[AT] Rationale for firing orders

Herbert Metz metz-h.b at mindspring.com
Mon Mar 22 18:53:27 PST 2004


Larry,
.........horizontally opposed four ala Volkswagon; also Subaru's
horizontally opposed four, and recently Subaru's horizontally opposed six.
Herb

----- Original Message ----- 
From: "Larry D. Goss" <rlgoss at evansville.net>
To: "'Antique tractor email discussion group'"
<at at lists.antique-tractor.com>
Sent: Monday, March 22, 2004 8:33 PM
Subject: RE: [AT] Rationale for firing orders


> I think there are probably some good arguments in favor of the in-line
> six as being POTENTIALLY the smoothest running engine.  It has the
> unique condition of being both dynamically and physically balanced.  I
> have never done an actual comparison of the harmonic balancers on the
> front end of the crank, but I was led to believe they are lighter and
> smaller for the horsepower of the engine than other designs.  But then
> there's also the horizontally opposed four ala Volkswagen.
>
> Larry
>
> -----Original Message-----
> From: at-bounces at lists.antique-tractor.com
> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Steve W.
> Sent: Monday, March 22, 2004 11:53 AM
> To: Antique tractor email discussion group
> Subject: Re: [AT] Rationale for firing orders
>
> The firing order is to even out the power pulses. In a four stroke
> engine with 4 cylinders you set it up so that one piston is always
> producing power.
> In your example starting with No.1 firing at TDC and No2 is on BDC the
> start of compression, No3 would be at TDC on exhaust and No 4 would be
> at BDC on the intake stroke. This assumes a flat crank with throws at
> 180 degrees.
> JDs make that unique sound because they actually coast 360 degrees
> between each power impulse.
> That is also the reason why Harleys make a unique sound, and why they
> shake your teeth out when they run.
> The firing order and power impulses are also the reason why an Inline
> engine or a 180 degree V are the smoothest running engines, Power pulses
> come evenly spaced. The next best are the 90 degree V engines.
>
> Steve Williams
> Near Cooperstown NY
>
>
> ----- Original Message ----- 
> From: "Roger Welsch" <captneb at micrord.com>
> To: <at at lists.antique-tractor.com>
> Sent: Monday, March 22, 2004 12:09 PM
> Subject: [AT] Rationale for firing orders
>
>
> > Can someone help me with a brief and simple explanation of why a
> motor's
> > firing order wouldn't always be one-two-three-four?  My Allis WCs are
> > one-two-four-three but I have no idea why....  I love to kid my
> in-laws that
> > they've always prefered John Deere Bs because they can remember the
> firing
> > order.....
> >
> > Roger
> >
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> >
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