What is Engine Blueprinting and Why Does it Matter?
If you're into cars you may have heard the term blueprinting but never known what it was, and why it matters. Your buddy just got a “fully built” motor, making tons of horsepower, from a genius tuner who charged him extra to blueprint it. What the heck is he on about? It’s time to have a talk…
What is it?
Blueprinting isn’t as complex as you might think, but there is a lot to it. The term gets tossed around pretty freely and it’s often not understood in full. True blueprinting refers to going over every single aspect of a motor, measuring tolerances, and making certain all the components interact with each other properly. It is very precise and meticulous. To put it simply: Blueprinting is verifying and adjusting the tolerances on all components to ensure they are correct.
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How is it done?
Blueprinting is done with precision tools and experience. The problem is, when you order parts they sometimes aren’t exactly the size specified down to the third or fourth decimal place. In a perfect world that piston is exactly the diameter it says on the box, but we don’t live in a perfect world (though it is much closer to a perfect world than it used to be, thanks to computer controlled machining). Small differences in size, still within the manufacturer's tolerances, can add up to make big problems. This is referred to as “tolerance stack up.”
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Give me an example
Okay. For example, let’s say you are building a motor, and you get around to installing the camshaft. This part typically comes with a card that shows the specifications of the cam such as lift, duration, lobe center, intake opening and close, exhaust opening and close, etc. Why not just throw it in and call it good? Because you need to verify exactly what you are installing. You would measure run out (how perfect or eccentric the roundness is) as well as degree the cam to verify the lobe center, lift, and duration. I have heard horror stories of cams being several degrees off from the specifications, which is an easy enough fix when putting it together if you know it is a problem. It is even possible that the cam you got was mislabeled, and not the one you ordered. This is why you blueprint!
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How much is it worth?
That all depends. A properly running engine is like a Swiss watch. From controlling blow by, to making sure the valves are opening at exactly the right moment, everything matters. When each part does the job it was assigned and does it the way it was intended to, the engine will last longer and perform better. If things are haphazardly slapped together, who knows how much power or efficiency you are missing out on. You might not get any more power than the published figure, but you will be more likely to get that much, and you will continue to get it for a lot more miles than otherwise.
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Blueprinting is not modifying
An example of blueprinting in the truest sense is when an engineer designs and specs a motor with very accurate measurements, tight tolerances, and specific angles of relationship for maximum performance. Then, in a sport like Formula 1 or Le Mans where the engine is designed to meet a set of rules, it is delegated to an assembly department who follows these blueprints to a much tighter tolerance than the hourly workers at the Honda plant. Think of it as a kind of quality control for your engine.
When your engine builder blueprints your motor, they double check everything. In stock class racing, the advantage from blueprinting comes from making sure your motor is right up against the maximum allowable stock tolerances, and everything is as smooth and freely moving as possible. Hopefully, this clarified what blueprinting is an expanded your knowledge about engine building. Thanks for reading!
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