preload on hydraulic lifters

[stroker mike]

I have a new set of roller rockers from ohio crankshaft, and I need some one to tell me how to set the appropriate amount of preload on these hydraulic lifters. I am doing this for the first time, I have set lash on a solid lifter setup, but never this. Also, can anyone tell me if they have ever heard of the rocker shaft failing with roller rockers? I was told that induction hardened shafts were recommended for these rockers, but I was also told that the factory shafts never seem to wear out under normal street conditions. I don't intend to race, I just want a hot street machine. But, it should be noted that I intend to run a 75 hp shot of N02, I am not sure if that is a real concern in this issue specifically, but I am trying to think of any factors that may be of consequence. Any word of wisdom would help, thanks.

[pishta]

Crane says between .020 and .060 on their website. if you have a fine pitch adjuster (and you should) its about 2 1/2 turns after your pushrod touches it. spin the pushrod and turn the adjuster until you feel it touch, then go 2 1/2 turns.

[charger_dan]

Originally Posted by stroker mike

can anyone tell me if they have ever heard of the rocker shaft failing with roller rockers?

do your rockers utilize needle bearings at the rockershaft surface?
if so, i'd go the induction hardened route.

[MrChemist]

I usually get it to where the push rod touches, then ¾ to 1 turn.

BTW, I have to tell you that you really shouldnÂ’t run NO2 through your motor. Nitrogen dioxide is highly soluble in water, making nitric acid (a strong acid)Â…this would destroy your motor faster than Nitrous (N2O)Â….Sorry, I had to be a smart a$$.
:

[John Kunkel]

Most rocker adjusters have a 3/8"-24 thread so each full turn of the adjuster will preload the lifter about .042". A half-turn will give .020" preload, three-quarter turn is .030" and so on.

I wouldn't go over .040".

[stroker mike]

yeah, N20 is better than NO2, and I'm just a bit dyslexic, or spun out on coffee and rock stars, who knows? I appreciate the input, I will use it well. I do not have a fine pitch adjuster, what is that? Does it have another name? What does it do? I have a rusty craftsman tool box full of mismatch sockets, a mammoth breaker bar, and a used torque wrench from the swap meet. And a box of band aids.

[dave571]

I usually go 1/2 turn from zero lash.

I've measured as little as .009 lifter preload on a non adjustable application, and the valvetrain was still not noisy.

I agree .040 is a good max.
I seem to remember some reference source saying that .030 was optimum but I can't say for sure.

[pishta]

Originally Posted by John Kunkel

Most rocker adjusters have a 3/8"-24 thread so each full turn of the adjuster will preload the lifter about .042". A half-turn will give .020" preload, three-quarter turn is .030" and so on.

I wouldn't go over .040".

Ooh, my bad! that should be 1 1/2 turns! I remember the fine pitch stuff now.

[pishta]

Originally Posted by stroker mike

yeah, N20 is better than NO2, and I'm just a bit dyslexic, or spun out on coffee and rock stars, who knows? I appreciate the input, I will use it well. I do not have a fine pitch adjuster, what is that? Does it have another name? What does it do? I have a rusty craftsman tool box full of mismatch sockets, a mammoth breaker bar, and a used torque wrench from the swap meet. And a box of band aids.

Fine pitch meaning the adjuster on the rocker arm has a 24 TPI pitch, like a fine threaded bolt. Itll have a lock nut or an interference fit (old 273 rockers)

[Fastesteddie]

I agree!

Sorry, just trying to get to 10 posts so I can view attachments.

[mrsmallblock]

Usually 1/2 to 1 turn works good but if you plan on turning up the rpms, a 1/4 would work well because the lifters wouldn't pump up as soon.

howard
mrsmallblock

[stroker mike]

I will be keeping it below 6000, I would have to upgrade alot more to go past there. I will rarely even hit that, my limiter will be set at 5900, I think. just to be safe.