- Check the groove in the camshaft bearing surface for depth. It should be .035 deep. This can be corrected on an engine lathe.
- Grooving the engine block cam bearing bore is one way to insure oil flow up to the rocker arm shafts. An alternate method is to use a camshaft bearing that has a groove machined in the outside diameter of the bearing shell to permit 360 degree oil flow to the oil flow machined galley in the cylinder head. The purpose of adding a groove in the O.D. of the bearing or adding a groove in the engine block cam bearing bore is to cure bearing index hole mis-alignment in installation or turning in use. Verne Schumann is the source for a set of Dura-Bond F9A camshaft bearings with the 360 degree groove in the center cam bearing.
Vern's contact information is:
Schumann's Sales & Service, Inc.
P.O. Box 128
Blue Grass, IA 52726
[phone 563-381-246 fax 563-381-2409]
- The idea of pressurizing the rocker arm shafts is advocated by some and avoided by others. The debate for me is influenced by the purpose of the overflow tubes. The driver's side overflow tube is intended to supply oil to the distributor gear where it meshes with the camshaft. The overflow tube on the passenger side is intended to provide lubrication to the timing gear set. Personally, I advocate a compromise of crimping the overflow tubes to restrict oil flow out of the rocker arm shafts for engines I rebuild for street and highway use. For high rpm and racing applications or for engines using aluminum rocker arms, I see benefit to pressurizing the rocker arms and drilling a hole in the block face to tap the oil flow to the front camshaft bearing to provide needed oil to the timing set.
Hope this helps!
a.k.a. Charlie Brown
near Syracuse, New York