Engine blueprinting has become standard procedure in many performance engine shops. Blueprinting is an absolute necessity to obtain maximum power and to insure the longest possible engine life and reliability.

Blueprinting an engine means hand building an engine with perfectly fit components using maximum recommended clearances, and minimum recommended volumes. These specifications should be determined using the engine manufacturer's tolerances for the engine being built.

All parts must be one hundred percent clean. The block should be boiled out making certain water jackets are perfectly clean. All bolt holes should be re-tapped, cleaned and oiled, as well as their mating bolts. Any surfaces being refinished should have all holes chamfered, and any casting burrs or irregularities should be ground away.

The V type block should be align bored exercising extreme care to maintain perfectly equal deck heights and keeping the crankshaft parallel to the decks. Any variation in these areas will result in irregularities in combustion chamber volume.

After align boring, the cylinders should be bored with the main bearing caps still torqued in place. The cylinders should be finish honed to their proper size using a 220-280 grit stone and taking care to obtain a good cross hatch pattern. After honing the block should be thoroughly cleaned, taking care to remove all honing grit from the bores and also from the lower end of the block. Be sure to oil cylinders after cleaning.

Some engine builders paint the inside crankcase area of the block. This is recommended as a detergent to carbon or sludge buildup, and also seals the pores of the iron preventing oil from washing deposits, left in the pores after cleaning, into the oil. Painting will help insure the absolute cleanliness necessary for top quality performance and engine life.

The crankshaft must have correct angularity of the rod throws as well as be perfectly straight. It should be 100% inspected for cracks and have the journals ground to perfect angular index. Fillet radii should be held to recommended arc as well as having oil holes chamfered and bearing surfaces polished. The oil passages should be cleaned thoroughly with a good brush. Some builders use fully grooved main bearings or groove or cross drill the crankshaft main bearing journals. These procedures are also helpful in insuring longer engine life.

The connecting rods should be carefully checked for imperfections and Magnafluxed. All rods should be reworked so they are EXACTLY the same length from crankshaft centerline to wrist pin centerline. Performance builders recommend allowing from .002-.003 for rod stretch at high speeds. Generally the length of the rods will be controlled by working to the minimum manufacturer's clearance for piston to deck. Any burrs and irregularities should be removed from the rods, and always use new rod bolts and nuts. The rod alignment and side clearance are also critical.

The pistons should be individually and carefully fit to the respective pins. Chamfering any sharp edges on the piston reduces possibility of localized hot spots which cause pre-ignition and/or detonation. Each piston should be carefully matched for clearance with each bore. Too little clearance will result in scuffing and too much clearance reduces the effectiveness of the rings.

The compression rings should each be placed in the bore and straightened with the top of a piston to square the ring in the bore. Gaps can then be checked, with .0035 per inch of bore the minimum allowable gap. Staying as close to minimum as possible is recommended. Also be sure to check ring side clearance in piston groove. The maximum is .006 but .003-.004 is most desirable.

Now that the main reciprocating components are selected and fit, the engine should be balanced. It is recommended the balancing be done with all ring, S, pistons, rods, bearings, crankshaft and also flywheel and crankshaft dampner and pulley. Some engines

(Ford 427 for example) recommend an allowance for oil weight in the crankshaft when balancing. These specs are available from A.E.R.A. or from the manufacturers of balancing equipment. Additional weight is added to the bob weights in these cases to compensate for oil weight.

Balancing will provide insurance for engine durability, and will also help obtain maximum horse-power.

The cylinder head should be disassembled, cleaned and carefully inspected for cracks. If the surface is in questionable condition or the head is warped, it should be resurfaced. If resurfaced all holes and sharp edges should be carefully chamferred and deburred. Bolt and spark plug holes should be retapped and cleaned. The valve guides should then be checked and replaced or repaired as necessary. Remember to also check valve stems and replace those valves not acceptable. This is also the time to machine the valve guides if necessary for the installation of Hastings P.S. seals. The valve job should be done according to recommendations for the engine. Make sure valves and seats are not worn so as to sink the valves too far into head. A valve stem height gauge should be used to keep all valve stem ends the same height above the spring seat. All burrs and irregularities should be polished out of the combustion chamber. After this the chambers should be checked for volume in cubic centimeters. The chambers should be enlarged to the volume of the largest chamber. When all chambers are equalized the desired minimum CC's can then be reached by milling the heads carefully until the correct volume is reached.

In order to check the CC volume of the chamber a Plexiglas plate, light oil, and a chemical burette are needed. With the spark plug and valves installed the plate is placed over the combustion chamber and sealed with a light coat of lubricant. Using the burette it is then a simple matter to measure the amount of liquid needed to fill the combustion chamber.

Valve springs should be checked for tension and installed height, and replaced or shimmed as needed. If the head has individual rocker arms on studs the stud should be threaded or pinned in its boss.

In engine assembly be very sure to follow recommended procedures for bearing and ring installation. Torque main bearing and rod bolts slowly and in progressive steps to the proper tension. Use protectors on the rod bolts to prevent crankshaft scars, and keep rotating the engine as each step in the installation of the crankshaft and pistons is taken. This will enable spotting the exact location of any misfit or mismatched parts.The use of Plastigage here will serve as a double check on clearances.

Many performance engine builders are using support "girdles" for the lower end of the block. These girdles are readily available for most popular engines and are a very important aid in strengthening the engines lower end. The girdle supports the center mains and also serves to stiffen the engine block.

When installing the timing gears and chain the use of a camshaft degree wheel will insure perfect crankshaft to camshaft timing.

Offset keys or cam gear bushings are available to allow accurate adjustment of possible timing discrepancies.

After installing the heads, making sure they are torqued to the proper specifications, the valve train should be completed and checked. In cases where higher lift camshafts have been installed it is possible to have the valve spring bottom out, or the canoe type rocker be interfered with by its mounting stud. Where this happens the spring must be changed, and the rocker arm relieved to provide the necessary clearance.

The complete engine build must be performed as painstakingly and accurately as possible. Always keep in mind that dirt is the greatest enemy of engine life. Perform your engine build under the most antiseptic conditions possible. The blueprinted engine is the utmost in performance and durability possible, and its success is a real testimony to the expertise of the engine builder.

(P22-24)

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