What would cause my rocker arms to get loose over and over. I have tightened them every way possible but it keeps happening.

Engine is a:
350 Chevrolet street engine with a mild cam.

cam is wearing

Or cheap rocker nuts happened to buddy bought a remake engine for his boat rockers kept loosing up stock type rocker lock nuts but had no resistance when I finally got a call to look at it brought over thirty year old used ones haven’t loosened up in two years

not much info for anything other than a wag

What rockers? Stud mount or shaft mount?
Is it all of them or just a couple that are loosening?

Is the performance the same after you make adjustments? Or is it continually falling off?

could even be a geometry issue working the nuts loose

More info please....

Pressed in studs?

Poly locks?

Seems to me we have an obvious Messiah in waiting, that has all the answers, if only he would appear. I give you Michael Beard!

It’s all stock Chevrolet parts

It seems to be a problem with all the rockers. It’s not just the same one over and over.

quote:

Originally posted by fastracer482:
It’s all stock Chevrolet parts

So, aSSuming it's hydraulic flat tappet, it's either wearing the cam lobes off, the rocker nuts are backing off, or the studs are pulling out of the head.
Larger than stock lift and spring pressure can contribute to that.
Could be a valve smacking a piston every once in a while?
Teenage driver?

Place a straight edge on the tops of the studs to see if any are taller.

Put a set of poly locks on it.

quote:

So, aSSuming it's hydraulic flat tappet, it's either wearing the cam lobes off, the rocker nuts are backing off, or the studs are pulling out of the head.
Larger than stock lift and spring pressure can contribute to that.
Could be a valve smacking a piston every once in a while?
Teenage driver?

Place a straight edge on the tops of the studs to see if any are taller.

Put a set of poly locks on it.

"Despite the high cost of living, it remains popular."
Dave Cook
N375

x2

quote:

Originally posted by Canted Valve:
Seems to me we have an obvious Messiah in waiting, that has all the answers, if only he would appear. I give you Michael Beard!

What does making a dig at Michael have that have to do with this tech question?

Absolutely no dig! Just an attempt at levity with "loose rocker" word association. Please excuse if I was misunderstood.

quote:

Originally posted by rusty:

quote:

So, aSSuming it's hydraulic flat tappet, it's either wearing the cam lobes off, the rocker nuts are backing off, or the studs are pulling out of the head.
Larger than stock lift and spring pressure can contribute to that.
Could be a valve smacking a piston every once in a while?
Teenage driver?

Place a straight edge on the tops of the studs to see if any are taller.

Put a set of poly locks on it.

"Despite the high cost of living, it remains popular."
Dave Cook
N375

x2

X3.
As Dave suggested, if you have pressed in rocker studs, do a quick check with a straight edge on the studs, to make sure some aren't pulling out. If you have a dial indicator, you can confirm your valve lift is correct and consistent, to rule out worn cam lobes. And if it is just the nuts backing off, try a fresh set of them. They should be the "prevailing torque" style of nuts, that feel tight all the way down as you put them on the studs. Same thing as you loosen and remove the existing ones, you should not be able to turn them by hand at any point until they are off the studs. If the studs are old and have had nuts run up and down on them many times, the threads on those can wear out too. So if you get new nuts, and they thread on easily by hand, you need new studs too.
One other possible issue - check to make sure the center part of the valve spring retainers is not contacting the guide seals at full lift. That can also lead to bent pushrods, etc.

if I remember right those nuts were subject to wear and would back off. A new set may solve the Delema