engine cylinder volume querry

why the exact cylinder volume of engine is always lower than the rated
value??
means a 1546cc engine is rated as 1600 cc engine,
why not companies make 1600 cc

because when the greeks invented pi they didn't use the metric system.

D

> On 3/8/2006 3:11 PM ... jas wrote:
> why the exact cylinder volume of engine is always lower than the rated
> value??

Rounding up, I guess.

> means a 1546cc engine is rated as 1600 cc engine,
> why not companies make 1600 cc
>

VW used to list their engines in cc on the old '60's and '70's Beetle
and Karmann-Ghia models. In fact, I think that was true on the VW
"micro-bus". Most were 1300cc and 1600cc. I bet the badge was rounded
up then as well!

jas wrote:

> why the exact cylinder volume of engine is always lower than the rated
> value??
> means a 1546cc engine is rated as 1600 cc engine,
> why not companies make 1600 cc



Not necessarily lower. My Integra's engine is 1,808cc. It's referred to
as an 1800.

And I believe in your example the engine ought to be referred to as a
1500, since you'd be rounding down.

Sometimes this happens for tax reasons (a tax that kicks in at 1500
results in engines being 1490cc, etc.), sometimes because the engine
maker is using some existing tooling or parts, space limitations in the
block, maximum bore diameters, all sorts of reasons.

jas wrote:

>why the exact cylinder volume of engine is always lower than the rated
>value??
>means a 1546cc engine is rated as 1600 cc engine,
>why not companies make 1600 cc

In metric countries it's often done that way to qualify for
competition classes based on maximum displacement. Some countries
also tax according to displacement. In years gone by it also wasn't
unusual to allow for a rebore or two along the way and still remain
within spec -- no doubt old habits die hard.

Of course if you wanted exactly 1600cc you'd need to use square
pistons -- since Pi is an irrational number... Unless you happen to
use the biblical version... "ten cubits from the one brim to the
other... thirty cubits did compass it round" (1 Kings 7:23).

--
John H

Hugo Schmeisser wrote:

> jas wrote:
>
> > why the exact cylinder volume of engine is always lower than the
> > rated value??
> > means a 1546cc engine is rated as 1600 cc engine,
> > why not companies make 1600 cc
>
>
>
> Not necessarily lower. My Integra's engine is 1,808cc.



Correction! 1,834cc. Referred to as an 1800.

Bore 81mm, stroke 89mm. Interestingly. this gives a CID of 111.949,
just about an even 112 inches. Did Honda intend to do this?

More (irrelevant?) inches info:
Ford 302 engine: bore 4", stroke 3". CID 301.593
Ford 351W engine: bore 4", stroke 3.5". CID 351.858

Now why is the 302 called a 302 but the 351 is not called a 352?

On Wed, 08 Mar 2006 19:44:38 -0600, "Hugo Schmeisser"
> wrote:

>Hugo Schmeisser wrote:
>
>> jas wrote:
>>
>> > why the exact cylinder volume of engine is always lower than the
>> > rated value??
>> > means a 1546cc engine is rated as 1600 cc engine,
>> > why not companies make 1600 cc
>>
>>
>>
>> Not necessarily lower. My Integra's engine is 1,808cc.
>
>
>
>Correction! 1,834cc. Referred to as an 1800.
>
>Bore 81mm, stroke 89mm. Interestingly. this gives a CID of 111.949,
>just about an even 112 inches. Did Honda intend to do this?
>
>More (irrelevant?) inches info:
>Ford 302 engine: bore 4", stroke 3". CID 301.593
>Ford 351W engine: bore 4", stroke 3.5". CID 351.858
>
>Now why is the 302 called a 302 but the 351 is not called a 352?
>
>

Because Ford already had a 352; from '58 to '67, I believe.

On Thu, 09 Mar 2006 05:03:45 -0500, Nate Nagel >
wrote:

>There's other examples of engines being advertised as something slightly
>different than their actual displacement... Chevy sold the 402 CID
>engine as a "396" because the smaller, similar 396 had already built a
>reputation (I think the 402 was a .030" overbored 396, basically) for
>one... I know there's others...

A lot of GM engines that were just over 400 CID were listed as just
under--The corporation had a ban on engines over 400 in intermediates,
but the individual divisions wanted the biggest engines they could in
muscle cars. For some reason calling a 402 a 396 made it OK
according to corporate standards. In larger cars, they called the
same engine a 400.

--
A people who extend civil liberties only to preferred groups start down the
path either to a dictatorship of the right or the left."
-Supreme Court Justice William O. Douglas

Dave Johnson wrote:
>
> On Thu, 09 Mar 2006 05:03:45 -0500, Nate Nagel >
> wrote:
>
> >There's other examples of engines being advertised as something slightly
> >different than their actual displacement... Chevy sold the 402 CID
> >engine as a "396" because the smaller, similar 396 had already built a
> >reputation (I think the 402 was a .030" overbored 396, basically) for
> >one... I know there's others...
>
> A lot of GM engines that were just over 400 CID were listed as just
> under--The corporation had a ban on engines over 400 in intermediates,
> but the individual divisions wanted the biggest engines they could in
> muscle cars. For some reason calling a 402 a 396 made it OK
> according to corporate standards. In larger cars, they called the
> same engine a 400.

In later years they did call it a 402. You need to be sure which engine
you are talking about because Chevy also had a 400 ci small block.
Stan

>
> --
> A people who extend civil liberties only to preferred groups start down the
> path either to a dictatorship of the right or the left."
> -Supreme Court Justice William O. Douglas

Stan Weiss wrote:


>>A lot of GM engines that were just over 400 CID were listed as just
>>under--The corporation had a ban on engines over 400 in intermediates,
>>but the individual divisions wanted the biggest engines they could in
>>muscle cars. For some reason calling a 402 a 396 made it OK
>>according to corporate standards. In larger cars, they called the
>>same engine a 400.
>
>
> In later years they did call it a 402. You need to be sure which engine
> you are talking about because Chevy also had a 400 ci small block.
> Stan

And of course there was also the Oldsmobile 403. GM had a ridiculous
number of overlapping engines because they never went to a "corporate"
engine lineup the way Chrysler and Ford did.

But the funny-business with displacements works both ways. The Ford
"427" was actually about 425 CID. It was called the 427 because that was
the displacement limit for the class it raced in. The Ford 428 (same
basic block, but in a smaller bore/longer stroke setup more amenable to
big street-driven cars and police cars) was actually as advertized. So
was the later Ford 429 (different engine family that replaced the FE
family on which the "427" and 428 were both based).

And let's not forget that the "Ford 5.0" (302 CID) is actually a bit
less than 5 liters. But the 300 CID 6 cylinder was already listed as a
4.9L engine.