- Built to withstand 480 lbs* max open spring pressure
- Oversize full-complement caged bearings designed for oscillating (rocking) loads, paired with oversize precision ground trunnions to reduce friction.
- Intricately balanced lightweight arms ensuring vital valvetrain stability - focusing attention on the harmony of the entire engine. 50% less oscillating nose weight eliminates valve float in upper RPM range allowing for higher rev ceiling.
- Extruded from aircraft grade aluminium, perfect for dissipating excess top-end heat.
- Proven bolt-on shaft mount design that mounts both inlet/exhaust to common shaft, effectively increasing footprint and clamp load twofold without any further cylinder head modification.
- Various ratios available, catering for every camshaft grind. High ratios allow for additional lift on stock and aftermarket camshafts.
- Chrome moly steel hardened and ground roller tips of generous diameter (positively retained by internal circlip) preventing abrasion of valve tips and guides commonly seen with non-roller tip rockers. Allows for smoother, quieter operation. Maintains lash and reduces necessary and tedious engine maintenance.
Please note: Due to inconsistencies in GM castings, these rockers may require clearancing on the heads in the locations pictured.
Tech Specs
| PART NO | YT 6725 |
| BRAND | ULTRALITE PRO |
| APPLICATION | FACTORY REPLACEMENT/STREET |
| MAX OPEN SPRING PRESSURE |
480lbs |
| MAKE | CHEVROLET |
| ENGINE | LS3/LS9/LSA/L98 |
| MOUNTING STYLE | SHAFT MOUNT |
| ROCKER ARM RATIO | 1.8 |
| STUD SIZE | 8mm |
| ADJUSTABLE/HYDRAULIC | HYDRAULIC |
| ROCKER ARM STYLE | FULL ROLLER |
| ROCKER MATERIAL | ALUMINIUM |
| ROCKER ARM BODY STYLE | STANDARD |
| ROCKER ARM NUT STYLE | CAPSCREW |
| MAX SPRING DIAMETER | 1.437" |
| INLET OFFSET | YES |
| QTY | SET OF 16 |
| NOTE | EASY FIT |
