Date: Wed, 16 Feb 2005 23:19:30 GMT From: "Dexter J" <lamealameadingdongnospamlamelame.org> Subject: Re: new saab motor for 9-3 series
Salutations: On 16 Feb 2005 22:21:43 GMT, Dave Hinz <DaveHinznospamcop.net> wrote: > On Wed, 16 Feb 2005 22:18:33 GMT, Dexter J > <lamealameadingdongnospamlamelame.org> wrote: >> >> Actually - BMW built them for years, both Porsche and VW swiped the >> basic >> timing and layout for their own engines, the Russians I think still >> build >> them as a cycle motor and they are the stock and trade of most Onan >> Generators. Several aircraft engines use a an opposed twin as well. > > Ah, but that's a boxer - both pistons are at TDC at the same time. > Apparently a V-2 or flat V-2 has one at TDC, one at BDC. Lots of > mass moving in the wrong directions there. AHHH - that's what the commentary was about. Thanks. >> Not to appear unfriendly or anything - but they are perhaps the most >> smooth operational twin cylinder design I can think of off hand >> actually. >> The only trick to them is that the moving components have to be in >> practically perfect balance or then, as you comment, they start to beat >> themselves to death almost immediately. > > Synchroninzing those Bing carbs is an absolute bitch, at least on > the '77 R100/7 that I had. Nice bike, but MAN, those carbs... > > Dave Hinz A popular mode was to fit a narrow balance tube between the manifolds around here. Don't know that it helped much though. I don't know - I went with a series of Kawasaki solutions after my one and only BSA tried to kill me repeatedly the only summer I owned it. Traded it for a carton of Dunhills and a case of bear in the fall - and still think I got the better of the deal to this day.. : ) .. As to the offset V - I was reading Smokey Yunick's book on performance V-8's and he had some interesting observations on this. A lot of F1 engines were supposed to be 180 degree offsets. If I understand waht he wrote - basically - he was in favour of the 180 degree V sequence if you can carry a big enough crank lobe to offset the power being delivered. On a V-Twin, I'll wager they trying increase the torque output on the engine at the cost of higher revolutions. Put in a wide enough set of pistons and a long enough set of rods and you might get a much bigger torque figure for the rated horse power. But, RPM would have to be severely limited and you would need a fairly over square bore to make the crank lobes big enough. Pretty much any engine design can ultimately be balanced out on it's crank I now figure. However - depending on what you do, you start to eat into the safety margin pretty quickly as you increase the internal weight according to Smokey. All that said - what the hell do I know - I can't figure out if a series of small problems on my 93 Aero are indicating a larger problem - or if they are just a series of small problems that seem to be interrelated. -- Radio Free Dexterdyne Top Tune o'be-do-da-day Sinatra Martin Davis - When You are Smiling http://www.dexterdyne.org/888/035.RAM all tunes - no cookies no subscription no weather no ads no news no phone in - RealAudio 8+ Required - all the Time Dexter J's fab SAAB 900 for sale: http://www.dexterdyne.org/310.HTM
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