latch and preload??
12-02-2004, 12:43 PM
#1
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latch and preload?? ok guys could you all pls explain to me what latch and preload are and how they relate with lifters. Plz answer me as if you where talking to a 5 year old or to someone that has never seen an internal conbustion engine( in other words brake it down plz)
12-02-2004, 12:50 PM
#2
It's lash...not latch. Lash is where you have slack in the valvetrain(a gap between the rocker tip and valve tip) Preload is where you have no slack in the system and you have tension on the valvetrain. That tension is there because of the spring in a hydraulic lifter. After you put preload in the system, the lifter is designed to keep tension on the valvetrain and eliminating any slack in the system.
12-02-2004, 01:30 PM
#3
Both are needed so that the lifter can transistion the ramps of the lobe, both opening and lclosing. The clearance keeps the lifter from crashing into the lobe. Lash is the term for mechanical clearance as UNA has explained. Pre load is set with all hydraulic as the the "clearance" needed for the ramps is obtained by the hydraulic valving in the lifter which has oil above and below. Hope this helps.
Chris
Chris
