how do i set initial valve lash for my roller rockers? its a freshly rebuilt engine, i plan on doing the initial start up tonight

 

is this a new or rebuilt engine

 

new. all new parts

 

make sure you prime the engine before starting start at top dead center #1 turning the pushrod with one hand tighten with the other...when it stops.... a half turn tighter ....do both.....turn crank 1/4
turn now do #8 both rockers....turn the crank 1/4 turn....#4 repeat......the firing order 18436572

make sure you prime the engine before starting

 

i know i have to prime the engine before the break in, but do i have to prime before setting the rockers?

 

I have done it both ways

 

well i started at TDC with #1 and 6, turned the pushrod with my fingersand tightened the nut untill the the pushrod was hard to turn then i tightened the nut a half turn more. turned the crank 1/4 turn and did #8 and 4, ect.. and i did this without priming the engine first. but now they feel really tight almost too tight

 

do each one in the firing order 1...8...4....3.....6.......5.....7....2..
do you have roller lifters?

 

i did it like you explained but at 0 degrees cylinders 1 and 6 were at TDC, then 1/4 turn later 8 and 5 are at TDC, 4 and 7 then 3 and 2. so i set 2 cylinders at a time, but no i have hydraulic lifters, with a hydraulic flat tappet cam and proform roller rockers.

 

The pushrod can still turn with preload on it. Try to check for up and down slop, when thats gone then do your 12/2-3/4 turn or whatever the lifter mfr recommends.

 

im going to bring back this thread for peace if mind reasons, i set my roller rockers like i said above^^ now when the engine is running do i have to do any other adjustments ? or can i go ahead and put on my valve covers?

 

I failed to read this thread earlier.

I don't agree with the methods being suggested here. The "proper" position to adjust a rocker is with the lifter on the heel of the lobe.

What you should do is turn the engine over (slowly) until you see the exhaust valve start to move - now adjust the intake valve on that cylinder. Now turn the engine over until the intake valve has fully opened and is about 2/3rds closed - now adjust the exhaust valve on that cylinder. Doesn't matter what order you do them in, as long as you are watching and adjusting the rockers on a single cylinder. You can do all of the exhaust valves in the firing order if you like, then go back and do all of the intake valves in firing order, but I found it just as easy to just go down one bank of cylinders at a time.

That is the most "exact" way, and should always be used for solid lifters. But, there is an easier way that is completely adequate for hydraulic lifters.

Loosen all of the rockers so they all have slack. Turn the engine over until the timing mark on the damper is on the "zero" on the timing tab (doesn't have to be exact, just close) - doesn't matter if you are on #1 or #6 firing position. Tighten all of the rockers to just take out the slack. Now turn the crank over 1/2 turn. Tighten any rockers that are loose to take out the slack (check all 16 rockers). Give the crank another 1/2 turn - you guessed it, tighten any rockers that are still loose to take out the slack. Now give the crank one more 1/2 turn, and tighten any loose rockers (there should only be 4 left, but check all 16 anyway). Now every lifter is set at zero lash. Go back and give each one 1 turn down (that is the correct preload for Chevy lifters - not 1/2 turn down, not 3/4 turn down - 1 full turn down).

There are other ways of determining when a lifter is on the heel of the lobe, but this one is probably easiest.

You do not need to "prime" the engine in order to do this as long as you are careful to only take out the slack and do not preload the lifter plunger in the initial step.

You can also adjust hydraulic lifters with the engine idling, but if you do the initial adjustment properly, you won't have to go back and do them again with the engine warm or idling.