I thought the longer rod also pushed the piston farther "up" the
cylinder wall, thus compressing the gas MORE... and that's where the
power gain came from...
Isn't that also the case?
Eddie
Gordon Glasgow wrote:
> The guys at Circle Track magazine did a pretty thorough test of this a few
> years ago. Basically a longer rod will broaden the power band because the
> piston sits at TDC longer and the angularity of rod and crank improves the
> leverage slightly. In a 350 ci Chevy at 9000 rpm, it makes a difference, but
> you probably won't be able to tell the difference on a street motor.
>
> Basic truths for the technically-inclined:
>
> With a longer rod, the piston will remain near TDC and BDC longer. At TDC on
> the Power stroke, this allows cylinder pressures to build a bit higher.
>
> Since the piston has to traverse the whole cylinder during each cycle, and
> since the maximum piston speed at the middle of the cycle will be the same
> regardless of rod length, this means that piston ACCELERATION will be
> somewhat greater with a longer rod. Again, this may be a factor at 9000 rpm
> with super-light pistons, but not in a street motor.
>
> A longer rod will also weigh more than a shorter rod, while the piston
> weight will change very little (if at all). This may reduce the ability of
> the engine to rev, partly offsetting the gains from the first factor.
>
> Gordon Glasgow
>
> -----Original Message-----
> From: datsun-roadsters-bounces@autox.team.net
> [mailto:datsun-roadsters-bounces@autox.team.net] On Behalf Of Daryl Smith
> Sent: Wednesday, April 08, 2009 4:21 PM
> To: Tim Waltz; datsun-roadsters@autox.team.net
> Subject: Re: [Roadsters] long rod (r16) stroker
>
> I keep hearing about it, but haven't heard any definitive information on the
>
> correct pistons to use.
> The rod angles will be slightly smaller, but from my reading this will
> minimally affect power and torque.
> The 280/300z pistons may however be cheaper than U20 pistons which may make
> it a more attractive option to some.......
> Read this thread for a detailed discussion:
> http://www.gofastnews.com/board/engine-technology/85-rod-ratio-vers-eng-acce
> leration.html
>
> Daryl
>
>
> From: "Tim Waltz" <printner@att.net>
>
>
>> Another stroker option I've heard of is using the longer (R16) rods, and
>> later Nissan (280Z, 300Z?) pistons.
>>
>> Has anyone ever heard of this, done this, or have any insight on this?
>> I've heard it has more torque and lower rod angles. Sounds like a great
>> option, but I need more info.
>>
>> TIA
>>
>> Tim
>> 67.5 1600 waiting to be stroked
>> (that doesn't sound right)
>>
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