Hot Rod Forum banner

New motor one lifter bad

176 4
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?
1 - 5 of 5 Posts

·
Registered
Joined
·
2,429 Posts
Sometimes when setting up new lifters they will bleed down and you have to leave them sit for a bit and they will eventually will pump back up and tighten back up to your lash setting. I wish I could explain more but I have not really had that problems with setting up hydraulic lifters over the years but I have had where first setting them the rocker arm was loose enough I could wiggle it some when set but after rotating the engine over while setting the others and then I went back to check them they were tight after that and correctly set.

Make sure you do the pushrod moving up and down method and not spin it with your fingers as you can get a false zero lash feel if your new to doing this.
Unless the engine is producing oil pressure , neither a lifter or anything else is going to " pump" up . There is an internal spring in thee valve lifter that will return the plunger to the top , if it does not , either the lifter is defective or has debris in it IMO
 

·
Registered
Joined
·
16,075 Posts
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
 

·
Registered
Joined
·
5,003 Posts
I never meant like high rpm "pump up", all I meant was that when the lifter will go soft at times if you let it sit for a few minutes then the plunger will work its way back up and the valve lash should be tight like it should.

At least that is how it has always worked with me on my roller lifters. I did not have the best of words I could think of to describe it in the proper terms. I had seen that in a video before on setting valve lash on small block chevy engines.

I know sometimes they might stay loose and bleed down but once the engine is started it builds pressure and is good to go if properly set.

My apologies if I caused any confusion and just read Bogies post as he gives all the best info you need to have it described.
 
1 - 5 of 5 Posts
Top