b__sosick Posted August 3, 2005 Share Posted August 3, 2005 I don't understand it. How is it that there are 2 liter inline sixes, and then on the other hand, there are 3.0L+ with the same amount of cylinders? what, exactly does displacement measure? I'm not even sure what i'm asking here. i'm sick of talking about things that I don't fully understand. thanks Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted August 3, 2005 Share Posted August 3, 2005 get out your calculator the formula is BORE x BORE x stroke X NUMBER OF CYLINDERS x .7854= displacement DISPLACEMENT is the voluum of the cylinder formed by the travel the pistons displace between top dead center and bottom dead center times the number of cylinders, example if an engine had a 4" dia. piston and it moved down 3.48" between its upper and lower extremes that cylinder would displace, aproximately 43.73 cubic inches, eight of those in a sbc 350 would be the displacement 43.73 x 8 =349.8 or rounded to the nearest inch,to 350 EXAMPLE 4.030" bore times 4.030 " bore times 3.75" stroke times eight cylinders times .7854 = 382.7 OR a 383 sbc heres other usefull calculators http://www.csgnetwork.com/compcalc.html http://www.angelfire.com/fl/procrastination/motor.html http://www.4racecars.com/calculators/displacement_calculator.html http://hotrodworks.net/hotrodmath/hotrodmath.html http://users.erols.com/srweiss/index.html#jcalc http://users.erols.com/dmapes/GEARCLC.HTM http://www.doverusa.com/compression-height-calculator.htm http://kb-silvolite.com/calc.php http://www.bgsoflex.com/crchange.html http://victorylibrary.com/mopar/intake-tech-c.htm http://www.rbracing-rsr.com/runnertorquecalc.html http://www.newcovenant.com/speedcrafter/calculators/runnerarea.htm http://www.newcovenant.com/speedcrafter/calculators/intake.htm http://www.bgsoflex.com/intakeln.html http://www.me.psu.edu/me415/SPRING02/intake/intake.html http://headerdesign.com/extras/engine.asp#Intake_Manifolds http://www.team-integra.net/sections/articles/showArticle.asp?ArticleID=466 http://turbonation.com/intake.htm http://cochise.uia.net/pkelley2/DynamicCR.html http://victorylibrary.com/mopar/header-tech-c.htm you might want to buy and read this http://www.overstock.com/cgi-bin/d2.cgi?...&kid=281466 http://hpbooks.carshopinc.com/product_in...6119779a324aaa8 http://sabooks.carshopinc.com/product_info.php/products_id/46840/06 you really should get these books and read them before going any further, it will help a good deal, while only the basic info is presented it still makes for a good knowledge base, and referance DO YOURSELF A HUGE FAVOR buy these books, FIRST it will be the best money you ever spent, read them, and you will be miles ahead of the average guy. youll save thousands of dollars and thousands of hours once youve got a good basic understanding of what your trying to do! http://www.amazon.com/exec/obidos/tg/det...F8&v=glance http://www.amazon.com/exec/obidos/tg/det...nce&s=books HOW TO BUILD THE SMALL BLOCK CHEVEROLET by LARRY ATHERTON&LARRY SCHREIB http://www.amazon.com/exec/obidos/tg/det...2699400-6836852 . HOW TO BUILD MAX PERFORMANCE CHEVY SMALL BLOCKS ON A BUDGET by DAVID VIZARD . JOHN LINGENFELTER on modifying small-block chevy engines Quote Link to comment Share on other sites More sharing options...
auxilary Posted August 3, 2005 Share Posted August 3, 2005 in layman's terms, what grumpy is saying, your displacement is the volume of the space between the piston at full up stroke and full down stroke. let's say you have a 2.8 liter L6... Stock bore is 87mm (diameter of the cylinder) and stock stroke is 79mm. Using grumpy's formula, BORE x BORE x stroke X NUMBER OF CYLINDERS x .7854, and plugging in the numbers, the result is 2,817,784 mm^3, or 2.8 liters. So to stroke it to a 3 liter (hence the term, 3 liter stroker motor) the common thing to do is to replace the crankshaft with more aggressive lobes. This makes the piston rod travel farther up and down, and therefore the stroke (or the length piston has travelled from lowest point to top dead center) is increased from 79mm to 83 using a maxima diesel crankshaft. Now, if you plug in the numbers using the same formula, you get 2,960,457 mm^3, or 2.96 liter stroked motor...roughly 3 liters. When a motor is bored, it means the cylinder diameter is increased, and you would fit larger pistons into the block in order to increase the displacement without changing the stroke. Or you could combine both for optimal displacement. However, boring a block can only be done so much because of the thickness of cylinder sleeve walls. Too thin and you run the risk of cracks and breaking. Hope that helped Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted August 3, 2005 Share Posted August 3, 2005 I am amazed at the restraint shown by Alex and Grumpy. Good Show Gents. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted August 3, 2005 Share Posted August 3, 2005 Yep, displacement has nothing to do with number of cylinders. It's a "sweep volume" of all cylinders combined Some truck has a 12L inline 6, which work out to be 2 liter per cylinder. While on the other hand some race engines are low displacement V8s or V12s Quote Link to comment Share on other sites More sharing options...
auxilary Posted August 4, 2005 Share Posted August 4, 2005 I am amazed at the restraint shown by Alex and Grumpy. Good Show Gents. lol, no problem? do I come off as that much of an ***? Quote Link to comment Share on other sites More sharing options...
Tim240z Posted August 4, 2005 Share Posted August 4, 2005 lol, no problem? do I come off as that much of an ***? ....oh no....just too easy... Quote Link to comment Share on other sites More sharing options...
auxilary Posted August 4, 2005 Share Posted August 4, 2005 Tim http://dictionary.reference.com/search?q=rhetorical .........*shaking head* art of sarcasm is long lost on you, oh indigestion-plagued one with fierce power of mudbutt Quote Link to comment Share on other sites More sharing options...
skipzoomie Posted August 4, 2005 Share Posted August 4, 2005 Very good and easy to understand info, you guys. bo is a youngn'. Remember, we all started just as he is. Thanks to all for the patience. Sure beats some of the crap I've seen. Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted August 4, 2005 Share Posted August 4, 2005 lol, no problem? do I come off as that much of an ***? Not anymore, did you get laid recently? That usually fixes the problem. *Sorry for the curde remark, but I don't know how else to say it. Quote Link to comment Share on other sites More sharing options...
auxilary Posted August 4, 2005 Share Posted August 4, 2005 Hey, if I was rude to you, I apologize, I don't really recall. I will give newbies who don't follow simple instructions a hard time.... Did I get laid? no. Opposite, I lost the one I love (not in the sense of mortality) Quote Link to comment Share on other sites More sharing options...
BrandonsZ Posted August 4, 2005 Share Posted August 4, 2005 Alex, Sorry to hear about that, been there, I always improved because of it though. Agreed, I was probably an idiot anyway, I take this board more seriously now. Good luck on the swap. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted August 5, 2005 Share Posted August 5, 2005 Did I get laid? no. Opposite' date=' I lost the one I love (not in the sense of mortality)[/quote'] Crap... Quote Link to comment Share on other sites More sharing options...
b__sosick Posted August 5, 2005 Author Share Posted August 5, 2005 Thanks! Keep in mind, guys...you all had to start somewhere :[ Quote Link to comment Share on other sites More sharing options...
Here comes trouble Posted August 6, 2005 Share Posted August 6, 2005 I am re-starting after 2 years and have difficulty following a lot of the new threads...... Bo.... just hang in there there is method to these fellow's madness Quote Link to comment Share on other sites More sharing options...
b__sosick Posted August 6, 2005 Author Share Posted August 6, 2005 so low displacement, large number of cylinder motors (l20, rb20 etc) have 6 very small pistons/cylinders, correct? : Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted August 6, 2005 Share Posted August 6, 2005 Yes. small bore or short stroke or both. Quote Link to comment Share on other sites More sharing options...
b__sosick Posted August 7, 2005 Author Share Posted August 7, 2005 that's really....goofy I don't understand what the point of having such low displacement but with all the added bweight of extra pistons and such. *shrug* Quote Link to comment Share on other sites More sharing options...
auxilary Posted August 7, 2005 Share Posted August 7, 2005 it's not that significant. the beauty of inline 6 engines is that they're balanced, produce much better torque curves than their inline4 counterparts, and are smoother. If you go by your question, why not just have one big 6 liter cylinder, right? When you drive a stock Z, it feels pretty smooth, doesn't it? no serious engine vibrations, low end torque off the line I think cyl 1 and 5 on the Z motor basically cancel each other out when it comes to vibration 4 cylinder engines in rwd configurations weren't common until later in the century because there was no real need to have a 4 cyl. 4 cylinder engines really came out of necessity when everyone started converting to fwd, and it helped a lot with space up front because now the transmission had to sit to the side of the motor Quote Link to comment Share on other sites More sharing options...
b__sosick Posted August 7, 2005 Author Share Posted August 7, 2005 ^^^ That helps alot! thanks! Quote Link to comment Share on other sites More sharing options...
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