i saw an engine for sale they said it was
balanced/blueprinted... what does this mean??

 

They literally wiegh and balance all of the rotating mass of the motor....... I looked it up one day....


Blueprinting





In engine blueprinting, all the specifications are double-checked. Usually this indicates closer-than-factory tolerances, with custom specifications appropriate for a street car or a race car. The goals usually are to:

• Ensure the engine puts out the rated power (because not all mass-production engines put out the rated power) for its manufacturer's design

or

• Make more power out of a given engine design, by extra careful measurement and assembly
• Balancing of reciprocating parts and rotating assemblies, to reduce engine vibrations thus achieving more power due to recovery of power "lost" to vibrations

Ideally, blueprinting is performed on components removed from the production line before normal balancing and finishing. If finished components are blueprinted, there is the risk that the further removal of material will weaken the component. However, lightening components is generally an advantage in itself provided balance and adequate strength are both maintained, and more precise machining will in general strengthen a part by removing stress points, so in many cases performance tuners are able to work with finished components.
For example, an engine manufacturer may list a piston ring end-gap specification of 0.003 to 0.005 inches for general use in a consumer automobile application. For an endurance racing engine which runs hot, a "blueprinted" specification of 0.00045 to 0.00050 may be desired. For a drag-racing engine which runs only in short bursts, a tighter 0.00035 to .00040 inch tolerance may be used instead. Thus "Blueprint" can mean tighter or looser clearances, depending on the goal.

 

is that something that most DO-IT-YOUR selfers pay to have done?? or is that fairly easy to do ??

 

Im pretty sure that its out of the realm of the average shadetree there Bro......We are talking about a lot of work, specailty tools, machines and equipment.....then again we are talking about a true "balance & blueprint"....

 

It takes alot more effort to blueprint an engine than just build it. Crank and cam journals are checked for trueness in releation to the deck and core shift. Piston to deck clearance is usually checked on all four corners with a dial indicator. Camshaft will be degree'd and valve lift will be checked. There's alot of other stuff I can't remember right now.

Definately outside the area of expertise of anyone other than an experienced engine builder. And definately worth the money. This is a must if you intend to turn you engine over 5000 rpm alot.

 

Balanced simply means the crank has been weighted correctly for your specific bob weight which is the weight of your rod and bearings, piston,pin and rings added together on one hole.
Blue printed means you will get a sheet from the builder/machine shop listing all the measured specs of the motor.
These terms are just meant to differentiate between an assembly line rebuild and a custom shop rebuild.

 

+1

 

It's common to get an engine balanced. For a high RPM engine, it's a necessity. It's not something anyone can do without a balancing machine and a lot of experience on how to do it.

Blueprinting is unlikely by the average person or a typical machine shop. Typically blueprinting means more than just checking tolerances. All factory clearance specifications have a tolerance. If clearance between two components had a factory spec of .010" +/- .002" then anywhere from .008~.012 is fine. A blueprinted engine will be adjusted until the spec is exactly .010". Same goes for every other specification in the engine.

Assembling an engine is just checking specifications enough that it will go together and be close enough that the engine should run and stay together but there's no guarantee it won't fail (typical backyard build). Building an engine requires tearing the engine down multiple times to check and test clearances. Blueprinting means doing changes until all the specifications are exact.

My engine is balanced. It's been built properly but I won't consider it blueprinted although it may be since I did changes to make sure specifications were very close to perfect such as checking pushrod length for proper valve train geometry etc. Since I never did degree my camshaft, I suppose it was never fully blueprinted.

 

what does it me to "degree" you camshaft?? is there anything else that can be degreed?? im trying to figure out what all this means so i dont sound stupid when i goto a shop.. i dont want them to think im stupid i know they wont do as good of a job and charge more..
And thanks to every one replying!! i am getting a much better understanding of what to do and to stay far away from lol

 

Degreeing a camshaft means to check and adjust the camshaft timing so that it is at the exact times specified on the cam card. This is accomplished by a number of methods. Normally you use offset dowel bushings in the cam gear. Simply installing a camshaft doesn't mean it's 100% accurate.

 

The machinist will put a big "degree wheel" on the crankshaft and turn the engine with one cylinder head installed with one set of valves/springs/rocker arms installed and check to make sure that the intake and exhaust valves open and close when the cam card says they are supposed to. He may also advance or retard the camshaft to further tune the combination.

 

Keep in mind unless you know the person or they have a really great reputation of being honest the phrase of "Balanced and Blueprinted" is as worthless as "It's got a 3/4 cam." I have heard many people use that phrase because they think it makes them sound cool. Some even claim it [Balanced and Blueprinted] means an engine has more power.

 

I was going to mention that but didn't. Balanced and blueprinted is 1960's terminology similar to the 3/4 race cam, cheater slicks, stall converter and all those other old terms which mean nothing today but people still use them. Back then tolerances were not as precise as they are with modern engines. Even in the 70's, ProStock cars only ran 8 second 1/4 miles with what was available. We now have turbo and NOS street cars that can do that.

 

not to change the topic.. but im going to take advantage of all you guys being helpful.. im trying to figure out what would be a good set up.. i want my car to have a loud idle sound like you know its fast a better way to put it is i want it to rumble at an idle... and i will be taking it to the drag strip every second friday.. and only drive it in the summer time but to fool your selfs i will be hard on this car on and off the track.. so heres what im thinking after talking to alot of people this seems good for my needs... CORRECT ME IF IM WRONG! PLEASE..
so i got off the phone with a transmission shop.. the guy said he thinks people make the mistake of going with a high stall torque converter he suggested i go with

a 700r4 with o/d and a stall of 2200
i told him i want a Detroit locker as i plan to do lots of dragging.. he suggested the rear end gear be a 3.75 and if this sounds good let me know other wise please correct me... and what size tire would i have to go with for this application ??
I have found an engine i want to buy this weekend to rebuild... its a 1995 gmc 350ci out of a 3/4 ton van... would that be a 4bolt main?? i will be rebuilding it as a 383 stroker i heard the cam can have effect on the converter ?? as you know i want the car to idle loud but i dont want to loss power by having it like that at the same time.
this is all the information i have for now im hoping that with this you guys can help me better my knowledge and come up with a approximate 11sec 1/4 mile car.. i hope to get around 350 to 400 hp out of this engine.. i wont be adding nos i might later decide to super charge it.. it is going to have carburetor not to sure what size my geuss is around a 750 edelbrock or holly

 

So many components are best suited depending on other components. The best converter stall speed is based on the camshaft grind. With a street/strip car, the converter should stall about 500 RPM into the powerband. For full race, it should stall about 1000 RPM into the powerband. If you know the total duration of the camshaft, not the .050 number, I can give you a good estimated stall speed.

Now other things such as tire size, gear ratio, exhaust, induction etc all come into play depending on what you want to do with it. A good street setup won't perform 100% at the track and a full race setup won't have good street manners.

 

im looking for something in between... i was told 2200 stall from a transmission shop... and they said racers usually go around a 3000 stall why are you saying to go so low ??
what are the +/- to lowwer stall verses higher stalls ?? i was told to work my way from the back end to the front i dont have any parts yet im trying to figure out what all works good for a budget car that does close to 11's in the 1/4 thats okay to drive in and out of city...

 

When you are looking for the cam you want in the engine it will have the recommended stall speed needed for an automatic as well as the rear gears.

Too much stall 2 things happen in city driving. One to much will burn the transmission up because the torque converter it slipping and you will be wasting a lot of gas.

Too little say you run a stock (or not high enough) converter and a lobey cam your engine will stall every time you come to a stop. If you idle it up too much you will have to apply the brakes hard just to keep it stopped and it will cause a hard jerk when going from park to reverse or drive.

 

makes sense so.. a 2200 stall should be a good choice now i just have to tell the guy doing my rear end that its a 2200 stall as well inform the guy whos going to do work on the engine?? so he can match the cam to my stall ?? is this a good way to do it.. ?

 

Not really, you pick the stall speed of the converter based on the power band of the engine, not the other way around.

 

this is frustrating lol people say start from the rear end work you way to the engine but it seems like i cant pick anything with out knowing how much power i have...
so i should decide how much power i want.. build an engine to fit my needs/wants ;P
and well i know im going with a 700r4 o/d... and i want a detriot locker posi rear end..
so what next ? do i pick the rear end gear size or do i decide what size stall converter to put in . it seems to me the stall converter would be the very last thing to decide on ??

 

You don't have to start at one end or the other. You just have to make sure all the peices work in the same range.

2200-2400 works well with a moderate cam and 3.55-3.73 gears on the street. You are gonna want to get a lock up converter to keep your highway mileage somewhat decent and an additional transcooler. Run that in series with your radiators trans cooler. The higher your stall speed is the more heat is generated tooling around town.

 

yea reading your post has got me intrested. i have a 1977 glastron jet boat with a 460 ford i bought what was supposed to be a marine engine but no luck with it. im thinking of having the next one balanced but how far do i go it will turn around 55oo to 6000 rpm i need help cant keep a motor in it

 

A balanced engine will run with a lot less vibrations and the bearings will last a lot longer. In an engine, we're talking ounces of weight down to the gram.

An example of an imbalance.

Take a one pound weight in one hand with your arm fully extended. Spin around in circles. You can feel the weight pulling you off balance. Now take that weight and tie it to a 10 foot string and do the same thing. The faster you spin, the heavier that weight becomes. You have to lean back now to keep your balance as you're spinning around. If you were a crankshaft, how hard are you leaning back into the bearings.

Now put another weight and string on your other arm so it balances out the other and spin around. You stay more upright without having to pull back on either weight.

That's roughly what a balanced engine does, but because the pistons/rods are not in the same plane as the counterweights, there are more angles involved but the theory is the same. The faster the engine is spun, the more precisely balanced it should be. For a low rpm engine that rarely gets over 5000 rpm that's put back together with the parts it came with from the factory, balancing isn't usually required. As soon as you start using aftermarket rotating assembly parts such as crank, rods or pistons, all the engines should be balanced.

 

You want a big block to turn that rpm all day long for hundreds of hours expect to pay 30 or 40 grand.
I'm not familar with jet drives but what you really need is to regear so you can spin a safer rpm at the same speed.

 

Most often, that phrase means the same thing as "out of a Vette" or "fully built".

Basically, sucker bait.

This not being a Frod 460 or Glastron forum, I won't comment on that.

 

Unless he has paper work for it, hes full of ****. I would talk him down even more if he stated that it was fully balanced and blueprinted and doesn't have any paperwork to back it up.

 

im sorry i didnt know this was a specific forum ill see if i can get someone who dosent care to help a guy with a motor whatever is in to help me thankyou for all your professinal help

 

Blueprint and balancing are two main topics of guys running Super Stock.And those are extremely expensive.

 

I registered on this site just now so that I could reply with a gushing thank you for posting this, as this finally clicked for me. My prior searches ended ultimately in a hazy-at-best understanding, never really getting it while tripping over minutiae. I'm not sure why, but the way it's parsed here just works for me. Thanks, and given that I'm replying to a five-year-old post, REVIVE! (Seriously though, thanks for posting that, as you've helped a mostly-idiot gain a small understanding that was previously unattainable.)