What are the ideal clearances ( rod, piston, ring end gap etc) in a clone engine and what are the min and max values seasoned engine builders feel comfortable with using? This is for an AKRA rules based engine.
Rod to crank: .002 to .0035, I shoot for .0025. Piston to bore: .002 to .006, .003 to .004 is typical. End gap: Ring makers suggest .004 per inch of bore. 3 inch bore would be .012. Most go much tighter. I would not go less than .004 total but its been done. Piston to head: I like .030 typically on engines but these stock clones will tolerate much less (like .015) IF you keep fresh rods in them and the side cover good and snug and dont over rev. Piston to valve: .050 but you can keep it much tighter if you dont over rev and keep good springs in it. keep in mind, I am a consevative guy who likes them to last. Too tight sometimes means too broke. Good luck.