5.7 vs 6.0 Rods

[The Dark Side of Will]

A longer rod weights more , than it need heavier crank counterweights...

This difference is offset by a slight lighter piston?

Correct. I you spend about 20 minutes looking at component weights on the Summit website, this should be evident. The long rod/short piston combos take a lighter bobweight.

[Stan Weiss]

Note: For the 6" / 152.4 mm rod I increased weight to 600 grams from 570 grams for the 5.7" / 144.78 mm rod
Note: This is with GAS PRESSURE = 0
Note: Since I did not have large and small end weight of the rod I let the program calculate these.
Stan

Code: Select all

Bore = 101.4   Stroke = 90.0   Rod Length = 144.78   RPM = 8000
Crankshaft Degrees at which Rod and Crank are 90 Degrees 72.7339

Crank      Piston     Crank       Rod    Cylinder   Cylinder
Angle      Travel      Rod       Bore     Volume     Volume
Degree       mm       Angle      Angle      CI         cc
-ATDC 
 90.0000 52.170958   71.89156  18.10844  25.70949  421.30305

Piston Weight = 500.0   Rod Weight = 570.0
Small End Rod Weight = 190.0   Big End Rod Weight = 380.0
Rod CG / Distance from Small End = 96.52

            Reciprocating    Total     Piston Side
Crank Angle    Force         Force        Force
  Degree      Newtons       Newtons      Newtons
 90.000     -7126.304     13957.749    -2330.397

------------------

Bore = 101.4   Stroke = 90.0   Rod Length = 152.4   RPM = 8000
Crankshaft Degrees at which Rod and Crank are 90 Degrees 73.5494

Crank      Piston     Crank       Rod    Cylinder   Cylinder
Angle      Travel      Rod       Bore     Volume     Volume
Degree       mm       Angle      Angle      CI         cc
-ATDC 
 90.0000 51.795192   72.82594  17.17406  25.52431  418.26858

Piston Weight = 500.0   Rod Weight = 600.0
Small End Rod Weight = 200.0   Big End Rod Weight = 400.0
Rod CG / Distance from Small End = 101.6
            Reciprocating    Total     Piston Side
Crank Angle    Force         Force        Force
  Degree      Newtons       Newtons      Newtons
 90.000     -6832.577     14362.423    -2111.647

Edit: Here is 6" / 152.4 mm rod with same weight as 5.7" / 144.78 mm rod

Code: Select all

Piston Weight = 500.0   Rod Weight = 570.0
Small End Rod Weight = 190.0   Big End Rod Weight = 380.0
Rod CG / Distance from Small End = 101.6

            Reciprocating    Total     Piston Side
Crank Angle    Force         Force        Force
  Degree      Newtons       Newtons      Newtons
 90.000     -6734.969     13762.062    -2081.481

[tt 383]

Maybe someone should start a thread about gapless rings and light/heavy rotating weight acceleration just for funnzies???

[Warp Speed]

Maybe someone should start a thread about gapless rings and light/heavy rotating weight acceleration just for funnzies???

[Stan Weiss]

Code: Select all

Bore = 101.4   Stroke = 90.0   Rod Length = 144.78   RPM = 8000 

Piston Weight = 500.0   Rod Weight = 570.0
Small End Rod Weight = 190.0   Big End Rod Weight = 380.0
Rod CG / Distance from Small End = 96.52

                     Reciprocating        Total         Piston Side
Crank Angle             Force             Force            Force
  Degree               Newtons           Newtons          Newtons
 90.00000000000     -7126.3042027     13957.7491289    -2330.3969332

---------------

Reduce piston weight by 30 grams

Piston Weight = 470.0   Rod Weight = 570.0
Small End Rod Weight = 190.0   Big End Rod Weight = 380.0
Rod CG / Distance from Small End = 96.52 

                     Reciprocating        Total         Piston Side
Crank Angle             Force             Force            Force
  Degree               Newtons           Newtons          Newtons
 90.00000000000     -6816.4648895     13802.1281963    -2229.0753274

---------------

Reduce rod weight by 30 grams

Piston Weight = 500.0   Rod Weight = 540.0
Small End Rod Weight = 180.0   Big End Rod Weight = 360.0
Rod CG / Distance from Small End = 96.52 

                     Reciprocating        Total         Piston Side
Crank Angle             Force             Force            Force
  Degree               Newtons           Newtons          Newtons
 90.00000000000     -7023.0244316     13363.9394456    -2296.6230646


---------------

Reduce rod weight by 30 grams all on small end

Piston Weight = 500.0   Rod Weight = 540.0
Small End Rod Weight = 160.0   Big End Rod Weight = 380.0
Rod CG / Distance from Small End = 101.8822 

                     Reciprocating        Total         Piston Side
Crank Angle             Force             Force            Force
  Degree               Newtons           Newtons          Newtons
 90.00000000000     -6816.4648895     13802.1281963    -2229.0753274

[russrace]

Rod length always a good bench race, but has anyone else heard of Hendricks building oversquare bore/stroke 358 cid combos with 5"+/- rods in their NASCAR Cup motors?