1200+1300=1400 Help!!

[buzbi]

just ruined my day could any one shead some light on how this conversion actually works in a 1.2 block? as far as i can see and have heard you still use the 1200 pistons and block with 1300 crank and con rods??

heres my problem,

got new head bolts today. i thought before i build it back up i'll dig out my college notes and measure the actual cc of the engine. now i was told by the previous owner that it had the 1.3 crank and rods fitted and that makes it 1400 high compression...

now

bore area = bore x bore x pie / 4

so:

7.8 x 7.8 x 3.14159 / 4 = 47.78

stroke = 6.25

volume of one cylinder = 47.78 x 6.25 = 298.63

volume of all cylinders = 298.63 x 4 = 1194.52 cc

so after all that its just a standard :mad: or have i done somthing wrong?

[rallydak]

i am almost sure it is pie mulitplied by the radius squared mulitplied by the stroke and then multiply it by 4

so this should be
bore radius - 3.89cm
stroke - 7.34cm

3.14 x (3.89x3.89) x 7.34 = 348.9354834

348.9354834 x 4 = 1395.741934cc

your stroke seems to be over a cm too short. however im no expert on this stuff im just working this out from looking at the haynes manuals and my knowledge of maths.

[burgo]

BORE (mm) X BORE (mm) X STROKE (mm) X .0031416 = Engine Displacement in CC's

[MK999]

i am almost sure it is pie mulitplied by the radius squared mulitplied by the stroke and then multiply it by 4

so this should be
bore radius - 3.89cm
stroke - 7.34cm

3.14 x (3.89x3.89) x 7.34 = 348.9354834

348.9354834 x 4 = 1395.741934cc

your stroke seems to be over a cm too short. however im no expert on this stuff im just working this out from looking at the haynes manuals and my knowledge of maths.

how did you get 3.89 bore radius from a 7.8 diameter? and (pi)R^2 is the same as ((pi)D^2)/4

[burgo]

how did you get 3.89 bore radius from a 7.8 diameter? and (pi)R^2 is the same as ((pi)D^2)/4just use the formula i put and you dont need to worry about pie or any of that shizzle

[mowgli]

just use the formula i put and you dont need to worry about pie or any of that shizzle

burgo's calcultation works fine for any 4 cylinder engine.



the 1300 is 73.4 stroke & the 1200 is only 62.9

i'm guessing somebody told you a bit of a lie about your engine.

[Stuart]

or have a play with the engine capacity calculator in sig linky :D

[rallydak]

well the bore is 77.8mm which is 7.78cm which is the diameter and half of this which is 3.89cm thats how i got the radius.

[mowgli]

well the bore is 77.8mm which is 7.78cm which is the diameter and half of this which is 3.89cm thats how i got the radius.

we all know that. the issue was not with the sums, it was the outcome, which was basically that the lad has got a 1.2

[MK999]

just use the formula i put and you dont need to worry about pie or any of that shizzle

Actually your formula has pi/1000 in it :p It's exactly the same formula reworded lol

rallydak, my bad, late night dividing by 2 went balls up lol

[buzbi]

cheers for all your input guys. but its just a 1.2 :cry:.

now next question: how does the conversion work? because at tdc the piston is level with the block, so with the 1300 crank and rods for a longer stroke to get 1400, surely the pistons would protrude from the block?:confused:

http://photos-g.ak.fbcdn.net/hphotos-ak-snc1/hs010.snc1/2891_76601922709_682607709_1596550_2731712_n.jpg

[mowgli]

cheers for all your input guys. but its just a 1.2 :cry:.

now next question: how does the conversion work? because at tdc the piston is level with the block, so with the 1300 crank and rods for a longer stroke to get 1400, surely the pistons would protrude from the block?:confused:

http://photos-g.ak.fbcdn.net/hphotos-ak-snc1/hs010.snc1/2891_76601922709_682607709_1596550_2731712_n.jpg

the crank is a longer throw, but the rods are shorter. and the piston height is the same