Ever seen this? Rocker arm cutting into stud
11-07-2006, 01:29 PM
#1
Drifting
Thread Starter
Ever seen this? Rocker arm cutting into stud
This is a continuation/detour on my '85 Trans Am with 305 4-bbl Chevy small block.
Loud rapping at higher rpms. Removed driver's side valve cover, #5 exhuast valve rocker a little off-center of valve stem. Removed rocker and ball, some off-center wear inside rocker...but the rocker arm has cut perhaps an eighth of an inch or a little more through the rocker stud, and was working in this groove.
I'm going to try to replace with a screw-in rocker stud, new rocker and ball ($4 at NAPA, $25 at Dealer!), but I was curious if anyone else had ever encountered this type of failure.
I'm guessing high miles on the engine, without any major work previously.
Steve
Loud rapping at higher rpms. Removed driver's side valve cover, #5 exhuast valve rocker a little off-center of valve stem. Removed rocker and ball, some off-center wear inside rocker...but the rocker arm has cut perhaps an eighth of an inch or a little more through the rocker stud, and was working in this groove.
I'm going to try to replace with a screw-in rocker stud, new rocker and ball ($4 at NAPA, $25 at Dealer!), but I was curious if anyone else had ever encountered this type of failure.
I'm guessing high miles on the engine, without any major work previously.
Steve
11-07-2006, 01:35 PM
#2
Instructor
Member Since: May 2004
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Had it happen on a 69 Vette 350/350. Bent the push rod also. Dealer replaced the stud, push rod and rocker arm. Never had a problem after that. Stud was a press fit. Only had 46,000 mi on it at the time...
11-07-2006, 01:40 PM
#3
Race Director
where exactly was the groove cut in the stud? looking down on the stud and using a clock face as a guide with 9:00 facing the front and 12:00 facing the carb/FI where was it cutting the groove?
11-07-2006, 01:54 PM
#4
Drifting
Thread Starter
Originally Posted by bobs77vet
where exactly was the groove cut in the stud? looking down on the stud and using a clock face as a guide with 9:00 facing the front and 12:00 facing the carb/FI where was it cutting the groove?
11-07-2006, 02:18 PM
#5
Race Director
rocker arms do fail perhaps that happened to you
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i switched out the old rocker arms and then i broke a stud...
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[/IMG]i switched out the old rocker arms and then i broke a stud...
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Last edited by bobs77vet; 11-07-2006 at 02:23 PM.
11-07-2006, 02:31 PM
#6
Drifting
Thread Starter
"rocker arms do fail perhaps that happened to you"
I agree, although it looks like the stud was failing as a consequence of wear on the rocker arm.
"i switched out the old rocker arms and then i broke a stud"
This is what I'm seriously afraid of, I'd rather not pull the cylinder head. I bought a "rocker stud puller and tap guide", that rides on the adjacent stud --I'm hoping that the groove won't have weakened the stud to the point that it will break instead of pulling out.
I agree, although it looks like the stud was failing as a consequence of wear on the rocker arm.
"i switched out the old rocker arms and then i broke a stud"
This is what I'm seriously afraid of, I'd rather not pull the cylinder head. I bought a "rocker stud puller and tap guide", that rides on the adjacent stud --I'm hoping that the groove won't have weakened the stud to the point that it will break instead of pulling out.