Balancing and blueprinting...what are they doing?

[gogriz91]

Had my engine rebuilt 7 years ago and asked that it be balanced but not blueprinted if for no other reason than I didn't know what it meant and didnt want to pay for it. (Balancing sounded important, blueprinting sounded like a luxury)

What exactly is involved and what are the benefits to be gained for future reference?

[dogma420]

uhh, there's this thing called google, you type in "engine blueprinting" and click on the first thing that comes up...you can do this for other things too!

http://www.hastingsmfg.com/Service Tips/engine_blueprinting.htm

[=Enigma=]

Good question. I've never bothered to look it up because I have never really needed to know, but I always wondered. Let us know what you find on your Google quest.

[montoya_fan01]

did you try to access that site? link doesn't work for me.

http://www.hastingsmfg.com/Service%20Tips/engine_blueprinting.htm

[gogriz91]

Uhh dogma420...I'd love to go to Google but the system I have access to blocks it as well as every other search engine probably because of the advertising wiseass. I'm deployed for 120 days and I wouldn't recommend it unless you really like your earth tones as that's all this experience is "good for". Thanks for the hastings link, now that's useful information!

[=Enigma=]

Blocks search engines but allows you to come to here? That's the first time I've heard that one. Why would anyone do this? Absolute blasphemy.

[26th-Z]

Briefly answered, but I encourage you all to read about balancing and blueprinting - I'm certainly no expert. However, I have built a few engines in my life and this is how I understand it.

The engine has a number of revolving and reciprocating parts. The crankshaft revolves and the pistons and rods reciprocate. Like getting your tires balanced, the crankshaft and everything connected to it that goes round and round with it, is subject to the weights and balances of the parts. This includes the clutch, flywheel, and front pulley / dampener. You know what a tire feels like when it is out of balance; the same is true of the revolving crankshaft in your engine. The reciprocating pistons and rods also affect this motion and their weights react to the balance of the revolving parts. Because of the RPMs involved, this becomes a very accurate situation. Other things come into play, like harmonics, but keeping the explanation simple; the closer one can get to perfect revolving balance to the revolving parts and equal weight to the reciprocating parts, the less power will be consumed making up for the imbalance and less wear on the engine. The engine will rev faster, have more horsepower, and will be smoother.

The designers of the engines specify a certain tollerance of weights and balances. But every time you change a clutch, for example, you technically throw the engine out of balance. I just did the engine for 26th and my machinist said it would feel much smoother. The top of the block deck was stamped with numbers that correspond with the piston weights. The pistons were stamped accordingly, and they were within 3.5 grams of each other. They are now equal weight. Same for the rods, rod caps, and bolts. The crankshaft was balanced with the front pulley, flywheel and clutch plate assembled. I'm supposed to notice the difference.

On a side note, the crankshaft for an early engine like mine was subject to a vibration within a certain RPM range. This "flaw" was later corrected with another crankshaft design. You may notice a metal plate welded to the side of the oil pan on an early engine. (26th's engine number is L24-2338) This is because the oil pans cracked in this area due to the harmonic vibration of the early crankshaft design.

[bpilati]

Blocks search engines but allows you to come to here? That's the first time I've heard that one. Why would anyone do this? Absolute blasphemy.

Enigma, government computers have strange blocking settings, and it also depends on the DOIM.

[gogriz91]

I appreciate the responses. When the guy rebuilt my engine he offered both and said the balancing was a must if we were going to the effort of rebuilding and the blueprinting would be better considered a nice to have. I'm sure I'll have the engine rebuilt at some point and will be able to pay more but I've always wondered what I gave up in order to save a few bucks and what the likelihood would be that it would come back to bite me in the arse. The guy who rebuilt the engine did an excellent job as far as I can tell but I'm a novice when it comes to the deeper mechanical aspects of the car.

I won't even begin to second guess the folks who decide what gets blocked and what doesn't. If I delved into that world my melon would overflow and something important would be lost like how to walk or brush my teeth!

[Zedrally]

Very good question to raise.

Balancing is understood, however can someone please explain Blueprinting?

MOM

[cremmenga]

I can explain blueprinting a bit! I went to a few machine shops, i'm having my 350sbc bored and howned, and all the goods for my z. I ask about balancing and blueprinting. The 4 shops i went to all said the same thing basically. they do balance but they all said you don't need to blueprint. They explained to me that blueprinting was getting all of the measurements back to "factory" or original specs. but they also all said that it is kinda obsolete because, most of the parts now adays are made so well and to exacte specs so it is not needed in most cases!

[montoya_fan01]

Very good question to raise.

Balancing is understood, however can someone please explain Blueprinting?

MOM

follow the link provided earlier in the thread and your question will be answered

OK, here it is again.

http://www.hastingsmfg.com/Service%20Tips/engine_blueprinting.htm