Riley 2½ Modifications




563/2001 Commencing number first sanction.


2019 Round air fitter, with carburettor elbow and rocker boxes to suit. 90 Jets, EE needles for carburettors.


2020 Battery reversed (terminals to rear).


2043 10" steering wheel.


2056 Strengthened lower struts on front suspension and aluminium crash pads, shorter clutch pedal, "A" member with added bracket.


2089 Introduction of 10" clutch with flywheel housing to suit. 570/2169 Corrected speedometer.


2196 4 core radiator black replaces 3 core.


2202 Heavier rear springs (13 leaf D.5704).


2414 Stiffener to front numberplate, modified rockers and shafts.


2511 Weaker top spring fitted to front brakes.

Reason: To stop spring pulling brake shoes over centre.


2642 MK. II headlamps and cowls. Hardened clutch centre.


58S/2582 Clamp bolt on torque tube deleted.


2861 Screwed oil retainer to front hub.


2863 Brake linings MR.4I front, Don rear.


2959 100 B.H.P. engine introduced. Larger inlet valves, cylinder head modified, solid tappets introduced. 5/16" rocker ball pins introduced, push rods modified.


2976 Clutch plate fitted with RYZ lining, light bowl, moulded friction ring.


2998 Longer anti-roil bar with brackets to suit.


3001 Commencing number second sanction.


3047 MR.41 linings front and rear.


3071 2.LS front brakes lined MR.41.


3077 Introduction of two leading shoe type front brakes with MR.41 linings.

Reason: Improvement to design.


3225 Propshaft and torque tube increased in length by ¼". (from 52 7/16" to 52 11/16") Measured from trunnion centre to machined face to axle casing to which torque tube housing is bolted.

Reason: To straighten shackles.


3275 Internal bonnet locks.


3352 Extruded rubbers to doors.


3397 Hand dip switch.


59S/4119 Leys crown gear housing to rear axle.


4203 Softer rubbers fitted to trunnion members. Reason. To overcome vibration (5 round rubber rings, I square edge ring).


4611 PV6 type rear shock absorbers fitted in place of the PR6 type.

H5081 rear shock absorber O/S PV6/68 type SA133-72 replaces PR6 V5799.

H5082 rear shock absorber N/S PV6/69 type SA133-71 replaces PR6/69 V D5800.


4766 Modification to the kingpin bushes which is an increase in length of the steel bush, Pt. No. A2618, and the shortening of the brass bush, Pt. No. A2525 to prevent grease reaching and damaging the rubber bushes. The new part numbers for the bushes are:-


A2712 bronze bush, A2718 assembly of screwed bush for kingpin.


5131 to 5135 inc.     )

5138 to 5145 inc.     ) Common bodies 2½ litre and 1½ litre R.H.D., with

5147 to 5158 inc,     ) new body trim and door cappings, concealed

5164 to 5210 inc.     ) visors, new floorboards and gearbox cover, but

5212 to 5217 inc.     ) fitted with old type (1949) facia and round

5219 CO 5234 inc.   ) instruments.

5241                     )

5004 5235            )

5005 5236            )

5095 5237            ) Common bodies 1½ litre and 2½ litre R.H.D., with new

5096 5238            ) body trim, door capping., concealed visors, new floor-

5137 5239            ) boards and gearbox covers. New type 119501 facia

5146 5240            ) board and square instruments.

5211 5242            )

5218 (onwards)   )


5235  Cars now filled at works with Lockheed No. 33 brake fluid. For service purposes Girling or Lockheed 33 brake fluid may be used. It has been confirmed that the Girling brake fluid is also suitable for Arctic conditions, either will mix.


5256 Previous to this chassis number headlamps had a cut-off rear body to clear the wing blade. The wings have been indented and will now take a standard domed rear body. Cars with the old wing will still be serviced with the old lamp. The new lamp part nos. are as follows:-

Home- H.8228 N/S and H.8229 0/S

Export - R.H.D. H.8229 dip left

         L.H.D. H.8230 dip right


5363 Improved venting for rear axle. 5/32" hole drilled in top of casing 8" off centre on the right hand side and new filler plug, pt. no. 500004, or blank off hole in existlng plug and drill as indicated.


5437 New type starter M459/L5/26038A (without switch) pt. no. S.811 replaces S.64, and new dynamo Lucas C.45PV/4-L0 S.812 replaces S.63 (engine no. B.3896). New solenoid (ST.950) switch on bulkhead. New control box RF/95/2 Lucas 37076.E must be uced.


5490 New type front suspension rebound rubbers (taper type) pt. no. A.2728.

Introduction of front suspension lower links with longer web plates (and replaces all older type links). New pt. nos:

500043 bottom link assembly RH (1 pair comprising)

500045 bottom link assembly (rear RH)

500047 bottom link assembly (front RH)

560044 bottom link assembly LH (1 pair comprising)

500046 bottom link aasemtly (rear LH)

500048 bottom link assembly (front LH)

Reason: Improved type.


5510 Exhaust manifold on RHD cars, pt. no. S490 replaced by LHD manifold, pt. no. S668. Front exhaust pipe H6194 replaced by H8281 now common RH and LHD cars.

Reason: To use common manifold on RHD and LHD models.


59D/5006 to  Trouble has been experienced of excessive hood covering wear and

6016506      damage caused by friction of the fabric when travelling with the hood folded down.

A service scheme has been prepared to rectify this trouble, details from the factory.


59S/6095 11" brake drum, rear, replaces 12° brake drum. Reason: Improved braking.


60S/7337 (saloon) 7564 (coupe) Floorboards, gearbox cover and ramp plate have been modified to a flanged and bolted down type in place of the previous clip down gearbox cover. All floorboards, ramp plate and gearbox cover flange joints are now made with a strip of ¾" wide Prestik jointing material. This material is supplied in rolls suitably cut off and stuck to all floorboard and gearbox cover edges, the parts fitted on top and the bolts pushed through the Prestik during assembly. Redundant holes in ramp plate (on cars without heater fitted) are covered up with leather cloth fixed with Bostik "C" adhesive. An additional steering column grommet is added to steering column on the front face of the bulkhead. The ramp plate sound baffle board and felt backing are done away with and new padded carpets are added. Full modification details from the factory.


6064 Pressure type radiator cap now fitted to radiator and the top radiator to cylinder head hose externally reinforced. New hose pt. no. X6255. Vacuum releaoe valve opens at 1 lb per sq. inch. Pressure release valve  6¼ - 7¼ lb per sq. inch..


7681 Brake pipes re-run so that brake hoses are now fitted behind the

           suspension links instead of in front. New part nos. are:-

           A7005 front suspension assembly

           500193 assy of pipe, tee piece to 0/S hose (RHD)

           500194 asay of pipe, tee piece to N/S hose  (RHD)

           A7008 front suspension assembly

           500219 assy of pipe, tee piece to N/S hose (LHD)

           500218 assy of pipe, tee piece to O/S hose (LHD)

           500188 assy of hose bracket RH

           500189 asap of hose bracket LH

           500245 front brake carrier plate RH

           500246 front brake carrier plate LH (RHD and LHD)

           Reason: To prevent chafing of front brake hose against rim of road wheel.


           Front shock absorber pt. no. D5670, lining DA6/6 1"` bore telescopic have been superseded            by pt. no. 500157 Girling type CDRS 1½" bore telescopic.

                      New part numbers:-

           500157 front shock absorber  2 off

           500110 anchorage sleeve  2 off

           500113 nut for anchorage sleeve  off

           F410801814 bolt 7. BSF x 24. (additional)  2 off

           500111 front shock absorber bottom lug RH  1 off

           500112 front shock absorber bottom lug LH  1 off

           500114 dowel pin bottom Wishbone  2 off


           Telescopic rear shook absorbers type DAS9 replace PV6 piston type. This also necessitates            the fitting of a new exhaust tail pipe and expansion box assembly.

                      New part numbers:-          

           500158 rear shook absorbers  2 off

           D5636 washer  4 off

           FN108Z nut  4 off

           SW108Z spring washer  4 off

           PW110Z plain Washer  2 off

           500036 assy of shook absorber mounting bracket  2 off

           500213 shock absorber bracket   1 off

           500214 shock absorber bracket LH  1 off

           500171 expansion box and pipe assembly  1 off

           500155 tail pipe  1 off

           Reason: improvement to design.


From October 1950

           Introduction of Carburettor jet with two feed holes, 0.140. diameter replacing jet with 10 feed            holes of .093" diameter. Jets are Interchangeable the old part number is retained.


From November 1950

           Introduction of a modified door lock incorporating a stronger bolt spring pt. no. 0041-349.            When modifying earlier locks, in addition to stronger spring pt. no. RS41-349, the existing            bolt   assemblies must be replaced by the following parts:-

           front door lock - (with one stud on the bolt assembly acting between the operating lever and            spring reaction lever)

           LH side new bolt assembly pt. no. L3321/A

           RH side new bolt assembly pt. no. L3321/B

           Rear door lock (with two studs positioned across the bolt assembly)

           LH side new bolt assembly pt. no. L3320/B

           RH side new bolt assembly pt. no. L3320/A


           (approx) body no. 69593. Scuttle ventilator modified by moving the pivot from the centre

           position to the extreme rear.

           Reason, To increase opening and improve interior ventilation.

           1" dia front brake wheel cylinders pt. no. 300741/2 LH and RH replace pt. no. 300319/20 LH

           and RH (1&1/8" dia).

           Reason: To improve ratio between front and rear brakes.

           Export LHD - as above. Fitting of 1&1/8" front brake wheel cylinders pt. nos. 300319/20 LH

           and RH recommenced.


62S/9353   Introduction of RMB/2 type power unit incorporating the following modifications,-

           1. Water pump mounted on the top front of the timing chain case enabling the fan to be            mounted on the water pump spindle and driven by a single belt.

           2. The oil relief valve is now pre-set and requires no adjustment. It is incorporated in the oil            pump body and a floating type oil filter employed.

           3. The camshafts will have ½" wide ramped cams resulting in much quieter valve gear            operation.

           Note, however, that the first 200 engines will be fitted with camshafts having ¾" wide cams.            The tappet setting is .011. (hot) in either case.

           4. The new camshaft results in a slightly different valve timing;

           inlet valve opens 12° B.T.D.C.

           inlet valve closes 53° A.B.D.C.

           exhaust Caine opens 55° B.B.D.C.

           exhaust valve closes 20° A.T.D.C.

           5. The compreesion ratio has been reduced from 6.85:1 to 6.7:1.

           6. The direction of rotation of the distributor has been altered to anti-clockwise.

           7. The location of the front engine mounting has been changed to allow for the fan belt run,            the front suspension cradle and engine mounting cross tube having been modified to suit.


62S/9304   Air scoops pt. nos. 500531 (RH) and 500532 (LH) of swivelling type are now available for            attachment to the front doors and are fitted as standard from the above chassis number.

           Reason: Improved ventilation control.


8873           New type steering wheel pt. no. 500677 introduced incorporating a collet type clamp with            fluted lock ring in place of split clamp with bolt and lock nut.


RMF/9911           Introduction or front hubs incorporating ANF threaded studs.

           Introduction of hypoid rear axle with open propeller shafts and hubs incorporating A.N.F.            threaded   studs and stronger rear road springs. Hypoid 90 oil now used for the rear axle and            gearbox as well.

           Introduction of full hydraulic brake gear.



Engine Nos.


B3157        Connecting rod assembly S553 replaced by S863. S863 has wider big end bolt centres.

           Rods should be serviced singly for the respective engine numbers (as they are different

           weights) or as a set of four S553, or a set of four S863.


B6020 Piston and bore sizes changed from millimetre to inch measurements. Pistons now marked

           with the correct size of cylinder bore for which they are suitable. The marking on the block

           should correspond accordingly.


B7339 Guide for dipstick fitted to crankcase. New part nos:

           dipstick 166086             )

           dipstick forrule 13454   ) 166087

           dipstick washer 13455  )

           dipstick guide 166085   )

           Reason: Improvement to design.


           Cylinder head with increased depth of combustion spaces, pt. no 166160 replaced pt. no.            S810.

           Reason: Change to lower compression ratio.


           Timing chain adjustor, pt. no. 166316 replaces pt. no. S136.

           Timing chain adjustor bolt, pt. no. 23150 replaces set screw, pt. no. 1114 (to block).

           Timing chain adjustor bolt tab washer, pt. no. 166337 and timing chain adjustor plug, pt. no.

           R50 are both deleted,

           Cylinder head stud (short) pt. no. 166344 replaces S335.

           Cylinder head stud (long) pt. no. 166345 replaces S336.

           Push rod tube, pt. no. 166346 replaces S235.

           Push rod assembly pt. no. 166347 replaces S748.

           Reason: To compensate for increase in height of head.


           Introduction of high output dynamo pt. no. 164439 (Lucas type 045 P0-5) improved dynamo

           adjusting bracket and dynamo split pulley with the addition of combined dynamo fan and

           blanking plate for better cooling.

           Dynamo pt. no. 164439 replaces pt. no. 164422.

           Dynamo adjusting bracket pt. no. 166097 replaces pt. no. S28.

           Dynamo split pulley front pt. no. 166103 ) replaces pt. no. S19.

           Dynamo split pulley rear pt. no. 166104  )

           Dynamo fan with blanking plate pt. no. 164450 added.


           Special batch of 200 RMB2 engines built using inlet camshaft pt. no. 166257 and exhaust

           camshaft pt. no. 166258 with the width of the cams increased to ¾ Tappet setting hot is .011".

           Reason: Test purposes.


           1" diameter tappets with angular holes pt. no. 166256 replace 15/16" diameter tappets pt. no.


           Reason: Improved drainage for foreign matter.


           Introduction of water pump assembly with modified spindle and one pair of split cotters

           replacing spindle with circlip. The water pump spindle collar pt. no. 166139 has been modified

           to accommodate the use of the split cotters, and a modified collar must be set out if it is

           wished to fit the modified spindle and cotters to engines prior to engine no. RMB2/531.

           Water pump spindle pt. no. 166511 replaces water pump spindle pt. no. 166136.

           Water pump split cotters pt. no. 166512 (1 pair) replaces water pump circlip pt. no. 166136        

           (1 off).

           Reason: Improvement in design.


           Introdution of a new oil pumo relief valve guide pt. no. 166551 in case iron replacing pt.


           Reason: To prevent noise made by flutter of the oil pump relief valve ball.


           Introduction od split type connecting rod pt. no. 166165 with renewable bearing shells pt. no.

           166519 bottom half steel backed white metal lined and pt. no. 166520, top half copper lead.

           Con rod bolts pt. no. 166292 with U.N.F. threading 5/69 A/F also fitted.

           Reason: Improved design enabling connecting rod to be pasaed up cylinder bore.


RMB2/2050   Gearbox no.  CA495.  A special batch of 100 gearboxes have been

           fitted with a new mainshaft pt. no. 166552 having .008" extra

           clearance with the top and 3rd speed hub.

           Reason: To obviate synchromesh rattle.


RMB2/1280   Oil level indicator pt. no. 166557 replaces pt. no. 166076 with

           increase in oil capacity of gearbox from 2 to 2&5/8 pints.

           Reason: To raise oil level.


RMB2/1288    (RHD)  RMB2/LX/1316 (LHD). Distributor pt. no. 166250 with suction

           operated advance and retard control unit replaces distributor

           pt. no. 166182.  Carburettor pt. no. 166348 including auto-

           ignition adaptor fitted to suit.

           Reason: Improved design.


RMB2/1332   Introduction of water pump spindle pt. no. 166561 in harder

           material replacing water pump spindle pt. no. 166511.

           Reason: To avoid possible breakage due to out of balance of

           fan blades and overhang from pulley drive.


RMB2/1332   Cast iron fan pulley pt. no. 166517 replaces aluminium fan

           pulley pt. no. 166145 necessitating the fitting of water pump

           spindle of greater hardness (see water pump spindle modification)

           Reason: To eliminate the tendency of hub bore wear.


RMB2/7226   Deletion of oil hole in timing chain oiler pt. no. S285-  The

           pt. no. remains unchanged though the part is now known as the

           timing chain case damper stud.

           Reason: Oil bleed to timing chain not necessary.


           For service purposes pt. no. 166516 has been allocated for

           gudgeon pins .002" oversize, the pistons with slack gudgeon

           pin holes must be reamed out to suit.


           The timing chain tensioner bracket pt. no. 5309 (mod 2) has been

           modified with slots 21/64" x 9/16" long in place of the two holes

           of .328" dia.  When the modified bracket is fitted in lieu of the

           original type, a plate pt. no. 166554 together with longer bolts

           pt. no. FS104/4Z replacing pt no. 4214 must also be fitted.

           Reason:  To give added adjustment on tensioner.



Gearbox Nos,


CA37          approx. (17.6.52).  Introduction of gearbox mainshaft pt. no.

           166241 with an indent added and an additional retainer ball in

           the synchro hub.  The seven balls will be retained by peening

           into the hub to prevent any chance of ejection.