Are Stud Rockers inherently a flawed design?

[GARY C]

It all depends on what your doing and the set up, people running shaft rockers break rockers, pedestals, mounting bolts or pull them out of the head all the time.

[xr4x4ti]

If it's set up right the rocker is down on the solid shoulder of the stud not up in the air.

Yes, I have thought about this and have seen references on the web about shimming the base of the rocker stud to get the rocker as low as possible on the stud, but I never see anybody actually doing it.

[xr4x4ti]

As do millions of production GM LS engines.

That was sort of the point of my comment in the opening post. It seems that GM came to the same conclusion as I did during the LS design.

Why couldn't a simple pedestal mount be made for SBF, SBC etc to do the same thing without going to a full shaft setup or the height issue of a girdle.

This probably only makes sense with a hydraulic roller where you don't need to adjust the lash.

[xr4x4ti]

Something like this. These are only $50, if these could be designed to work with a readily available rocker.

I will have to whip one up when I pull my engine apart over the winter.

[GARY C]

If it's set up right the rocker is down on the solid shoulder of the stud not up in the air.

Yes, I have thought about this and have seen references on the web about shimming the base of the rocker stud to get the rocker as low as possible on the stud, but I never see anybody actually doing it.

On my solid roller stuff I put a arp head stud washer under the rocker stud, it set the height needed perfect..

This is a picture of a picture so it sucks but you can see the marks on the stud so it gives you an idea where it would be if it wasn't shimmed.

[jsgarage]

IMHO, stock stud pivots aren't any more so than stock shaft rockers that run metal to metal with inadequate lube. Re-engineering a 'production-rationalized' design is a balance of money vs what you want from an engine that it can't do right now. When I was playing with powerful-for-the-time turbo Buick V-6s, a few nearly wore the rocker pivots thru if they didn't permanently wear out the shafts.

Now, no longer constrained by "stock", aluminum Ford stagger-valve heads & aftermarket studs, roller rockers and a stud girdle that all fits under stock valve covers are compact, economical, has over a dozen fewer bolts to torque with less complication, and runs the valves without breakage up to rpms that make me fearful of a stock block failing, not the rockers.... My 2¢; YMMV.

[Geoff2]

CJ,
Read Zmechanics post where he claims a continuous rocker shaft system only works for inline valves. The Poly was an ingenious design that had angled valves AND a single rocker shaft. Anybody who has driven a 318 Poly will tell you they feel more like a 418...

[cjperformance]

CJ,
Read Zmechanics post where he claims a continuous rocker shaft system only works for inline valves. The Poly was an ingenious design that had angled valves AND a single rocker shaft. Anybody who has driven a 318 Poly will tell you they feel more like a 418...

Yes mate i did read that. Single shaft of course works for inline and not canted.
The poly is just 2 sets of inline valves as opposed to valves canted off if bore centerline in 2 directions.
Cool idea in the day, loads if interesting gear from that era.
Anyone have flow figures on stock and modded poly heads.

[Truckedup]

Smokey Yunick claimed when he saw a early production Chevy V8 he thought the stud mounted rockers were junk..GM head engineer supposedly told him to try and find more power with shaft rockers. Yunick said he could not get any more power after fitting shaft rockers...Of course this was 1954 with the cam technology then....Years later Yunick bitched about Chevy stud rockers burning up in Nascar racing
As bad as they are, Chevy stud mounted rockers have likely won more races than all rocker shaft engine combined..

[swampbuggy]

But that does not mean in anyway that it is the best choice nowadays. Mark H.

[BBO Omega]

At what point is a Stud Girdle become necessary with a 7/16" Rocker Stud set-up? X-LBS of Valve Spring pressure or X-RPM with X-Rocker Ratio?

[GARY C]

Any thing that makes the valve train more stable is a plus.

If you guys are on Face Book then it's worth watching the last 20 minutes of this video, it's a rep from Trend talking about what they find on the Spin Tron and things to address.
https://www.facebook.com/jepistons/vide ... 917130179/

[Truckedup]

But that does not mean in anyway that it is the best choice nowadays. Mark H.

Of course not...But it all depends on the intended use of the engine...The original Chevy V8 was intended as an inexpensive V8 for GM's lowest priced car....It outlasted every other ohv V8's that were supposedly better...Inexpensive, reasonably light weight and compact, responds well to tuning is hard to beat...Call it what you want but the word is...Successful...

[pamotorman]

the stud mounted rockers originally came out of Pontiac engineering not chevy.

[Geoff2]

CJ,

An in-line valve head is a head where all the valves are inline, not some of them.

As for numbers..., I can give you two examples. Wheels magazine tested a 1958 318 Poly Powered Plymouth Belvedere with 3.23 axle. It ran a top speed of 118 mph, almost unheard of that time in Oz. Oh, & it had a two bbl carb. If you don't believe it, I have the magazine & you can come & look at it...

Mate had a 64 Plym with 318 Poly, 2bbl. Beat his mate's GT Phase 3 HO Falcon from a standing start.