Big Healey Gearbox Specs

Austin-Healey

Tech Data for 100/6 & 3000, Mk 1 – 2- 3

(information from AUSTIN-HEALEY: OWNERS WORKSHOP MANUAL, by Kenneth Ball, Autopress Ltd. 1973)


Dimensions are in inches unless otherwise stated

“A” refers to the 2639 cc engine with 2 port head
“B” refers to the 2912 cc engine 
“C” refers to the 2639 cc engine with 6 port head


While I have tried to be accurate as possible, it is very likely that there are typos and errors on this page.  Please note that no one associated with austin-healeys.com assumes any liability arising from the information presented here.  If you find a mistake, please let me know from the contact page and I will correct it.


CLUTCH & GEARBOX DETAILS

Clutch:    
      A and B make   Borg and Beck
     A   Mks I and II type Dry plate
     B   Mks II and III (from No. 29F.4898) 9 DSG diaphragm
     A   Diameter 9 (229 mm)
     B   Mks I and II 10 (254 mm)
     A   Friction area 2 x 36.5 sq in (235 sq cm)
     B   2 x 39 sq in (241.5 sq cm)
     A and B  Thickness .150 (3.8 mm)
     A and B  Release bearing Copper carbon graphite
     A   Number of springs 9
     B   12
     B   Colour of springs Yellow/light green
     A   Total axial spring pressure 1215 to 1305 lb (551 to 592 kg)
     B   1620 to 1740 lb (735 to 789 kg)
     A and B  Distance thrust race to thrust plate .10 (2.54 mm)
     A and B  Thrust plate travel to fully released .42 to .47 (10.66 to 11.93 mm)
     B        Mks II and III from No. 29F.4898    
               Clutch plate diameter   9.63 (203.2 mm)
               Material   Wound yarn
               Number of damper springs   6
               Damper spring load   110 to 120 lb (49.8 to 54.3 kg)
               Damper spring colour   Dark grey/light green
               Release bearing   Graphite (MY3D)
               Fluid   Castrol Girling Amber Brake Fluid
Transmission:    
     A and B  Gearbox type Synchromesh on 2, 3, top
     A and B  Gear type Helical constant mesh
     A and B  Overdrive type Laycock de Normanville (electric control)
     A                           Gear Ratios     First 3.076:1
     B   2.93:1
     From engine #10897 (overdrive)    
     Engine #11342 (without overdrive)   2.83:1
     MkIII   2.637:1
     A      Second 1.913:1
     B                            As above   2.053:1
                 2.06:1
                 2.07:1
     A      Third  1.333:1
     B   1.309:1
                 1.31:1
                 1.306:1
     A      Overdrive third  1.037:1
     A and B      Fourth  Direct
     A      Overdrive  .778:1
     B   .822:1
     MkIII   .820:1
     A      Reverse  4.16:1
     B   3.78:1
                 3.72:1
     MkIII   3.391:1
Standard box:    
     A      First  12.027:1
     B                           (3.545:1 axle)   10.386:1
     From engine #11342   10.209:1
     Mk III   9.348:1
     A      Second 7.48:1 
     B   7.877:1
                  7.302:1
                 7.341:1
     A      Third  5.212:1
     B   4.640:1
                 4.743:1
                 4.629:1
     A      Fourth 3.91:1
                 3.545:1
     A      Reverse 16.4:1
     B   13.4:1
                 13.127:1
                 12.021:1
Including overdrive:    
     A      First  12.6:1
     B                           (3.909:1 axle)    11.453:1
     From engine #10897   11.257:1
     MkIII   10.308:1
     A      Second  7.84:1
     B   8.025:1
                 8.052:1
                 8.095:1
     A      Third  5.47:1
     B   5.116:1
                 5.120:1
                  5.105:1
     A      Third, overdrive 4.24:1
     B   4.195:1
                 4.198:1
                 4.188:1
     A      Fourth  4.1:1
     B   3.909:1
     A      Fourth, overdrive 3.19:1
     B   3.205:1
                 3.205:1
                 3.207:1
     A      Reverse  17.1:1
     B    14.776:1
                 14.541:1
                 13.255:1
Layshaft bearing:    
     A and B Type Needle roller
     A and B Number of rollers 46
     A and B Length of roller 1.551 (39.6 mm)
     A and B Diameter of roller 3.118 (3 mm)
     B  End float .0120 (.30 mm)
Mainshaft bearing:    
     A and B Make R&M
     A and B Type MJ 35
     A and B Size 1.39 x 3.15 x .827 (35 x 80 x 21 mm)
First motion shaft bearing:    
     A and B Make R&M
     A and B Type IM.J40.G
     A and B Size 1.58 x 3.55 x .905 (40 x 90 x 23 mm)
Oil capacity standard box   5 pints (2.8 litres)
Oil capacity overdrive fitted   6 1/4 pints (3.6 litres)
   Synchromesh hubs end float      Second  .007 (.18 mm)
                    Third. fourth  .031 (.8 mm)

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