Broken Stud
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Broken Stud
Anyone ever have a rocker arm stub break? Mine are 3/8" from Comp Cams and I had one break the other day. They said that they have never had any problems with this before, but then again what would you expect them to say. Thankful it only damaged the rocker arm
Race Director
Joined: Aug 2000
Posts: 11,506
Likes: 4
From: Vancouver,Wa.
Re: Broken Stud (cshuman)
How much spring pressure are you running? Any sign of the push rod bent on that rocker? Any piston to valve issue?
[Modified by Corvette0096, 8:08 AM 11/27/2003]
[Modified by Corvette0096, 8:08 AM 11/27/2003]
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Broken Stud (cshuman)
I've had them break on BB Chevy's before, and it was always due to an interference problem. He**, I've even seen sections of the cylinder head torn off right at the stud area on BBs.
There are several different possible causes:
Using stock type "ball and sled" rockers with the short slots causes the rocker slot of eat into the stud causing the stud to eventualy break. This happens when running high lift camshafts.
Valve spring(s) stacking solid (coil bind);
Pushrod binding
Incorrect pushrod length or
Factory defect in stud itself.
Most often it's a valve train geometry problem.
Pull the other rockers and check those studs for signs of interference. Check the rockers too, to see if there is any sign of interference, like hitting the underside of the valve cover, etc.
Jake
There are several different possible causes:
Using stock type "ball and sled" rockers with the short slots causes the rocker slot of eat into the stud causing the stud to eventualy break. This happens when running high lift camshafts.
Valve spring(s) stacking solid (coil bind);
Pushrod binding
Incorrect pushrod length or
Factory defect in stud itself.
Most often it's a valve train geometry problem.
Pull the other rockers and check those studs for signs of interference. Check the rockers too, to see if there is any sign of interference, like hitting the underside of the valve cover, etc.
Jake
Instructor
Joined: Aug 2003
Posts: 163
Likes: 0
From: Glendale Az
Re: Broken Stud (cshuman)
Fortuniately when a rocker arm stud breaks the valve is forced closed by the spring. I have replaced many a rocker stud on both BBC and SBCs. If you are going to start running any lift or spring pressure required for high rpms, you will need to go to a better stud. If you think you have gone the most with 3/8s studs, then upgrade to 7/16. Stamped steel rockers will grove the side of the stud causing weak spots. Whatever the cause, if one broke chances are the rest are not far behind. :chevy
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Re: Broken Stud (69vetteracer)
These are comp cams studs. They said they should do the job. When I rebuilt the engine all the clearances were checked by my machinist. They installed one of the heads and checked it all. The pushrod is fine, it only damaged the roller rocker. I was driving slow, went around a corner, and when the transmission downshifted and the engine speed went up, thats when it happened. I'm hopeing that it was just a bad stud.
