Nick, When you have already lightened the flywheel to maximum with a reasonable safety factor so it will not self destruct, the next thing to go are the counterweights and a reduced balance factor. Its one of those things where you take of more and more till it goes bang, then back of a notch or two.
Cheers, Feral Errol mailto:[EMAIL PROTECTED] http://www.datrats.com.au/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: Thursday, 15 November 2001 12:36 PM To: [EMAIL PROTECTED] Subject: Re: V-6 or 4cyl? Errol, I am guessing that the only reason to chase smoother engine running is to remove the high frequency vibrations. This means that you can rev higher for longer before connecting rod/piston/big-end bolt fatigue failures occur. And if your engine can rev 500 rpm more than the opposition, you can get 500 revs worth of power by changing cam profiles etc... If you are rev limited, then I suppose the only advantage is increased reliability If you want to reduce rotational inertia you are better off lightening the flywheel. I wish that my engine was as well built as a race engine, an 8,000rpm pick-a-part L20 mmm... Nick > > From: "E Smith" <[EMAIL PROTECTED]> > Subject: RE: V-6 or 4cyl? > Date: 14/11/2001 21:12:38 > To: <[EMAIL PROTECTED]> > > Yep Daniel, > The Mitsi Astrons use counterbalance shafts. They have counterweights that > must be timed to knock out some of those secondary forces???? > If people are looking to stretch the grey matter in engine designs, how > about looking at the balance factors in engines. The balance factor is the > ratio of the conrod and piston assembly masses compared to the crank > counterweight mass/es. A balance factor of unity would in theory have > minimal secondary force losses except at 90 degrees and 270 degrees crank > rotation rotation from TDC where the rod design causes some losses. I have > seen race Datto engines running balance factors as low as 30 percent to > reduce rotational inertia. This is a testament to the strength of their > basic design. People overseas are doing some interesting things with balance > as most of the secondary forces are energy that is lost and wasted. > Any though or LOL's???? > > Cheers, > Feral Errol > mailto:[EMAIL PROTECTED] > http://www.datrats.com.au/ > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Daniel Kroehn > Sent: Wednesday, 14 November 2001 11:43 AM > To: [EMAIL PROTECTED] > Subject: Re: V-6 or 4cyl? > > Sorry trev, your right on that one! Static balancing is only used when the > distribution of mass is known or can be measured without dynamically mving > the system. Its hard to put what is going on in a cylinder into words!! > Little animations make things so much clearer! From what they tried to > teach us, a six usually has its journals spaced 120 degrees apart to make it > balance the primary forces of piston motion. The secondary force as I said > acts perpendicular to the direction of travel of the piston which can cause > a "rocking" moment inside the engine. That's why sometimes masses which > counter-rotate to the direction of crankshaft movement are used, to correct > this. Someone told me that the 2.6l astron engines have such an > arrangement, can anyone confirm this. > > Daniel Kroehn > Datrats, quality Datsun performance parts > www.Datrats.com.au > > ----- Original Message ----- > From: "Pooley, Trevor" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Wednesday, November 14, 2001 10:00 AM > Subject: RE: V-6 or 4cyl? > > > > Daniel, > > > > My understanding of engine balancing is that only the rods and pistons are > > statically balanced. The reciprocating parts are dynamically balanced. > > > > I found this link about L6 harmonics. > > http://www.zhome.com/ZCMnL/tech/harmonics.htm > > > > I know from people in my club that a good quality aftermarket crank front > > pulley is a must for L6 race engines as the harmonics are great enough to > > destroy the std front pulley or even snap crankshafts. > > > > The last time I saw a pic of an L6 crank it was not mearly an extended L4 > > crank with journals 180deg apart. Although I can't remeber the exact > > configuration at the moment. > > > > Regards > > Trev > > > > > > -----Original Message----- > > From: Daniel Kroehn [mailto:[EMAIL PROTECTED]] > > Sent: Wednesday, 14 November 2001 9:51 > > To: [EMAIL PROTECTED] > > Subject: Re: V-6 or 4cyl? > > > > > > It hard to get your mind around this shit, I just had a three hour exam on > > balancing and the like at uni yesterday. Its not static balancing like > when > > you get the pistons, rods, crank, flywheel combo balanced, its all about > the > > dynamic balancing where froces from the piston firing create forces and > > moments which lead to imbalances inside the engine. Can someone tell me > why > > the secondary forces in a 6 completly cancel out as I'm not 100% clear on > > why, I guess I'm picturing it as a four only with two more cylinders(hence > > primary force cancelation). > > > > Daniel Kroehn > > Datrats, quality Datsun performance parts > > www.Datrats.com.au > > > > ----- Original Message ----- > > From: <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Wednesday, November 14, 2001 8:20 AM > > Subject: Re: V-6 or 4cyl? > > > > > > > Even if your engine is built by Swiss watchmakers with no expense > spared, > > you cannot escape the unbalance caused by the engine configuration. > > > But of course if the engine has been manufactured to sloppy tolerances > > then it will be much worse than an engine built by our Swiss mates. > > > Nick > > > > > > > > From: "mark krawczuk" <[EMAIL PROTECTED]> > > > > Subject: Re: V-6 or 4cyl? > > > > Date: 13/11/2001 21:39:44 > > > > To: <[EMAIL PROTECTED]> > > > > > > > > hi, so what if their un balanced, anybody doing up a high > performance > > > > engine always gets the engine full ballanced........................ > > > > > > > > > > > > > > > > > > > > > > > > mark k > > > > > > > > ----- Original Message ----- > > > > From: <[EMAIL PROTECTED]> > > > > To: <[EMAIL PROTECTED]> > > > > Sent: Tuesday, November 13, 2001 2:30 PM > > > > Subject: RE: V-6 or 4cyl? > > > > > > > > > > > > > Beautiful... :) > > > > > > > > > > -----Original Message----- > > > > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] > > > > > Sent: Tuesday, 13 November 2001 13:15 > > > > > To: [EMAIL PROTECTED] > > > > > Subject: Re: V-6 or 4cyl? > > > > > > > > > > > > > > > The theory behind engine configuration is about balance and > packaging > > > > > > > > > > A 'V' engine (except v12) is fundamentally unbalanced. i.e they > shake > > and > > > > > vibrate because all the rotating and reciprocating components are > not > > > > fully > > > > > balanced. > > > > > V engines are compact, this is their advantage. > > > > > > > > > > An in-line four cylinder also unbalanced - but you can add two > balance > > > > > shafts to compensate > > > > > > > > > > straight 6 engines are fully balanced for most harmonics, that is > why > > BMW > > > > > still use them when a v-6 would be lighter, cheaper, and more > compact. > > > > > > > > > > Flat 'boxer' engines are fundamentally balanced and use a very > short, > > and > > > > > therefore stiff, crankshaft. > > > > > This is why Subaru and alfa-sud engines are so smooth and responsive > > > > > compared with inline fours. > > > > > > > > > > Straight 8's are fully balanced but the crankshaft is long and not > > > > > torsionally stiff and you'd need a long engine bay to fit it all in > > > > > > > > > > PS just because some engines are smoother than others it doesn't > mean > > that > > > > > they can't go just hard > > > > > > > > > > Nick > > > > > > > > > > > > > so can you explain why? > > > > > > > > > > > > > > Drag cars are v-8's because noone makes straight 8's... > > > > > > > > > > > > > > If your theory is true why aren't all motors Vees? > > > > > > > What about the boxers? > > > > > > > > > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > > From: James Marmont [mailto:[EMAIL PROTECTED]] > > > > > > > Sent: Tuesday, 13 November 2001 12:08 > > > > > > > To: '[EMAIL PROTECTED]' > > > > > > > Subject: RE: V-6 or 4cyl? > > > > > > > > > > > > > > > > > > > > > no way!!!!!! Thats why all top fuel drags are "V"s > > > > > > > > > > > > > > -----Original Message----- > > > > > > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED]] > > > > > > > Sent: Tuesday, 13 November 2001 12:42 PM > > > > > > > To: [EMAIL PROTECTED] > > > > > > > Subject: RE: V-6 or 4cyl? > > > > > > > > > > > > > > > > > > > > > that's just for space reasons I thought... > > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > > From: James Marmont [mailto:[EMAIL PROTECTED]] > > > > > > > Sent: Tuesday, 13 November 2001 11:20 > > > > > > > To: '[EMAIL PROTECTED]' > > > > > > > Subject: RE: V-6 or 4cyl? > > > > > > > > > > > > > > > > > > > > > the "v" says it all > > > > > > > > > > > > > > -----Original Message----- > > > > > > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED]] > > > > > > > Sent: Tuesday, 13 November 2001 11:32 AM > > > > > > > To: [EMAIL PROTECTED] > > > > > > > Subject: V-6 or 4cyl? > > > > > > > > > > > > > > > > > > > > > Hey All, > > > > > > > > > > > > > > Does anyone know whether it is the number of cylinders or the > > capacity > > > > > of an > > > > > > > engine that determines it's torque? > > > > > > > > > > > > > > That is would a 2l V6 have more torque that a 2l 4 cyl?? > > > > > > > > > > > > > > Iggy (dreaming again) Sandejas > > > > > > > Sydney NSW > > > > > > > Datsun 1600 FJ20t > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > This message was sent through MyMail http://www.mymail.com.au > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > This message was sent through MyMail http://www.mymail.com.au > > > > > > > > > > > > > This message was sent through MyMail http://www.mymail.com.au --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ ---------------------------------------------------------------------
