Rocking back and forth may mean that the lifter has bled off the oil, and you will have movement side to side. That can be normal on higher mileage engines. Check to see if you have any up / down movement in the pushrod. That is the more important thing to check. If so, then you may have a stud pulling out. High lift cams can do that to press in studs. You may also have a loose nut on the rocker arm, too. The nylon locknuts do sometimes wear out. If they've been used several times (like when changing cams), they may have lost their strength, even tho they seem tight. There are studs available now that you can install without having to mill the boss on the head / removing the head. They simply need to be drilled and tapped, then screwed in.

 

i would just tighten down 1/2 turn and add another locking nut on top of the one on there and go from there and see what happens. wes

 

you can check the stud by measureing the hight it sticks out of the head then measure a tight one

when i had that noise and looseness in my 351 W the #3 intake lifter and cam lobe were trash

only way i know to check that is with the motor running and the cover off

if you have a friend with solid lifters they might have a cut out cover so you don't make a mess

check the movement of the rocker in question

does it move like all the rest?

does the valve open as far as the rest?

have fun
chris

 

My first thought was that the nut was loose, but it seems to be on pretty tight. I have not looked at torque specs yet, but when I checked with a regular 3/8" drive wrench, I am not sure if I could even tighten down the nut anymore. There is some up/dowm movement on the pushrod.
I will check it with height of the others when I get home from Church. I am supposing 1/8" or so would make a huge difference.
Since I have changed the cam (this started before the hot cam was removed) I wonder if I could drive the stud back in)

BTW - thanks for any help. (already have some - thanks to everyone)

 

The only way you could drive the stud back in and get it to hold would be to drill thru the boss and the stud, and insert a pin to hold it. Common trick before the advent of screw in studs. Sounds like it is pulling out, and the rocker nut is bottomed out on the threads. Best bet is to remove it, tap the hole and get one of the screw in studs that do not require machining of the head. Hhhhmmmmm -- Unless....you have a reason to pull the heads anyway....bigger valves, ....3 angle valve job....better springs....aluminum heads - yea, that's the ticket !!! LOL Good luck, Tony

 

Thanks Tony,
The PO had put a cam in with close to .500 valve lift (IIRC) and that probably caused the problem. I ran into him after I had the engine running, and I asked about how he picked the cam - he said he just went into the parts store and said "give me the biggest hydraulic cam you have for a 302" and I think that is pretty much what he got.
He was moving, so I got a good deal on the car with the engine out - good enough to chance some of this stuff.

I actually have two rocker arms loose - the other is not as bad, but will probably not get any better, so I will probably replace both studs - I am not a fan of going back to do stuff over.

Thanks again for the help.
Beri

 

Just a quick thought. Check your lifters and make sure you are not wiping out a cam lobe. measure your stud height to the good ones.

 

Good idea - I did have some weird stuff with the old cam - the front cam bearing was worn badly even after only 1k miles or so (almost like the cam was bent. I replaced the lifters and cam bearings with the new cam, but I probably don't have 200 miles on it.

Like they say - if it ain't one thing, it's five others.

Thanks again to everyone.

 

When I got my 'vert that had been sitting for quite a while, it was the same way. The easiest way to check the studs is to lay a straight edge across all of them. They may not be exact, but if one has pulled, you will know it. Also check the pushrod again. Rotate it in your fingers and see if it is bent. Mine was bent and the stud was pulled. I just tapped the stud back in, replaced the pushrod and it has been fine since. You may not get so lucky, but it's worth a try I think.