Calculating displacement?
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Calculating displacement?
Following up on a post in general.......when you bore a 454 .30 how is the displacement figured? Volume of a cylinder is V= p r2 h or pie x radius squared x height. Can someone fill in the measurements? When thee bore is .30 over the post said it engine becomes 460 but .60 over it becomes 468. If the bore increase is .30 how can there be a difference of 6 cu in. to 8 cu in.? 454 vs 460 vs 468
Burning Brakes
Joined: Sep 2004
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From: Ft.Worth Texas
The increases are proportional not linear. 
Try your math using only the increase numbers....you will see that the result of the .03 test times 2 does not equil the .06 test.
Try your math using only the increase numbers....you will see that the result of the .03 test times 2 does not equil the .06 test.
Last edited by David Ey; Feb 25, 2006 at 12:45 PM.
Thread Starter
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2017 C3 of Year
Originally Posted by David Ey
first, that would be .03 and .06 rather than .30 and .60
The increases are proportional not linear.
The increases are proportional not linear.
Pro
Joined: Jan 2006
Posts: 599
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From: New York
454..
.30 over would give u a 4.28 bore with about 460 cubic inches n were in pa. r u...if u go 2 roadster.com there is a ton of big block info.....good luck....
Last edited by jerrylee; Feb 25, 2006 at 04:36 PM.
Pro
Joined: Jan 2006
Posts: 599
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From: New York
454 bore...
if u do a 30 over bore u r increasing the cylinders by 300th's of an inch wich will give u an increase of about 6 cubic inches of air/fule mixture....40 0ver will give u about 462 c.i. but these r not an exact science because the stroke also comes into play here....anybody else have some input...
Drifting
Joined: Jul 2002
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From: The only Corvettes in Highett Victoria
aussiejohn's Universal Capacity Formula
G'day,
Not much help to you big block guys, but I have discovered a universal method of determining capacity for any V8 engine with a 4.000" bore. The formula is:-
Capacity = stroke x 100 +2
Take a 350 Chev, stroke =3.48", multiply by 100 = 348, add 2 = 350.
327 has a 3.25" bore, multiply by 100, = 325. Add 2 = 327
Same with 302, 3.00" bore x 100 =300 +2 =302.
Chrysler 392 had 4.00" bore x 3.90" stroke, a Holden 308 has a 4.00" bore and 3.0625" stroke, etc. etc.
Now look at a Ford "351" (Cleveland or Windsor) with a 4.00" bore and a 3.50" stroke. According to the formula, its actual capacity is 352 cubic inches. No wonder they have trouble getting their stuff to work properly.
Regards from Down Under
aussiejohn
Not much help to you big block guys, but I have discovered a universal method of determining capacity for any V8 engine with a 4.000" bore. The formula is:-
Capacity = stroke x 100 +2
Take a 350 Chev, stroke =3.48", multiply by 100 = 348, add 2 = 350.
327 has a 3.25" bore, multiply by 100, = 325. Add 2 = 327
Same with 302, 3.00" bore x 100 =300 +2 =302.
Chrysler 392 had 4.00" bore x 3.90" stroke, a Holden 308 has a 4.00" bore and 3.0625" stroke, etc. etc.
Now look at a Ford "351" (Cleveland or Windsor) with a 4.00" bore and a 3.50" stroke. According to the formula, its actual capacity is 352 cubic inches. No wonder they have trouble getting their stuff to work properly.
Regards from Down Under
aussiejohn
Drifting
Joined: Dec 2004
Posts: 1,345
Likes: 3
Originally Posted by aussiejohn
G'day,
Not much help to you big block guys, but I have discovered a universal method of determining capacity for any V8 engine with a 4.000" bore. The formula is:-
Capacity = stroke x 100 +2
Take a 350 Chev, stroke =3.48", multiply by 100 = 348, add 2 = 350.
327 has a 3.25" bore, multiply by 100, = 325. Add 2 = 327
Same with 302, 3.00" bore x 100 =300 +2 =302.
Chrysler 392 had 4.00" bore x 3.90" stroke, a Holden 308 has a 4.00" bore and 3.0625" stroke, etc. etc.
Now look at a Ford "351" (Cleveland or Windsor) with a 4.00" bore and a 3.50" stroke. According to the formula, its actual capacity is 352 cubic inches. No wonder they have trouble getting their stuff to work properly.
Regards from Down Under
aussiejohn
Not much help to you big block guys, but I have discovered a universal method of determining capacity for any V8 engine with a 4.000" bore. The formula is:-
Capacity = stroke x 100 +2
Take a 350 Chev, stroke =3.48", multiply by 100 = 348, add 2 = 350.
327 has a 3.25" bore, multiply by 100, = 325. Add 2 = 327
Same with 302, 3.00" bore x 100 =300 +2 =302.
Chrysler 392 had 4.00" bore x 3.90" stroke, a Holden 308 has a 4.00" bore and 3.0625" stroke, etc. etc.
Now look at a Ford "351" (Cleveland or Windsor) with a 4.00" bore and a 3.50" stroke. According to the formula, its actual capacity is 352 cubic inches. No wonder they have trouble getting their stuff to work properly.
Regards from Down Under
aussiejohn
Displacement is porportional to the SQUARE of the bore.
The Assie constant for 4" bores is actually 100.531 and just eliminate the +2 fudge factor
=8 * pi * (4*4)/4
The universal equation for 8 cylinder displacement is:
Displacement=8 (cylinders)*Stroke in Inches *(3.1416(pi)*((Bore in Inches)*(Bore in Inches))/4
This is 8 cylinders times the stroke times the area of one cylinder (=pi *d^2/4=pi * r^2 (pi(e) diameter squared divided by 4 = pi(e) radius squared)
350 Chevy= 8 * 3.48 * 3.1416* (4*4)/4 = 349.85
454 Chevy= 8 * 4 * 3.1416 *(4.25 * 4.25)/4 = 453.96
350 .030" overbore Chevy= 8 * 3.48 * 3.1416* (4.03*4.03)/4 = 355.11
454 .030" overbore Chevy= 8 * 4 * 3.1416 *(4.28 * 4.28)/4 = 460.39
Simple Math......
Last edited by StickShiftCorvette; Feb 25, 2006 at 05:41 PM.
Melting Slicks
Joined: Aug 2004
Posts: 2,063
Likes: 1
From: Beverly Massachusetts
Originally Posted by aussiejohn
G'day,
Not much help to you big block guys, but I have discovered a universal method of determining capacity for any V8 engine with a 4.000" bore. The formula is:-
Capacity = stroke x 100 +2
Take a 350 Chev, stroke =3.48", multiply by 100 = 348, add 2 = 350.
327 has a 3.25" bore, multiply by 100, = 325. Add 2 = 327
Same with 302, 3.00" bore x 100 =300 +2 =302.
Chrysler 392 had 4.00" bore x 3.90" stroke, a Holden 308 has a 4.00" bore and 3.0625" stroke, etc. etc.
Now look at a Ford "351" (Cleveland or Windsor) with a 4.00" bore and a 3.50" stroke. According to the formula, its actual capacity is 352 cubic inches. No wonder they have trouble getting their stuff to work properly.
Regards from Down Under
aussiejohn
Not much help to you big block guys, but I have discovered a universal method of determining capacity for any V8 engine with a 4.000" bore. The formula is:-
Capacity = stroke x 100 +2
Take a 350 Chev, stroke =3.48", multiply by 100 = 348, add 2 = 350.
327 has a 3.25" bore, multiply by 100, = 325. Add 2 = 327
Same with 302, 3.00" bore x 100 =300 +2 =302.
Chrysler 392 had 4.00" bore x 3.90" stroke, a Holden 308 has a 4.00" bore and 3.0625" stroke, etc. etc.
Now look at a Ford "351" (Cleveland or Windsor) with a 4.00" bore and a 3.50" stroke. According to the formula, its actual capacity is 352 cubic inches. No wonder they have trouble getting their stuff to work properly.
Regards from Down Under
aussiejohn
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Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
formula again
Stickshift,
Of course you have the correct "exact" formula, but only a very small miority of people can work that out without a calculator. My formula works perfectly for any eight cylinder engine within one cubic inch, providing it has a 4.000" bore. Period.
Liquid,
Sorry to confuse you, of course I made ONE mistake. With the 327 engine, I said "3.25" bore" when I meant 3.25" STROKE. All here should know that 302's, 327's and 350's ALL have a 4.000" bore, and my formula works for them all, even the "383". Most engines here use a 350 block and a "400" crank which came from an engine with a 3.125" bore and a 3.750" stroke. Put that 3.750" stroke crank in a stock bore 350 block and you have, according to my formula, 377 cubic inches. And that is true, but most people who do this also bore the engine out to say 4.030" and it is this increase in bore that gives a final displacement of 383 cubic inches.
Regards from Down Under
aussijohn
Of course you have the correct "exact" formula, but only a very small miority of people can work that out without a calculator. My formula works perfectly for any eight cylinder engine within one cubic inch, providing it has a 4.000" bore. Period.
Liquid,
Sorry to confuse you, of course I made ONE mistake. With the 327 engine, I said "3.25" bore" when I meant 3.25" STROKE. All here should know that 302's, 327's and 350's ALL have a 4.000" bore, and my formula works for them all, even the "383". Most engines here use a 350 block and a "400" crank which came from an engine with a 3.125" bore and a 3.750" stroke. Put that 3.750" stroke crank in a stock bore 350 block and you have, according to my formula, 377 cubic inches. And that is true, but most people who do this also bore the engine out to say 4.030" and it is this increase in bore that gives a final displacement of 383 cubic inches.
Regards from Down Under
aussijohn
Melting Slicks
Joined: Aug 2004
Posts: 2,063
Likes: 1
From: Beverly Massachusetts
Originally Posted by aussiejohn
Stickshift,
Of course you have the correct "exact" formula, but only a very small miority of people can work that out without a calculator. My formula works perfectly for any eight cylinder engine within one cubic inch, providing it has a 4.000" bore. Period.
Liquid,
Sorry to confuse you, of course I made ONE mistake. With the 327 engine, I said "3.25" bore" when I meant 3.25" STROKE. All here should know that 302's, 327's and 350's ALL have a 4.000" bore, and my formula works for them all, even the "383". Most engines here use a 350 block and a "400" crank which came from an engine with a 3.125" bore and a 3.750" stroke. Put that 3.750" stroke crank in a stock bore 350 block and you have, according to my formula, 377 cubic inches. And that is true, but most people who do this also bore the engine out to say 4.030" and it is this increase in bore that gives a final displacement of 383 cubic inches.
Regards from Down Under
aussijohn
Of course you have the correct "exact" formula, but only a very small miority of people can work that out without a calculator. My formula works perfectly for any eight cylinder engine within one cubic inch, providing it has a 4.000" bore. Period.
Liquid,
Sorry to confuse you, of course I made ONE mistake. With the 327 engine, I said "3.25" bore" when I meant 3.25" STROKE. All here should know that 302's, 327's and 350's ALL have a 4.000" bore, and my formula works for them all, even the "383". Most engines here use a 350 block and a "400" crank which came from an engine with a 3.125" bore and a 3.750" stroke. Put that 3.750" stroke crank in a stock bore 350 block and you have, according to my formula, 377 cubic inches. And that is true, but most people who do this also bore the engine out to say 4.030" and it is this increase in bore that gives a final displacement of 383 cubic inches.
Regards from Down Under
aussijohn
its and easy formula to use as well. thanks
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
reply
LIQUID,
Thanks for the reply, I'm glad that you now understand it. I remember when I first started on this Forum about three or four years ago, there was a popular saying that I haven't seen for a while:-
"Knowledge gained and not shared is knowledge lost."
I heartily concur.
Regards from Down Under
aussiejohn
Thanks for the reply, I'm glad that you now understand it. I remember when I first started on this Forum about three or four years ago, there was a popular saying that I haven't seen for a while:-
"Knowledge gained and not shared is knowledge lost."
I heartily concur.
Regards from Down Under
aussiejohn
Le Mans Master
Joined: Jan 2006
Posts: 8,319
Likes: 7
From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by aussiejohn
LIQUID,
Thanks for the reply, I'm glad that you now understand it. I remember when I first started on this Forum about three or four years ago, there was a popular saying that I haven't seen for a while:-
"Knowledge gained and not shared is knowledge lost."
I heartily concur.
Regards from Down Under
aussiejohn
Thanks for the reply, I'm glad that you now understand it. I remember when I first started on this Forum about three or four years ago, there was a popular saying that I haven't seen for a while:-
"Knowledge gained and not shared is knowledge lost."
I heartily concur.
Regards from Down Under
aussiejohn
I like your rule of thumb my friend from down under, will make for a good discussion at the local watering hole with my gearhead friends tonight
tim
Last edited by sweethence; Mar 1, 2006 at 09:51 AM.
Safety Car
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From: Algonac Michigan
