shaft rockers vs rocker stud girdles

[grumpyvette]

always call the cylinder head manufacturer for their input on rocker stud girdles,BEFORE PURCHASING THEM< because rocker stud spacing, and stud angles can vary, between head designs and models

READ THRU THIS THREAD ALSO

its not horsepower, its the stress on the valve train, that makes a rocker stud girdle and its increased rigidity useful,
and thats more closely related to average stress levels, RPM and VALVE SPRING LOAD RATES
any time your occasionally exceeding 6000rpm or getting close too 330 lbs of open valve load rate Id strongly suggest screw in rocker studs
any time your intentionally exceeding 6000rpm and exceeding 350 lbs of open valve spring rate a rocker stud girdle might be a good idea.
shaft rockers add rigidity , to the valve train,by eliminating the rocker stud flex issues,
but keep in mind that a rocker stud girdle can be added to the stock type of valve train,
and when used with quality roller rockers they add a good bit of rigidity to the stock style valve train.

shaft rockers add rigidity , to the valve train,by eliminating the rocker stud flex issues,
but keep in mind that a rocker stud girdle can be added to the stock type of valve train,
and when used with quality roller rockers they add a good bit of rigidity to the stock style valve train.
short answer, as a rule of thumb,shaft rockers are advisable

(1) any time your valve open loads exceed 400 lbs and/or you want to exceed 6500 rpm regularly.
(2) any time you intend to exceed 7000 rpm regularly and valve open loads exceed 500 lbs they would be considered almost mandatory..
yes you can in most cases use a stud girdle, with quality roller rockers,
but the shaft rocker design tends to be more rigid, and tends to aid durability
cranes gold roller rockers are decent quality rockers for a small or big block chevy,Ive used those, ERSON, CROWER and COMP CAMS ROLLER ROCKERS, many of them come with jam nuts that require a 3/16" allen key
and look a great deal like these posted here below

but these are NOT locking jam nuts designed to work with a rocker stud girdle

http://www.summitracing.com/parts/tfs-3 ... /overview/
BTW.IF YOUR BUILDING A SBC
http://brodix.com/heads-2/small-block-chevrolet-compatible-heads/ik-series
http://www.jegs.com/i/Brodix/158/1021001/10002/-1

brodix ph# 1-479-394-1075 (ALWAYS VERIFY PART NUMBERS SEVERAL,
TIMES FROM AT LEAST TWO SOURCES, BEFORE ORDERING PARTS)
the brodix rock stud girdle is part # BR-6435 and LIST price is about $230 you can get it for less if you shop carefully
BE AWARE that the I.K. 200 heads were shipped with BOTH 3/8" and 7/16" rocker studs ,
and the poly locks for the 7/16" rocker studs ONLY fit that rocker stud girdle
obviously you need to verify what your heads have before you order the matching rocker stud girdle
Verifying your engines clearances, and rocker geometry, and use of A rocker stud girdle and high quality roller rockers go a long way towards maintaining valve train durability

rocker stud girdles require significantly longer shank jam nuts , but you need to mount the rocker stud girdle up out of the way so the upper surface of the rockers can,t touch the lower surface of the stud girdle at full lift

RELATED THREADS
http://garage.grumpysperformance.co...-rockers-vs-rocker-stud-girdles.663/#post-911

http://garage.grumpysperformance.co...-in-vs-threaded-rocker-studs.2746/#post-43539

http://garage.grumpysperformance.co...ich-is-best-steel-or-aluminum.3124/#post-9141

http://garage.grumpysperformance.com/index.php?threads/roller-rockers.3009/#post-8361

http://garage.grumpysperformance.com/index.php?threads/cam-lobe-aceleration-rates.2627/#post-8341

http://garage.grumpysperformance.co...and-setting-up-the-valve-train.181/#post-1192

http://garage.grumpysperformance.com/index.php?threads/valve-train-clearances-and-problems.528/

http://garage.grumpysperformance.co...er-tip-vs-full-roller-rockers.2875/#post-7458

http://garage.grumpysperformance.co...-pushrods-and-check-info-you-might-need.5931/

http://garage.grumpysperformance.co...n-v-vi-to-adjustable-rockers.4564/#post-12170
http://www.summitracing.com/parts/pro-66950

http://www.summitracing.com/parts/sum-141010

viewtopic.php?f=52&t=181&p=215#p215

Ive used them several times,BECAUSE the guys paying the bills insisted on them,or had them on the heads they supplied.

http://store.summitracing.com/partdetai ... toview=sku

http://www.enginebuildermag.com/Article ... itch_.aspx

the net result IN MY opinion is that a set of roller rockers and a rocker stud girdle come very close to duplicating the results,of the shaft rocker systems on most engines that are spinning at under 7000rpm but keep in mind most of the engines I built are designed to run UNDER 6700RPM MAXIMUM rpms and most are either 383 or larger sbc or 496 and larger BBC engines, theres not much reason to spend mega buck$ on an engine designed to spin up in the 7500rpm plus power band on the street when its usually cheaper to just add displacement, when your not limited by class rules limiting you to a set displacement for a given weight

on many hydraulic roller lifter applications a REV KIT on hydraulic roller lifters adds several hundred RPM to the power band before valve control issues develop

the idea is that normally stud mount rockers relies on a single studs rigidity to stabilize the valve train for each single rocker, but adding a stud girdle or shaft mounted rockers adds a good deal of stability due to several studs and their combined stability & rigidity stabilize the rockers,with spring load rates and lifts commonly used on flat tappet cams its probably no big deal, with roller rockers and their increased spring load rates and lifts the stud girdle or shaft rockers might be a good idea but roller rockers with roller bearings become almost mandatory add enough spring pressure, lift and rpms and the individual rocker stud flexes enough so that either the stud or the cylinder head its mounted in will eventually fail
the one area where they make sense is when you've got offset push rods due to huge ports, so the valve train geometry won,t be correct with the standard rocker stud location

 

[grumpyvette]

lonnies performance posted this info

http://www.lonniesperformance.com/

Stud girdles can definitely help valvetrain stability & also prevent breaking the stud bosses on factory big block heads with stiff springs.

They do make the valves more of a pain to adjust & also require tall covers to clear. My '68 Camaro now requires the wiper motor to be removed to get the valve cover off.

keep in mind shaft mount roller rockers spread the valve train stress over a much wider area, so they are usually less likely to cause stress related parts failure problems and tend to increase the valve train stability at upper rpms
http://www.jobberwarehouse.com/aluminum ... 35001.aspx

I prefer the T&D rockers for most applications. They offer pressurized roller bearings & optional oil passages for spring cooling. I used a few sets & they hold their lash settings for a very long time. Many pushrod offsets are available to allow clearance for larger ports. They also allow disassembly & reassembly of the valvetrain while holding their adjustments... this way you can change valve springs & the lash is still correct when you reassemble. They are over $1000/set, but once you add up the price of rockers, guideplades & girdles, they are not much more, considering the amount of reliability that they provide.
READ THESE RELATED LINKS VERY CAREFULLY
http://garage.grumpysperformance.com/index.php?threads/valve-train-clearances-and-problems.528/

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://garage.grumpysperformance.com/index.php?threads/rocker-push-rod-wear-issues.9815/#post-54232

some roller rocker too retainer combo clearance issues cause problems easily solved with beehive springs and smaller retainer diameters

due too the design of most rocker stud girdles and the locking nut designs in many cases your choices will be limited ,
but I prefer to keep the lower rocker girdle surface a minimum of about .060 from any portion of the roller rocker in its arc if I can manage that

SOME ROLLER ROCKERS CAN AND DO BIND ON ROCKER STUDS, or rocker adjustment nuts, youll need to check carefully

some roller rocker too retainer combo clearance issues cause problems easily solved with beehive springs and smaller retainer diameters

the POLY LOCKS that are used with most roller rockers AND ROLLER ROCKER SIZES, (come in a variety of lengths AND DIAMETERS AND THREAD SIZES) so you might find you need tall valve covers to allow clearance BUT in most cases swapping to shorter poly locks reduced that problem from mandating taller valve covers, be aware that the outside diameter of the locks is a darn important factor in allowing the rocker to reach full potential lift!
it should be obvious that youll need to carefully check clearances over the full rotation and lift in several areas if you chance valve train components and retainer to rocker and internal rocker clearance slot to poly lock are two of many potential places the valve train may bind if theres not the correct clearance

look through this thread
http://garage.grumpysperformance.com/index.php?threads/two-loose-valve-locks.9687/#post-47884

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://store.summitracing.com/partdetail.asp?part=TFS-30400700&autoview=sku

http://store.summitracing.com/partdetail.asp?part=TFS-30400701&autoview=sku

its very common to find you'll gain a couple horsepower with the addition of a rocker stud girdle employed,
as youll have both more precise valve train control and less deflection, Ive seen guys instantly gain an extra 150 rpm-200 rpm,
before they started feeling valve float or loss of valve train control and its certainly less stress on the cylinder head casting and rocker studs.
the one thing ID suggest is that before you buy any rocker stud girdle you ask questions, many cylinder head designs use non-standard rocker stud spacing.

its not horsepower, its the stress on the valve train, that makes a rocker stud girdle and its increased rigidity useful,

http://www.popularhotrodding.com/engine ... ewall.html

STUD GIRDLES ADD A GREAT DEAL OF RIGIDITY TO THE VALVE TRAIN
the older comp chrome moly rockers work well but on some applications had clearance issues with spring retainers

Ive used the previous or older design comp cams steel rockers on lots of engines with good results, that the newer design has recently replaced, the older design with the advantage of having a slightly stronger and lighter design and having more retainer to rocker clearance, btw lash caps on the valve stems can be used to increase clearance in some cases, if your having that problem but their use, may require longer push-rods
http://www.summitracing.com/parts/CRN-9 ... N-99421-16

remember the object is to maintain the proper valve train geometry, to have minimal side loads , and the roller rockers lower friction resulting in low heat as well as maintaining the lighter valve train, with the new components

but Ive also used these two rockers
ERSON extreme duty

http://www.pbm-erson.com/store.php?catId=24

which Ive used for dozens of engines over many years with ZERO FAILURES so far, just be aware that the extreme duty rockers are ,a more robust design that the standard ERSON rockers which I don,t recommend

READ THIS LINK!
http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

and the CROWER stainless ROCKERS
http://www.jegs.com/i/Crower/258/73670-16/10002/-1

theres ARE big differences in the quality of the metal and hardness, look closely at the PROCOMP Chinese rockers above, notice the tip of the rockers axle, its obviously been flared,like a rivet indicating a fairly soft metal, rather than forced into place with an interference fit like the comp cams rockers they try to duplicate

Here is a link to these.
http://www.tdmach.com