It doesn't matter what type of (or who built) the engine. Jasper, Hendrick, or Dodge -- it has a rod knock. From what you say, the knock was caused by low oil pressure. Chances are that the machine work that was done on the engine prior to building was poor. Oil pumps are usually not to blame for spun bearings (or worn bearings) -- which in turn cause rod knocks. Shotty machine work is. Oil pressure in engines IS NOT created by the oil pump. Oil pumps are positive displacement pumps (or they just move oil from one place to another). Oil pressure is created by the resistance within the oiling system. Bearing clearances (measured in the thousands of an inch) are just some of the areas inside of an engine where oil pressure is created. When the machine work that is done to set the bearings in place is off (or done wrong) the bearing will wear out prematurely - thus creating a larger gap between bearing and the crank shaft - thus reducing the oil pressure (because of the less resistance) - thus causing the rod to knock.
All that being said -- if you rebuild the Jasper motor, the crankshaft mains must be align honed, and the crankshaft itself, should be magnifluxed and possiblely rechromed. By the time you get done with all the "proper" machine work, it may be cost effective to just get a new short block and put it in.
Monday, March 29th, 2010 AT 10:28 PM