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RE: Crank Balancing ( Math )

To: "Albaugh, Neil" <albaugh_neil@ti.com>,
Subject: RE: Crank Balancing ( Math )
From: Dale Krumheuer <dmirror3@yahoo.com>
Date: Tue, 12 Oct 2004 13:49:40 -0700 (PDT)
Ok Neil, now that you gave me enough information to get me thinking, why is it 
that you can completely balance a V12 but not a V6 ? Now, to reduce the 
question, can a V-twin be completely balanced ? 
Thanks Neil,
Dale Krumheuer
Cleveland Ohio, where its gettin' cool

"Albaugh, Neil" <albaugh_neil@ti.com> wrote:
Rick;



It isn't possible to balance a 4-cylinder engine completely, no matter
what you do. All you can do is minimize the vibration.



On the other hand, an in-line 6 cylinder engine or a V-12 can be
balanced but a V-6 or V-8 can't be completely balanced. There are
"rocking couples" that cause vibration in engines that do not have
symmetry.



Now--- someone explain to me the rationale behind a 10- cylinder engine.
??????



Regards, Neil Tucson, AZ





-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net] On Behalf Of Rick Yacoucci
Sent: Monday, October 11, 2004 10:46 AM
To: land-speed@autox.team.net
Subject: Crank Balancing ( Math )



I got a "what if" for the math guru's



Let say you want to take 4 cylinder engine and take out two pistons and
run

it as a two cylinder.

You need to put weight back on the crank journals for the engine to stay
in

balance



But how much weight???........



I would think you would need to put the whole rotating weight of the rod
and

bearing

Plus a portion of the reciprocating weight of the whole piston and rod

assembly



The firing order is 1-2-4-3 so we would either run 2 and 3 or 1 and 4

because they run 360 deg apart





Rod weight

Total Weight 346 grams

Rotating Weight 251 grams

Reciprocating Weight 95 grams

Center to center 4.775



Main bearing weight 23.5 grams



Complete Piston weight 293.3 grams





Rick

                
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