Re: straight-6 vs. v-six (archive)

: You're confusing a number of almost unrelated problems. The problem of torsional vibrations in the crankshaft of in-line sixes became past history about 45 years ago when the engineers won one small victory over cost accountants in getting permission to lay down 6 cyl designs with 7 realtively narrow main bearings rather than 4 wide ones. The aspect in which in-line 6s and V12s are supremely smooth is a matter of the harmonics created by the reciprocating rather than the rotating parts. There have been a number of good articles on this problem for non-engineers in _Hot Rod_ and _Road and Track_ over the years and one of them appeared in the past year or so, so I might be able to find the exact citation this weekend -- can't search before that because I've got a report for a faculty committee due on Friday.
: The preference for V6 motors in Japanese and American cars has most to do with packaging: it's hard to fit an inline 6 into a front-drive and/or "cab-forward" package, although Volvo recently thought the extra smoothness of the in-line 6 to be worth the effort for their top-of-the line series -- I suspect that the exclusively in-line layout of their engine building facilities had something to do with it, too, though.The reference to the Volvo V6 is interesting. Volvo was forced to drop the Volvo model PRV engine because it was plagued with reliability problem. The Peugeot & Renault version of this "PRV" engine are expected to run for 200,000 to 300,000 miles. Volvo followed the heart of the acountant and did not provided balance shafts in the 90 degree v6.
Kevin B.

Follow Ups:

The real problem with the Volvo-assembled version Jim Baron 07:47 6/11/2000 (0)

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