1954 Corvette: Service Bulletin: Engine Valve Noise

Subject:   Engine Valve Noise
Model and Year:   1954 Powerglide Engines
Source:  Chevrolet Technical Service Bulletin
Bulletin No:   DR - 168
Section:   VI
Date:    April 8, 1954

TO:  ALL CHEVROLET DEALERS

In cases where valve squawk exists on 1954 Powerglide Engines, the rocker arms may be drilled as outlined below to provide additional lubrication between the rocker arm and valve stem also a slight increase at the valve stem and guide.

Other fixes such as grooving the arms, removing the seals, reaming the valve stem guides, etc. must not be performed as these may cause other difficulties including excessive oil consumption.

Valve noise varies somewhat with different driving speeds.  During extended periods of idling a valve squawk may occur which cannot be eliminated without the possibility of excessive oil consumption and eventual sticking of the valves.

PROCEDURE

Inlet

Identification - reinforcing rib on each side of arm.

Drill an additional 7/64" hole in the rib 5/16" toward the rocker arm pad from the original oil hole.

This hole should be drilled directly into the oil groove.

Exhaust

Drill an additional 7/64" hole in the wide side of the rocker arm bearing boss, measuring  13/16" in a straight line toward the pad from the existing oil hole and 5/16" in from the edge on the wide side of the bearing boss.

Caution:   This hole should be drilled straight in but must not break into the oil groove in the rocker arm bearing.

Carefully remove all burrs on the inside so as not to effect the bearing area.

Do not close up the original oil holes in the rocker arms.

Torque rocker arm shaft bolts 25 to 30 ft./lbs.

Flat rate time on the above operation is 2.2 hours.