I wanted to share an update on my April '75 2F. Since I replaced the valve stem seals and got the exhaust totally clear of oil burn, I decided to investigate the click in my valves by taking apart a couple spare rocker arm assembly. I had two big discoveries.
below is from a collection of free FJ60 parts. You can see how there is a dimple where the head studs and bolts locate the position of the rocker arm shaft, just left of the compression spring. This is there to clock-in the oiler holes relative to the bushing grooves in the rocker arms. If you try to run the head studs and screws thru the rocker arm supports with the rocker arm in the wrong place, you will create a dent because you are defeating the dimple, like a previous owner did to this one. You can shine a flashlight thru the valve-side holes in the supports, and it will be clear what I am talking about. Don't force it the installation if it won't go, get the parts in line.
So, the audible click on my '75 rocker arm is partly due to worn bushings. The arm gets clicked from the action of the valves and push rods. So, I can't do much about the wear, however, it went away when I dialed the valve lash in a bit.
Actually, I dialed the valve lash in somewhat beyond factory specs! I did this because when you look at the rocker arms on all of my 2F assemblies, they are worn at the valve side (shiny part of the arm in the image below). So when you run a feeler gauge in between the arm and the valve stem, it is measuring across a step from wear. So, I figured the step was, on average, about .003 inches. So I reduced the lash by that much. I picked up an 1in of Hg in vac as a result (my intakes still have oil baked on their tops when the manifold is removed, so that is a contributing hindrance, but it is still better than ever). Actually, I saw hot rodders on YouTube do a really tight valve lash to get upper rpm dyno horsepower, because it is only helping to fill on the intake stroke, and dump exhaust on the exhaust stroke (as long as there is some lash at all operating temps to maintain compression). They also replaced their new hydraulic lifters for older-style technology, like on our F and 2Fs as well for more positive response to cam lift.
below is from a collection of free FJ60 parts. You can see how there is a dimple where the head studs and bolts locate the position of the rocker arm shaft, just left of the compression spring. This is there to clock-in the oiler holes relative to the bushing grooves in the rocker arms. If you try to run the head studs and screws thru the rocker arm supports with the rocker arm in the wrong place, you will create a dent because you are defeating the dimple, like a previous owner did to this one. You can shine a flashlight thru the valve-side holes in the supports, and it will be clear what I am talking about. Don't force it the installation if it won't go, get the parts in line.
So, the audible click on my '75 rocker arm is partly due to worn bushings. The arm gets clicked from the action of the valves and push rods. So, I can't do much about the wear, however, it went away when I dialed the valve lash in a bit.
Actually, I dialed the valve lash in somewhat beyond factory specs! I did this because when you look at the rocker arms on all of my 2F assemblies, they are worn at the valve side (shiny part of the arm in the image below). So when you run a feeler gauge in between the arm and the valve stem, it is measuring across a step from wear. So, I figured the step was, on average, about .003 inches. So I reduced the lash by that much. I picked up an 1in of Hg in vac as a result (my intakes still have oil baked on their tops when the manifold is removed, so that is a contributing hindrance, but it is still better than ever). Actually, I saw hot rodders on YouTube do a really tight valve lash to get upper rpm dyno horsepower, because it is only helping to fill on the intake stroke, and dump exhaust on the exhaust stroke (as long as there is some lash at all operating temps to maintain compression). They also replaced their new hydraulic lifters for older-style technology, like on our F and 2Fs as well for more positive response to cam lift.
