318 V8 with roller rockers

Hi I am assembling a 2nd pair of heads for my old V8.
this pair of heads will have adjustable rollerrockers on them.

The lifters in the block are hydrolic lifters

my question is - What do I set the valve gap to with these ajustable
rockers? Im guessing ZERO to mimic the old steel rocker that you normally
find in these heads.

 

With hydraulic lifters and adjustable rockers you want to preload the lifter
a specific amount, .020" to .030" is common. Most adjusters have 24 threads
so one turn equals .0417"; a half turn will preload the lifter about .020"
and three quarters of a turn will preload about .030".

With each lifter on the heel of the cam lobe, turn the adjuster until all
free play is removed (spin the pushrod to feel the drag at zero lash) and
then turn the adjuster an additional 1/2 to 2/3 turn and tighten the jam
nut.

 

what year 318???

 

No, you have to center the plunger of the lifter in its bore when its
body is on the heel of the cam. Simply setting the arms to "zero
lash" won't do anything constructive at all...you must adjust them so
the plunger is in the center of its travel in the body. Most people
do this while the engine is idling hot by backing off the adjusting
nut or stud until continuous "click" is heard and then tightening them
down around 2/3 of a turn.

Having adjustable rockers on a hydraulic lifter equipped engine isn't
very useful; there are tons of better mods to do to that LA to get
better longevity and/or efficiency, and this ain't one of 'em.

 

Oh, yes!! - Im not saying its a really usefull Mod - The roller rockers were
all all I had in my parts bin, so Im using them - If I had new normal
rockers, I might hav used those instead.

Thanks for you help and advice anyway...
Andrew

 

Nonsense, adjustable rockers allow one to adjust the lifter preload to a
desired dimension rather than the happenstance preload that results from
machine work. (head/block milling, valve sinking, etc.)
Adjusting to the middle of the plunger's travel isn't the goal, adjustment
is normally made to a minimum preload dimensiion like .020"-.030".

 

DeserTBoB wrote:

Only if you want to promptly burn all your exhaust valves, and/or kiss
the pistons with ALL the valves. "The center of its travel" is WAY too
much pre-load!!!! About .020 is correct.