How do I calculate cubic inches

WRONG! 1/2 x PI x radius squared x stroke x # cylinders. Must be all this new math that gets everybody screwed up. How can such a simple question end up taking 5 pages to answer?

 

http://www.youtube.com/watch?v=W8qcccZy03s

 

Nope. That just turns a 302 cu. in. engine (4" bore, 3" stroke 8 cylinders) into a 151 cubic inch engine. And my 421 example a few posts back turns into a 210.5 cube job. Take that "1/2 x" off the beginning of your equation and you'll be alright.

 

Maybe these guys can help y'all:
http://www.youtube.com/watch?v=Bfq5kju627c&feature=player_embedded

 

This is the formula that I have, too.

 

Ouch! My math dyslexia gave me a head ache reading all this.

 

My bad, I deserve a lashing.

 

Hate to jump too much, but did I just read that flathead had a 4.3' crank? are all flatheads undersquare that much, or was that a typo?

 

the bore was off by an inch. stock bore/stroke on the later Ford flatty was 3 3/16 x 3 3/4 but the merc had more stroke, and there was room for even more.

 

Love these kind of threads...

 

It got old already.....

 

Yep, this is the equation I use. Also works on straight 8's, horizontally opposed 8's and radial 8's

 

.7853981634... = pi/4
6.283185307... = 2pi

Both are shortcuts based on the bore being cylinder radius x 2, getting squared giving a factor of 4 (½² = ¼). That's why bore² x stroke x pi will give you the capacity of a four cylinder engine - the 4's cancel out. Using 2pi instead, as in the NASCAR formula, gives the capacity of an eight cylinder engine.

 

I know pi, my son knew it to 50 decimal places for a while, it's a very common constant. pi/4 or 2pi are strange numbers, that don't stick easily in the brain, or on a calculator ****on, or marked on a slide rule (if you want to do it right).

Some of us math science nerd geek types can derive the formula more easily than we can remember the .7**x number

 

i'm hungry.

 

If the cylinders are truly oval then C.I.D. =Width of oval X Length of oval X .8 X Stroke X 2

 

The ".7854" part of the equation is something I chanced upon in Hot Rod Mag MANY years ago discussing FORMULAS for this and that, car-related. As said above, it's 1/4 of 3.1416...pi, so it is "pi" related. Not a hard number for me to remember, and it's ONE, very simple formula to figure the area of ANY circle, whether it's the bore of a cylinder, or the sq. inches in a pizza...DIA. X DIA. X .7854 = SQ. INCREMENTS AREA of the circle in question. It's the only formula I've used for area of a circle for over forty years. DD

 

6 pages of this....really ??

 

╥$² x $ x No. of Cyl.= Cubic Inches

 

Well **** howdy, I love learning ****. Never made that connection

 

Stuff like this supports the idea that man never went to the moon.

The average pc is more powerful than anything available 40 years ago. So how could they actually achieve something so complex and difficult, then, when people most people can't calculate volume now ?

 

There are several formulas that will get you the same numbers within a close range, this is the one that I always use as it's the one the math teachers drilled into my thick skull. You can get there with any of the mathematically correct but different equations, this one is just very easy for me- starting in 9th grade, saw Pi x (R squared) x L = volume of a cylinder on the blackboard many times
One of my favorites:
4.232 bore/ 2 = 2.116 x 2.116 = 4.477456 x 3.1416 (Pi)= 14.066 x 3.984 stroke= 56.039 x 8 cylinders= 448.31 ci, which is a cl***ic 427 block/ 428 crank stroker

Lots of ways to get there, the "best" is the one your pea can remember without having to look it up

 

I saw photographs of those and, if I remember correctly, the cylinders weren't elliptical but oval like a very short milled slot. That is to say, they each had two 180° curved faces and two flat faces. So, each cylinder could be defined in terms of a bore diameter and a bore axis spacing (the lesser dimension of the oval being equal to the bore and the greater equal to the bore plus the bore axis spacing).

So, I'd propose:

((pi x B² / 4) + (B x D)) x S x N
​

where
B = bore
D = bore axis spacing
S = stroke
N = number of cylinders

 

Got it! Got it!
Empirical, impeccable PROOF!

Pie R Square!

 

Nedd, I've seen them, they really do exist and yes they run. Yes, you are precisely right- the cylinder bores look like a milled slot. As one can imagine, honing of the cylinders, and the ring design and cost of manufacturing was the down fall to the design. The piston as well as the actuall cylinder was quite simple to manufacture and machine. The plus side was the ability to in theory open up many new aspects of cylinder HEAD design, valve placement, layout/angles and of course port design and placement. TR

 

My guess is that not many people here were involved in the moon shots.

The technology to make todays computers was developed while we were inventing the stuff that allowed us to go to the moon.

 

.....

 

We went to the moon?

 

If that is true...then I agree with Nedd's formula for displacement.

Believe it or not, there are a couple guys who worked on Apollo still hanging around my place of work.