Page 1 of 1

66 F100, 77 300, Replaced all lifters, now bad rocker stud

Posted: February 21, 2014, 1:06 pm
by jfm
I had another post on the subject here:
viewtopic.php?f=1&t=31847
but it kind of petered out. I think folks figured it was pretty much solved, and if anyone more experienced was doing the work, it probably would be.

Anyway, I just replaced a bent pushrod and rocker arm on by 66 slick with a 77 300 engine. The rocker stud has grooves where the rocker was flopping around, and I'm afraid it will cause the new rocker to bind again and put me right back where I started. So I'm thinking I should replace the stud, if at all possible. It is a pressed-in stud, and it is in there good and tight. I don't think it will be a problem to remove, but what about the new one? Can I put a new pressed-in stud in the same hole, and how is that best done?

Also, I replaced the lifter on the affected valve and decided to go ahead and replace them all while in there. My preference is to adjust the rocker arms while running via the procedure in the other thread, since I understand that. The problem is where to start? How do I know how much to tighten the rockers initially so the engine will run okay while I do the adjustment?

Sorry for all of the questions. I'm a good tinkerer but not much of a mechanic, I'm afraid. Still, I like to do stuff myself if I can. Needless to say, all help and suggestions appreciated.

Re: 66 F100, 77 300, Replaced all lifters, now bad rocker st

Posted: February 21, 2014, 1:27 pm
by William-in-St George
I think you have solved the problem by replacing the bent push rod and damaged rocker. Installing new lifters was a good move. Adjusting the valve lash cold and following that with a warm running adjustment should be the end of it. I would not worry about some scratching on the stud. Check to be sure it is not bent and that the threads are not damaged and have at it. IMHO.

Re: 66 F100, 77 300, Replaced all lifters, now bad rocker st

Posted: February 21, 2014, 3:25 pm
by jfm
William-in-St George wrote:I think you have solved the problem by replacing the bent push rod and damaged rocker. Installing new lifters was a good move. Adjusting the valve lash cold and following that with a warm running adjustment should be the end of it. I would not worry about some scratching on the stud. Check to be sure it is not bent and that the threads are not damaged and have at it. IMHO.
Thanks, but how tight to start? We didn't note how far down the nuts were to begin with. Short-sighted, I know, but that's where we are.

Re: 66 F100, 77 300, Replaced all lifters, now bad rocker st

Posted: February 21, 2014, 3:40 pm
by jfm
Looking back, I see that I wasn't clear about the rocker stud damage, and the photo doesn't clearly show the extent. This is not just a bad scratch; it consists of a deep groove on each side, maybe 1/8" wide by nearly the same depth. That's why I was worried. Still, it may do okay, I suppose. I would, however, be more comfortable if it were replaced, but I do not want to chance making the problem even worse.

Re: 66 F100, 77 300, Replaced all lifters, now bad rocker st

Posted: February 22, 2014, 2:19 pm
by William-in-St George
OK. As for the starting point look at one of your original pictures. I still think you will be OKAY with the damage on the stud. Have you checked the lobe on the damaged rocker and compared that with a couple others?

Re: 66 F100, 77 300, Replaced all lifters, now bad rocker st

Posted: February 22, 2014, 5:41 pm
by Toyz
If in fact the damage is nearly an 1/8" deep on each side; then yeah, it is weakened. With the components replaced, it is probably no more likely to rub again than any other rocker. If it is going to worry you, talk to a good automotive machinist about your options, or pull the head and have it professionally repaired. I'm not knocking your abilities, but replacing the stud is best left to experienced parties. From your pictures, I would not be concerned about it; however if a stud of that size has actually lost that much of it's diameter, it's damaged.If you drive long distances, it may be better to repair it for peace of mind.
Paul

Re: 66 F100, 77 300, Replaced all lifters, now bad rocker st

Posted: February 24, 2014, 2:32 pm
by Blackwaterforge
Threaded studs are available.