but, when they balance and/or blueprint an engine, does it have to be together, or do they do everything separately: each rod, the crank, etc, or do they do it all at one time when they put everything back together ???

 

I believe they do it while putting it together....for instance adjusting the weight of the piston/connecting rod assemblies. I don't think everything is done individually if that's what you mean.

 

alright, thanks. i plan on doing some motor work this summer, and i was just wondering if i could put it together which would save on labor, and just have them balance it, or if they needed to put it together so they could balance it

 

The way an engine is 'balanced' is part by part. The way one goes about doing this is to weigh each specific part. With pistons, what you do is weigh each one. After you find the lightest one, you begin removing metal from each one respectivly, until each piston weighs the same as the lightest one. Same with the rods. So, obviously to do this, the parts need to be out of the engine. This is what is involved in 'balancing' and engine.

 

To expound upon this a bit, they take the whole bottom end rotating assembly and balance it together. They take 1 rod, 1 piston, the crank, balancer, and flywheel or flexplate and balance them together usually with a few ounces. They give you a sheet as well with the specifics of the balance job. Of course this is after they match weight the pistons to each other and rods to each other as well, and all the crank work is done and so on.

 

To add yet another tidbit.... Blueprinting is just the process of measuring all the components and documenting EVERYTHING, including the weights of pistons, rods, etc...

 

so in other words, the machine shop will need everything to do it, which means ill be forking out $$ for the labor of them putting it together too then, right ??

 

not necessarily! it all depends on how the shop you use defines "blueprinting" and "balancing". there are two methods of balancing also, static or weight matching and dynamic. the weight matching is what has already been described, where each rod and piston is weighed and then they are ground to match the lightest of each set. dynamic balancing is the best method and much expensive to do but necessary if you plan on high rpm operations. with this method, the rods and pistons with rings are first weight matched, then the big ends of each rod are weighed on a special rig which holds the rod horizontally with the small end stationary and the big end on the scale. after this, they figure out what is called the "bob" weight and then put the crank in a balancing machine with the correct amount of bob weight attached and also have the flywheel and damper attached to the crank. the crank is then spun at a certain speed and the technician then adds or subtracts weight from the crankshaft counterweights until they get the balance down to almost zero. they use something called mallory metal to add weight and it is expensive also. the dynamic method is the best but you really don't need this done for a street machine IMO unless you have lots of cash just laying around with nothing better to spend it on! LOL
Blueprinting means doing the necessary measuring and machining to bring the block to dead on factory dimensions and specs without any piling up of factory tolerances allowed. this involves align boring the mains and decking the block to the correct centerline dimensions and boring the cylinders so that everything is square and parallel to the centerline of the crankshaft. there are other steps that can be included depending upon the machine shop you choose.
you can get all this done and still assemble the engine yourself if you want to do it. just make sure to get the right size bearings and stuff to match the machine work done in the shop and keep the pistons and rods matched up to each other to keep the balance right on.

 

thats a lot of info. but, i appreciate it. now, you said dynamic is the best, yet most expensive. would i need the dynamic balancing if i plan on turning say at the very most 6500rpms ?? or would static be ok ?? i plan on gettin a stroker kit this summer, and want everything done right the first time so i dont have to worry about it down the road.....and if u do recommend the dynamic balancing, how do you think on avg that plus blueprinting would cost ?

 

I don't think you need to go with the dynamic balancing unless you're building a race only engine. And I don't have a clue what it costs either. call around to some local machine shop and they can give you some prices I'm sure.