shaft rockers vs rocker stud girdles



shaft rockers vs rocker stud girdles

Postby grumpyvette » November 9th, 2008, 6:58 pm

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



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

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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

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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

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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
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: shaft rockers vs rocker stud girdles

Postby grumpyvette » November 11th, 2008, 1:45 pm

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
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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.

Here is a link to these.
http://www.tdmach.com
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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