Through some miscommunication, I did not have adjustable rockers installed on my fresh engine as the Edelbrock RPM head instructions require. I have plain stock rockers. I have some sets of Isky adjustable rockers and a few sets of different length pushrods. My engine builder has set the spacings on the shafts already but due to health issues, I should probably install the rockers. Is there a technique found in a repair manual or book somewhere? I have installed solid lifter rockers on other engines many times, but not hydraulic lifters combined with adjustable rockers.

No lash, plus 1/2 to 3/4 turn preload.

there is an excellent utube vid on pushrod length that might benefit you. type in "rocker arm geometry" & the best one is by straub industries,scott foxwell.

This.

Pushrod length should have 1 or 2 threads showing under the rocker after adjustment. Also check that throughout the rocker motion the pushrod cup rim does not contact the rocker.

If using Isky rockers you should dump the stock shaft clamps as well as the shafts and upgrade both. You will need to readjust the spacing and make sure that you check pushrod clearance to the head and block through the whole motion - on EVERY single one !! You may need to grind the block or head for clearance.

Buy a set or two of rocker shims. Using the springs between each set of rockers (like they do on hemis) is fine BUT you should install a shim on each side of every rocker - this is to prevent wear from both the shaft clamp and the spring.

Now you should be good to go.

So regardless of how much oil is in the lifter, the spring in the lifter will keep it against the pushrod and rocker? Then I can do this operation with the engine cold?

Absolutely.


You should soak the new lifters in an oil bath for a day to get some oil in them - although its questionable just how much they fill like that.

To adjust the preload, get the lifter on the base circle and spin the pushrod while tightening the adjuster. When you achieve ZERO lash the pushrod will be hard to spin. Now you can give the adjuster the appropriate number of turns for the preload. Tighten the nut and you're done.

The method I was taught many years ago to has never failed me.

EO/IC rule (Exhaust Opening and Intake Closing). using a remote starter button/ switch to bump the motor around

Set the intake valve when the exhaust valve is beginning to open. This will put the intake lifter at the base circle which is where you want it to be.

Then set the exhaust valve when the intake valve is almost closed.

If adjusting hydraulics, loosen the adjuster until there is noticeable play between the rocker and pushrod / valve

While rolling the pushrod between two finger tips, begin slowly tightening the adjuster.

Just as you hit Zero lash you will feel a slight but distinct resistance. You can loosen a 1/4 turn or so and retighten to confirm several times until yo get the "hang" of it.
the above resistance will be felt even with empty lifters. You will also note the " free play" is gone.

From that point, depending on adjusters threads per inch determines how far to tighten. Most are 3/8 x 24. So if one divides 1inch by 24 =.0416" per turn. All camshaft Manufacturers' I am aware of recommend. 0.020" to .040" preload.

So I use 1/2 turn beyond zero lash.

And in closing years ago I soaked and pumped up a set of hydraulics before installing them. After 3 days several were still holding the valves open and would not bleed down. Haven't done that since

The same "EO/IC rule (Exhaust Opening and Intake Closing) method can be used with solids using feeler gauges to set the lash.
I prefer to start at the front valve, and work my way back 1 at a time. Then repeat on the other side