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Author Topic:   Hydraulic lifter shims
mini stock owner
Dirt Newbie

Total posts: 1
posted May 21, 2003 10:38 AM  
I own a mini stock and was wondering how to measure the hydraulic valves and see why I need shims for the lifters, help appreciated

joeracer95
Dirt Roller

Total posts: 15
posted May 29, 2003 12:12 PM  
for racing purposes you should maintain .040" to .050" lifter preload.achieve this by pumping down the lifter(several times to be sure you have gotten all of the oil out of them).reinstall the lifter and follower and collapse the lifter and measure the gap between the base circle of the cam and the follower.this measurement is the lifter preload.shim the lifter or cut the valve tip accordingly.hope this helps.
Mark-Fast Forward Racing Engines

shaggy12
Dirt Roller

Total posts: 13
posted May 31, 2003 08:52 PM  
Yes and no......first of all, the valve length will need to be "adjusted" by installing a solid lifter ( with the serated edges cut off) in the lifter bore. Install a rocker and adjust the solid lifter to have 0 clearance with the cam at the base circle. Measure the total valve lift with a dial indicator on the retainer. If the total lift is correct, you are ok. If the length is less than cut the valve tip shorter. If length is more, then add lash caps and remeasure. Remove the solid lifter. Bleed all the oil from the hyd. lifter and install in the bore. Push down on the lifter side of the follower and measure the clearance again at the base circle of the cam. .040 to .050 Either shim between the bottom of the lifter and the bore, or cut off the bottom of the lifter as needed. DO NOT cut the valves to adjust the correct clearance at this point. That is a good way to ruin a set of valves by having the follower fall off the edge of a valve!! Chad Ruwe Speed Pro Cylinder Heads 208-362-5040

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