Hello Dan et. al.:
I asked the question due to the reason that I aint very smart and I have to learn from others. Sometimes I get good information and sometimes I am not so fortunate. I have had engines reworked by "experts" where the results ranged from less than useable. same as stock prior to reworking, to an engine that was better than stock. Was the overall effort worth the extra time and cost?
I have noticed that some engines are a loose fit, some a slight press fit and some a shrink fit. I am assuming the designer of the engine gave a great deal of thought, well a bit, concerning this matter. I have been taught the different rates of expansion/contraction of various materials but the question that keeps me awake at night is, what was the designer's considerations when the engine was designed. Of course the more precise the dimensions, the higher the cost of the engine. Close fits cost money! Often the laws of dimensioning returns raises its ugly head and dictates what the designer wises to accomplish with his design at what price point. Expensive engine are more satisfying to use than less expensive engines.
Getting back on topic, I have learned that it is best to duplicate the fits that the engine was designed to have from the factory. I think that they know what was required to be best with their product.
Best to all,
Frank McCune