1971 small block rocker arm hardware question.

[Rick Church]

I noticed a little rocker arm tap after the cruise two weekends ago. Tonight I drove the Vette out to my dad's place. The Vette developed a heck of a valve rocker arm tap by the time I got there (12 miles). We pulled the passenger side valve cover (after using the stethascope) and sure enough, the most forward rocker arm retainig nut was loose. I tightened it until the tap went away, backed off to hear the tap, then tightened it again until quiet, and then went another 1/2 turn, put the valve cover back on, and drove home. About six miles into the 12 mile trip home, the tap was back. I drove (nursed) it slowly home and soon the tap was as bad as it was when I had arrived at my dad's house earlier. I called the old man and he told me the rocker arm bolt was worn and "further more," all the rocker arm retaining nuts should have been replaced when I did the cam/lifter upgrade two months ago! He said there was no way to know how many times they had been removed and installed in the last 103,000 miles! Soooo, I have a tapping rocker arm and a dad willing to help with plenty of advice. My question is, is dad right about the hardware. Obviously, the nut loosened up again or I didn't get it tight enough. Chime in brothers! Thanks as usual!!
Rick in Tennessee

[john38706]

Re: 1971 small block rocker arm hardware question.

the nut should be hard to turn. if not replace them all. also do you have screw in studs or are they stock press in? the studs can start to pull out and cause this problem. see if the studs all look the same height. do you have a miss at all? a cam lobe going away will also do this.

[Pat Bush]

Re: 1971 small block rocker arm hardware question.

Rick -

I would agree with John's post. Factory studs were pressed in on small blocks. Some folks drilled and pinned the studs in place. Others removed them altogether and had a machine shop pull the press-in and replace with screw in studs. If you don't have a miss, I would lean on the stud or the nuts. Check the studs with a straight-edge across the top. If the tapping one is higher than the rest, the stud is pulling out of the head and will need to be replaced. If that checks out OK, replace the nuts with new ones.

Regards -

Pat

[Rick Church]

Re: 1971 small block rocker arm hardware question.

Gents,
We put in a new lifter set and a Comp Cam 270 three months ago so I believe they are okay or should be. We did not replace the rocker arms or nuts. When the tapping started the engine did produce a noticible "mis" especially during acceleration. Looks like the nut may be loose. When I tightened the nut it had hardly any resistance until I put the additional 1/2 turn. Even then the resistance was minimal. I didn't check to see if the stud was loose. Does the "mis" indicate a loose nut problem more than a loose stud? Thanks for all the help!

[Pat Bush]

Re: 1971 small block rocker arm hardware question.

Rick -

Sounds like a nut to me. Check the height of your studs as posted previously. The nut is a quick fix and cheap. I would try that first.

Regards -

Pat