Rocker stud issue

[djseth]

Hi All,
I have a 1970 TA, Ram Air 3 4-speed car. Nunzi did all the machine work on my motor 10 years ago, but have had it out since. I've had a couple issues with rocker studs in it over the last couple of years and I could use some help. Nunzi installed the screw in rocker studs on my car and a couple of years ago, one of the rockers came loose. Luckily, I shut down and all that happened was my valve cover got dented from the inside, but the push rod was still up top and nothing horrible. My rockers are Crane roller tip. I bought a new pushrod and a new rocker, and installed Poly Locks to put that issue to bed. Fast forward a year and while on a leisurely ride, she started to misfire. Pulled over and found a a broken rocker stud... same valve as the other issue. Easy enough to replace the stud, but cannot have this all the time. What would cause this? How do I solve permanently?

 

[melsg5]

Without knowing the specifics of your engine it is hard to say. If you cam is providing too much lift for the valve springs causing the coils to bind or the valve spring is different from the others or it is incorrectly shimmed the rocker stud may break. Did you correctly set the valve lash when you installed the new push rod and rocker by having that cylinder at TDC and after achieving zero lash turned an additional 1/4 to 1/2 turn assuming you have a hydraulic cam? Did you try to contact Nunzi?

 

[djseth]

Hi Mels,

Thanks so much for your reply, really appreciate it. I bought the cam, lifters, springs and all from Crower. I talked to Dave Crower on the phone directly and told him everything I have and he designed the whole thing. I was actually pretty flattered to talk with him directly and over email! Last night as I was trying to sleep, TRYING, this actually floated all through my head and I thought of two things. One was to contact Mr Crower and the other was I wondered if it was a lift thing and my Crane roller tip rockers were not able to move that well with the hydraulic roller cam and maybe I need to go full roller????

 

[melsg5]

who assembled the engine?
did they check for coil bind?
again how did you go about adjusting the valve when you replaced the parts?
did you check the rocker arm slot to make sure at full lift the stud isn't binding against the slot in the rocker arm?
I'm also a little puzzled as to which roller tip rockers you are using. You stated you got a complete kit from Crower and then state the rockers are from Crane. The only company I could find that has them is Competition Cams