# B17 Crank into LS

Discussion in 'Engine Building' started by 22crazy, Feb 2, 2003.

1. ### 22crazySenior Member

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is there a way to calculate the displacement using the stroke, bore, rod lenght? oh yah what about putting in a b17 crank into an ls...would that help to rev higher...and what are the draw backs

2. ### lsvtecGNU/Linux Evangelist

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Yes, if you know bore and stroke you can calculate displacement.
Displacement in cc's (divide by 1000 to get liters) = r^2 * 3.14159 * stroke (in centimeters) * 4
r = 1/2 the bore in mm * 10
Yes, you can run a B17 crank in an LS engine, you lose displacement.

3. ### K2e2vinSenior Member

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simpler way to say it- pi(r^2)s*cylinders=displacement
convert to cm (for mm to cm, move decimal one to the left), r=.5*bore, s=stroke

if you are using custom rods or something (shorter rods) deck height-.5s-rod=x
replace the s with the x in the formula above and add that to the answer you got.

ex: b18c block, b18c rods, b17 cranks;
3.14(4.05^2)8.14=419.4cc per cylinder, 1677.6cc total
18.15-(8.14*.5)-13.79=.29cm; 3.14(4.05^2).29=14.94cc per cylinder, 59.76cc gained