Somerford Mini Ltd. Ordering Parts Using This Catalogue

Cylinder Head - 970, 1071 and 1275cc (Cooper S)
No. Part No. Description Qty. Remarks No. Part No. Description Qty. Remarks
Rocker Cover and Fixings
32 AEG172 ROCKER COVER, steel, with breather pipe 1 1963-64, open circuit breathing.
33 AEG512 ROCKER COVER, steel, no breather pipe 1 1964-71, closed circuit breathing.
34 CAM6822 ROCKER COVER, alloy, without breather 1 Accessory (also MG Metro) item for
pipe
closed circuit breathing models.
A range of polished or painted alloy accessory rocker covers is available from Somerford Mini; please
contact us for details. Some accessory rocker covers require different fixings from the standard items.
35 - PLATE, engine name 1 See note belo w.
- DECAL, engine name 1 See note belo w.
- PLATE, engine patent 1 See note below.
- DECAL, engine patent 1 See note belo w.
For details of the large range of plates and decals fixed to rocker covers, please see the ‘Chassis Plates
and Decals’ section in the Interior Body Fittings area of the Somerford Mini catalogue.
36 12A402 CAP, oil filler, black plastic, without 1 1963-64 open circuit breathing
breather models .
37 13H2296 CAP, oil filler, black plastic, with breather 1 1964-71 closed circuit breathing
models.
38 GFE6007 CAP, oil filler, red plastic, with breather 1 For CAM6822 alloy rocker cover.
39 12A403 SEAL, plastic oil filler cap 1 For 12A402 and 13H2296 caps.
40 GEG417 GASKET, rock er cover, original 1 With notches to clear head fixings.
GEG401 GASKET, rocker cover, replacement 1 Must be notched before fitting.
41 CAM6822FK CHROME FIXINGS KIT, rocker cover 1
Includes chrome nuts, chrome distance pieces, chrome cup washers and rubber bushes. Originally for
alloy rocker covers such as CAM6822,may also be used to enhance restored steel rocker covers.
42 2A150 NUT, rocker cover to engine 2 Original zinc finish.
CAM6823 NUT, rocker cover to engine 2 Alternative chrome finish.
43 1B2925 DISTANCE PIECE 2 Original zinc finish.
12G687 DISTANCE PIECE 2 Alternative chrome finish.
44 1A2156 WASHER, cup 2 Original zinc finish.
12G679 WASHER, cup 2 Alternative chrome finish.
45 12A1358 BUSH, rubber 2
46 12A1968 LIFTING EYE, engine, temporary fitment 2 Fit to engine only while lifting work
is taking place .
Rocker Shaft, Rockers and Fixings
47 12G1926 PEDESTAL, rocker shaft, with oil hole 3
48 12G1927 PEDESTAL, rocker shaft, with tapped hole 1
Note that 12G1926 and 12G1927 are the late design of pedestal - there were several earlier designs in
differing materials, none of which are now available. The outstanding design difference is that both types
of the late pedestals have oil holes in them, which certainly isn’t the case with the untapped pedestal in
earlier designs. This means that late type pedestals can be swapped around in their relative positions,
wherever the tapped pedestal needs to be to secure the rocker shaft in place (early rocker shafts
secured by grub screw to the pedestal closest to the front of the engine, whereas the later shaft - the
only one now available - secures to the second pedestal along). Swapping the first two pedestals, if they
are of early design, in order to fit a later rocker shaft will result in no oil feed to the rocker shaft or
rockers...
49 2A258 SCREW, locating rocker shaft 1
50 2A515 PLATE, securing screw 1 Original item.
51 2A259 PLATE, securing screw 1 Replacement item.
52 51K885 STUD, long, rocker cover and pedestal 2 Outer pedestals.
53 CHS522 STUD, short, rocker pedestal 2 Inner pedestals.
54 LNZ205 NUT, nyloc, pedestal to cylinder head 4
55 PWZ105 WASHER, plain 3 Not used on tapped pedestal.
56 PWZ106 WASHER, plain 3 Not used on tapped pedestal.
57 AEG399 ROCKER SHAFT ASS’Y 1 Original item.
58 12A1950 ROCKER SHAFT 1 Replacement item.
59 6K878 END PLUG , plain 1 Included in AEG399 rocker shaft ass’y.
60 2K4608 END PLUG, screwed 1 Included in AEG399 rocker shaft ass’y.
61 12G1221 ROCKER, forged 8 Original item.
62 CAM289 ROCKER, scintered 8 Replacement item.
Only forged rockers were fitted to Cooper S engines when built. However, after the introduction of the
scintered rocker on other A Series engines in 1974, either forged or scintered rockers were offered as
replacement parts. The forged rock er is acknowledged as the stronger of the two and is of course
correct for originality. However for normal road use it does not matter which type of rocker is used, so
long as (i) all eight on the rocker shaft are of the same type; (ii) all eight are either the same age from
the same engine or are new; and (iii) the tappet adjusting screws and nuts, plus the rocker spacing
washers, are correct for the type of rocker. Note that the forged rock ers have replaceable bushes,
whereas scintered rockers do not.
Several designs of high-lift and roller rockers are also available for tuning purposes, along with special
valve springs to avoid coil binding, if necessary. Please contact Somerford Mini for details of these and
other engine tuning parts.
63 2A21 BUSH, rock er 8 Included in forged rocker.
64 5C2436 RIVET, bush to rocker 8 Included in forged rocker.
65 AEG167 SCREW, tappet adjusting 8 Use with forged rocker.
66 NT605061 NUT, locking screw 8 Use with forged rocker.
67 12H3376 SCREW, tappet adjusting 8 Use with scintered rocker.
68 51K1178 NUT, locking screw 8 Use with scintered rocker.
69 6K556 SPRING, rocker spacing 3
70 AEG168 DISTANCE PIECE, exhaust rock er 6 For forged rockers.
71 2A18 WASHER, double coil, outer ends of shaft 2 For scintered rockers.
The distance piece AEG168 is used to shim forged rock ers on their shaft correctly over the exhaust valves.
It is only required on big bore (970, 1071 and 1275cc) cylinder heads, where the valves are spaced
further apart than is the case on other A Series engines. The correct locations for the six ditance pieces
are as follows:
One on either side of each of the outer exhaust rockers (four in total).
One on the pedestal side of each of the inner exhaust rockers (two in total).
The wider scintered rockers do not require these shims , so instead rever t to the more usual A Series set
up of using double coil (or ‘Thackery’) washers at either end of the rocker shaft.
72 6K555 WASHER, plain, outer ends of shaft 2
73 ZPS314 SPLIT PIN, outer ends of shaft 2
Valve Guides and Valve Seat Inserts
Originally on the 12A185 and AEG163 cylinder heads the valve guides were different for inlet and exhaust
valves. The 12G940 head had a single valve guide design, and this is now offered for all Cooper S
cylinder head applications. This valve guide, 12G1963, will accept the later ‘top hat’ type valve stem oil
seal (ADU4905) if required and has the classic high-flow ‘bullet nose’ profile at the port end.
If you are intending to fit non-standard valves in your cylinder head, you will need to be aware that
12G1963 valve guides are cast iron and will operate only with conventional steel or chromed valve stems .
They will not work with stainless steel or EN214N valves unless the stems are chromed.
74 12G1963 GUIDE, inlet and exhaust valve 8
75 12G1089 INSERT, inlet valve seat 4 Not lead free fuel compatible.
76 12G2675 INSERT, exhaust valve seat 4 For 12A185 and AEG163 heads .
TAM2069 INSERT, exhaust valve seat 4 For 12G940 heads; lead free fuel
compatible.
Valves and Valve Springs
As stated in the introduction to this section, the valve stem lengths are particular to the cylinder head
castings found on Cooper S models, as are exhaust valve diameters. The age of the car provides no
guarantee as to which cylinder head will be present. Please check your casting number and valve sizes
before ordering replacements from Somerford Mini. A range of uprated valves , valve springs and caps to
suit most uses are also available from Somerford Mini; please contact us for details .
12A185 and AEG163 Cylinder Head Castings
(originally 1963-69 models)
77 AEG593 VALVE, inlet, 1 13/32" (35.6mm) dia. 4 Nimonic 80 (EN214N) material.
78 AEG594 VALVE, exhaust, 1 7/32" (31mm) dia. 4 Nimonic 80 (EN214N) material.
79 C-AEA525 SPRING SET, valves, outer and inner 1
80 AEA767 SPRING, valve, outer 8 Included in spring set.
81 12G1137 SPRING, valve, inner 8 Included in spring set.
82 88G459 SPLIT COLLET, pair, valve retaining 8
83 AEA653 CAP, upper, valve springs, steel 8
84 AEA403 COLLAR, lower, valve springs 8
85 AEG327 OIL SEAL, valve stem 8
12G940 Cylinder Head Castings
(originally 1969-71 models)
86 AEG592 VALVE, inlet, 1 13/32" (35.6mm) dia. 4
87 12G1322 VALVE, exhaust, 1 5/32" (29.4mm) dia. 4
CAM4601 VALVE, exhaust, 1 5/32" (29.4mm) dia. 4 Alternative.
88 C-AEA525 SPRING SET, valves, outer and inner 1
89 AEA767 SPRING, valve, outer 8 Included in spring set.
90 12G1137 SPRING, valve, inner 8 Included in spring set.
91 88G459 SPLIT COLLET, pair, valve retaining 8
92 88G617 CAP, upper, valve springs 8 Original item.
AEA653 CAP, upper, valve springs , steel 8 Uprated alternative.
93 AEA403 COLLAR, lower, valve springs 8
94 AEG327 OIL SEAL, valve stem 4
Oil seals were usually fitted on the inlet valve stems only, but they can be fitted on exhaust valves too.
Opinions differ on which is better - the choice is yours.
Tel. 01249 721421 Fax. 01249 721316 www.somerford-mini.co.uk
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