Maxy_UK

What does the term blueprinted engine mean?

TonyBurns

iTrader: (3)

Its basically an engine thats built within certain tolerances, normally greater than a standard engine (ie if an engine has say 2 thou play this one will have 1 thou).
Its of a greater engineering quality, the down side is that a "proper" blue printed engine doesnt last very long (ie an F1 engine is a proper blue printed engine but does run at 18k rpm ).
The blue print is now more of a loose term rather than a proper term and means just greater tolerences.

Tony

[Edited by TonyBurns - 5/5/2003 2:39:25 PM]

TonyBurns

iTrader: (3)

Just to back my statement up here's something i found earlier
Misconceptions
There is a misconception amongst racers and sadly some buyers that a so called "Blueprinted" engine is a tuned engine. This is not the case, a blueprinted engine is an engine that has been measured and adjusted/modified so that it meets exactly the dimensions and tolerances that the designer of the engine specified. There are very few, if any, of these engines in circulation, as the manufacturer is most unlikely to allow anyone access to the data from their drawings.
If you were to be able to buy a blueprinted engine it would offer negligible performance gains due to the accuracy and consistency of modern production methods. It would however run more smoothly and efficiently. Because of the closer tolerances it would take longer to 'break in' but, with proper maintenance, would last longer. The person who would gain the most advantage from such an engine would be the engine tuner, who would have an accurate baseline upon which to calculate his/her modifications.
As mentioned above, some buyers are given the impression that they have purchased a "blueprinted" engine. Whilst the seller could try to justify that the engine is made from blueprints of the original drawings, and therefore it is a blueprinted engine, it is a deplorable and unforgivable way of making a sale. The customer usually pays an extra amount for this 'high performance' engine only to find out later that it is a standard "off the shelf" engine.
This practice by, thankfully, a minority of unscrupulous dealers will continue as long as there are customers who do not do their homework and impulse buy an engine that they are lead to believe is faster or better than it actually is.


Tony

pat

Our definitions seem to differ somewhat. My definition of a blueprinted engine is one which is produced from normal production parts, but assembled in such a way as to achieve the best possible clearance match, mass match etc without having to further machine the components to achieve a perfect match.

A standard engine is simply assembled, with whatever is in the parts bin at the time, obviously an "A" grade piston will be used for an "A" grade bore, etc (for definitions of A and B grade bores see the workshop manual). A blueprinted engine may have the components further measured to ensure that they are indeed the size expected, it may have the rods & pistons measured for weight and four closely matched ones used etc. An engine builder would take the extra step of machining the rods & pistons to ensure that they are within 0.5 grammes of eachother.

As far as engines coming out of the factory go, a "blueprinted" engine should have a better dynamic balance and will therefore run smoother and be more stress-free, so should be able to rev higher without unduly shortening the life expectancy.

Cheers,

Pat.

KungFuMonkey

I always though a blueprinted engine was built from standard parts with all clearances etc to the better side of the production dimensions.

I.e if a bore is a width +/- 2 thou, and the bore being the width +2thou will improve performance, it gets bored to +2thou.

Same with weights etc.

As always i could be wrong.

Jono

Mr.M

I always though that a 'Blueprinted' engine is one that nearly or exactly matches the designers measurements i.e. No or very little manufacturing tolerances for dimensions and mass.

Working in a design office, blue prints where electronic photastatic copies of original designs. So when you talk about blueprints in terms to engines, it would mean engineering to the original dimensions as per designers output. Nowadays, blueprints are generally not seen around due to cheap laser plotters.

High volume manufactured engines generally are made within a tolerance to the original designers specifications. e.g. A casting process may increase weight to what was stated by designer for engine cases etc.

When an engine is blueprinted each component would be measured and weighed to see if it exactly matches the original drawing measurements. Components can be re-machined to loose mass and/or measurements in order to be as close to the orginal dimensions.

Leslie

The term "blueprinted" first became well known when the original Formula Ford started. The engine had to be built from standard Ford parts. The engine builders used to sort through many stock items to find parts such as camshafts etc which were built within the tolerances but were on the side which would give the best performance from the engine. When all the small gains from each part were added up it would make a significant increase to the engine's performance. This was called "blueprinting".

Les

Hobbsy

I always though the term blueprinting is when things like inlet manifolds, exhaust manifolds etc are painted with engineers blue and fitted to their respective part. A blue outline will be imprinted on say the head and the excess material is removed
??????

Fatman

Is it then true that STI engines are blueprinted whilst normal Turbo/WRX engines are not (i.e. assembled to finer tolerances, better matched internals etc)?

Pavlo

Generally, in racing terms, a blue printed engine is one that is able to generate the most power whilst still being within the homologation fiche. So for forumla ford, they would mean things like minimum usable cam clearance, biggest possible valve throats, spot on stroke (tolerances only allow under) and so on and so forth.

For most people building any sort of engine, using uprated or factory parts, they build to the within the factory tolerances anyway, which are quite tight on the Subaru in my opinion.

Paul

submannz

A blue printed engine is one who's parts are matched precisely, all parts are the same length, weight and balanced, crank shaft is aligned, the strokes are equalised and the valve train accurately to the manufacturers specifications, a lot of these measure down to 10,000th of an inch. Depending on the desired result there are many other things done also

My friend actually has genuine copies of the engine blue prints ex japan he is a Subaru rally team works engine builder in New Zealand.

Kingsize K2

I don't know what I thought a "blueprinted" engine was - but I think I know now

Thanks gents

Diesel

I remember reading in that initiall damn 'get yer wallet out' showroom brochure that the engine on my STi V is blueprinted. I understand this to mean parts measured and tolerances matched up nicely, rather than just bolted together out of various boxes - whether one (say piston) is at the smaller end of tolerance and the other (say bore) at the wider end of tolerance! I think

D

Leslie

I think what you say is right Fatman. That's what I was trying to say Pavlo

Les

[Edited by Leslie - 5/7/2003 11:04:26 AM]