LOSS OF OIL TO ROCKER ARMS
A common problem with the Y-Block engine is the loss of oil to the rocker assembles. Sometimes this occurs after many miles of use, sometimes a freshly rebuilt engine has little oil to the rockers. If your engine has many miles on it
there are two likely causes. One is sludge blocking the oil passage through the block and up to the heads. You can remove the rocker assemblies and drill out the sludge in the head with a 1/4" drill bit. This will not clear the passage all the way to the cam bearing since the passage makes a jog at the head gasket surface. The head must be removed
to clean the entire passage. The other common cause is a combination of worn cam bearings and a cam with a shallow oil groove. If the groove in the cam is not cut deep enough it will be blocked by the ridge that occurs as the cam bearing wears. The cam can be removed and the groove cut deeper which should restore oil to the rockers but it is best to also replace the cam bearings.
On newly rebuilt engines the problem is generally caused by a shallow groove in the camshaft. Many new cams have a very shallow groove. On rare occasions the cam bearings are installed incorrectly or the cam bearing may rotate in the block due to improper fit.
When assembling and installing the rockerarms it is imperative that the shaft be installed with the 1/4" oil holes lined up with the holes in the rocker stands. The hole on top of the shaft must be at the right hand side of the assembly.