For what your doing, just a good check over of your parts would more than suffice .... Balancing is taking the rods ,pistons ,crank and flywheel , plus the weight of the rings and rod bearings and creating a perfectly balanced rotating group... Rods and pistons and crank can be forged or cast poured... Either way the amount of material isn't always perfect...!! So they dril, grind, and machine material off to match every piece with its group of parts.. The flywheel, crank, and balancer all get spun balanced together... They take the weight of the pistons and rods and figure in the inertia (pulling force ) and add/subtract weight to the flyweights... That in turn helps counter balance the thrust created by the pistons and rods...

Blueprinting is puting things into exact specs of one another ... As well as different amounts of material in the forge/casting process , parts arnt always perfect spect size/length to one another.. Several ways to match up these batch runs is to group them into closet, match, measurement groups... From there stock engines simply get assembled with these parts...
Blocks can be untrue when they're line bored and decked at the factory..so the Blueprinting of a block measures deck height to crank journal , they can be off by 30-40 thou ... Called an un square engine block .. Milling machines these days are very precise though, so a typical engine bore and deck fixes any of these flaws.. Say if you assembled an un square block and looked close front to back or vise versa ,the pistons would be up higher on one end...

So Blueprinting is ??? Making everything as perfectly matched and squared as possibly... In a sense creates a perfectly mathematically volume balanced engine... Because now you know that each cylinder piston stroke is even with the others...
Heads get flow polished to balance out and equal the volume passing through them ,to feed the cylinders...

When I was assembling my S10 now buggy motor #3 piston (drivers side second one back) I noticed the piston was crooked front to back... I only noticed this because the block had been decked... Ended up being a bent rod...!! This was after all the balancing and everything...!!

 

Brad...was not thinking of this for my current project. I was just curious since I had read posts refering to the two terms and just wanted opinions on the true meanings. Those terms seem to be thrown around a bit with different meanings. Read one saying is engine was "blueprinted" since he had the machine shop deck the block and bore the cylinders. But that was all that was done. (Different board btw.) Thought that was like me saying I am a mechanic because I have done a little, very little, work on my vehicles over the years...lol. Make sense?

 

Lol ya !! I learned a lot hangin out down at my brothers work.. He was a machinist for many years building engines and stuff.. Before he left they purchased a new surfacing machine the sets the block down on the crank journals to square up and surface... That particular block (V8) was really off... Great topic !!!

 

I believe that blueprinting would also include CC ing the combustion chambers and equalizing the volume of all of them. Dennis

 

Blueprinting is simply measuring everything and making sure it is within in spec. As in everything matches the blueprints. CC'ing the heads and masuring piston dish, actual stroke and deck clearance would all be included. This type of work also includes accurately recording all your findings.

Balancing is simply bringing all the rotating assembly within balance. So all rotating a reciprocating parts will have to be weighed, matched and then the crank balanced with bob weights to bring it within the industry norm of 2oz or better.

 

Blueprinting is simply measuring everything and making sure it is within in spec. As in everything matches the blueprints. CC'ing the heads and masuring piston dish, actual stroke and deck clearance would all be included. This type of work also includes accurately recording all your findings.

Balancing is simply bringing all the rotating assembly within balance. So all rotating a reciprocating parts will have to be weighed, matched and then the crank balanced with bob weights to bring it within the industry norm of 2oz or better.

2 oz.? that seems like an awful lot of variance...? Interesting that linear tolerances are on the order of thousandths of an inch but mass / weight tolerances are on the order of ounces.

Not trying to bust your balls, just trying to learn / understand. FWIW, I thought your explanation of blueprint vs. balance was excellent, but I was surprised by the 2 oz part.

 

LOL your right mean Grams (g). Ignore that last part

 

Betterthan...So you are saying a rebuilt engine within the specs tolerable range is therefore a blueprinted engine? I was under the impression it needed to be perfect, not just within tolerable ranges. Thanks for all the replies!

 

There's still a difference... Resizing rods, turning the crank , surfacing the head... Those are comin things done in a rebuild... Blueprinting goes beyond factory specs and gets things as close to perfect as possible... CC ing tdc and the combustion chamber... Port matching, porting and polishing , chamfering the oil jurnals on the crank for maximum oil delivery ... I've seen blocks polished internally , then painted for oil return... It gets maddening !! The list goes on and on..
A well built motor having a balance job and some porting and polishing runs very strong as it is...

 

Isuzu gives a tolerance range on just about every engine spec. Building to within that range is NOT blueprinting. Blueprinting is taking it beyond mass production specs and trying to get as close to the tightest spec in the range as possible. Like brad said matching pistons to the bores ect. Obviously a $100,000 F1 engine that turns 12-14k rpm all day long is going to take this to the extreme. The same with balancing. Balance to spec range is OK but you can get much better. You don't just make sure the rods are the same weight you make sure the each end of the rod is the same weight. You get the idea. There is a lot of performance and especially durability to be had from making an engine as tight and well balanced as possible. it'll also run so much smoother.

 

There's still a difference... Resizing rods, turning the crank , surfacing the head... Those are comin things done in a rebuild... Blueprinting goes beyond factory specs and gets things as close to perfect as possible... CC ing tdc and the combustion chamber... Port matching, porting and polishing , chamfering the oil jurnals on the crank for maximum oil delivery ... I've seen blocks polished internally , then painted for oil return... It gets maddening !! The list goes on and on..
A well built motor having a balance job and some porting and polishing runs very strong as it is...

This was my understanding as well Brad. In Betterthanyou's post it mentioned "within" spec so I assumed he meant within the tolerances allowed in fatory specs which allow less than perfection due to mass production. Example: say the deck distortion limit is .2mm and you are right on the limit of that. I would think that wouldn't qualify as blueprinted since it is on the outside of the "tolerance" and not as near perfect as possible. I am not saying that makes it a bad rebuild or engine but not "blueprinted". I may have misinterpreted Betterthanyou's post. I am probably splitting hairs as well and making too much of this so please take no offense to my questions Betterthan. BUT, I am learning :wink:

 

Brad,

As you say, can get "maddening"! While reducing friction losses and out of balance conditions are good for any engine, how far would you recommend? Considering our engines are not run at race car rpm's, where those issues are extremely critical for maximum longevity and power, where do we stop? Is there a formula, cost effectiveness vs intended usage? Would shotpeening, cryogenic stress relieving, and other procedures on reciprocating assemblies be of real benefit?

Thanks,

GB

 

Nah !! Taking stock parts and having them sized (making sure there still within specs) polishing or turning the crank , then getting everything balanced (balancing is roughly $150 ) would give you a very smooth long lasting engine.. These things stock run a long time... But if you want to run it hard 5-55 maybe 6 grand the balancing comes into play... On the performance side the polishing and port matching improves run ability in those rpm ranges... And the machinery used at good shops these days generally trues up engine blocks... The old mills would square up off the top of the block, thus why you'd get variances... And the example of an engine with one or two lower compression cylinders still runs good...!! It doesn't have to be perfect, but the closer you are the more efficient your engine is... Squatch, Betterthanyou ,and Dsuzu all have great points !!! There is a buttload of information and techniques that goes into building... You can diegrind or dremal ports and pieces to open and polish... Cnc machines build heads and rods for race cars... It gets down right anil... But everything bolts together with such precision it has an awesomeness all it's own...

My buggy motor is built to the nutts ,arp rod bolts ,screw in rocker studs, forged pistons, stainless steel valves, titanium pushrods , and pinky rods... All balanced and possibly close to blueprinted... It runs really strong , can pull 7-8 grand..!!
It just has a stock Chevy crank, it's not a race car engine... It is a great power plant..!!

 

Very well said. Helps me better understand realistic parameters, build to use intended, the best I can!

Thanks,

GB