Staggered main clearance inline 6

[pamotorman]

It's amazing how strong he Slant 6 and Nash flathead were with 4 mains, ore even the Ford Flathead
of all the (passenger car not truck industrial) 6s the AMC has by far the strongest bottom end

both the AMC and GMC 6 cylinders were tried at the indy 500. barney navarro the AMC and wayne horning the GMC

[Kevin Johnson]

The differing clearances can help in transforming vibrational energy into heat rejected into the coolant (oil flow). Dedicated crankshaft dampeners often do this with high molecular weight silicone fluids or various polymers.

Hi Kevin,

Is your theory that greater ( or lesser) clearance provides more damping, or the increased clearance permits greater oil flow with greater cooling?

regards,

Dan T

Not my theory:

damping.gif

==============

Hi Kevin,

I think that paper refers to radial damping, not torsional.

regards,

Dan T

Sorry to drag this up again. It is a convenient or simplifying fiction in mechanical analysis that vibrational excitation of a stiff shaft that results in lateral movement (radial) does not also result in axial undulations in differing oblique planes. The move is made that a stiff shaft is a theoretically perfectly rigid shaft. Some research (referenced in the paper) tacitly acknowledges same by shifting the bearing supports laterally, presumably mounted on a perfectly rigid bed.

Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is.

Rigid: unable to bend or be forced out of shape; not flexible.

Torsional damping of a non-perfectly-rigid crankshaft is coupled to the out of plane bending movements. "Coupled" is a term of art.

https://en.wikipedia.org/wiki/Coupling_(physics)

[mag2555]

It would pay for you to resize those main Bores by means of the technic that leaves them with more Bearing clearance at the parting line rather then just more overal clearance.

[modok]

I am not so sure.
chrrysler v10 had crankshaft harmonic problems,
upper bearing shells with zero eccentricity seems to have been part of the solution.