Everything I read about setting up adjustable pushrods says to adjust to zero lash, then lengthen the pushrod according to the manufacturer's instructions and then *wait* for the lifter to bleed down.
So what causes the lifter to pump up in the first place? My engine has been torn apart for weeks because I am changing cams (and still waiting for parts) and installing new adjsutable pushrods.The lifters are installed and I do not plan to remove them from their bores. So is there residual oil inside the lifter making it necessary to wait for the lifters to bleed down in my case even if the engine has been sitting for a long time? How would the installation differ if I installed brand new lifters?
Thanks

 

If you installed new lifters, you would probably put some oil on them to prelube them.
So the install would be similar.

the reason you wait to move to the next cylinder is because you cant compress a liquid, (basic physics), and as your adjusting your pushrod, you are opening your valves aswell. So after you lenthen the pushrods, you need to wait for the lifters to push the oil out of there bodies and alow the valve to close. If you dont wait 20 min. or so you will like bend the valve as you rotate the engine over to the next cylinder.

 

lifters are hydraulic so you can adjust them with zero lash. by installing to manufacture specs, say 3 full turns after zero lash, prevents lifter noise. this is why you don't need to do periodic lifter adjustments as you would with solid lifters. Bleed down is the release of fluid in the lifter. Turning the engine over after installing new lifters and adjusting allows the lifter to bleed down. otherwise it takes about ten minutes for a primed lifter to bleed down after adjustment. You did prime them before installing?

 

The lifters are not new and have not been removed. They have been sitting in their bores doing nothing for a while. So are they still primed or have they release their fluid over time is the basic question.

 

I am so glad you don't have to wait for each hydro lifter to bleed down on a SB Chevy after you adjust the valves would never make the feature race if you changed the adjustment. I must be very lucky because we keep the lifters in oil drop them in the motor preload them turn motor over to get to the bottom of the lobe drop next one in if two are doing it we will do two at a time till done no waiting for bleed down. (I just don't understand)

 

Just want to keep track of this thread, seems to be varying opinions.

 

Letting the lifter bleed down is to make sure you have zero lashBEFORE making the final adjustment. It's to make absolutely sure your pushrod is long enough to keep in constant contact with the rocker. I think waiting a few minutes to make sure it's bleed down is better than trashing your engine. I did two or three cycles just to make sure I had zero lash dialed before doing the final adjustment just to be on the safe side.

 

Eeeewwwww...

VicW.

 

new lifters should be submerged in oil upright, when you do this you see the "bubbles" almost immediatly. Same goes for lifters you take out and plan to use again.

 

So by that logic Mentor70, if you started your engine which pumps up your lifters, your valves would hit your pistons. even tho they are adjusted correctly