Blueprinting in regards to vehicles

What does it mean?

I grew up in a construction household, so to me, blueprints are the plans to build things. But here in car world, it seems to mean something entirely different, as it's always listed as an upgrade; ie blueprinted injectors, hubs, motors.

Is this a fancy way to say "rebuilt to original spec" or an actual process that adds or removes material for reasons?

I think it's more "build to tighter specs" but I could be and often am wrong. 

"(re)build to tighter specs" is pretty much what it means, with the implication that machining is involved.

I interpret it as "build to ideal spec".

Pretty much what z31 said.  Usually much smaller variances in tolerances, and weighing things like pistons and rods and making sure their weights ar as close as possible to each other.

I plan on blueprinting my oil pump.  It consists of grinding the components to closer and matching size along with removing all rough edges and polishing all surfaces.  Supposedly good for a few free  horsepower and better oiling.   

The difference between an assembled engine and a built engine.  Lots of small details can make two engines with identical components perform differently.  Similarly to installing a cam vs using a degree wheel and such.

Does port matching fall into blueprinting also?

Typically blueprinted and balanced with all component having the same weight in relation to each other.

Machining tolerances on an assembly line can be (were) quite large for high performance anything, so taking more of a craftsman/machinist's approach delivers you something called 'blueprinting'. For something like a small block V8 from day's of yore, I'd imagine it had a pretty big effect on performance. Now, I'm not so sure. I think the lack of 'break-in' periods on modern engines has something to do with that too. But I'm probably wrong on that.

Ok this makes far more sense than what I pictured of having a map/diagrams made. 

In casting, I've seen it referred to blueprinting when you use blue machinist dye on flat surfaces to find highs and lows and make things fit better. I thought that might have something to do with it, and it sounds in a roundabout way like it does. 

For the longest time I only remember hearing it done with built motors, then I started seeing blueprinted miata hubs and thought it seemed strange. Catching Tom's post about injectors threw me into a confused loop so I had ask. 

http://performanceunlimited.com/oilpumpmods/index.html

Instructions, note the next page button on the top right.

Any surface imperfections lead to weak spots and stress risers.  If you polish pretty much any component it will get stronger and lighter.  Think of all the casting junk on a hub or tie rod end, axle center section, engine block, lots of useless material.

The way a performance engine builder described it, "blueprinting" is essentially an engine built to "zero" tolerance, meaning that if a clearance spec is .00X, +/- .00Y, the clearance is built to .00X - exactly. Without the .00Y tolerance taken into consideration.  A term often used, but rarely done except in very high performance applications as it is quite time consuming (costly) to do.

I must be old reading this thread.  When I started dinking around with cars in the late 60s, early 70s the first thing you did to an engine being built for competition was take it to a specialist machine shop to have it blueprinted and balanced and then to another specialist shop to have it ported and polished, some shops did it all.  It was a common first step and everyone knew exactly what that meant. 

Engine tolerances and balance from mass production back then were notoriously bad, stuff would be out of spec all over the place and the whole idea was to make every part of the engine match perfectly to the design specs, and ensure the balance of the entire rotating assembly was perfect as well.  Machine shops that had people with the talent to do this where not the norm, but they weren't hard to find either.  It seems that nowadays engines are pretty much exactly on spec when they leave the plant, and the old standard practice of doing a blueprint and balance/port and polish has died.

Engines also tend to last a hell of a lot longer these days, more proof that they are far better built from the start. 

HapDL said:

I must be old reading this thread.  When I started dinking around with cars in the late 60s, early 70s the first thing you did to an engine being built for competition was take it to a specialist machine shop to have it blueprinted and balanced and then to another specialist shop to have it ported and polished, some shops did it all.  It was a common first step and everyone knew exactly what that meant. 

Engine tolerances and balance from mass production back then were notoriously bad, stuff would be out of spec all over the place and the whole idea was to make every part of the engine match perfectly to the design specs, and ensure the balance of the entire rotating assembly was perfect as well.  Machine shops that had people with the talent to do this where not the norm, but they weren't hard to find either.  It seems that nowadays engines are pretty much exactly on spec when they leave the plant, and the old standard practice of doing a blueprint and balance/port and polish has died.

Engines also tend to last a hell of a lot longer these days, more proof that they are far better built from the start. 

Agreed, I learned from old timers, and todays engines are better out of the box.  With the exception of some chevy v8's that got worse before they got better.  Vortec era got a little loose on the whole concept of in or out of tolerance and tolerance stacking.  Small piston, big bore, Meh, they are both in spec.

In reply to akylekoz :

That reminds me how primitive the oil pumps were on the old motors. They were mostly driven with an extension from the distributor.  Most new engines have the oil pumps mounted on the snout of the crankshaft now.

I feel pretty stupid about not polishing the oil pump gear on my 4AGE now, considering that it's the biggest weak spot in terms of RPMs...looked into buying a super-costly billet pump gear, but didn't know polishing the gear was a thing that could help.

RossD said:

Machining tolerances on an assembly line can be (were) quite large for high performance anything, so taking more of a craftsman/machinist's approach delivers you something called 'blueprinting'. For something like a small block V8 from day's of yore, I'd imagine it had a pretty big effect on performance. Now, I'm not so sure. I think the lack of 'break-in' periods on modern engines has something to do with that too. But I'm probably wrong on that.

To give an idea of how important blueprinting was in years past, if the deck height on an engine had a spec of 9.000 to 9.020, the guys who ran the lines at the engine plant would deck them at around 9.020 because they could run the line faster.

Decks were machined by ramming the block through a big broach.  Which is why decks were rarely square end to end from the factory, as the block would compress under the loads and cut differently.  I still want to see a video of this operation, it sounds gnarly.

In reply to Knurled. :

Here you go (or at least a modern version, the process hasn't changed much except for the equipment).

The machining party starts around 3 minutes, but it's worth it to start at the beginning up see the casting part.

Now imagine this with older equipment, and you can see why blueprinting made such a huge improvement in the old v8, eh?

I saw an old grainy video of it being done in the 60s once, but I couldn't find it here.

In reply to WonkoTheSane :

That is way more precision than the process described to me for the old iron blocks.

Picture a freight train of SBC casting cores being rammed at high speed through a too-small tunnel, with the tunnel walls being made of very coarse files.  GRAUNCH.  Out comes a block casting with its decks and main registers "machined".  Sort of like a Play-Doh Fun Factory that squirted out engine blocks.

So I asked my engine builder/machine shop proprieter about the phrase "blueprinting" yesterday. He has been in the business for well over 20 years building sprint car, land speed, and drag race V8s. 

I says to him "Ray, I understand what it is supposed to mean. What do you think of blueprinting"

He rolled his eyes so hard I thought they might just fall out and asked if I wanted a three quarter race cam too?

Even though his invoices include every conceivable measurement and clearance in thousandths and every fastener's torque specs he has to have a "Blueprinting" line item in quickbooks if a customer is over 50 or they will complain that he didn't do it.

He actually got a little agitated talking about it. I might have struck a nerve.

See, this is the kind of thing that makes me wish I could send GRM to my 14 year-old self.