engine cylinder volume querry

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

D

Rounding up, I guess.

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!

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.

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). :)

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.

If I had to guess I'd say it's because Ford (and Packard as well) had built a "352" engine back in the 50's.

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...

nate

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.

Who knows? With the Supreme Court stacked on the right, they might actually try it. ;-)

ford at times has had the "same" engine come from two different sources, wisconsin being one, and cleveland being the other.

and isn't there a 352 ford engine (or was)?

what size was the old '32 ford flathead engine?

m h o =A0v =83e

ford at times has had the "same" engine come from two different sources, wisconsin being one, and cleveland being the other.

and isn't there a 352 ford engine (or was)?

what size was the old '32 ford flathead engine?

Ford had, as you mentioned what they called a 351 Cleveland and a 351 Windsor. Similar engines, but not exactly the same.

The old Ford 352 was of the same series that included the 312, the 390, the

428. The 406 and 426 crossbolts and wedges were similar blocks, but had a number of differences..

The 32 Ford flathead had a nominal 221 cid, and about 65 horses.

The last Ford flathead went into 1953 production. I had one of those turds.

Pardon...That should have been 427, not 426. And I meant to say that the

406 and 427 crossbolts were similar to the 312-428 series, but with some differences. You could actually crossdrill one of the milder blocks and build them out to similar specifications as the 427, but I believe the 427 was beefier in some areas.

My guess is that it is a simple shorthand way of putting the engine into a size-based class.

As I understand it capacity measurement is computed from bore and stroke with the good old geometry formula for the volume of a cylinder. It doesn't take into account the uneven piston top or the shape and size of the combustion chamber.

If that is true then the resulting number is really only an approximation of true volume anyway.

...and the term "displacement" has nothing to do with it?

Displacement, capacity, volume, size and several other terms are used more or less interchangably to define how big an engine is. The amount of air that the piston in one cylinder pushes out or displaces in one complete upstroke is not accurately measured by Pi x radius squared x height. That formula assumes a cylinder with a flat top and bottom.

...but the volume swept by the piston from BDC to TDC can be represented by a true cylinder defined by bore and stroke, irregular piston tops notwithstanding, can it not?

Hmmm...I think you are right.