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I have a 94 zu trooper, but had to rebuilt the whole engine. I had to bore over the block (0.60 over). I know the piston diameter is something like 3.67" and makes it a 3.2L, but somebody knows how to calculate the real size of my engine???
And also, does anybody knows if it does any change in engine power???
 

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angel.sanchez said:
I have a 94 zu trooper, but had to rebuilt the whole engine. I had to bore over the block (0.60 over). I know the piston diameter is something like 3.67" and makes it a 3.2L, but somebody knows how to calculate the real size of my engine???
And also, does anybody knows if it does any change in engine power???
Should be simple. The original bore was 3.67" Your new bore is 3.73". You know that the volume of a cylinder is the Pi*r^2*d,where r is the radius or 1/2 the bore and d is the stroke. Nothing else changed but you know the bore increased by a ratio of 3.73/3.67. Since the radius is sqared in the above formula,square that ratio,and you get 1.033. That means your final displacement is about 3.3.

(actually,the original displacement is closer to 3.15L if you multiply the numbers out in the service manual which puts you around 3.25L)

A larger displacement should increase power by a small amount. Increasing bore and stroke is a classic way to increase power. I cant imagine a 3% increase will give you much,but it should give you something.
 

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mallen said:
angel.sanchez said:
I have a 94 zu trooper, but had to rebuilt the whole engine. I had to bore over the block (0.60 over). I know the piston diameter is something like 3.67" and makes it a 3.2L, but somebody knows how to calculate the real size of my engine???
And also, does anybody knows if it does any change in engine power???
Should be simple. The original bore was 3.67" Your new bore is 3.73". You know that the volume of a cylinder is the Pi*r^2*d,where r is the radius or 1/2 the bore and d is the stroke. Nothing else changed but you know the bore increased by a ratio of 3.73/3.67. Since the radius is sqared in the above formula,square that ratio,and you get 1.033. That means your final displacement is about 3.3.

(actually,the original displacement is closer to 3.15L if you multiply the numbers out in the service manual which puts you around 3.25L)

A larger displacement should increase power by a small amount. Increasing bore and stroke is a classic way to increase power. I cant imagine a 3% increase will give you much,but it should give you something.
You forgot to square the hypotenuse of the kitchen sink and carry the two.

:lol:
 

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:lol:
 

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Since that formula only calculates the displacement increase of ONE CYLINDER... I think you'll need to try again.

0.060" over is huge for most blocks, hope you still have some meat between the cyls.

~psguardian
 

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I was gonna say something before but didn't. 60 thou is the max allowed at most local race tracks and that big of an increase in bore size is massive! Of course without the cams and intakes and exhaust etc to feed those holes, your not gonna see a lot of improvement.
 

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angel.sanchez said:
I have a 94 zu trooper, but had to rebuilt the whole engine. I had to bore over the block (0.60 over). I know the piston diameter is something like 3.67" and makes it a 3.2L, but somebody knows how to calculate the real size of my engine???
And also, does anybody knows if it does any change in engine power???
SINCE THE ORIGINAL 3.2 ENG WAS ACTUALLY 3176 CC BORING IT 1.5 MM (.060) YOU NOW HAVE 3267 CC WHICH WOULD BE ADVERTIZED AS A 3.3 ENG

POWER WOULD GO UP SOME , SINCE THE COMP RATIO ALL SO INCREASED PROB A TENTH OF A POINT

ACTUALL HP INCREASE PROB A SAFE 6-8 HP.

THAT WAS ACTUALLY A BIG CUT IN THE CYL WALLS , SURE HOPE YOU USED NEW HEAD BOLTS, AND HAVE A GOOD COOLING SYSTEM YOU DONT WAN TO OVER HEAT THE ENG NOW WITH THE CYL WALLS THAT THIN,

JERRY
 

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psguardian said:
Since that formula only calculates the displacement increase of ONE CYLINDER... I think you'll need to try again.

0.060" over is huge for most blocks, hope you still have some meat between the cyls.

~psguardian
Nope,becuase the ratio of the original to final volume of a single cylinder is equal to the increase for the entire engine. Thats all I did was calculate what the ratio was,then apply that ratio to the total volume.
 
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