What is Blueprinting?
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Senior User
Joined: Jun 2002
Posts: 252
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From: Vancouver - BC - Canada
What is Blueprinting?
Alright folks... Can someone please tell me what blueprinting and balancing an engine is?
I know its a stupid question, but there are no stupid questions right?
I have never bothered asking anyone and have heard people talking about it over the years... I would just sort of nod and say.. wow.. that sounds good...
So if someone could explain to me what this means and maybe explain some other commonly used terminology when talking shop I would appreciate it
Thx in advance.
Randall
I know its a stupid question, but there are no stupid questions right?
I have never bothered asking anyone and have heard people talking about it over the years... I would just sort of nod and say.. wow.. that sounds good...
So if someone could explain to me what this means and maybe explain some other commonly used terminology when talking shop I would appreciate it
Thx in advance.
Randall
Senior User
Joined: Aug 2003
Posts: 152
Likes: 0
From: Maple Ridge BC Canada
What is Blueprinting?
Balancing is just like it sounds, Its just like balancing a tire, You add or take off weight on the rotating assembly. The rods and pistons are weighed so they are all the same weight, the crank, flywheel, and balancer are done much like a tire.
Blueprinting refers to the care in which the engine is assembled, eg; the heads are cc'd to make sure they are correct size, and all are the same volume. The clearances bearings, rings ect are precise. The deck heights are all equal. Everything is checked ..It can be a very time consuming process....d44hd
Blueprinting refers to the care in which the engine is assembled, eg; the heads are cc'd to make sure they are correct size, and all are the same volume. The clearances bearings, rings ect are precise. The deck heights are all equal. Everything is checked ..It can be a very time consuming process....d44hd
Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
What is Blueprinting?
Lets say you have 8 pistons. You weight them and find find they vary as much as 4 grams between the highest and lowest. Using a formula (RMS or whatever) you find a varient of 2 grams is acceptable for a given horsepower target. So, you shave 2 grams off the worse pistons and leave the others alone that fall within that 2 gram margin from the worse pistons.
Then you write the results down.
When it is all said and down, you have almost no difference in rotating mass between any piston. A piston that weighs a bit more, might have a rod that weighs a bit less, since you generally do not lighten a rod.
From watching people do it, I would guess the most important thing is making sure bearing clearance is uniform.
As a loose examples, since the most I have done is slap heads and stuff on already built engines or put crank and bearings into 350 Chevys.
I have watched guys work in machine shops doing engines. Though I could see myself weighing a set of pistons, I think drilling and shaving cranks is a bit of g-whiz I will probably never do myself. Watching that crank spin a thousand times a minute all I want to be is in the next room
Then you write the results down.
When it is all said and down, you have almost no difference in rotating mass between any piston. A piston that weighs a bit more, might have a rod that weighs a bit less, since you generally do not lighten a rod.
From watching people do it, I would guess the most important thing is making sure bearing clearance is uniform.
As a loose examples, since the most I have done is slap heads and stuff on already built engines or put crank and bearings into 350 Chevys.
I have watched guys work in machine shops doing engines. Though I could see myself weighing a set of pistons, I think drilling and shaving cranks is a bit of g-whiz I will probably never do myself. Watching that crank spin a thousand times a minute all I want to be is in the next room
Senior User
Joined: Jan 2002
Posts: 314
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What is Blueprinting?
Rods are balanced when you do a balance job. You equalize them end for end ( big end first ). That extra material on the little end and on the cap are balance pads. Spinning the crank isn't particularly hazardous unless you are doing an internal balance on an externally balanced crank ( where you have to add mallory metal to replace the weight of the externally weighted flywheel and harmonic balancer). Once in a while, the crank will start to ' dance ' in the v-blocks in extreme cases. You just learn to be quick on the control ****! Hines balancer spins 500 rpm. V engine cranks are bobweighted before spinning. The weight is made up of a formula using the weight of one piston, pin, and keepers ( if used ), rings, and one rod small end ( this is called the reciprocating weight ) plus the weight of two rod big ends and two pairs of bearings ( called the rotating weight ). This formula is for a 90 degree V8, and is also known as balancing 50%, since you are using half the reciprocating weight per journal.
Postmaster
Joined: Apr 2003
Posts: 2,703
Likes: 4
From: Harrisburg, NE
What is Blueprinting?
blueprinting started off long ago in nascar stock cars when they were actually stock. engine builders would go into fords part rooms with thier micrometers and try to find the best fitting parts that would work best with little or no machining. this is mostly why those old engines were so bullitproof,the blueprinting and balancing(which has already been throughly explained) made the engines smooth and effortless to turn over (except for compression of course) and it is %100 worth it- the 460 that i drive has about 30,000 miles on her rebuild and is stock cept for the balencing and blueprinting, that is probably why that old truck lived to talk about what its like to top 5500 rpm in that monster of an engine!
