Iam not sure where to post this so forgive me if its in the wrong forums.
Just want to know why solid rollers make so much more horsepower than a hydralick? I know they can handle more RPM than a hydralick setup (right?) but is that the main reason serious builders choose a solid roller?
And what is valve lash? How do you check/adjust it and everything?

Sorry if these are dumb questions, just some things ive always wondered

 

A hydrolic lifter requires oil pressure internally for it to open and close the valve. If you open the valve too quickly, it looses this pressure and "collapses" resulting in all sorts of bad things.

A solid lifter doesnt have the hydrolic plunger in it. This means it you can open and shut the valve much more quickly, resulting in more power.

Lets say two cams open the valve for the same amount of time start to finish (this is called advertised duration). One cam is a hydrolic, the other a SR. The hydrolic cam follows a slower ramp rate (like following the smokey mountains). The solid opens the valve for the same amount of time, but follows a rate like the rockey mountains, very quick assent, higher peak and decent, yet the total time the valve is open remains the same. That results in more power across the board because the faster you can get that valve open, and hold it there, the more airflow potential an engine has.

The downside is that valve lash must be often checked and reset with a SR cam. Valve lash is the gap between the rocker arm tip (or roller) and valve stem when the valve is fully closed. Since a hydrolic lifter has a plunger, you can set valve lash quickly by just loading the plunger a little. The plunger will accomodate any wear and tear, heat expansion etc. A solid lifter doesnt have this give (its SOLID), so things have to be checked often, and readjusted to whats going on.

Thats my basic 101 explanation

 

Awesome, THanks! Great explanation!


Last question, how would one go about adjusting the valve lash? I see valve lash adjustment tools in summit mags and stuff but i cant figure out what exactly you do.

 

You adjust valve lash by tightening or lossening rocker arm nuts.

There are several different ways to do it on a hydrolic setup. This page will give you a basic idea.
http://shbox.com/1/4th_gen_tech2.html#adjust_valves

For a SR cam, you can use any of the "engine not running" ways above, with method 3 being your most accurate option. The main difference however, that you insert a feeler gauge, of the desired lash you want, between the rocker tip and the valve stem and then find zero lash. Once this measurement is found, you do NOT add any additional turns. Then you remove the feeler gauge, the lash will be the thickness of that gauge. For the most part, you will be looking at mid/low twenty thousandths of an inch range for SR lash, but each cam will call for something different (including different intake and exhaust lashes).

 

Got it, thanks! Think i might stick with a hyd setup whenever i get the money to rebuild the lt1 as i drive the car every other day in the summer, lots of miles.
Thanks again!