Lifter preload effect on cam
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From: Frozen Tundra, WI
Lifter preload effect on cam Does anyone know if the lifter preload will have an effect on the cam specs (the engine sees)?? If the rocker is torqued (22lbs) with 1 1/4 turns in comparison to 1 3/4 turns (with a longer pushrod of course)...does this impact the overall cam specs (duration or lift) the engine sees?? There is around .040" difference in that range?? Or, does the oil in the lifter not compress at all during operation and the amount of preload really has no impact on the overall cam specs the engine sees?? 
Could this be a way to cheat a cam a little in one direction or the other for performance, clearance or whatever you may need??
Could this be a way to cheat a cam a little in one direction or the other for performance, clearance or whatever you may need?? 
You cannot cheat the cam with longer/shorter pushrod, the rocker ratio will not change at the valves. Too much and too little is bad either way you cut it. Stay with pre-load spec for the lifter you are running.
way shorter with little to no preload will reduce lift and wreak havoc on your valve train, too long will bottom the lifter out and hang your valves open before the cam even moves the lifter up the lobe...
way shorter with little to no preload will reduce lift and wreak havoc on your valve train, too long will bottom the lifter out and hang your valves open before the cam even moves the lifter up the lobe...
Last edited by 03Sssnake; Apr 28, 2013 at 12:10 PM.
Thread Starter
TECH Resident
Joined: Sep 2009
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From: Frozen Tundra, WI
But, your other statements are exactly what got me wondering...if you are within the correct torque spec and preload "range" for a lifter, is there a difference in how much (or how long) the valve actually moves if you were to torque (within spec) at each end of the range...1 1/4 turns verses 1 3/4 turns (torqued to 22 lbs)??
