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RE: kinda o/t engine question

To: datsun-roadsters@autox.team.net
Subject: RE: kinda o/t engine question
From: TCR2B@aol.com
Date: Sat, 22 Mar 2003 02:12:08 EST
Adam,

A couple of things:
New bore dia. = 78.762 mm 
1mm=.03937in.
.030/.03937=.762(mm) oversize
Your displacement calculation appears to be correct:
it was easier for me to figure it in inches and then convert back to mm


displacement=volume x 4
volume=area x height
area=pi x r (squared)  


77.6 / 25.4 =  3.0551 in (stroke value) [height]
78.762 / 25.4 = 3.100 in
3.100 / 2 =  1.550 in (radius value of  bore)
1.550 x 1.550 x 3.1415 (pi) = 7.5474 cu. in. 
7.5474 cu. in. x 3.0551 = 23.0573 in. cu. (per/cylinder)
23.0573 x  4 (cylinders) =  92.229 in. cu.
1 liter = 1000 cc ~ 61 in. cu.
92.229 / 61 = 1.511 liters = 1511 cc

As far as compression ratio goes:  this hasn't changed at all.  Compression 
ratio is a function of stroke at top dead center (high as the piston goes) 
vs. bottom dead center (as low as piston goes).  You've changed the bore 
diameter, not the stroke.  
Some of you other old-timers can check me on this, I believe I'm right.

Mike Davenport
'67 1600
President - Rustburg Roadsters Club

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