brian eiland
Guru
- Joined
- Jul 17, 2013
- Messages
- 930
- Location
- USA & Thailand
- Vessel Name
- RunningTide
- Vessel Make
- 37 Louisiane catamaran
brian eiland said:The in-line 6 is the most inherently balanced configuration for a 4cycle engine
Note that I did NOT say the inline 6 was the best engine, just the most inherently balanced engine
I repeat:
An inline six engine is in perfect primary and secondary mechanical balance, without the use of a balance shaft. The engine is in primary couple balance because the front and rear trio of cylinders are mirror images, and the pistons move in pairs (but of course, 360° out of phase and on different strokes of the 4-stroke cycle). That is, piston #1 mirrors #6, #2 mirrors #5, and #3 mirrors #4, largely eliminating the polar rocking motion that would otherwise result. Secondary imbalance is avoided because the crankshaft has six crank throws arranged in three planes offset at 120°. The result is that the secondary forces that are caused by differences from purely sinusoidal motion sum to zero.
So the in-line 6 requires the least counterbalances on the crankshaft,
Primarily, and because there are less counterweights involved the wear and tear on the crankshaft bearings ultimately is less.Are you referring to the balance of reciprocating and rotating parts only?
I would challenge you to prove that statement....that a straight 8 is a better balanced configuration than a straight 6.mannyboats said:Of what significance is that when the torsional vibrations from power strokes (and perhaps other factors) make the 8 cyl engine much smoother?