| Date |
Topic |
Description |
Change Effective
Chassis # | Engine # |
Service
Memo # |
| May 55 |
First MGA,
First BP15GB Engine |
First MGA production engine, prefix BP15GB. Not necessarily in the first MGA. Engines may be out of sequence +/-100 numbers. |
10101 |
101
First engine not necessarily in the first car. |
|
| Jun 55 |
Body |
Boot floor changed from welded to stamping |
10166 |
|
BD-107B |
| Oct 55 |
Engine |
Timing chain tensioner added, front engine plate and cover modified to match. |
|
259 |
|
| Nov 55 |
Dynamo |
Windowless yoke type dynamo introduced |
|
487 |
|
| Hood & Sidescreens |
Hood frame, canopy and sidescreens modified |
10501 |
|
|
| Dec 55 |
Gearbox |
Gearbox rear extension oil seal modified to second type with rubber seal and felt washer instead of leather seal and felt washer. |
|
744 |
CSM_MG/242 |
| Rear Axle |
Handed hub nuts introduced on rear axle (disc wheel cars) |
10917 |
|
|
| Body |
Word on Car No. plate changed from "Guarantee" to "Warranty" |
10979-11563 |
|
RT-107A |
| Jan 56 |
| Rear Axle |
Handed hub nuts introduced on rear axle (wire wheel cars) |
11450 |
|
|
| Clutch |
Banjo deleted from clutch slave cylinder |
11768 |
|
|
| Feb 56 |
Distributor |
Distributor type DM.2.R4 with pre-tilted contact breakers introduced (part no. 1H811), cable run modified. (New model supersedes old model for all earlier cars replacement parts). |
|
1809 |
|
| Mar 56 |
Engine |
Gearbox mounting plate modified with oil escape recess and groove machined in front face, to prevent oil leaking on clutch. |
|
3289 |
|
| Wipers |
9-1/2” wiper arms with 8” blades introduced on LHD cars |
12800 |
|
|
| Coupe |
MGA Coupe prototype |
13355 |
|
VT-101C1 |
| Apr 56 |
Engine |
Main bearings modified |
|
3511 |
|
| Increased diameter exhaust valve throats and shorter valve guides |
|
4046 |
|
| Harness |
Wiring harness, LH headlamp and flasher lead modified |
13473 |
|
|
| Wipers |
9-1/2” wiper arms with 8” blades introduced on RHD cars |
13612 |
|
|
| Instruments |
New style instruments introduced |
14090 |
|
|
| Heater Control |
Blower switch changed from air control knob to temperature control knob. Exact date and car number for this change are not known, but assumed to happen along with other significant changes in April 1956. |
|
|
See 1st Edition of SPL and
1st Edition of Operator's Manual |
| May 56 |
Clutch |
Clutch withdrawal lever modified with larger diameter pivot bolt. |
|
4525 |
|
| Engine |
Pushrod ends increased in diameter, tappets modified to suit. |
|
5504 |
|
| Diameter of oil return thread to crankshaft rear main bearing reduced. |
|
6615 |
|
| Suspension |
New coil springs with reduced free length |
15152 |
|
|
| Jun 56 |
Engine |
Chromium-plated piston top rings introduced. |
|
5682 |
|
| Vacuum pipe to distributor modified to incorporate fuel trap. |
|
6625 |
|
| Hood |
Vynide hood modified, seams capped and welded after stitching |
16101 |
|
|
| Rear axle |
O-ring seal added to bearing hubs; (axle)3725 for disc wheels; (axle)5225 for disc wheels; (Date uncertain. Not in SPL Jun-56, but is in SPL May-57) |
|
|
WSM Sec H.10 |
| Jul 56 |
Engine |
Improved material spec for water outlet elbow. |
|
7538 (approx) |
|
| Gearbox |
Gearbox front cover improved and oil seal fitted, with attendant changes. *(This is likely misleading, as a rubber oil seal was not introduced until much later in production). Also adding a venting duct (in the front cover) and change of shift rods. |
|
7981 |
|
| Facia |
Facia panel piping modified |
17220 |
|
|
| Instruments |
Speedometer and rev counter cables modified |
17588 |
|
|
| Aug 56 |
Engine |
Connecting rods and caps modified |
|
8570 |
|
| Sep 56 |
Body |
Sill finishers added to improve appearance |
19949 |
|
|
| Hood |
Rear three-quarter lights added to hood canopy (3-window top) |
20162 |
|
|
| Coupe |
First Coupe |
20671 |
|
|
Gearbox
and
Propshaft |
Propeller shaft modified at front. 1-in 10-spline changed to 1-1/16-in 10-spline, and change of length. Dust cover changed from straight welded to bell shape stamping. Seal changed from external to internal type. GB rear housing, output shaft and speedo drive gear changed. |
20753 |
|
|
| Brakes |
Handbrake cable sheathed with PVC to prevent water entering and retain grease |
21021 |
|
|
| Oct 56 |
Gearbox |
Gearbox rear extension oil seal modified to third type with leather seal and leather washer |
|
10990 |
CSM_MG/242 |
| Engine |
Adapter for external oil pipe modified. |
|
11298 |
|
| Vacuum pipe for distributor modified. |
|
11301 |
|
| Rear tappet cover modified |
|
11935 |
|
| Nov 56 |
Cylinder head heater outlet increased in diameter to reduce restriction in flow. |
|
12723 |
CSM_MG/198 |
| Brakes |
Rear wheel cylinders, banjo fitting changed from straight to right angle |
22741 |
|
CSM_MG/198 |
| Dec 56 |
Throttle |
Auxiliary return spring added to throttle cable |
24594 |
|
CSM_MG/197
CSM_MG/202 |
| Jan 57 |
Engine |
Cylinder head gasket changed from steel/asbestos to copper/asbestos. |
|
15688 |
CSM_MG/205 |
| Coupe |
External lock fitted to Driver's door (previously always fitted to LH door) |
25110 |
|
|
| Internal locking door handle fitted to Driver's door (now both sides, previously only fitted to RH door) |
25110 |
|
CSM_MG/202
May be an error. See addendum to CP-113 |
| Feb 57 |
Clutch |
Stronger clutch pressure plate springs fitted to reduce clutch slip, clutch cover modified to suit. |
|
16225 |
CSM_MG/205 |
| Dynamo |
Dynamo pulley reduced in diameter and fan belt shortened to increase dynamo speed. |
|
17061 |
CSM_MG/205 |
| Body |
Bonnet lid wood batten modified |
26681 |
|
|
| Mar 57 |
Engine |
Enlarged inlet port necks in cylinder head. |
|
17151 |
|
| Thermostat modified. |
|
17538
(approx) |
|
| Valve rocker cover joint increased in thickness to improve oil sealing. |
|
18418 |
CSM_MG/205 |
| Brakes |
Brake piping and rear brake banjo connections, UNF threads standardized (disc wheel cars) |
27989 |
|
|
| Apr 57 |
Gearbox |
Improved second/third gear synchronizer |
|
19383 |
CSM_MG/205 |
| Brakes |
Brake piping and rear brake banjo connections, UNF threads standardized (wire wheel cars) |
28540 |
|
|
| Body |
Splash plates added in front of rear wheels |
29935 |
|
|
| May 57 |
Engine |
Copper ferrules fitted to cylinder head gasket |
|
20501 |
CSM_MG/206 |
| Jun 57 |
Inlet valve guides modified. Also found on engine no's 23175 to 23200 inclusive. |
|
23448 |
|
| Style of engine number prefix changed from BP15GB to 15GB-U-H |
sometime
after 34231 |
sometime
after 24348 |
|
| Jul 57 |
Gearbox |
Gearbox rear extension oil seal , leather type replaced by synthetic rubber type with leather washer (fourth type) |
|
25112 |
CSM_MG/210
CSM_MG/242 |
| Aug 57 |
Engine |
New type of Tecalemit oil filter, Purolator oil filter introduced as alternative, and oil filter seal modified. This change also applied to engine numbers 26661 to 26700 inclusive. |
|
(26661-26700) and commencing 26934 |
CSM_MG/227 |
| Sep 57 |
Pistons and rings modified |
|
27909 |
|
| Oil dipstick min mark raised from 3/4” to 3/8” below the max mark. |
|
28979 |
CSM_MG/213 |
| Oct 57 |
Modified bracket for ignition coil mounting on dynamo |
|
29710 |
|
| Oct 57 |
Hubs |
Knock-ons changed (old 81614/81615, new ATB4222/ATB4223) |
40857 |
|
|
| Oct-Nov 57 |
Engine |
Water pump, changed design of bearing ass'y and pulley hub |
|
Com. 30865 except 39401 to 39525 |
|
| Nov 57 |
Engine |
Carburettor distance pieces made from harder material and gaskets added |
42613 |
|
CSM_MG/213 |
| Dec 57 |
Body |
Smaller screen washer jets, modified control unit |
45186 |
|
|
| Jan 58 |
Engine |
Front tappet cover and crankcase vent pipe modified |
|
35809 |
|
| Feb 58 |
Heavier gudgeon pins with smaller center holes, pistons modified. |
|
38484 |
CSM_MG/229 |
| Suspension |
Time setting for rear shock absorbers reduced to improve ride |
48674 |
|
CSM_MG/218 |
| Hubs |
Knock-ons changed (old ATB4222/ATB4223, new 1B8077/1B8078) |
48730 |
|
|
| Paint |
Roadster: Ash Green color introduced instead of Tyrolite Green (last Tyrolite Green roadster was 48333) |
48980 |
|
|
| Coupe: Ash Green color introduced instead of Island Green (last Island Green Coupe was 48178) |
49000 |
|
|
| Mar 58 |
Engine |
Water pump with one-piece bearing introduced. Also found on engine numbers 39365 to 39400 inclusive. |
|
(39365-39400) commencing 39526 |
|
| Two holes drilled in oil cavity in cylinder block rear main bearing cap and cutaway machined in oil return housing. Drain pipe discontinued. |
|
40106 |
CSM_MG/212
CSM_MG/229 |
| Wheels |
Disc wheels modified in area adjacent to brake adjuster hole |
50270 |
|
CSM_MG/218 |
| Apr 58 |
Engine |
Pistons with deeper grooves and rings of increased radial thickness to decrease oil consumption. |
|
40825 |
|
| First MGA Twin Cam, car and Engine |
First MGA Twin Cam car and first Twin Cam engine, start of production. |
TC_501 |
TC_101
First engine not necessarily in the first car. |
|
| Body |
Bonnet crown height increased, and internal bracing changed. Inner wings changed with new indents. |
(c)50979
(or earlier) |
|
|
| Jun 58 |
Engine, T.C. |
Radiator overflow pipe modified.
[except (c)575, 613, 623, 633, 648] |
TC_651 |
TC_131 |
SPL 3rd ed. C.1 |
| Possible change of camshafts and valve timing (not confirmed). |
|
TC_141 |
|
| Thermostat with lower operating temperature |
|
TC_194 |
SPL 3rd ed A.16 |
| Packing plate added to LH engine mount to improve clearance between starting handle dog and steering rack. Air cleaners with positive filter element location, |
TC_528 |
|
WSM A.18 |
| Doors, Coupe |
Coupe: door hinges with smaller stops to increase door opening |
52916 |
|
CSM_MG/221
CSM_MG/229 |
| Jul 58 |
Steering |
Cup and fiber washers added below grease nipples, grease escape drilled in steering ball socket cap on LHD cars |
53875 |
|
CSM_MG/229
CSM_MG/233 |
| Suspension |
Steering knuckles, levers and nuts modified (1/2-in UNF to 5/8” UNF) |
54247 |
|
|
| Steering |
Cup and fiber washers added below grease nipples, grease escape drilled in steering ball socket cap on RHD cars |
55545 |
|
CSM_MG/229
CSM_MG/233 |
| Clutch |
All BMC clutch plates between 7¼ inch and 11 inch changed from 6 to 4 spring, interchangeable. |
|
|
|
| Aug 58 |
Gearbox |
Gearbox rear extension oil seal, leather washer replaced by felt washer (fifth type). |
|
45412 |
CSM_MG/232 |
| Engine |
Modified bracket for ignition coil mounted on dynamo |
|
45905 |
|
| Electrical |
Relay for twin fog lamps fitted on cars for North America |
55633 |
|
|
| Jun 58 Sep 58 |
Twin Cam
Coupe |
First MGA Twin Cam Coupe |
TC_553 |
|
Rego No. PKG1
twincam/tc107-553.htm |
| Sep 58 |
Engine |
Oil pump suction pipe moved forward to prevent starvation when cornering or braking. Pump strainer and studs all modified. Also applied to engine numbers 46045 to 46100 inclusive. |
|
(46045-46100) and commencing 46342 |
CSM_MG/237 |
| Engine, T.C. |
Smaller dynamo pulley and shorter fan belt to alter dynamo speed and increase charging rate. |
|
TC_272 |
CSM_MG/237
CSM_MG/237A |
| Body, T.C. |
Roadster: detachable panels in front wheel arches for improved access |
TC_592 |
|
SPL 3rd ed
R.1, R.4 |
| Coupe detachable panels in front wheel arches for improved access |
TC_594 |
|
| Cooling, T.C. |
7lb relief valve added to overflow pipe from radiator header tank; also on cars (c)575, 613, 623, 633, 648. |
TC_652 |
|
CSM_MG/234 |
| Chassis, T.C. |
Five holes added to front cross member for acccess to sump front bolts |
TC_662 |
|
|
| Doors, Roadster |
Roadster: door hinges with smaller stops to increase door opening |
56069 |
|
CSM_MG/221 |
| TC_Engine |
Connecting rod assemblies for replacement should not differ by more than 3 drams (5.316 grammes). Later superseded by SM MG/236 5 Nov 1958, and SM MG/252 24 Apr 1959. Assemblies not to std weight are stamped to indicate drams above or below std. Successive SMs introduced additional weight ranges. |
TC_652 |
|
CSM_MG/231 |
| Layshaft oil pump gear and oil pump spindle with more teeth. |
|
TC_313 |
SPL 3rd ed p1 |
| Windscreen |
Windscreen hood pegs changed from plated brass to plated mild steel |
57100 |
|
CSM_MG/232 |
| Oct 58 |
Engine |
Tappet adjusting screw locknuts modified. |
|
47901 |
|
| Engine, T.C. |
Layshaft oil pump gear and oil pump spindle with more teeth. Also T.C. engine no. 313. |
|
TC_315 |
CSM_MG/240 |
| Spinners Germany |
Octagonal spinners on cars for Germany |
TC_708 |
|
SPL 3rd ed p1 |
| Instruments, T.C. |
Longer speedometer cable for LHD cars. Centigrade temperature gauge instead of Fahrenheit gauge on LHD cars not for North America (Twin Cam) |
TC_713 |
|
|
| Instruments |
LHD cars (not for North America) fitted with Centigrade temperature gauge instead of Fahrenheit gauge |
57574 TC.713 |
|
|
| Hubs |
Octagonal spinners introduced on wire wheels for Germany instead of knock-ons. |
57574 (approx) |
|
|
| Nov 58 |
Engine |
Rocker shaft brackets modified |
|
48911 |
|
| Engine, T.C. |
Pistons with twin-segment scraper ring to reduce oil consumption. |
|
TC_446 |
CSM_MG/240
CSM_MG307
CSM_MG325 |
| Dynamo adjusting link changed. |
|
TC_448 |
|
| Cooling, T.C. |
Radiator changed from ARH0098 to ARH0121 |
|
after TC_801 |
Data collected by MGA T.C. Enthusiasts Group |
| Pedals |
Brake pedal modified. Clutch pedal on LHD cars modified. |
58713 |
|
|
| Headlamps |
European export cars (except France and Sweden) fitted with asymmetrical headlamps; rim fixing screws and adapter modified |
58918 TC.824 |
|
|
| Brakes, T.C. |
Modified disc brake caliper units (Twin Cam) |
TC_836 |
|
TC_SPL 3rd ed H.3, K.2 |
| Suspension |
Front spring spigot increased in diameter to eliminate spring noise |
58996 TC.842 |
|
CSM_MG/240 |
| Dec 58 |
Engine, T.C. |
Ignition cables lengthened and re-routed round front of cylinder head. |
|
TC_556 |
|
| Water inlet pipe straightened |
|
TC_574 |
|
| Water inlet elbow lengthened |
|
TC_581 |
|
| Modified top ring to pistons to overcome piston noise. |
|
TC_606 |
CSM_MG307
CSM_MG325 |
| Cylinder block rear side cover breather pipe modified to prevent oil leaking onto exhaust system. |
|
TC_657 |
|
| Headlamps France |
Asymmetrical headlamps introduced on cars for France |
60340 |
|
|
| Tonneau Cover |
Tonneau cover, LHD cars: fasteners deleted from door tops, zip lengthened, steering wheel bag deleted. |
60637 TC.994 |
|
|
| Brakes T.C. |
Brake master cylinder box and strengthening plate modified (Twin Cam) |
TC_997 |
|
article TC-206 |
| Gearbox & Propshaft |
New propshaft with flanged input and sliding spline. Gearbox modified with flanged output (still low starter). Only some cars until car #61504. *(This would be a very rare gearbox with low starter and flanged output). |
61037 |
|
|
| Jan 59 |
Pedals |
Clutch pedal on RHD cars modified. |
61100 |
|
|
| Heater |
Heater water valve improved design |
61160 |
|
|
| Last 15GB Engine |
Final engine number in 15GB series |
|
51767 |
|
First 15GD Engine
Gearbox,
Propshaft
Body |
Introduction of 15GD series engine, no blanking plate for mechanical fuel pump, high starter. Gearbox modified with high starter and flanged output (mounting plate, casing and rear extension). Gearbox cover (on tunnel) with rubber cover for Bendix drive (in cockpit), RH toe board and carpet modified to suit. LHD cars only: speedo cable 3-in longer to clear starter. New propshaft with flanged input and splined sliding joint at front. (Also cut-out in the high crown bonnet internal brace to clear front SU carburetor on the Twin Cam engine). |
61504 |
101
First engine not necessarily in the first car. |
|
| Electrical |
Wiring harness connections to stater switch and starter motor modified. |
63435 |
|
|
| Wheels |
New disc wheels, stronger but lighter. New wheels supersede old model for replacement parts on earlier cars. Optional Rimbellishers discontinued. New optional Ace Mercury wheel discs. |
63577 |
|
CSM_MG/25 |
| Feb 59 |
Tonneau Cover |
Tonneau cover, RHD cars: fasteners deleted from door tops, zip lengthened, steering wheel bag deleted. |
64332 |
|
|
| Engine, T.C. |
Tappets increased in length by 0.25in to 1.5in to eliminate risk of fractures |
|
TC_1087 |
CSM_MG/253 |
| Mar 59 |
Connecting rods modified with bosses at small end for balancing purposes. Heavier big end bearing caps. |
|
TC_1343 |
CSM_MG/231
CSM_MG/236
CSM_MG/252
CSM_MG/262 |
| Gearbox, T.C. |
Close ratio gearbox introduced as an option. When fitted with this gearbox, engine prefix should be 16GB-Da. |
|
TC_1379 |
|
| Headlamps France, T.C. |
Asymmetrical headlamps introduced on cars for France (Twin Cam) |
TC_1618 |
|
|
| Knock-ons, T.C. |
Knock-ons of bronze introduced instead of steel knock-ons (Twin Cam) |
TC_1826 |
|
|
| Apr 59 |
Accessories |
Battery covers made available as optional extras. |
|
|
CSM_MG/249 |
| Engine, T.C. |
N.3 spark plugs introduced to reduce heat at piston crown. (21-Apr-59) |
|
TC_???? |
CSM_MG/253
CSM_MG/282
CSM_MG/288 |
| Cast iron sleeves introduced for tappet bores in cylinder head to reduce wear. |
|
TC_1587 |
|
| Engine |
Connecting rod bearings modified |
|
6530 |
|
| Rear Hub, T.C. |
Rear hub extensions modified (Twin Cam) - Identified by either thin or thick casting behind knock on thread. Was ATB7252/3, became AJC5182/3 (number swap error in SPL) |
TC_1840 |
|
|
Frame,
Suspension |
Chassis front extension and front suspension spring pan assemblies modified to permit installation of optional anti-roll bar (not T.C. at this time) |
66574 |
|
|
| May 59 |
Sun Visor, T.C. |
Coupe: New type optional sun visor (T.C. only at this time) |
TC_2061 |
|
|
| Last 1500, Last 15GD Engine |
Last MGA 1500. Final engine number in 15GD series. |
68850 |
7816 |
|
| First 1600 |
First MGA 1600.
Chassis: New 1588cc engine type 16GA; gearbox modified to prevent disengagement of third gear; front disc brakes. Half shafts and differential wheels with (26) involute splines (T.C. not until July)
Body: larger sidelamps/indicators with modified front wings; separate rear indicators and new tail lamp plinths; flasher relay deleted; new sliding sidescreens with new fixing nut, additional hood latch on windscreen (roadster); new range of colors for paint, trim and hood; new series of body numbers prefixed with B.
Coupe: Spare wheel relocated in boot with new rear bulkhead and (narrower) rear window shelf.
Dipswitch: on LHD cars repositioned for easier operation. |
68851 |
|
|
| First 16GA Engine |
First MGA 1600 engine type 16GA; gearbox modified to prevent disengagement of third gear. |
|
101
First engine not necessarily in the first cer. |
|
| Jun 59 |
First 1600 style T.C. Coupe |
First “1600 style” Twin Cam Coupe. Body specifications as for first 1600 Coupe. 2189, 2190, 2191, 2192 were built as CKD cars in South Africa, so build completion may have been later. These cars were incorrectly recorded as roadsters. |
TC_2189 |
|
|
| First 1600 style T.C. Roadster |
First “1600 style” Twin Cam roadster. Body specifications as for first 1600 roadster. |
TC_2193 |
|
|
| Disc Brakes & Disc Wheels |
Front disc brake studs replaced by bolts on disc wheel cars (non T.C.) |
69505 |
|
|
| Frame & Suspension T.C. |
Chassis front extension and front suspension spring pan assemblies modified to permit installation of anti-roll bar, which was immediately standard on the Twin Cam model only. (non T.C. was done in April) |
TC.2275 |
|
CSM_MG/278 |
| Headlamps |
Cars for USA fitted MK VIII sealed beam headlamps with modified gasket integral with dust excluder |
70222 TC.2278 |
|
|
| Dipswitch, T.C. |
Dipswitch on LHD cars repositioned for easier operation (non T.C. was done in May) |
TC_2281 |
|
|
| First 1600 style T.C. Coupe |
First 1600 style Twin Cam Coupe. Body specifications as for first 1600 Coupe. |
TC_2292 |
|
|
| Disc Brakes, Wire Wheels |
Front disc brake studs replaced by bolts on wire wheel cars |
70276 |
|
|
| Jul 59 |
Engine, T.C. |
Shorter carburetor damper pistons for improved even running and maximum speed. These cars are identified by the carburetor caps being stamped 'O'. |
|
TC_???? |
CSM_MG/264 |
| Pistons with modified scraper ring and expander ring added. These were also fitted to a few earlier engines. |
|
TC_2057 |
CSM_MG/278
CSM_MG307
CSM_MG325 |
| Pressure Cap |
Radiator filler cap changed from 4-lb to 7-lb to prevent boiling. New part supersedes old model and should be fitted to all earlier cars. |
71832 |
|
CSM_MG/289 |
| Halfshaft Splines T.C. |
Half shafts and differential wheels with (26) involute splines (non T.C. Done in May) |
TC_2371 |
|
CSM_MG/278 |
| Headlamps, Sweden |
Cars for Sweden fitted with asymmetrical headlamps |
72040 TC_2418 |
|
|
| Aug 59 |
Engine |
Thermostat modified. |
|
4788 |
|
| Engine |
Float chamber mounting modified from banjo bolt to double threaded stud and nut. Parts interchangable as a set. |
Date of change unknown, but thought to be during early 1600 production. |
Refer to article: CB-111A |
| Electrical |
Dynamo type C.40/1 introduced, control box modified, harness with Lucar snap connectors for dynamo and control box. New fan belt. New ignition coil bracket. |
74489 |
6272 |
|
| Sep 59 |
Dynamo pulley and fan belt modified. |
|
6396 |
|
| Instruments |
Speedometer cable modified on RHD cars |
74979 TC_2467 |
|
|
| Engine, T.C. |
Air cleaners modified to incorporate venturi. (T.C. Only) |
TC_2468 |
|
CSM_MG/286 |
| Oct 59 |
Brake Pads Disc Wheels |
Front disc brake pads improved material on disc wheel cars |
78106 |
|
CSM_MG/290 |
| Brake Pads Wire wheels |
Front disc brake pads improved material on wire wheel cars |
78114 |
|
CSM_MG/290 |
| Engine |
Dipstick cranked away from crankcase for better accessibility. |
|
9649 |
CSM_MG/294 |
| Hood Frame, Battery Hatch, Stowage Bag, Hood Stick, Wider Canopy |
Hood frame modified. New sidescreen stowage envelope and modified battery hatch to enable hood to be stowed under rear tonneau panel with sidescreens stowed on top of battery hatch, and improved seating adjustment. New hood stick, wider canopy. |
78249 |
|
CSM_MG/294 |
| Nov 59 |
Hood frame and canopy modified. Same as for 1600 cars, above (Twin Cam) |
TC_2540 |
|
CSM_MG/294 |
Mirror,
France |
Rear view mirror with safety rim fitted on cars for France |
79663 |
|
|
Body
(non T.C.) |
Windscreen wiper wheelbox modified |
80284 |
|
|
| Body |
Windscreen washer bottle, bottle neck increased in diameter from 1-1/2” to 2-3/16”, control module modified |
80390 TC.2544 |
|
|
| Body, T.C. |
Windscreen wiper wheelbox modified |
TC.2545 |
|
|
| Dec59 |
Body |
Coupe: New type optional sun visor (T.C. was done in May 59 at (c) 2061) |
81532 |
|
|
| Differential Splines |
Half shafts, differential wheels and assembly modified on wire wheel cars, 25 spline (was 26 spline) |
82749 |
|
|
| Half shafts, differential wheels and assembly modified on disc wheel cars, 25 spline (was 26 spline) |
82892 |
|
|
| Gearbox |
Gearbox front cover bosses modified |
|
12834 |
|
| Engine, T.C. |
Tappets modified |
|
TC_2211 |
|
| Jan 60 |
New type distributor less vacuum unit, to prevent over-advancing with possible consequent piston failure. Supposedly retrofitted by campaign change to all earlier cars. Concludes with car/chassis 2561 |
|
TC_2222 |
CSM_MG248
CSM_MG282
CSM_MG288
CSM_MG301 |
| Gearbox, T.C. |
Gearbox front cover bosses modified |
|
TC_2228 |
|
| Mar 60 |
Engine, T.C. |
Alternative low compression pistons (8.3:1) introduced, with resulting decrease in power from 108bhp to 100bhp. High and low compression pistons fitted with plain instead of chromium-plated top rings. Stronger valve springs fitted. |
TC_2609 |
TC_2251 |
CSM_MG307
CSM_MG310
CSM_MG325
CSM_MG/34 |
| Crankshaft main bearings and big end bearings of lead-tin type introduced as alternatives. |
|
TC_???? |
|
| Radiator Cap |
Radiator filler cap modified |
88192 |
|
|
| Number Plate |
Number plate lamp, 2 bulbs instead of one |
88844 |
|
|
| Apr 60 |
Engine |
Exhaust valves of improved material |
|
20846 |
|
| Connecting rods with thicker webs, bearing caps modified. |
|
21705 |
|
| Crankshaft modified to increase oil return scroll clearance to cylinder block. Introduction of VP3 lead-indium main bearings in place of white metal. |
|
21805 |
CSM_MG/327 |
| Competition Suspension |
Four-wheel Dunlop disc brakes and center-lock disc wheels introduced as option, with related changes (the “Deluxe” model). Requires different accellerator pedal and cross shaft assembly for LHD cars, and mounting ignition coil on top of generator. Requires separate clutch and brake master cylinders, different clutch pedal and slave cylinder and related fittings, different steering rack (slightly farther forward), different steering arms, hub assemblies, front wheel bearings, brake calipers and rotors at all four wheels. In short, it is a complete Twin Cam chassis with pushrod engine and a hybrid body shell (except apparently the sway bar was optional, not standard equipment). |
91240 |
|
CSM_MG/327 |
| May 60 |
Engine, T.C. |
Estimated final Twin Cam engine number |
|
TC_2272 |
|
| Number Plate |
Special number plate lamp on cars for Switzerland |
92679 |
|
|
| Fuel Pump |
Rubber cover for fuel pump discontinued |
93225 |
|
|
| Last T.C. |
Last MGA Twin Cam |
TC_2611 |
|
|
| Jun 60 |
Engine |
Thicker, stiffer cylinder block side covers to reduce the possibility of oil leaks. |
|
25740 |
CSM_MG/337 |
| Jul 60 |
Tool Kit |
Tool kit reduced, new type Shelley ratchet jack |
93548 |
|
|
| Aug 60 |
Sidescreens |
Sidescreen rear flap removed and hood valance modified to improve waterproofing, on cars with GRAY hood/sidescreens. |
96269 |
|
CSM_MG/337 |
| Sidescreen rear flap removed and hood valance modified to improve waterproofing, on cars with BEIGE hood/sidescreens. |
96806 |
|
CSM_MG/337 |
| Sidescreen rear flap removed and hood valance modified to improve waterproofing, on cars with BLUE hood/sidescreens. |
97104 |
|
CSM_MG/337 |
| Nov 60 |
Sidescreens |
All sidescreen part numbers supersceeded to use bare aluminum sidescreens for all MGA |
|
|
CSM_MG/338 |
| Feb or Mar 61 |
Dash |
Turn signal warning lamp relocated from 10 o'clock to 1:30 o'clock relative to the the T/S switch (LHD) or from 2 o'clock to 10:30 o'clock relative to the the T/S switch (RHD) , and the depression in the dash deleted. . |
~100000 |
|
|
| Mar 61 |
Engine |
Exhaust valve outer springs modified. |
|
31640 |
|
Last 1600,
Last 16GA Engine |
Last MGA 1600. Final engine number in 16GA series. |
100351 |
31660 |
|
First 1600 Mark II,
First 16GC Engine |
Engine: New 1622cc engine type 16GC; new distributor type DM.2 with rolling weight centrifugal advance mechanism.
Gearbox: Casing modified, welch plugs deleted.
Rear Axle: 4.1:1 rear axle ratio standard;
Body: New radiator grille; new combined stop/tail lamps and rear indicators on horizontal plinths (with silver/gray rubber gasket) below boot lid; seat belt mounting points added; Facia now covered in Vynide on roadster, scuttle on roadster and coupe covered in Novon. Optional paint colors and interior colors changed. |
100352 |
101
First engine not necessarily in the first car. |
|
| Engine |
Low compression engine pistons modified |
|
127 |
|
| Apr 61 |
Facia Piping, Coupe |
Coupe: On white cars with black trim, piping color for black facia trim roll changed from white to black; |
100596 |
|
|
| Fuel Pump |
Fuel pump specifications upgraded from AUA 54 to AUA 154 |
100612 |
|
|
| May 61 |
Engine |
Low compression engine distributor modified |
|
1012 |
|
| Body |
Rear lamp plinth gasket replaced by cream Prestik |
101353 |
|
|
| Roadster: Modified door seal finishers on shut pillars, and change shutface panels to incorporate "rain gutter" raised edge |
101292 |
|
|
| Steering Lock, Sweden |
Steering lock fitted to cars for Sweden |
|
|
|
| Jun 61 |
Facia Piping, Roadster |
Roadster: On white cars with black trim, piping color for black facia trim roll changed from white to black; |
101490 |
|
|
| Dynamo, Control Box, Compression, Police Cars |
Police cars: C42 dynamo and RB340 control box introduced. Low compression engine standardized on police cars. |
101840 |
|
|
| Jul 61 |
Steering Lock, Germany |
Steering lock fitted to cars for Germany |
|
|
|
| Jul 61 |
Engine |
Oil gallery plugs commonalised. Also on engine numbers 2157 to 2225 inclusive. |
|
2327 |
|
| Body |
Two distance pieces added to rear bumper brackets to bring bumper further away from body, so to avoid risk of rear number plate fouling body. |
102381 |
|
|
| Brakes |
Dust covers added to front disc brakes on standard model with disc wheels. |
102589 |
|
|
| Body |
Six (6) sealing plugs added to boot floor |
102737 |
|
|
| Oil Cooler Coupe |
Oil cooler fitted as standard on export cars (coupe models) |
| Headlamps |
Headlamps on cars for USA changed from Mark VIII type to Mark X type |
102857 |
|
|
| Brakes |
Dust covers added to front disc brakes on standard model with wire wheels. |
102929 |
|
|
| Aug 61 |
Oil Cooler Roadster |
Oil cooler fitted as standard on export cars (roadster models) |
102950 |
|
|
| Tires |
Nylon tires introduced as standard, except on cars for Germany |
103192 |
|
|
| Sep 61 |
Engine |
Lightened flywheel introduced. |
|
3708 |
|
| Brakes |
Modified disc brake caliper dust seal on disc wheel cars |
103261 |
|
|
| Steering |
Common type Neiman steering lock fitted to cars for Germany and Sweden |
103759 |
|
|
| Brakes |
Modified disc brake caliper dust seal on wire wheel cars |
103834 |
|
|
| Oct 61 |
Gearbox |
Gearbox first motion shaft with involute splines formed by rolling, giving stronger spline section at reduced cost; clutch driven plate modified to suit. |
104022 (HC)
104469 (LC) |
3929 |
|
| Engine |
High compression engine distributor modified. |
|
4004 |
|
| Nov 61 |
Gearbox |
Gearbox casing of thicker section around bellhousing and incorporating stiffening ribs to reduce vibration. Longer bolts between bellhousing and engine. |
|
4748 |
|
| Dec 61 |
Reverse gear assembly modified. |
|
5403 |
|
| Exhaust Switzerland |
Exhaust system with twin silencers on cars for Switzerland |
104805 |
|
|
| Headlamps |
Headlamps with skirted gasket with integral dust excluder, separate dust excluder deleted on UK and RHD export cars (and LHD cars not for Europe/USA) |
105362 |
|
|
| Jan 62 |
Starter |
Starter motor modified. |
|
6435 |
|
| Feb 62 |
Headlamps Canada |
USA-type sealed beam headlamps fitted on cars for Canada |
107031 |
|
|
| Apr 62 |
Engine |
Crankshaft front oil thrower and front pulley modified. Engine front cover modified, felt oil seal replaced by rubber oil seal. |
|
8263 |
|
| High compression engine distributor and cover modified. |
|
8422 |
|
| May 62 |
Last Coupe |
Last coupe |
107031 |
|
|
Last MGA,
Last 16GC Engine |
Last MGA 1600 MK II. Last engine number in 16GC series. |
109070 |
8851 |
|
