Date: Thu, 17 Feb 2005 17:35:38 -0000 From: "John Hudson" <mypcnospam.com> Subject: Re: new saab motor for 9-3 series
"Dave Hinz" <DaveHinznospamcop.net> wrote in message news:37i3kqF5f0fraU1nospamvidual.net... > On Wed, 16 Feb 2005 23:15:00 +0000, Colin Stamp <col.dustbinnospamp.plus.com> wrote: > > On 16 Feb 2005 20:27:05 GMT, Dave Hinz <DaveHinznospamcop.net> wrote: IIRC a piston engine cannot have its secondary forces balanced unless it has at least 6 cylinders. Saab attempt to reduce the problem on their 4 cylinder engines with balance shafts which are not needed on a 6 cylinder or more motor. I think we would all agree that a good 6 cylinder will always be smoother than a good 4 cylinder, all other things being equal. Please don't ask for a proper explanation of secondary forces as I put my books on the subject away some 50 plus years ago!