Originally Posted by Bowtie man
When you are running a solid lifter cam. Do you remove any of the oil valley plugs at the front of the block above the timing chain cover? Just wondering what the thoughts are on this topic across forum.
No, this would result in a pressure leak to the pan with a large, if not complete, loss of pressure in the lubrication system.
There are reams of pages written about shutting off the lifter oil supply when converter a block from hydraulic to solid lifters. Frankly, I think this is an exercise in a fantasy that accomplishes nothing meaningful and with some engines, the Chevy's a case in point, can be downright fatal to the valve train.
Leaving pressure oil in the lifter galleys when running solids only saves for the engine that oil which leaks around the lifter through its bore clearance, not very much in oil the big scheme of things.
Additionally, the Chevy in particular uses oil passing thru the lifter, whether that lifter is a solid or hydraulic, to furnish lubrication to and thru the push rod to the rocker and spring. This oil also serves to cool the spring, which is an extremely important function necessary to avoid loss of tension and/or breakage of the spring. Full up race engine builders that cut off the OEM oil supply from the lifters to the overhead, must, and do, build an external oil supply to the rocker box to replace GM's normal oil routing that has been terminated. If you're building a serious race engine, especially one using a dry sump, this technique of rocker-box oiling has some advantages of being able to put oil exactly where its needed and in proper quantities. For anything less this is an exercise and expense with not enough return as the stock system is quite adequate for anything short of NASCAR long distance races.
So my advice is this:
- First you need to be sure your feeding oil to the upper push rod end, the rocker trunnion, especially if it's the OEM ball and socket type, rollers are tolerant of much less lube, unless theyre Chinese made knock-offs in which case keep 'em really oil wetted, lastly oil to the valve and spring assembly. Oil to the valve and spring assembly lubricates the valve stem and guide, lubricates the ends of the spring where it is riding on the head and the retainer and the oil provides cooling to the spring.
- Second is then either selecting lifters that feed oil to the pushrod for delivery to the rocker box, or if selecting a non-feeding lifter, purchasing or fabricating an externally mounted lubrication system into the rocker boxes to provide for the needs of lubricating and cooling the components contained there-in.