I'm sorry Larry, but that can't be it. Just the volume in one combustion
chamber is in the 20s of cc. Mine (increased a bit) are 24cc. On 4
cylinders, that would add up to almost 100cc, not the 1.7cc that Toby is
missing. My personal guess is that one of the stated numbers in his manual
is incorrect.
Ulix (currently about 1390cc + 100cc = almost a Big Healey :-)
<hopefully back down to 1380cc soon :->
on 11/11/00 11:21, Larry Macy at macy@bblmail.psycha.upenn.edu wrote:
> Well his calculations are correct for the displacement/swept volume,
> whatever.
>
> However, the capacity of the engine, here 1274.8, is not the same thing.
> The capacity is measured as total volume, not the displacement.
>
> I used to think that was the right way too. I read a tech article a
> couple years ago, where the exact same question was asked. Only on a
> different engine. Where the calculated displacement was less than the
> stated size.
>
> The answer is, that the manufactor states CC in total volume, not
> displacement. If you do this calculation on any number of engines you
> will find the same dicrepency.
>
> Larry
>
>>>>> On 11/11/00 12:36 PM so and so (Guy Weller) said. (And I quote:)
>
>> But Larry, he is calculating swept volume.
>> The volume of the combustion chamber, dished pistons and gasket
>> thickness etc, will effect CR but not swept volume; shouldn't make any
>> difference should it?
>>
>> ----- Original Message -----
>> From: "Larry Macy" <macy@bblmail.psycha.upenn.edu>
>> To: "Toby Atwater" <Toby@intri-plex.com>; "Spridgets@Autox. Team. Net
>> (E-mail)" <spridgets@autox.team.net>
>> Sent: 11 November 2000 04:18
>> Subject: Re: British Pie!
>>
>>
>>> You are also assuming that the head is exactly flat across the top
>> of the
>>> cylinder.
>>>
>>> It ain't.
>>>
>>> Larry
>>>
>>>>>>> On 11/10/00 8:39 PM so and so (Toby Atwater) said. (And I
>> quote:)
>>>
>>>> Hey, Im tripping over here.
>>>>
>>>>> From Haynes & Workshop manual:
>>>> "
>>>> Bore 70.61mm
>>>> Stroke 81.28mm
>>>> Capacity: 1274.8 cc
>>>> "
>>>> everytime I calculate it I get 1273.1 ccs.
>>>>
>>>> Are the british using some kind of different Pi? (3.14159265358979)
>>>>
>>>> (Bore/2)squared X PI X stroke X 4 = displacement right?
>>>>
>>>>
>>>> (70.61/2)=35.305
>>>> 35.305 squared = 1246.443025
>>>> 1246.443025 X PI = 3915.81625
>>>> 3915.81625 X 82.28 = 318277.5448372
>>>> 318277.5448372 X 4 = 1273110.17934
>>>> 1273110.17934 /1000 (convert to cc) = 1273.1101793 !!!
>>>>
>>>> Dude... what am I doing wrong? am I incorrect in asuming that all 4
>> cly are
>>>> the same? or what?
>>>>
>>>> Thanks
>>>>
>>>> Toby
>>>>
>>>> trying to calculate his CR.
>>>
>>>
>>> Larry Macy
>>> 78 Midget
>>>
>>> Keep your top down and your chin up.
>>>
>>> Larry B. Macy, Ph.D.
>>> macy@bblmail.psycha.upenn.edu
>>> System Manager/Administrator
>>> Neuropsychiatry Section
>>> Department of Psychiatry
>>> University of Pennsylvania
>>> 3400 Spruce St. - 10 Gates
>>> Philadelphia, PA 19104
>>>
>>> Ask a question and you're a fool for three minutes; do not ask a
>>> question and you're a fool for the rest of your life.
>
>
> Larry Macy
> 78 Midget
>
> Keep your top down and your chin up.
>
> Larry B. Macy, Ph.D.
> macy@bblmail.psycha.upenn.edu
> System Manager/Administrator
> Neuropsychiatry Section
> Department of Psychiatry
> University of Pennsylvania
> 3400 Spruce St. - 10 Gates
> Philadelphia, PA 19104
>
> Ask a question and you're a fool for three minutes; do not ask a
> question and you're a fool for the rest of your life.
>
Ulix __/__,__ ___/__|\__
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http://www.mirafiori.com/~ulix/ '67 Sprite '74 X1/9
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