Forged Cranks

D. Sea wrote:More information about balancing the Forged Scat Crank.
Some hidden costs about balancing that I learned the hard way. i.e. It may be more economical to have the forged crank balanced at the vendor i.e. AD Performance, Performance Crank shaft, River Racer etc...... Get your bob weights from your machinist and then give that information to the vendor. I had an additional $200 in machining added on to my crank for 4 hours of lathe time to cut weight out of the crank throws in order to make it balance:
Here's the weights from my balancing job. 4.310" Scat 4340 Crank with 6.8" Eagle H-beam rods L19 bolts, JE Flat Top 4.44 pistons

Rod (Big End) 525
Insert 55
Total 580
Times Rods/Throw 2
Total 1160
Oil 4
Rotating Weight 1164
Piston 602
Pin 174
Locks 4
Rings 57
Rod (Small End) 234
total 1071
Times Pistons/Throw 2
Reciprocating Weight 2142
times 50%
Each Half 1117.5
Recoprocating Factor 1071
Bob Weight 2235
Here's the balance notes:
F = Front
R = Rear
Start: Remove F 220 R 211.
Put in lathe & removed .070 from all counters
F 129 R 146
Took .050 off front 3 and .075 off 2 rear ones
F 51 R 63
Took .060 off #3 counter & .040 off 2 rear.
Needed to remove 29 grams from front and had to add a 3/4 X 1.120 piece of Heavy Metal to rear to kick.
Then was 29 to remove in front & 32 to remove in rear. Drilled to balance
F .2 R .1
Now the moral of this story is that my rods were a little lighter than a typical 810 gram H beam rod so if you plan on running an aluminum rod or lighter piston/rod combination then chances are you will need to cut a lot of weight out of the crank.
Hope someone learns from my error
Here's my crank after it was cut and balanced. Looks NICE now