Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/26/83; site ihuxk.UUCP Path: utzoo!linus!wivax!decvax!harpo!floyd!vax135!ariel!hou5f!hou5e!hou5d!hogpc!houxm!ihnp4!ihuxk!rs55611 From: rs55611@ihuxk.UUCP Newsgroups: net.auto Subject: Re: "v8, sixes and torque" Message-ID: <366@ihuxk.UUCP> Date: Fri, 17-Jun-83 12:54:26 EDT Article-I.D.: ihuxk.366 Posted: Fri Jun 17 12:54:26 1983 Date-Received: Tue, 21-Jun-83 02:09:46 EDT References: hou5e.560, <561@hou5e.UUCP> Organization: BTL Naperville, Il. Lines: 28 In regard to the question/comment on dynamic balancers used by Chrysler/Mitsubishi in their 2.6 liter in-line 4: 90 degree V-8s, 60 and 120 degree V-6s are inherently balanced by their geometry. In-line 4's, and 90 degree V-6's aren't. (I'm not sure about in-line 6's.) Thus, dynamic balancers help noticeably on in-line 4's (also due to the 4 just having a small no. of cylinders.) The other, related issue is whether the engine firing is evenly spaced. This is a problem for 90 degree V-6s (even-firing on a V-6 requires a cylinder bank angle of 60 or 120 degrees; of course an opposed, or 180 degree six is fine, too, as in Porsche 911's). For example, the first year or two of the Buick 3.8 liter V-6 is an "odd-firing" 90 degree design, with a lopey-sounding idle, and some roughness. This was at least partially solved by incorporating a crankshaft with offset con rod journals, to artificially cause even firing in the 90 degree design. The reason for the 90 degree block is that tight schedules forced the re-use of tooling from the V-8 line, which are of course 90 degrees. The newer V-6 engines from GM, such as the Chevy 2.8 liter (X-bodies, etc.) are designed from scratch, and are 60 degree designs. If I'm blowing smoke here on any of my statements (made from possibly fuzzy memories of magazine articles in Road and Track, etc.), feel free to send flames; I can take it. (I think!) Bob Schleicher ihuxk!rs55611 Bell Labs, Naperville, Ill.