kawa74
Expert Class
Posts: 226
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posted August 15, 2010 02:03 AM
G-Force's, why engines fail
The Force of Gravity will find the weakest part?? I found a formula on Engine & Fuel Engineering, Max Piston Speed, Rob Hughs of Orient Express, 23 Mar, 04 22:17, an 26 Mar, 04 0:58 hrs.
example: ZX-12 83mm bore x 55.4mm stroke , J&E replacement piston 229grams
Piston Speed Calculater=11,500, 55.4 = 4180ft per min = 69.67ft per sec
11,500 / 60 = 191.66 revs per sec 1 /191.66=.0052175 / 4=.0013 =
1 / .0013 = 769.23076923 x 69.67= 53592.3076922 / 32ft per sec, per sec=1675 Gs
1675Gs @ TDC & BDC, it stops 2 times every rev. A 229gr piston wt = 1675 x 229=383575=
382575 / 454(1 lb) = 844.87 lbs PER PISTON or = 1 gram = 3.689 lbs ??
845 lbs stop & starts, 2 x per rev of 191 per sec . 1 piston wt 845lbs x 4 = 3380 lbs flying around @ 11500 RPM, plus wrist pin , rings and clips. !! Rods and crank made of some good stuff ??
Ok bore an stroke it to 1375cc- 86 x 60 @ 11500. Plug in 60mm= 75.459ft per sec
75.459 x 769.23076923= 58045.3846153 / 32ft per sec = 1814 Gs x bigger J&E piston wt =260 grams = 471640
471640 / 454(1 lb) = 1038.85 lbs PER PISTON or 1 grm= 3.995 lbs 4 x 1038.85= 4155.40 lbs
Think about this 4155 lbs swinging @ 11,500 RPM"s, Stop & Starting
You have added= 775.40 lbs to rotating assembly, @ 191 revs per sec ?? BETTER HAVE the BEST RODS, PINS AND BOLTS MADE?? INCREASE STROKE , RPM"s or Piston wt, G-FORCES go UP ?? Buy the Strongest and Lightest , the VERY BEST !!! OR GAMBLE ??
Pass it On, PS . 93 BMW F1, V10, 3 liter, @ 19,000rpm's pulls 10,000Gs, outer space parts
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"I have never met a man so Ignorant that I coun't Learn from him"..."Galileo"
  
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