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BBC Valve train questions: Rocker stud breakage

943 Views 22 Replies 11 Participants Last post by  BillyGman
Has anyone here had an ARP BRAND 7/16" rocker stud break on their BBC engine?? And if so, please explain if you were running STUD GIRDLES or not, and if you ever narrowed it down to the exact cause for the stud failure, if it wasn't merely due to running a lot of valve lift and lots of open valve spring pressure. I also would be curious to hear if you think the failure was RPM related. I'm just trying to learn as much as I can from you guys before making any more decisions for my valve train parts choices than I already have. Thanks in advance.
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Same here (SBC) except the cheap studs that came with my World heads.
202 duration popping up to .462 lift. Not too high lift but it pops up quickly.

I also broke the balls off of spot welded push rods so only one piece rods for me from then on.

I learned not to play with toys an a valve train anymore.

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Not applicable really, but I had to heli-coil all the exhaust bosses and used extra long ( mounting boss side) ARP rocker studs on GM 074 heads. No issue with future massive abuse, but only 375 /140 springs and 7500 rpms.
 

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Most of the times I ever seen a rocker stud break was because the rocker nut did not engage of the threads enough, but I do know that ARP has had some fasteners that have been over hardened at times causing breakage. I have never had one fail though.
 

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Never broke a rocker stud. I did always try to make sure that the stud was long enough so that the set screw sat at least flush if not a little above on the poly locks. Anything over .700 lift had stuf girdles m.
 

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Discussion Starter · #10 ·
What cylinder head are you using that caused a ARP rocker stud to break? And was the breakage with the stud girdle?
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I'm not sure who your question was for since you didn't include a quote from anyone, nor address anyone by their name, nor by their username. So if I'm to guess that your question is for me, then I can only say that there seems to be some confusion here. Because where did I say that I broke an ARP rocker stud??? Anyway, thank you for chiming in.
 

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I'm not sure who your question was for since you didn't include a quote from anyone, nor address anyone by their name, nor by their username. So if I'm to guess that your question is for me, then I can only say that there seems to be some confusion here. Because where did I say that I broke an ARP rocker stud??? Anyway, thank you for chiming in.
Has anyone here had an ARP BRAND 7/16" rocker stud break on their BBC engine?? And if so, please explain if you were running STUD GIRDLES or not, and if you ever narrowed it down to the exact cause for the stud failure, if it wasn't merely due to running a lot of valve lift and lots of open valve spring pressure. I also would be curious to hear if you think the failure was RPM related. I'm just trying to learn as much as I can from you guys before making any more decisions for my valve train parts choices than I already have. Thanks in advance.

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Discussion Starter · #13 ·
I was merely asking if anyone here ever had an ARP rocker stud break. I never said that I had one break. I remember someone here, (don't remember who it was) chiming in on a thread by claiming that they had a stud break, but they didn't mention if it was an ARP brand or not, nor did they mention if a stud girdle was being used.

Some guys will swear that a shaft rocker set-up should be employed with anything above .700" lift at the valve, while there are plenty of guys who have used valve lifts well into the .800" lift neighborhood with stud mounted rockers, along with a girdle. However, it's rare that anyone ever mentions whether or not they break rocker studs, or have avoided it. That is precisely the reason for my inquiry since I plan to use a new camshaft I bought with .817" lift at the valve with ARP studs, stainless steel rockers, and stud girdles. I'd rather avoid spending $2 to $3K on shaft rockers if I can. But lately I've been wondering if that's a corner that I really shouldn't be cutting.
 

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I think one other thing to look at here is the type of shaft rockers used. Even when I did swap to a shaft rocker it was only the Jesel Sportsman rocker which really is not that robust compared to other shaft rocker designs. You are still relying on the rocker stud hole threads to hold it all in place. The flimsy tie bar offers no support from an adjacent rocker stand as the pro series does. That is one of the benefits of a shaft rocker is tying the parts to other rockers for strength
 

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Discussion Starter · #15 ·
I think one other thing to look at here is the type of shaft rockers used. Even when I did swap to a shaft rocker it was only the Jesel Sportsman rocker which really is not that robust compared to other shaft rocker designs. You are still relying on the rocker stud hole threads to hold it all in place. The flimsy tie bar offers no support from an adjacent rocker stand as the pro series does. That is one of the benefits of a shaft rocker is tying the parts to other rockers for strength
Ray, that^^^ is exactly what I've been thinking about. It seems to me that some shaft rocker set-ups might not offer much more stability than stud mounted rocker arms with a stud girdle. IDK if all stud girdles are created equal though. I have Crane gold girdles, ( at least they're gold in color anyway) but IDK if they're better or worse than any other girdle sets. I see that there's a pretty big price difference between various types of girdles. It seems that the "clamp-on" style tends to more expensive than the "solid" type. But again, IDK which type is better.....

Compare (summitracing.com)

A buddy of mine brought up what sounds to me like a good point.... one advantage of a shaft set-up is that the stress is placed lower and closer to the heads as compared to having rocker studs, which uses the stud itself as a leverage point kind of the same way a longer toque wrench makes it easier for the user to place more torque on any given fastener.
 

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Discussion Starter · #16 · (Edited)
I'm tempted to go with these since I have Brodix heads, and these are also made by Brodix, and I noticed these comments in one of the reviews: "If you have a cam bigger than .730 lift you need these instead of the one piece stud girdle. Fixed my issues instantly."


Brodix Cylinder Heads BR 1230 Brodix Cylinder Heads Stud Girdles | Summit Racing


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I don't understand the advantage of the snap rings on the above^^^ set-up though. I wonder if that would prove to be more of a hassle for valve lash adjustments
 

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Discussion Starter · #17 · (Edited)
I would think that girdles like these PRW brand shown below which clamp the intake stud together with the exhaust studs, would place stress on them since the BBC intake and exhaust studs have two different angles, no?

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Wouldn't girdles like these Brodix ones be better for BBC heads due to the opposing int and exhaust valve and stud angles?????....
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Discussion Starter · #18 · (Edited)
Here's a pretty expensive girdle set-up from Scorpion, (maybe the high price is only due to the name???). But here again, I can't help but wonder if this clamping type of girdle places a pre-loaded stress on the rocker studs with BBC heads. What do you guys think? Maybe I'm all wrong about that since I seem to remember reading the instructions for set like this, and it said that the torque used on the clamping bolts was only 15 ft/lbs.....
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