Re: [ihc] What does it cost to make a big hole instead of a small one?

[bearbvd@xxxxxxxxxxxxxx (Greg Hermann)]

At 8:22 AM 10/31/04, Jim Camery wrote:
>Digesters - something that's always made me wonder..

Short answer: because the mfgr. can GET more---

On a 392, the longer (but not necessarily reasonable) answer is that at
least SOME of the additional weight is in the counterweights on the crank,
and the crank is made of expensive material. (On the other hand, I would
bet that 392 and 345 (and quite possibly 266 and 304) cranks are all made
from the same rough forging--so there is LESS material (machining time,
cost) to be removed in completing a 392 crank than is involved in the
others--

Which takes us back to the SHORT answer---

Greg
>
>Does the US Mint charge more to print a $100 bill than a $20?
>
>Why did a 392 cost more than a 345 or 304?  Essentially, why does a
>motor with bigger holes for the larger pistons cost more than one with
>smaller holes?  Most everything else on the motors are the same or at
>least of equal complexity to design and manufacture.  In fact, in my
>minimal machine shop experience, making a SMALL thing is more difficult
>and exacting than making a BIG thing.  Steel is expensive now, but the
>extra 20 or 50 pounds still is just cents, not dollars.
>
>I know that in some cases, bigger motors come with bigger trannies,
>axles, brakes, etc., and then it makes sense that ordering the larger
>engine should cost more.  (Although, again, why would large drums and
>shoes cost so much more than small ones?)  With a modern Ford 150, you
>can order different engines without getting different drive trains and
>running gear, but the price changes radically.  With the older Light
>Line, you could closely specify all components and isolate the
>additional cost for the larger pistons.
>
>Similarly, why does a 750cfm 4bbl carb cost (quite a bit) more than a
>400 of the same design?  Same number of jets, pumps, circuits, chokes,
>etc., just generally larger orifices?  The mold and manufacture should
>be the exact same process, and shipping and distribution should be very
>close to the same.
>
>Jim with Questions
>(and two fewer travelalls - the scrap dealer paid me a visit!)