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New motor one lifter bad

303 Views 4 Replies 4 Participants Last post by  eric32
I am hoping someone can help me to know what is going on with one of my hydraulic lifters. I have a brand new crate sbc motor. I went through the valve train to confirm lash. I noticed that one of the lifters is not all the way to the top of the retainer ring. Is this lifter just low on oil because it is new? Can I bleed the lifter to fill it back up?
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The lifter’s plunger should not reside against the retaining ring once the preload is set.

With hydraulic lifters there is no lash like there is with a solid lifter. Hydraulics reside at a setting of zero lash and within the range of travel the plunger has from the top retainer ring to the plunger seat at the bottom of its bore where ever you set it between those two ends it will stay.

The proper procedure in setting preload which is the position you place the plunger between the stops I described above is to loosen the rocker retaining nut assuming this is a Gen1 or 2 Small Block Chevy. But first you need to rotate the engine through the firing order determining the TDC position on each cylinder to where both valves are closed. Then working only those rocker pairs do you loosen the rocker nut till the push rod can be spun between your thumb and forefinger. Then gently feeling for where the push rod can’t be spun with gentle finger pressure the nut is turned from 1/8 to 1/2 a turn further. Some people and manufactures recommend more here you and we need to know what you’re working on. This establishes the zero lash position that the plunger will afterwards maintain as it’s base zero lash point. So if for example you over rev the engine and pump up the lifters as they bleed down they will return to this point without you touching anything. On the other hand if a lifter bleeds down while sitting under spring pressure unless it has an internal leak that exceeds pressure oil being delivered to it then once the engine fires and oil pressure comes up it will raise the plunger to the preset zero lift position, “look ma no hands” applied.

Also as you go if the lifters were pumped up prior to assembly or the lifters were previously run in the engine so they have oil in them. as youre making the preload it might be necessary to give the lifter a few minutes to bleed as you set the preload.

If this is other than a Gen1/2 SBC them very likely the rocker stud has a positive stop for the rocker arm in which case the rocker nut is turned down to a torque value. Different brands do this process differently and different engines or even year of an engine do this differently so you need to know and so do we what engine you are working on.

Bogie
 
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