For my new lifters CC gave me the lash in inches, which makes sense for them. However, what works for me is now much of a turn. How many inches is a turn of the rocker arm nut? Factory stock studs. Thanks

 

No such thing, you need a feeler gauge, they gave you a number like 28" intake 34" exhaust right? that means the size feeler gauge you put between the rocker and the valve when at circle.
Is that a solid roller? If it's hydraulic roller set it running and hot, they might have given you prelim numbers.

 

did my HR setup half turn past zero lash

 

The number they gave is a range for the lash 0.02-0.06" This is just by memory so it could be off by an order of magnitude. I know I've seen people state the (inches of lash)/(turn of rocker nut) for factory stock heads. When I put them in I went 1/4 turn past lash while hot and running. I haven't had any immediate problems, I just wanted to follow up and make sure that a 1/4 turn was within the range CC gave. Thanks

 

Hydro cam, 1/2 past 0. JMHO

 

Just a quick question as I've never fully understood this. What is 0 lash (AKA how do you know you've gotten to that point when tightening the rocker arms)

 

I'm pretty sure if you had a hydraulic cam with comp cams R lifters people have said you would want 1/8 turn past lash.

 

0 lash is when you just feel a slight drag when you twirl the push rod between your thumb and index finger with the valve closed.

ONE way of adjusting preload.

Coil wire off.
Bump engine til Ex just starts to open. Adjust Int.
Bump again til INT opens fully and is on way to roughly half closed. Adjust EX.

Start with either bank and work your way around.

You might want to warm engine up. Start with one bank. When complete. Warm engine up again and remove valve cover on remaining bank and complete that one. (If you remove both v covers at the same time, the second bank will have cooled down before you get to it).

You probably don't have to adjust them hot, but it would'nt hurt to have all the lifters nicely primed. JMHO.

 

 

7/16-20 rocker arm nut threads (aka 7/16 fine) are 1/20 or .050 inches per turn.

1 flat on the nut is 1/6 *.050 or .0083. Figure .008/flat.

If you are adjusting hydraulics, BUBBA's method for finding zero lash is good, and you are then compressing the lifter.

 

So if Comp Cams says that they should be preloaded to 0.006" while the engine is hot. That number came with the lifters and is posted on their website. That would be (0.006")/(0.05"/turn), or about 1/8 of a turn past lash. I know I've heard that the "R" lifters are supposed to be adjusted to about an 1/8 of turn past lash but I didn't think that the Pro Magnum were also. I'm going to adjust my valves to this, so somebody please let me know if I'm doing something wrong. It worries me a little that the range of adjustment is actually 0.002"-0.006", where the loose end works out to 1/25 of a turn, can that be right? It's got to be pretty tough to determine zero lash within 1/25 of a turn in order to be able to make that adjustment properly.

 

I think you are reading WAY too into this. that is the beauty of hyd rollers, the lash is not super critical.. aim to be around 1/8th-1/4turn and you will be fine.