Big Healey Engine 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.


ENGINE SPECIFICATIONS

Bore and stroke:    
     A, C   3.125 x 3.5 (79.375 x 88.9 mm)
     B   3.281 x 3.5 (83.34 x 88.9 mm)
Compression ratio:    
     A   8.25:1
     B   9:01
     C   8.7:1
Crankshaft:    
     Main journal diameter:    
               A, B, C   2.3742 to 2.3747 (60.305 to 60.317)
     Main bearings:    
               A, B, C. Length   1.495 to 1.505 (37.973 to 38.227 mm)
               A, B, C. Material   White metalled steel shell, lead indium plated
Diametrical clearance:    
     A, B, C   .0013 to .0028 (.033 to .071 mm)
Undersizes:    
     A   -.010, .020, .030, .040
     B and C   -.010, .020
Crankpin diameter:    
     A, B, C   2.0000 to 2.0005 (50.80 to 50.8127 mm)
Thrust washers, standard:    
     A, B, C   .091 to .093 (2.315 to 2.366 mm)
                 +.0025 (.063 mm)
                  +.005  (.127 mm)
                 +.0075 (.190 mm)
                 +.010  (.254 mm)
Bore oversizes:    
     A, B, C   .010,.020,.030,.040 (.25,.50,.76,1.02 mm)
Firing order:    
     A, B, C   1,5,3,6,2,4
Torque:    
     A   142 lb ft at 2400 rev/min (19.77 kg m)
     B   167 lb ft at 2700 rev/min (23.09 kg m)
     C   150 at 3000 rev/min
BMEP:    
     A   139 lb/sq in (9.77 kg/sq cm)
     B   142 lb/sq in (9.98 kg/sq cm)
Engine idle speed (approx.):    
     B   500 rev/min
Connecting rods:    
     Length between centres:    
               A, B, C   6.601 to 6.605 (167.66 to 167.76 mm)
     Side clearance:    
               A, C   .004 to .007 (.10 to .18 mm)
               B   .005 to .009 (.13 to .23 mm)
Big-end bearing material:    
     A, B, G   White metalled steel shells, lead indium
Big-end diametrical clearance:    
     A   .0005 to .002 (.0127 to .051 mm)
     B   .002 to .0035 (.051 to .089 mm)
Small-end bush:    
     A   .8750 to .8755 (22.225 to 22.328 mm)
     B   .8749 to .8751 (22.22 to 22.23 mm)
Reground crankpin sizes:    
     A   .010, .020, ,030, .040
                 (.254, .508, .762, 1.016 mm)
     B   .010, .020 (.254, .508 mm)
Pistons:    
     Material   Low expansion aluminum
     A, B, C   Alloy
     Clearance at skirt (right angles to gudgeon pin):    
               A   .0226 to .0008 (.066 to .020 mm)
               B Top .0032 to .0043 (.081 to .109 mm)
               Bottom .0010 to .0016 (.025 to .040 mm)
     Width of ring groove:    
               A Compression .0952 to .0962 (2.410 to 2.436 mm)
               Oil .189 to .190 (4.81 to 4.83 mm)
               B Compression .1417 to .1482 (3.599 to 3.764 mm)
               Oil .1567 to .1632 (3.98 to 4.137 mm)
     Oversizes:    
               A, B, C   +.010,.020,.030,.040
                 (.25,.50,.76,1.02 mm)
Piston rings:    
     A, B   3 compression (2 taper), 1 oil control
     C   First ring taper
     Width compression:    
               A   .0938 to .0928 (2.383 to 2.357 mm)
               B Compression and oil .1262 to .1332 (3.2055 to 3.3832 mm)
               A Width-oil .1865 to .1875 (4.737 to 4.762 mm)
     Clearance in groove:    
               A Compression .0034 to .0014 (.086 to .036 mm)
               Oil .0015 to .0035 (.038 to .088 mm)
               B Compression and oil .0015 to .0035 (.038 to .088 mm)
     Ring gap:    
               A Compression and oil .009 to .014 (.23 to .35 mm)
               B   .013 to .018 (.33 to .46 mm)
Gudgeon pins. Type:    
     A   Clamped in rod
     A, B from #40501   Fully floating (circlips)
     A, B    Selective, push in piston
     A, B    .8748 to .8750 (22.215 to 22.220 mm)
Camshaft:    
     Journal diameters:    
               A, B Front 1.78875 to 1.78925 (45.434 to 45.447 mm)
               Middle front 1.76875 to 1.76925 (44.926 to 44.939 mm)
               Middle rear 1.74875 to 1.74925 (44.418 to 44.431 mm)
               Rear 1.72875 to 1.72925 (43.910 to 43.923 mm)
     End float taken on thrust plate at front end:

 

 
               A, B   .003 to .006 (.076 to .152 mm)
Camshaft bearings:    
     Number and type:    
               A and B   4 thinwall rolled bush
     Outside diameter:    
               A and B Front   1.9205 (48.780 mm)
               A and B Middle front   1.9005 (48.272 mm)
               A and B Middle rear   1.8805 (47.762 mm)
               A and B Rear   1.8605 (47.252 mm)
     Inside diameter, reamed in position:    
               A and B Front   1.79025 to 1.79075 (45.472 to 45.485 mm)
               A and B Middle front   1.77025 to 1.77075 (44.964 to 44.977 mm)
               A and B Middle rear   1.75025 to 1.75075 (44.456 to 44.469 mm)
               A and B Rear   1.73025 to 1.73075 (43.946 to 43.959 mm)
     Clearance:    
               A and B   .002 to .001 (.051 to .025 mm)
Tappets:    
     A and B Type Cylindrical, spherical foot
     A and B Diameter .93725 (23.81 mm)
     A and B Length 2.548 (64.72 mm)
Valves:    
     Seat angle inlet:    
               A   30 deg.
               B   45 deg.
     Seat angle exhaust:    
               A and B   45 deg.
     Head diameter inlet:    
               A   1.693 to 1.683 (42.99 to 42.75 mm)
               B   1.750 to 1.745 (44.45 to 44.32 mm)
     Head diameter exhaust:    
               A   1.420 to 1.415 (36.07 to 35.94 mm)
               B   1.5625 to 1.5575 (39.69 to 39.56 mm)
     Stem diameter inlet:    
               A and B   .34175 to .34225 (8.68 to 8.69 mm)
     Stem diameter exhaust:    
               A and B   .34175 to .34255 (8.68 to 8,69 mm)
     Valve lift:    
               A and B   .3145 (8.054 mm)
               Mks II and III   .368 (9.36 mm)
     Stem guide clearance inlet:    
               A and B   .0025 to .0015 (.063 to .038 mm)
     Stem guide clearance exhaust:    
               A and B   .002 to .001 (.051 to .025 mm)
     Seat face width inlet:    
               A and B   .091 to .097 (2.31 to 2.46 mm)
     Seat face width exhaust:    
               A and B   .198 to .217 (5.03 to 5.51 mm)
Valve guides:    
     Length inlet:    
               A and B   2.266 (57.55 mm)
     Length exhaust:    
               A and B   2.578 (65.49 mm)
     Fitted height above head:    
               B Inlet   1.348 (34.23 mm)
               B Exhaust   1.036 (26.32 mm)
Valve springs:    
     Free length:    
               A and B Inner 1.969 (50 mm)
               A and B Outer 2.047 (51.99 mm)
               Mks II and III Outer 2.031 (51.5 mm)
     Fitted length inner:    
               A   1.517 (38.53 mm) (load 25.3 lb. 11.476 kg)
               B   1.504 (38.2 mm) (load 26 lb. 11.8 kg)
     Fitted length outer;    
               A   1.607 (40.82 mm) (load 54.2 lb. 24.58 kg)
               B   1.594 (40.49 mm) (load 55.7 lb. 25.2 kg)
               Mks II and III   Load 67.5 lb. (30.63 kg)
Rockers:    
     Bushes:    
               A and B   Steel and whitemetal
     Outside diameter before fitting:    
               A and B   .913 (23.17 mm)
     Inside diameter (reamed in position):    
               A and B   .8115 to .8125 (20.62 to 20.65 mm)
     Clearance:    
               A and B   .0025 to .0005 (.083 to .012 mm)
     Bore of arm:    
               A and B   .909 to .910 (23.076 to 23.101 mm)
Valve timing: Marking:    
               A and B   Adjoining gear teeth marks
     Chain pitch and number of pitches:    
               A and B   .375 (9.525 mm) 62
     Rocker clearance for timing:    
               A   .0234 (.610 mm)
               B   .030 (.76 mm)
     Inlet valve opens:    
               A Mks I and II (to 29F.2285) 5 deg. BTDC
               B Mk II (from 29F.2286) 10 deg. BTDC
               MkIII 16 deg. BTDC
     Inlet valve closes:    
               A Mks I and II (to 29F.2285) 45 deg. ABDC
               B Mk II (from 29F.2286) 50 deg. ABDC
               MkIII 56 deg. ABDC
     Exhaust valve opens:    
               A Mk I 40 deg. BBDC
               Mk II (to 29F.2285) 51 deg. BBDC
               B Mk II (from 29F.2286) 45 deg. BBDC
               Mk III 51 deg. BBDC
     Exhaust valve closes:    
               A Mk I 10 deg. ATDC
               Mk II (to 29F.2285) 21 deg. ATDC
               B Mk II (from 29F.2286) 15 deg. ATDC
               MkIII 21 deg. ATDC
Valve rocker clearance:    
     A  Engine Hot .012 (.3 mm)
     B  Engine Cold .012 (.3 mm)
     Mks II and III (Competition)   .015 (.34 mm)
Oil pump:     
     Type:    
               A   Rotor
               B   Gear
Pressure, running:    
     A   55 to 60 lb/sq in (3.9 to 4.2 kg/sq cm)
     B   50 lb/sq in (40 mile/hr) (3.52 kg/sq cm)
Pressure, idling;    
     A   25 to 30 lb/sq in (1.758 to 2.109 kg/sq cm)
     B   20 lb/sq in (800 rev/min) (1.4 kg/sq cm)
Release valve spring length:    
     A   2.562 (65.09 mm)
     B   2.687 (68.26 mm)
     Number of coils:    
               A and B   13
     Diameter:    
               A and B   .484 +.000 -.015
                 (12.30 mm +.000 mm -.318 mm)
Oil filter type:    
     A   Fullflow – Tecalemit
     B   Fullflow-Tecalemit or Purolator
Oil capacity (including filter):    
     A and B   12 3/4 pints (7.25 litres)
Flywheel:    
     Diameter:    
               A and B   12.8125 (325.45 mm)
     Number of teeth on starter ring:    
               A and B   106
Cooling system:    
     Type:    
               A   Pump and thermostat
               B   Pressurized thermosyphon, thermostat
                 control, pump and fan
     Capacity (without heater)    
               A   20 pints (11 litres)
               B   18 pints (10.2 litres)
     Thermostat setting:    
               B   70 C (158 F)
               Mks II and III from engine #29F.2592

 

83 C (182 F)

 

2 thoughts on “Big Healey Engine Specs

  1. digby kirby

    Would like to find more information about the origin of the big healey power train and transmission. Were these engines and transmissions originally used in mail trucks or London
    double decker buses as we have heard? Enjoy your site. Good work.

    Reply

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