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Stud Girdles on BB ?
Thread Starter
Instructor
Joined: May 2003
Posts: 203
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From: Willows Ca
Stud Girdles on BB ?
We got all new roller set up. Ran real fine for about 100 miles. Then I lost a keeper on an exaust valve, broke the guide, bent the rod. Very lucky i retrived all the peices and the valve didn't drop.
I'm thinking the roller rocker wasn't riding where it should to cause that. I have the parts to replace, but started thinking is Stud Girdles a good idea?
I'm thinking the roller rocker wasn't riding where it should to cause that. I have the parts to replace, but started thinking is Stud Girdles a good idea?
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
A stud girdle has nothing to do with the rocker position except in a dynamic state and then only fractionally. If the rockers aren't where they're supposed to be with the enigne off, then a stud girdle won't be of any use to you in preventing this kind of failure. The real purpose of a stud girdle is to stabilize the studs so that they don't bend and have cyclic failure. Usually the stud will break off just below the rocker fulcrum or right at the base.
I would look at your guideplates and the rocker geometry.
I would look at your guideplates and the rocker geometry.
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
I believe in a stud girdle and always use one. That said I also found that stock push rod lengths don't work with installed heights of over 1.875. If you are using aftermarket heads there is a good chance your rockers are actually touching the retain. I am in the middle of correcting this problem right now
Thread Starter
Instructor
Joined: May 2003
Posts: 203
Likes: 0
From: Willows Ca
I have GM LS-6 hp heads on a 427 and the K11-420-8 kit from comp cams. You maybe right about touching the retainer, it had a small crater on the one that broke. How can I be shure on the rod length?
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Loosing a keeper can only be caused by a couple of things. At least it's the only two I know about.
#1 improper installation.
#2 Bottom of the rocker having contact with the retianer.
I'm running a solid roller with +.200 push rods and +.100 vavles with longer ARP studs because my spring diameter is so big that i had bottom of the rocker contact with my retainers.
I would never grind the rockers to gain clearance. I also never leave home without a stud girdle. Once you get up to 175+ pound seat pressures you can actually measure the stud deflection on a dial indicator by rotating the motor over twice. If your deflection exceeds .020 you need a stud girdle.
#1 improper installation.
#2 Bottom of the rocker having contact with the retianer.
I'm running a solid roller with +.200 push rods and +.100 vavles with longer ARP studs because my spring diameter is so big that i had bottom of the rocker contact with my retainers.
I would never grind the rockers to gain clearance. I also never leave home without a stud girdle. Once you get up to 175+ pound seat pressures you can actually measure the stud deflection on a dial indicator by rotating the motor over twice. If your deflection exceeds .020 you need a stud girdle.
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Originally Posted by gkull
Loosing a keeper can only be caused by a couple of things. At least it's the only two I know about.
#1 improper installation.
#2 Bottom of the rocker having contact with the retianer.
I'm running a solid roller with +.200 push rods and +.100 vavles with longer ARP studs because my spring diameter is so big that i had bottom of the rocker contact with my retainers.
I would never grind the rockers to gain clearance. I also never leave home without a stud girdle. Once you get up to 175+ pound seat pressures you can actually measure the stud deflection on a dial indicator by rotating the motor over twice. If your deflection exceeds .020 you need a stud girdle.
#1 improper installation.
#2 Bottom of the rocker having contact with the retianer.
I'm running a solid roller with +.200 push rods and +.100 vavles with longer ARP studs because my spring diameter is so big that i had bottom of the rocker contact with my retainers.
I would never grind the rockers to gain clearance. I also never leave home without a stud girdle. Once you get up to 175+ pound seat pressures you can actually measure the stud deflection on a dial indicator by rotating the motor over twice. If your deflection exceeds .020 you need a stud girdle.
This is a rocker arm touching the retainer. Us a mirror and look carefully
I run .100 longer pushrods and that takes care of this.
Another problem with stock length pushrods can be the slot in the bottom of the rocker touching the stud because it doesn't have enough travel
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Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
When you said roller setup 
I was thinking "Roller" setup. your picture kind of tells it all.
Roller tip rockers are bullet proof in comparision to stock stamped rockers. They are great for hot H-flat cams.
What you need to do is read up on valve train geometry. Stug girdle would be a waste of money for your setup. What you need is correct length push rods which have clearance and center on the tip of the valve stem throughout it's complete cycle.
I was thinking "Roller" setup. your picture kind of tells it all.Roller tip rockers are bullet proof in comparision to stock stamped rockers. They are great for hot H-flat cams.
What you need to do is read up on valve train geometry. Stug girdle would be a waste of money for your setup. What you need is correct length push rods which have clearance and center on the tip of the valve stem throughout it's complete cycle.