Hi All,
I have been doing a little bit a talking to people regarding an engine rebuild as mine is on the way out. Several people have really stressed getting the engine blueprinted. What does this entail and how much (even ballpark figures) does it cost.

Does it just means balancing the engine (as per search results <------------)

Thanks.

blue printing aqnd reconditioning are 2 seperate things.

blueprinting is a fantastic thing on older engines. each individual piston is measured and it's corresponding bore machined to suit that piston. then the conrod is machined to suit that piston, and the crank journal machined to suit that conrod etc etc. then they move onto bore number 2... it really is a good thing, except on newer engines it isn't really necessary (unles you drive a hyundai or a daewoo...!) as the people at toyota and honda do this already. for example my 1UZFE has indidually weighted and measured pistons and a forged crankshaft. not a lot to improve on there at all really...

reconditioning is just boring the engine out +1 or +2 sizes, and ordering pistons to match, machining the conrods and or crank +1 or +2 and then just putting it together. some clearances will be more, some will be less because no two castings are ever the same.

essentially, a blueprinted engine will be balanced better and last longer because of it, possibly maybe even produce more power. generally only needed in competition engines that need that extra reliability edge.

probably an overkill on a street engine, but if you plan on racing it a fair bit then i would recommend it.

all the extra over cost of blueprinting is in the labour too, and you get what you pay for.

For most of us, Blueprinting & Reconditioning are inextricably linked.
To Recondition means to restore the enginer to within specifications for a NEW engine. For example, the book may say that clearance between the piston & bore should be between 1/2 & 1-1/2 thou [as an example] If the cylindes are bored, then honed, then as long as they are within this spec, then all is well, but experience may tell us that 1 thou is ideal, so, the reconditioner takes a bit more time to ensure that all cylinders are exactly the same.

If piston weights, con red weights, con rod lengths etc. etc are all within factory specs, along with all factory dimentoins & clearances then it is reconditioned. There is even an allowance for cylinder block deck flatness.

A blueprinted engine is not just within specs, it is exactly ON spec. The deck must be flat, & parallel to the crank. IE the same distance from the crank centerline both front & rear. The bores must be perpendicular to the crank centerline. The camshaft timing must be on the exact specs, instead of "within allowable tollerances"
Naturally the whole assembly is balanced.

Hopefully you get the picture.
An engine built like this can cost a bundle & can take quite a while to build, but it will give you it's best, & if treated right, will run smoother & last longer than an engine that is "within specs"

Blueprinting doesn't have a specific definition. Like Dman says, it does mean that the tolerances, etc are "better" than the factory specifications. But exactly what the new "blueprinted" specfications are is up to the builder. It usually includes engine balancing, but doesn't have to.

For example, Datsun just install four pistons. An ace engine builder might weigh them, then machine the heaviest ones to match the grams of the lightest + or - a few grams (part of balancing).

But another blueprinter would machine them to + or - a few micrograms.

So it depends on what your builder wants to do exactly.

The factory gives a range, not an "on" spec. For example, A12 piston ring gap per Nissan is 8-14 thousands of an inch. Correct me if I'm wrong, but I don't see a specific "best" number assigned by Nissan. The blueprinter on the other hand may decide that it's gotta be between 13-14 thousands for a drag racing engine, or 8-9 thousands for a fuel-economy buildup (or is it vice-versa?).

When you look at the "big boys" of dragracing, they have their engines as close to perfect as possible. If you have your motor as close as humanly/electronically possible, you will beat the next guy if his isn't as good as yours. For a street motor that will see a bit of hard use, usally a balance will suffice. For a motor that is gonna get the living sh1t screwed out of it you would need to polish the conrods and rockerarms weight match everything and even check the spring load of each valvespring before shimming them up to the insalled height. Not to mention of coarse weight matching all the valve retainers after they have been lightened. The list goes on. What tolerance should you work too? It depends on how acurate (expensive) you equipment is. Most of the hardcore blueprinting requires equipment most of us don't have acsess to, Or can't afford to pay to have done.

I can remember when i was an apprentice [& dinosaurs roamed the earth] the test for a valve job was to turn the head with ports upermost, & part fill them with kero, diesel, or penetrating oil, then leave it overnight. If there was any moisture in the combustion chamber the next day, we had to re-seat the offending valves.

Old lessons die hard, & i still do this, but most rebuilders will laugh at me now.

Most custom built engines are blueprinted for their specific task, so race engines are built with looser tollerances, & i built my engines a bit tight as they are for lower output street duty, & i like 'em to last a long time. [they do]

As ddgonzal said, it's less of a specific definition, & more of a general description of the quality of the reconditioning, or rebuilding job, The degree of work is to some degree dependant on the intended use of the engine. [& that's as elastic a definition as i can come up with]

i think" balanced and blueprinted" has been confuesd abit with just "blueprinted". Getting weights of pistons, conrods and crank exact is balancing, getting tolerances exact is blueprinting, also geting torque settings exact is blueprinting.
The exact term comes from the use of putting blue dye on machined faces such as head and block face, also intake and exhaust sides for exact port matching, using the trace of the blue dye.

I had always thought that Blueprinting was a reference to the original blurprint of the engine, from the design team, before the production engineering team gave all the dimentions a "production tollerance" specification.

I was told that the original blueprint carried only one specific spec for each dimention.
Just shows to go ya.

Thanks heaps guys, very useful!