What does it mean to "Blue Print" and engine to U

[2wrench]

What does it mean to "Blue Print" and engine to U

First, tell me what it means to blue print an engine,
in your opinion.

Second: Tell me what you think it means in industry
parlance, if these two things be different.

I want to know what is required or expected of me and/or any
machine shop or mechanic I would contract to blue print.

 

[PeterK]

Re: What does it mean to "Blue Print" and engine to U

To measure and adjust all internal engine components to exact specifications, not just to tolerances.

 

[2wrench]

Re: What does it mean to "Blue Print" and engine to U

Thanks, Peter, and from where I am, I must say
good morning.

 

[TR3driver]

Re: What does it mean to "Blue Print" and engine to U

Generally, blue printing is only useful in racing situations where the rules require a "perfectly stock" motor. You get the specifications for what is legal (which include tolerances to allow for manufacturing variations), then take each and every tolerance to it's limit in favor of better performance.

For example, if the rules say that a .040" overbore is legal plus a .003" allowance for wear, you bore to exactly .043" oversize.

The factory generally considers a +/- 10% variation in power output to be normal, so you want to be sure you build that +10% motor.

 

[Bugeye58]

Re: What does it mean to "Blue Print" and engine to U

Generally, blue printing is only useful in racing situations where the rules require a "perfectly stock" motor.

I would mildly disagree with that statement.
Blueprinting properly can lead to not only power gains, but long term reliability.
For example:
You could have a crank journal on the low side of the tolerance, with a bearing bore on the high side, putting your bearing clearance at the upper limit of the tolerance. Still perfectly acceptable, but the bearings will wear out of the clearance <u>limits</u> sooner, leading to possible loss of oil pressure and accelerated wear.
The same holds true for all of the components.
Just a minor nitpick, but blueprinting isn't only for race engines.
I'm very familiar with the blueprinting process, and it's paid off for me over the years.
Jeff

 

[TR3driver]

Re: What does it mean to "Blue Print" and engine to U

I guess it depends on your point of view. Mine is that I would never grind a crank while it was still in tolerance. In fact I've got probably 50,000 miles on a motor that I put back together with the crank worn well under the limit; still ran fine.

And since I'm not bound by stock car rules, there are plenty of other, more cost-effective ways to squeeze out another 10hp than trying to adjust all the clearances within .0001".

 

[piman]

Re: What does it mean to "Blue Print" and engine to U

Hello 2wrench,

to me it is getting every dimension as close as possible to ideal, so is very expensive and time consuming.

It is not just bearing dimensions but things like crank throw angles, cam angles, piston and con rod weights, piston heights, block deck to piston height, valve height in the head, valve spring pressures.

Basically building the engine as close as possible to true dimensions in every aspect.

Alec

 

[tomshobby]

Re: What does it mean to "Blue Print" and engine t

Good Jeff,

Blueprinting ensures the moving parts are in correct geometric alignment.

Mine was both balanced and blueprinted and I feel the money was well spent.

Alec, we must have posted together. I did not see your post which is all exactly what is done. And like you say, it is time consuming. Also not something just any shop can do.

 

[2wrench]

Re: What does it mean to "Blue Print" and engine t

All valuable comments; especially regarding not something
just any shop can do. Why? Well, if I were so inclined,
of course I'd have to seek out the more elite.

I understand this means money. Question is: How much to
be worth it. I'll be doing further investigation.

 

[LastDeadLast]

Re: What does it mean to "Blue Print" and engine t

I'm sure that some may disagree with my opinion but:

Balancing will absolutely provide a benefit and is money well spent, just ask any engine builder. Blueprinting, well that's more theoretical if you ask me and a lot of money for not necessarily much benefit. Not saying that it doesn't help, but unless you want to race it.. well, there are better things to spend money on. Just my opinion.

 

[2wrench]

Re: What does it mean to "Blue Print" and engine t

I'm sure that some may disagree with my opinion but:

Balancing will absolutely provide a benefit and is money well spent, just ask any engine builder. Blueprinting, well that's more theoretical if you ask me and a lot of money for not necessarily much benefit. Not saying that it doesn't help, but unless you want to race it.. well, there are better things to spend money on. Just my opinion.

In my view the diversity in views; thoughts; opinions of
this Forum is its greatest asset. As a group, we must
agree to disagree without a fear of retribution or
alienation; to be beyond personal attack; but rather
respectful and mindful that the world is diverse in
experiences and approaches to problems.

In short, thank you for your candor. Your input is
appreciated. Keep on posting, just as you would.
Sincerely,

 

[rlandrum]

Re: What does it mean to "Blue Print" and engine t

I've blueprinted some parts of my Small Block Chevy, just to be sure I wasn't using a bad block.

For instance, I checked piston to valve height, main bearing tolerances, push rod lengths, valve spring rates, and a bunch of other things before doing final assembly. What this told me was that all of my mechanical components were within spec, and that they would work correctly with one another, which when dealing strictly with aftermarket components from different vendors, is a major concern.

If you're starting with something you know to be good, such as a running engine, then the process isn't quite as necessary. In that case, though, you want to check all the parts for wear. And that means a good set of mics AND a good set of eyes. A mic can't see that 1/64th stress fracture starting in the crank.

 

[TR3driver]

Re: What does it mean to "Blue Print" and engine t

What this told me was that all of my mechanical components were within spec,

Not to beat a dead horse, but that is NOT what I call blueprinting. Checking that everything is within the published specifications is just good practice; blueprinting is when you build to tighter tolerances than the original manufacturer found necessary.

 

[TR3driver]

Re: What does it mean to "Blue Print" and engine t

I'm sure that some may disagree with my opinion

Not me !

 

[2wrench]

Re: What does it mean to "Blue Print" and engine t

Again, these differences in points of view have value
so I can communicate a subcontractor just what is
expected, if I so chose, and to throw out a term of
art such as "blueprint" my engine, getting within
specs may well be all I'll get for a price...and just
maybe that is something, at least for the most part,
I could get myself...

I think you all understand my point; so, once again,
thank you for your candor and input.

 

[piman]

Re: What does it mean to "Blue Print" and engine t

Hello 2wrench,

it depends on what you want.

Blueprinting to get the engine as perfect as possible was essential for one make racing where there were strict limitations on modifications. I.e., that to be competitive required the best from a base engine.

It is cheaper to build an engine accurately and modify it as a means of getting more power than blueprinting to the 'n' th degree, which requires lots of measurement, assembly, and dis assembly and accurate machining until every thing is spot on. For a road car that is not really cost effective.

Alec

 

[mikespain]

Re: What does it mean to "Blue Print" and engine t

Hi -Iagree -blueprinting is essentially a photographic copy.ie each cylinder and all its components are modified,machined,balanced,taken to maximum or minimum tolerance to produce maximum and equal power per cylinder,making each cylinder an exact copy of the other,hence the word blueprinting,.A very time consuming process that basically derived as previously stated where minimum modifications are allowed in racing.the cost to power ratio is very very expensive compared to modifications such as cam change carb change etc.

 

[PeterK]

Re: What does it mean to "Blue Print" and engine t

What this told me was that all of my mechanical components were within spec,

Not to beat a dead horse, but that is NOT what I call blueprinting. Checking that everything is within the published specifications is just good practice; blueprinting is when you build to tighter tolerances than the original manufacturer found necessary.

Totally agree. It makes me wonder (there's that Zeppelin song in my head again!) when someone says their engine is blueprinted whether they just measured the parts (a standard practice in good engine building and a MUST DO IMO) and call it blueprinted. NOT.

And it's not a good practice to slap an engine together without measuring components to check for wear and damage, at least if you want your engine to last.

No offense to anyone here at all (especialy those that have actually had their engines professionally blueprinted), but as is often the case, a term with specific meaning is tossed around rather lightly.

Imagine taking your cylinder head to the machinist and asking to have the head decked .0033" then to have the machinist take off "a little bit." An analogy (maybe a poor one) between blueprinting and NOT.

Let's discuss porting and polishing. HAHAHA. A whole 'nuther can o' worms I suspect.

Poor horse...