Grn4fbody

iTrader: (2)

Is it a good idea to balance & Blue print the stock LT1 Bottom end? With Aftermarket Pistons.

skinnies

iTrader: (33)

Yes you want to balance it if you go with aftermarket pistons. In that case though, pick up some rods also, they aren't much more!

Grn4fbody

iTrader: (2)

You told me that "It was a waste of money with what im doing"

skinnies

iTrader: (33)

Either do both rods/pistons, or don't do pistons at all.

aboatguy

I still suggest the 6" Scat 7/16s bushed I-beam rods and the Mahle powerpack pistons with a 1.250” compression height -5cc piston. This rod piston combo ends up lighter than stock and your balancer will be removing metal from the crank to balance the assembly so you end up with a lighter stronger rotating assembly.

SLawson86

iTrader: (8)

definately get it balanced, and if your in there... i sure hope you would measure it all and check clearances/tolerances. (blueprint)

GOaT Cheese

"Blue printing" is alot more than checking your tolerances. Blue printing a block is a very in depth machining process that ensures all of your specs will be perfect.

SLawson86

iTrader: (8)

sure, but do you not accomplish this task by measuring??

dhdenney

iTrader: (53)

Isn't blueprinting simply where the machinist mics a piston, mics a bore, then works with that specific cylinder machining it specifically based on the micrometer's readings? Then he mics the crank journal, mics the main, then machines accordingly........

SLawson86

iTrader: (8)

thanks denney... i wasnt going to type it all

GOaT Cheese

What you described is standard engine machining, any competent builder will perform those steps on an average job. Blueprinting is when the machinist mills the back vertical surface of the block (where trans mounts) perfectly flat and at exactly 90 deg. to the crankshaft center line. Then the main journals are align bored ( not just honed) exactly straight, to much tighter tolerances than the factory uses. Then the deck surface is milled to be exactly 90 deg. to the rear block surface. After all is said and done, the block is EXACTLY PERFECTLY TRUE. You would be amazed at the difference between two otherwise identical short blocks, one truley bluprinted, and the other simply machined.

CoozePoodle

Mr. Cheese is right, Blue printing is far more in depth than just basic machine.
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Such as: (To name a few.)
cylinder bore diameter, Cylinder wall taper, Piston diameter,

Deck height of block Bearing clearances,

Crankshaft end play, Piston to valve clearance, Bolt torque specifications,

Lifter bore diameter and alignment. Piston skirt taper, Piston to wall clearance

Piston ring end gap, Rod side clearance, Valve adjustment,

Degreeing the camshaft, making sure correct oil pressure during priming.

Align hone checked and re-machined if needed.

Cylinders are bored to exact specifications.

Cylinders are precision "honed" with torque plates, Deck surfaces are machined in reference to the crankshaft centerline,

Blocks are hand de-burred, bolt holes are checked and re-tapped.

All internal parts are de-burred, hand washed and inspected.

Pistons, pins and connecting rods are pin fit to specification.

Crankshafts are computer balanced to within .5 grams or less.

Crankshaft oil holes are chamfered Crankshaft bearing surfaces are micro polished.

CC checking chamber size for correct compression Surfacing to insure deck flatness.

Setting spring height & retainer to guide clearance.

All bolt holes would be re-tapped, cleaned and oiled, as well as their mating bolts.

Any surfaces refinished will have all holes chamfered, and any casting burrs or irregularities will be ground away.

The V type block will be align bored to maintain perfectly equal deck heights and keeping the crankshaft parallel to the decks.

All rods are reworked so they are EXACTLY the same length from crankshaft centerline to wrist pin centerline.

also checking ring side clearance in piston groove.

All these are parts of "blue printing".

Checking things with a mic is something any engine builder would do.. or at lease "should" do. It's the little things the seperate the winners from the loosers.

dhdenney

iTrader: (53)

Got it. Never seen the steps explained before. Seen "blueprinted" in a few sigs before, but I am sure some couldn't tell ya why it was blueprinted, lol.

GIZMO

iTrader: (8)

Blueprinting is very involved and not really necessary unless you are building a serious race motor. Expect to pay a bunch for labor.