- Joined
- Apr 15, 2006
- Messages
- 22,471
- Reaction score
- 19,897
- Points
- 113
- Location
- Sth Auck, NZ
- Members Ride
- HSV VS Senator, VX Calais II L67
Borrowed from the ZZP website.
Each 1/2 turn of the rocker bolt is ~.050 of lifter preload. Your goal is to have between 1/2 turn and 1.5 turns if you have stock lifters .
LS7 lifters are preloaded and have to be installed between 3/8 and 3/4 turn (vs. 1/2 to 1.5 turns on stock lifters)
So that means stock lifters want 0.050" to 0.150" pre-load and the LS7 lifters want a bit less, about 0.0375" to 0.075" pre-load.
If zero lash is 6.9235" a 7" long push rod would give me 0.0765" pre-load which would be perfect for stock lifters and just a touch much on a LS7 lifter.
That means the even with the old worn pushrods in theory I'm still within the normal lifter working range. Seems though one doesn't like the extra compression and possibly the heavier valve springs.
Each 1/2 turn of the rocker bolt is ~.050 of lifter preload. Your goal is to have between 1/2 turn and 1.5 turns if you have stock lifters .
LS7 lifters are preloaded and have to be installed between 3/8 and 3/4 turn (vs. 1/2 to 1.5 turns on stock lifters)
LS7 Hydraulic Roller Lifters - Set of 12
Description When engines are equipped with a hydraulic camshaft, high rpm is limited by the improper position of the internal piston as the lifter inevitably "pumps up". This improper location results in open valves and therefore leads to lost power. These lifters are almost required for any...
zzperformance.com
So that means stock lifters want 0.050" to 0.150" pre-load and the LS7 lifters want a bit less, about 0.0375" to 0.075" pre-load.
If zero lash is 6.9235" a 7" long push rod would give me 0.0765" pre-load which would be perfect for stock lifters and just a touch much on a LS7 lifter.
That means the even with the old worn pushrods in theory I'm still within the normal lifter working range. Seems though one doesn't like the extra compression and possibly the heavier valve springs.