blue printing,balancing an engine

[david drenzek]

I would like to know what is blue printing/balancing a engine? Is it necessary in the rebuilding my 1962 engine, vs the cost of doing it. What is the basic cost in addition the the engine rebuild?

Thanks in advance

Dave 62

[Duke W.]

Re: blue printing,balancing an engine

"Blueprinting" is insuring that your engine is dimensionally correct. This begins by measuring the piston crown to deck clearance on disassembly to get and idea of the deck height and parallelism to the crankshaft. Carefully observe and document wear patterns on disassembly, then you measure EVERYTHING, to insure that it is to "blueprint specification".

It's too involved to get into here, but books like "How to Hot Rod a Small Block Chevy" and others publications cover engine blueprinting and balancing.

Cruciform crankshaft V-8 balancing is somewhat complicated, but new pistons and new or reworked connecting rods will have slightly different weights which will impact engine balance. Good machine shops have specialized equipment to balance all the reciprocating and rotating components. They'll need your pistons and pins, rods, crankshaft, and a set of rings and rod bearings to do the job.

As far as whether it is worth it or not depends on how anal retentive you are. A quicky rebuild will probably be okay if no major errors are made, but KNOWING that everything is correct is worth the extra effort and cost to me.

Duke

Duke

Duke

[don whitehead]

Re: blue printing,balancing an engine

I balanced my engine when I re-built it. New pistons, et al change the balance, It only cost a little extra to do it, and the engine/bearings etc. will run and wear better. Less vibration, less chance of throwing a rod IMHO. I also feel it is important to do it once, do it right.

[Daren Schneider]

Re: blue printing,balancing an engine

I am thinking about rebuilding my stock 67 L-79. Someone told me that I would not need balance and bluprinting as the 327 block is externally balanced. Was he full of bs?

[John H.]

Re: blue printing,balancing an engine

Yes, BS - 327's are all internally balanced; the only small-blocks that are externally balanced are 400's (and 383 stroker conversions), and '86-and-later 350's with the one-piece rear seal use a weighted flywheel with a neutral crank damper. With all the time and effort involved in a proper engine rebuild, the $100-$150 extra for balancing is a good long-term investment. Have the flywheel neutral-balanced separately by itself first so if you have to replace it at some future time you can just have the new flywheel neutral-balanced without affecting the balance of the rest of the reciprocating assembly.