Langdon's Stovebolt – Specializing in Inline Six Cylinder ...



235 / 261 VALVE TRAIN UPGRADESWhen rebuilding your 235 or 261 engine, the valve train components warrant close inspection for defects and wear. Some areas are as follows:Rocker Shaft Stands: Recent observation and calls from rebuilders have pointed out common cracking areas at the top bolt hole. These should obviously be replaced.Connecting the front three and the rear three stands with a “Tie Bar” will stabilize any movement aggravated by heavy springs and higher engine speeds.Pallet Wear: The contact of the rocker arm and the top of the valve stem is almost always worn in varying degrees.This causes loose valve lash compared to the perceived lash generated by the traditional feeler gauge method which “bridges” the wear. Regrinding the pallet is the fix. Reduced pallet wear can be achieved by using Chevy V8 valve lash caps to give 50% more contact areas.Valve lash adjustment screws can be upgraded to hex head, interference thread type from the GMC V6 305 / 351 / 379 / 401 / 478 truck engines. This requires difficult re-tapping of the rocker arms.The rocker shaft connecter or “Oiler” has evolved from an “Overflow” design to a direct “Full Pressure” design fed by an 11/32” orifice in the block (1959) This increase in oil flow to the overhead, will reduce wear but could impact oil consumption down the valve stems. Be careful NOT to eliminate lubrication to the inlet valves because they are NOT chrome plated and require some oil. ................
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