This may be a stupid question, but since I was 12 years old, I have been reading car magazines and such and have always heard about engines being "balanced and blueprinted." Now the balance part is straight forward to me and I know the advantages, but what does it mean by blueprinting? What is it, and what is the advantage?

 

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.

 

,,,,also not a stupid question,,, if you don't know ask, can't have folk's walking around not knowing thing's

 

When I had a motor balanced and blue printed there was a little more to it than just balancing-oil holes were also addressed and all rods were measured for identical length etc. I also ended up with a mass of paper work showing weights of each piston, rods, deck heights, etc. for future reference.

 

blueprinting gives you a massive amount of documentation.

Balancing is a benefit for a high revving motor.

 

Maybe I should have been more thorough, how about this:

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.

 

Blueprinting.
The engine is built to the original factory specs. The engine is "blueprinted" A blue print is a blue piece of paper with all the factory specs on it. The port openings on the heads will be opened up to the blue print specs, that means porting the exhaust ports and the intake ports.

Same goes for the rest of the engine.
Production engines can vary quite a bit, theres mold shifts, material differences, mold flashing build ups, etc.

Blue printing addresses all of these issues.

Its a term used by old school engine buliders as there are no more "blue prints" that is they are no longer blue.
CAD and CAM took care of that.

In short its an engine thats built the way it was designed.
Not possible in a production engine. Too costly.

 

You're not the only one who didn't know.

 

In short, balancing and blueprinting do not add power, they add tons of long term durability.

you pay for that precision.

 

They do add power. Theres no other reason to do it.

 

Hey Ravenlunatic....... The Browns are going to kick some road kill this Sunday

 

 

To all who replied - a thousand thankyou's. I am now enlightened!

 

Don't exactly agree with this. You blueprint to get the power to live a long life. In building one right you get more power. Kinda chicken and egg thing. Good engine guys consider thr terms inseparable.
BTW excellent write-up rave. Very well said.

 

Lunatic and Red, very well said. Mine was just simple (like me) course I paid to have mine done. As far as adding power-think of it this way-perfectly (as possible) balance and clearance=less friction, which does increase power. Ever notice how even a stock motor once broken in seems to have more power?

 

The motor I had done for my '67 was balanced and blueprinted. Have docs on all block mods, every clearance spec, PN, you name it. Motor was mocked up 2 or 3 times before the shortblock was even assembled, to double check all machine work, and quality/ fit of parts. Its very time consuming, and can be expensive if done right, but this is the difference between a cheap crate motor, and one that just runs harder and LASTS. This is one reason why the LIngenfelter boys get so much for their motors. Anyone selling a Balanced and Blueprinted motor should have all of this information.

 

 

ravenlunatic: I'm printing your post and keeping it! Awesome information...

...freakin' Shell answer man...

 

Hows that crow tasting teen angel???

 

Correct as can be...right up until the penultimate sentence.
All prodution engines are built to factory specs. Those specs include tolerances. Old skool, 'blueprinting" meant building an engine to the exact specs, with no tolerance allowed. For instance, if the factory (blueprint) spec was " .625" +/- .003" ", then the builder of a blueprinted engine made sure the dimension WAS .625"....not .627 or .622" which a production engine could have and still be acceptable. That way there was no build-up of tolerances to throw the power output off between cylinders.
If you measure a production engine's compression in each cylinder, they won't all be equal; a 10:1 engine may have a cylinder with 9.85:1 and another cylinder with 10.2:1, with the others being in between. An engine with perfect (impossible, of course) dimensions..."blueprinted", in other words...will be the most durable. It won't be the most powerful, necessarily. For instance, if all the cylinders on that hypothetical 10:1 engine came out at 10.25:1, then it would have more power, but not be blueprinted (even though it would be in spec...specs having tolerances).
Is all this confusing enough? If not, consider this; do you want a blueprinted engine if that means it is perfectly STOCK? I.e. add a cam kit and it isn't really blueprinted any more(since the cam and spring specs do not meet the factory requirements),even if all the other critical dimensions are dead-on. Just something to think about.
Larry