Genuine GM Performance LS7 Upgrade Hydraulic Roller Lifters for VT VX VY VZ VE VF Holden Commodore & HSV LS1 LS2 LS3 L76 L77 L98 LS V8

Set of 16 GM Performance LS7 style replacement stock lifters for all VT-VF LS1 LS2 LS3 L76 L77 L98. These lifters are THE replacement part for anyone looking to upgrade their LS engine with a new set of GM lifters.  They are also a great option for those wanting to remove the factory AFM/DOD lifters from their L76 or L77 engine (as part of a AFM/DOD removal). These lifters have several upgrades that make them a perfect addition to your LS engine build.

GM Performance Roller Hydraulic Valve Lifters (RHVL) are valve train components that convert the rotation of the cam shaft into linear motion. The roller provides minimal friction at the cam/lifter interface. GM Performance RHVL automatically eliminate clearance between valve train components to provide an adjustment and a maintenance-free system. The key to the automatically adjusting system is a high pressure chamber and the control of engine oil out of, and into, the chamber. A plunger that resides in the lifter body has a precise clearance to the body, forming an annulus. When the plunger is loaded during valve lift, oil is expelled through the annulus. During valve lift, the plunger expels oil allowing the plunger to displace a small distance within the body. When the engine valve closes and the load is removed, the plunger spring and oil pressure keep the valve train components in contact. The plunger moves within the body to recover the distance that the plunger traveled during loading, plus or minus any changes that may have occurred. The check valve opens and refills the chamber. This process is repeated for every valve event providing continuous automatic adjustment.

GM Performance's RHVL also feature a metered oil supply for lubrication of the engine overhead through the push rod. The metering valve is designed to minimize sensitivity to contamination.

Benefits:

• Anti-varnish design minimizes sensitivity to accumulation of dirt, gum and varnish
• Chrome alloy ball check valve provides more precise valve opening and closing events
• Hardened steel body and plunger minimize wear for life-of-engine service
• Low-friction roller bearing helps maximize fuel economy
• Roller surface is optimized to minimize the cost of cam lobe processing without loss of performance
• Oil metering provides lubrication to push rod interfaces and other valve train components
• Optimized dynamic performance design enables better control of the valve event at all engine speeds
• Optimized to minimize the occurrence of cold start noise with adequate oil supply

Specifications:

• Genuine GM Performance LS7 Lifter Set
• Part number: 12499225
• Set of 16 LS7 type lifters for LS-Series engines
• Maximum engine operating speed 6,000+ rpm (typical)
• Roller follower material High alloy bearing steel
• Roller follower crown radius 585 mm
• Roller follower diameter 17.775 mm
• Recommended maximum Hertzian contact stress 1,900 MPa with steel cam
• 1,650 MPa with austempered ductile iron cam
• 1,550 MPa with nodular iron cam
• Oil supply pressure 100-500 kPa (typical)
• Body outside diameter 21.4 mm (standard)
• 12 Month Warranty

Fitment notes:

• Suitable for VT VX VY VZ VE VF Holden Commodore & HSV LS1 LS2 LS3 L98 L76 L77 V8.
• L76 & L77 only suitable as a replacement when removing AFM/DOD system.