has anyone out there had any problems running self-aligned rockers w/o guide plates? setting zero lash is critical...but i'm wondering if there were any failures out there, especially running hydraulic lifters. guide plates seem like such a fool-proof and tested arrangement. i'm running 113 heads on a 350 and have no guide plates..anyone else doing this out there?

 

You're not supposed to run guide plates with self aligning rockers. There's a lot of self aligning setups in the world. Many of which are without issue. Guide plates work great, yes the are tested and fool proof, once set up correctly. But self aligning rockers are almost stupid proof.

 

I reckon to test that theory next week

 

thanks, stekman...i'm old school..trying to get with these newer ideas....!! with zero lash..i'm thinking the slight movement of the hydraulic lifters might cause the push rods to slip off....but that's just me worrying!

 

Self-aligning vs guide plates has nothing to do with lash.

Rather, they are alternate methods for keeping the rocker centered over the valve stem. There are 3 systems for this commonly used in SBCs; one AND ONLY ONE must be employed.

They are: the narrow holes in the heads for the push rods, which positively locate the push rods, and therefore the rockers (stock in most SBCs before the late 80s); guide plates, which REQUIRE that the holes in the heads be large enough to avoid the push rod touching the head casting, since it would bind if it did (stock in only a very few, mostly high-perf, SBCs); and self-aligning rockers, which use large holes so the push rods miss the casting, and little "rails" on the rocker tip to locate the rocker (stock from the late 80s to the present).

The "weakest" of the 3 methods is the holes in the heads, because there's more push rod between that "guide" and the rocker, which allows the push rod to bend, and everything to otherwise move around; and, the "guide" is cast iron, which can wear and is not replaceable.

Guide plates work the same way but are usually better because the guide is closer to the push rod tip, they're adjustable to some limited extent, and if they get damaged, you can replace them.

Self-aligning rockers are theoretically the best as locators, since they directly do what is required (locate the rocker on the valve) rather than indirectly (locate the rocker on the valve by locating the push rod). However, they have other issues, such as, they require a certain minimum amount of valve stem to be exposed at all times, and they tend to reduce the tendency of the valves to rotate, like they need to.

Lifter movement is not an issue. The lifters are at the opposite end of the push rod and have nothing to do with locating the rocker on the valve stem.

 

well, when we installed the rockers we didn't tighten the nuts down enough and several rods ended up bent 'cause they fell off the rocker arms! so, lash is important to keep the guided tips on the valve stems!!