Is there any advantage running one or the other. I'm WAITING(and WAITING) on a set of AFR 195's and looking into the purchase of rockers. Thanks.

 

self aligning are generally WAYYYYY more money. Functionality wise, no big diff either way.

oh, that's self aligning vs guideplate aligned right? Pushrods are what need the guidance

either from SA rockers
slots in the heads
or guideplates

pick any one you like.

 

Hey Sonix,
After all the questions I have posted,I might as well send you my parts and have you build my engine for me! Thanks for the info! I'm gonna e-mail AFR and see what they recommend for rockers. I know on their website they say that if I use comp pro-magnums,I'll need longer studs. Just wonder if they are the only rockers that would need the longer studs. Again, thanks for all of your help. Almost time for the build,a few more parts and some machine work and I'm off!

 

There are 3 ways to align the rocker

A) Self aligning rockers
B) Guide plates
C) Narrow pushrod holes in the heads (most common method)

 

longer studs needed for pro magnums? hmm, guess 'cuz they're a tall rocker..oh, and I think those require the use of poly locks, rather than the cheesy normal style stover nuts.
I imagine any of the full bodied rockers, or any time you're going to use poly locks, you'll need taller studs. (and tall valve covers I imagine, make sure to make note of that).

 

Pro Mags do need longer than normal rocker studs. The problem is the trunion... its too fat, so the poly-lock does not engage enough threads on the stud. Because of this, it snaps the top of the stud off. I've heard this many times, and I speak from experience as well. I changed to a set of 1/8"-ish longer ARP studs and never had an issue since.

They did still (barely) fit under stock height valve covers though. Had to 'massage' the breather baffles a little bit at the bottom, but otherwise fit fine.

 

One advantage the self aligning rocker have: it is guaranteed to be centered over the valve stem. This is side-to-side, which can be an issue with guide plate guided rockers.

Just went through this on the current engine. Installed 7/16" studs (Crane, slightly longer), stepped guide plates and Comp Pro Magnum full rollers (which come with poly locks).

A lot (all?) of the rocker roller tips sat partly off of the valve stem. Not a good thing. So I cut the guide plates in half, adjusted the halves so that the rockers were centered over the stems, and welded them back together. Number marked each set to the cylinder they fit.

A lot of work but the correct way to do the installation.

With self aligning rockers this would not have been required. Just pull the guide plates and if required space up the rocker studs with some grade 8 washers.

RBob.

 

The rockers aren't supposed to be perfectly centered on the valve stem.

They're supposed to be slightly offset, so that they tend to make the valve rotate.

If the valves don't rotate, then they and the seats will wear funny and fail prematurely, because the same point on the valve will always fall on the same point on the seat.

 

[QUOTE=sofakingdom;3072932]The rockers aren't supposed to be perfectly centered on the valve stem.

They're supposed to be slightly offset, so that they tend to make the valve rotate. . .QUOTE]

This can be argued against. When using self aligning rockers, how do the valves then rotate?

In my experience every time I've pulled an engine down the locks are tightly wedged into the retainer along with the valve stem. In order for the valve to rotate either the retainer needs to spin on the valve spring, or the whole valve spring needs to also rotate.

Not going to happen with any spring worth it's pressure.

RBob.

 

GM used things called 'valve rotator cups' or something like that to rotate valves, although it was usually just on exhaust valves IIRC.