Surprisingly, I did a search and found nothing on this. How do you know if you'll significantly benefit from having stud girdles (SB)? Any realistic power gains up top?

 

A stud girdle prevents rocker arm stud flex by anchoring/connecting all the studs together on a head ( small block ) THe only performance gain you would see would be the a motor with a stud girdle would stil be running while a similar motor without one would be on the side of the road after breaking a rocker stud.

Theoretically you could say there is a small performance gain, but you won't feel it, from the rocker not flexing and opening and closing the valve more precisely

 

Well what kind of power calls for one then? And wouldn't a pushrod bend before a rocker stud snapped?

 

They are now antiques and belong in a museum!If you are concerned with high RPM longevity,shaft mount rockers are now the way to go.

 

Push rods hold thier load from tip to tip, the strongest direction. A rocker stud is exposed to side loads reguardless of engineered geometry. So the answer to that is no, the rod will not break first if the load is maintained in its axis lenght. To answer the other question, the more spring pressures, RPMS, and lift the rocker is exposed to the more side loads on the studs. These studs can take alot of abuse, but they reach a point where they will start to give under the pressures and flex. At this point they could cause a push rod to break as they flex without failing themselves but this is usually not identified as the problem because they are not bent (visually). Stud girdles help to prevent this flexing by distributing the load to all the studs. Usually when a rod breaks with stud girdles its because of: 1-defective part, 2-overrevving and floating the valve train and lifters, 3-more pressure than the push rods are designed for, 4-failure of another valve train component. As long as the geometry of the valve train movement is good and the parts are designed for the loads they are exposed to all will be well and stud girdles help keep the geometry in check.
vic

 

Your rocker stud is basically a cantalever (flag pole, diving board) by tieing them together at the top the load is shared by the ajoining studs and they behave more like a beam (bridge). If you are running mechanical lifters you can expect longer intervals between adjustments, although adjustments with girdels is more work. I am using Moroso's on my 383 which allow me to release one stud at a time while making adjustments.

 

At what point is this something you should consider? Whether it be power level, total lift, rpm, or whatever.

 

to many variables on when to use:

If you have cheap rocker studs that tend to distort then a girdle may be needed on a 300HP engine.

If you have expensive studs on 500HP engine then a stud girdle may be of little use or need.

Material difference. Cast iron heads move less then an aluminum head. A girdle may be needed on a aluminum headed engine and not on an equal HP iron headed engine.

Power gain. Can be none can be some. If your application does not have stud deflection when not using a girdle and you put one on your power gain may be nill. If you have stud deflection and you are lift if varing on the cylinders then the stud girdle will gain you power.

Couple of other notes. If you install a girdle and it doesn't seem to fit. Check the concentricty of the studs. 16 studs that are out .010" can add up to the girdle not fitting. Don't force it replace the studs.

Set screws, about 15#/ft on them. Don't over tighten or you will crack the polylock at the base.

Chris
Stef's Performance

 

I had a 3/8" rocker stud sheer off with my solid roller (155lbs on seat, 440lbs open) at about 6000rpm. Bwwwaaa!! POP! POP! Sputter...Die. That's about what it sounded like.

The poly lock from the one that sheered bound up the rocker arm beside it, the pushrod bent, blew the side out of the lifter and beat the hell out of the valve.

Luckily enough I had installed screens in the lifter valley, which caught the debris.

So, one bad pushrod, one bad roller rocker, one bad lifter, one bad valve could have all been saved by the stud girdle.

I now have stud girdles, one side benefit is they LOCK the poly lock in place so the lash stays put and you don't have to adjust it as often.

 

I have stud girdles indeed and I checked my lash after 50 passes and it was still close to perfect on my solid roller..

 

Stud Girdles are cheap insurance if your running a performance engine with standard stud mounted rocker arms. There isn't going to be a down side to using them. They also do a good job preventing the polylocks from getting loose.


Chris,

Is there any place you're not? Drop me an e-mail if you get a minute.

Doug

dschriefer@barrygrant.com

 

Everyone makes very good points. Shaft mounted rockers are better, but also much more expensive. I have them for my solid roller springs pressures, which is the application that will most benefit from girdles/ shafts

 

Mike: I didn't know you went with shaft mounted rocker arms, what brand did you use? I am planning to build a 18* 427 and was going to go that route.

 

:o Oops, I was speaking of the girdles like in the title. I haven't gone to shaft mounts yet What 18* heads are you looking at? I've looked at the SB2 in the past, but the chambers were pretty small making compression too high for the pump gas, maybe things have changed

 

You gotta love these carb guys. . .since their stuff sits on top they think they can tell us guys that fasten to the bottom of the engine what to do. . .sure Doug. . .I'll drop you an e-mail

Chris Straub
www.stefs.com

 

Had I know better I would have gone a shaft rocker system in the first place it would have been about the same price as : Comp Cams Hi Tech SS rockers, Crane gold stud girdle, guide plates and I had to have all 16 of the Crane polylocks machined at the bottom to fit the Comp rockers

 

The price on shaft systems is getting to the point where there is no reason no to use them if you're building a performance engine.

 

Do you have to take your rockers off to install the stud girdles? Or do they just clamp on around the poly locks? Do I need any sleeves to go inbetween the girdle and the poly lock?

 

They clamp around the polylocks. Nothing comes off, but you have to use a longer polylocks.

 

What is the difference between the solid bar type and the spring loaded versions?

Also while I'm at it, I have a 383 (450-500hp) .540 lift cam does my engine warrant using these? Just to make sure.

...I plan to hit it with a 150 shot in the future.