223 oil return line question

[p38fighter]

My oil return line has a 1/16 hole punched in it just past the apex of the elbow above the rocker arm. It looks to me like somebody's attempt to relieve a clogged line. Does anyone else have this hole?

 

[flatford6]

It is on all of them. It is to prevent pressure building up in the hollow rocker arm shaft. Pressure would cause more oil to be sprayed on the valve stems from where it could run in excessive amounts into the ports and combustion chamber. Some misguided people with gunked up rocker arm assemblies would pinch off the line up flow of the hole in it to increase oiling to the rocker arms and shaft. Better to get the rocker arm assembly cleaned up.

 

[p38fighter]

so the line itself is insufficient for that task? I had a shop duplicate the line without the hole - mine was broken off at the head of the rocker support tower -