Jim Smart
June 30, 2007

What is Blueprinting?
Blueprinting is engine building with strict discipline and attention to detail. True blueprinting is methodical and challenging. It gets in the way of getting the job done quickly, which is why most don't bother with it.

Think of your V-8 engine as eight individual engines on a common crankshaft. Each cylinder bore has its own personality, making a significant contribution along a crank it shares with seven others. Each is important to power and smooth operation. When blueprinting:

  • Do a detailed inspection of every part.
  • Dress and deburr everything. Anything with a sharp edge needs to be smooth.
  • Mark all bores and inspect crosshatch pattern. Check decks, mains, and saddles for irregularities.
  • Disassemble and inspect the oil pump, checking side clearances and the pressure relief valve for proper operation. Always index the inner and outer rotor during reassembly. Pressure relief-valve piston movement should be smooth and without resistance. Apply Loc-Tite to bolts and use a torque wrench.
  • Blueprint all moving parts (pistons, rings,bearings, rods, crankshaft, flywheel, balancer) before balancing. Blueprinting often involves removing metal, which changes the weight.
  • Inspect each connecting rod for bending and other irregularities, and check each end for proper indexing. Record the inside diameter of both ends. Toss or machine anything out of spec. All edges should be deburred.
  • Make sure crankshaft counterweights are knife-edged for improved crankcase aero-dynamics. Polish rough surfaces smooth. Ground ragged edges and polish them smooth to prevent stress cracking. Polish radiuses and journals. Oil holes are chamfered for improved oil distribution.
  • Check that the crankshaft is snoot-dressed to remove rough edges. Examine Woodruff key for rough edges and dress as necessary. Chase threads.
  • Polish rough edges on pistons to reduce friction and prevent stress cracking. Ring grooves are massaged to improve travel. Skirts are dressed to remove ragged edges.
  • A thermal coating is applied to piston crowns to minimize heat issues.
  • Make sure riston rings are properly end-gapped and dressed to remove rough edges. Each set must be match-fitted.
  • Rod and main bearings should be inspected and deburred, then checked and match-fit to each rod and main saddle. Ditto for journals.
  • Check rear main journal seal grooves for rough edges; clean them for proper seal fit. Check all saddles for imperfections.
  • Dress main bearing cap mating edges with a file to improve fit. Do the same with rods and caps.
  • Massage all oil passages to remove rough edges. Passages are opened at main-bearing saddles for improved oil flow at the bearings.
  • Dynamic balancing is detailed to less than 1 gram difference per reciprocating unit. Consider the crank pulley if the engine is externally balanced.
  • Cam sprocket is dressed for a smooth fit. It should glide onto the camshaft. Dress sprocket teeth; smooth fit and operation mean longer life. Use a one-piece fuel pump eccentric.
  • Taper and dress oil drainback holes.
  • Buy new valves and guides. Valves should glide smoothly through guides. Remember: 0.0010 to 0.0027-inch clearance; max is 0.0045-inch.
  • Dress valvesprings to remove ragged edges.
  • Dress combustion chambers. Ragged edges and rough surfaces create hot spots, which cause detonation. Measure (cc) the chambers to determine volume(compression).
  • Measure (cc) the valve reliefs or piston dome rise(compression).
  • Five-angle or full-radius valve job improves flow and valve cooling.
  • Use nickel-hardened exhaust valve seats on old iron heads.
  • Port-match for improved flow. Don't over-torque intake manifold bolts.