| Description | Date | Identifier | |
| List of S.U. petrol pumps removed from Bentley chassis in April 1939, detailing mileage and reasons for rejection. | 5th May 1939 | Box 162 \ 1 img023 | |
| List of S.U. petrol pumps removed from Bentley chassis during March 1939, with owner complaints and pump mileage. | 5th Apr 1939 | Box 162 \ 1 img024 | |
| Summary of petrol pump complaints for 3½ & 4¼ litre Bentley models, recorded during March 1939. | 6th Apr 1939 | Box 162 \ 1 img025 | |
| Repair process, guarantee, and costing for S.U. Petrol Pumps. | 2nd May 1939 | Box 162 \ 1 img026 | |
| Dispute with the S.U. Company regarding the free-of-charge repair of petrol pumps. | 28th Mar 1939 | Box 162 \ 1 img027 | |
| The costs and processes for pump repair work, including proposals for flat-rate pricing. | 28th Mar 1939 | Box 162 \ 1 img028 | |
| Request for authority to arrange repair work and create a list of parts for pricing. | 28th Mar 1939 | Box 162 \ 1 img029 | |
| The failure of Bentley Headlamps supplied by Messrs. Joseph Lucas Ltd., due to sticking adaptors and other faults. | 15th Mar 1939 | Box 162 \ 1 img030 | |
| List of S.U. petrol pumps removed from Bentley chassis in January 1939, detailing mileage and reasons for rejection. | 6th Feb 1939 | Box 162 \ 1 img031 | |
| Summary of petrol pump complaints for 3½ & 4¼ litre Bentley cars recorded during January 1939. | 6th Feb 1939 | Box 162 \ 1 img032 | |
| Summary of petrol pump complaints for 3½ & 4¼ litre Bentley models recorded during October 1938. | 2nd Nov 1938 | Box 162 \ 1 img033 | |
| List of S.U. petro-pumps removed from Bentley chassis during October 1938, detailing reasons for rejection. | 2nd Nov 1938 | Box 162 \ 1 img034 | |
| The performance and testing of the K.L.G. FLB.50.X type spark plug. | 23th Jan 1939 | Box 162 \ 1 img035 | |
| Photograph of a broken spark plug with the threaded base detached. | 23th Jan 1939 | Box 162 \ 1 img036 | |
| Photograph of a fractured spark plug. | 12th Jan 1939 | Box 162 \ 1 img037 | |
| Condition of a KLG Ignition Plug after use in a Bentley. | 12th Jan 1939 | Box 162 \ 1 img038 | |
| Fault on a Fuse Box for Chassis B.145.HM caused by a long stud and the corrective action. | 25th Nov 1938 | Box 162 \ 1 img039 | |
| Faulty fuse box from a Bentley B.145.HM, questioning if a screw or drilling depth is at fault. | 21th Nov 1938 | Box 162 \ 1 img040 | |
| Results of comparative sparking plug tests on a J.B.IV engine. | 22th Sep 1938 | Box 162 \ 1 img041 | |
| Tests conducted on spark plugs, comparing Champion L.D.8 and KLG models for Bentley or 25/30 HP cars. | 22th Sep 1938 | Box 162 \ 1 img042 | |
| Electrical laboratory experiment testing the effect of spark plug electrode design on firing voltage. | 19th Sep 1938 | Box 162 \ 1 img043 | |
| Graph comparing the performance of Champion L88 and K.L.G. FLB30X spark plugs under various running conditions. | 19th Sep 1938 | Box 162 \ 1 img044 | |
| Graph comparing the performance of Lodge 640 single point and KLG FLB30X spark plugs. | 28th Feb 1935 | Box 162 \ 1 img045 | |
| Graph comparing the performance of Lodge and K.L.G. spark plugs under various running conditions. | 19th Sep 1938 | Box 162 \ 1 img046 | |
| List of S.U. petrol pumps removed from Bentley chassis during August 1938 with rejection reasons. | 5th Sep 1938 | Box 162 \ 1 img047 | |
| The performance and condition of K.L.G. FLB.50X ignition plugs on a Bentley. | 12th Sep 1938 | Box 162 \ 1 img048 | |
| Requesting the return of Bentley KLG.FLB.30X plugs to be sent to the makers for a report. | 7th Jul 1938 | Box 162 \ 1 img049 | |
| Rapid wear of Bentley KLG.FLB.30X spark plug anodes and whether to scrap or repair them. | 6th Jul 1938 | Box 162 \ 1 img050 | |
| Blueprint of an adaptor plate showing dimensions, materials, and assembly instructions. | 6th Jul 1938 | Box 162 \ 1 img051 | |
| Parts list and assembly instructions for an adaptor plate and boss for a battery box. | 27th May 1938 | Box 162 \ 1 img052 | |
| Modification to prevent battery lug failures from overtightening studs. | 27th May 1938 | Box 162 \ 1 img053 | |
| Complaints of Bentley K.L.G. FLB.30X plugs burning at the points. | 8th Apr 1938 | Box 162 \ 1 img054 | |
| New scheme to prevent the over-oiling of Bentley dynamo commutators. | 5th May 1930 | Box 162 \ 1 img055 | |
| The investigation of wiring faults on a Bentley owned by Mr. Crittall following a visit to Kingsbury. | 4th Feb 1938 | Box 162 \ 1 img056 | |
| Recurring headlamp bulb failure likely caused by a loose bulb holder and vibration. | 4th Feb 1938 | Box 162 \ 1 img057 | |
| Why certain failures of Bentley dynamos are not being treated as serious complaints. | 7th Jan 1938 | Box 162 \ 1 img058 | |
| Requesting further information on three faulty Bentley dynamos received without any complaint reports. | 5th Jan 1938 | Box 162 \ 1 img059 | |
| Battery failures for chassis B.28.KT and B.164.KT. | 26th Oct 1937 | Box 162 \ 1 img060 | |
| Investigation into a recurring battery failure, identifying the cause as mishandling by coachbuilders and proposing a preventative modification. | 21th Oct 1937 | Box 162 \ 1 img061 | |
| Customer complaint about a faulty battery on chassis B-28-KT. | 13th Oct 1937 | Box 162 \ 1 img062 | |
| Response to a complaint from Lillie-Hall regarding a faulty ignition switch on a Bentley chassis. | 3rd Sep 1937 | Box 162 \ 1 img063 | |
| Tester's report detailing a complaint about a faulty ignition switch and the subsequent adjustment. | 30th Mar 1937 | Box 162 \ 1 img064 | |
| Investigating a dynamo failure, specifically the effect of two connectors on the distribution board. | 16th Aug 1937 | Box 162 \ 1 img065 | |
| Dynamo failure in a 3.5-litre Bentley caused by shorting wires behind the distribution box. | 13th Aug 1937 | Box 162 \ 1 img066 | |
| Oil entering Bentley dynamos from the tachometer drive. | 10th Jun 1937 | Box 162 \ 1 img067 | |
| Oil entering Bentley Dynamos from the Tachometer Drive and the effectiveness of fitting a breather and oil level plug. | 18th Jun 1937 | Box 162 \ 1 img068 | |
| Two Bentley dynamo failures due to the continual blacking up of the commutators. | 17th Jun 1937 | Box 162 \ 1 img069 | |
| Complaints about oil on the commutator of Bentley dynamos and suggesting a solution. | 5th Apr 1937 | Box 162 \ 1 img070 | |
| Issue of oil entering Bentley dynamos from the tachometer drive. | 4th Jun 1937 | Box 162 \ 1 img071 | |
| Complaints arising from the use of over-heavy grease in tachometer tubes. | 9th Jun 1937 | Box 162 \ 1 img072 | |
| Dynamo lubrication issues, recommending the fitting of Gits oil seals and the deletion of breathers. | 4th Jun 1937 | Box 162 \ 1 img073 | |
| Oil leak issues found in a Bentley Dynamo W-3-BK and proposed modifications. | 30th Jun 1937 | Box 162 \ 1 img074 | |
| Instruction to drain oil from the gearbox of all Bentley Dynamos before despatch. | 30th Jun 1937 | Box 162 \ 1 img075 | |
| Examination of Bentley dynamo failures, suspecting considerable night driving as the cause. | 3rd Jul 1937 | Box 162 \ 1 img076 | |
| Investigating Bentley dynamo failures, suspecting considerable night driving as the probable cause. | 5th Jul 1937 | Box 162 \ 1 img077 | |
| Rotationally slack dynamo drive on 25/30 and Bentley models, caused by undersized rubber buttons. | 5th May 1936 | Box 162 \ 1 img078 | |
| Engine gear rattles on the 25/30 HP and Bentley Dynamo Drive, caused by a slack rubber drive. | 16th May 1936 | Box 162 \ 1 img079 | |
| Quality of Helsby high tension ignition cable and the testing of new samples. | 5th Apr 1937 | Box 162 \ 1 img080 | |
| Test report on K.L.G. type FLB.30X sparking plugs removed from a Bentley chassis. | 2nd Apr 1937 | Box 162 \ 1 img081 | |
| Faulty Helsby Ignition Cable due to perished and cracked rubber insulation. | 2nd Apr 1937 | Box 162 \ 1 img082 | |
| Clutch 'jagger' issue on a 4 1/4 litre Bentley, chassis number B134.JD. | 13th May 1937 | Box 162 \ 1 img083 | |
| Electrical breakdown on a 4 1/4 Litre Bentley. | 12th Mar 1937 | Box 162 \ 1 img084 | |
| Electrical fault with the dynamo charging circuit on a 4 1/4-litre Bentley. | 9th Mar 1937 | Box 162 \ 1 img085 | |
| Starter motors for 4.5 litre and 8 litre Bentley chassis. | 14th Jan 1937 | Box 162 \ 1 img086 | |
| Request for information on the frequency of changing gear pinions on Bosch starter motors for 4.5 and 8 litre Bentley chassis. | 13th Jan 1937 | Box 162 \ 1 img087 | |
| And providing the chassis numbers for the introduction of Helsby cables. | 27th Oct 1936 | Box 162 \ 1 img088 | |
| Misfiring and clutch issues with Professor Dodds' Bentley, with proposed solutions. | 17th Jul 1936 | Box 162 \ 1 img089 | |
| Investigating a complaint about dynamo armature windings rubbing and short-circuiting due to a manufacturing fault. | 17th Jul 1936 | Box 162 \ 1 img090 | |
| Responding to complaints about the supply and fitting of dynamo guards and engine dampers. | 26th Aug 1936 | Box 162 \ 1 img091 | |
| Graph comparing the performance of Champion L88 and K.L.G. FL830X spark plugs on a 6-cylinder engine. | 19th May 1938 | Box 162 \ 2 img001 | |
| Graph comparing the performance of Lodge and KLG spark plugs at various plug gaps and engine conditions. | 21th Jun 1939 | Box 162 \ 2 img002 | |
| Comparison test graph of Lodge 641 three-point and KLG FLB 30X spark plugs. | 3rd Jun 1941 | Box 162 \ 2 img003 | |
| Comparison of specifications for K.L.G. FLB 30X and K.L.G. FL 30X spark plugs. | 23th Feb 1940 | Box 162 \ 2 img004 | |
| Test results and comparisons of different K.L.G. spark plug models. | 23th Feb 1940 | Box 162 \ 2 img005 | |
| Specification comparison between Lodge 640 and Lodge 641 spark plugs. | 23th Feb 1940 | Box 162 \ 2 img006 | |
| Specification sheet and photographs for a Lodge 741 spark plug. | 23th Feb 1940 | Box 162 \ 2 img007 | |
| Test notes on Lodge spark plugs concerning voltage measurements, wear, and misfiring causes. | 23th Feb 1940 | Box 162 \ 2 img008 | |
| Specification and photographic comparison of Champion NA 8 and LB 8 spark plugs. | 23th Feb 1940 | Box 162 \ 2 img009 | |
| Test notes on Champion spark plugs L88, N8, and NA10. | 23th Feb 1940 | Box 162 \ 2 img010 | |
| Comparison of A.C. K.11 and A.C. 46 spark plugs with photographs and specifications. | 4th Aug 1950 | Box 162 \ 2 img011 | |
| Test report on three different AC short reach spark plugs, detailing their performance and suitability. | 4th Aug 1950 | Box 162 \ 2 img012 | |
| Conclusions from tests comparing Delco and R.R. ignition systems to resolve engine misfiring issues. | 27th Mar 1939 | Box 162 \ 2 img013 | |
| Tests comparing Delco and R.R. distributors, focusing on plug gaps and ignition performance with oxidised plugs. | 27th Mar 1939 | Box 162 \ 2 img014 | |
| Investigation into misfiring on the No. 6 cylinder of Wraith cars, diagnosing the cause as oxidised spark plug electrodes. | 27th Mar 1939 | Box 162 \ 2 img015 | |
| Tests to diagnose irregular engine running in a Wraith model. | 27th Mar 1939 | Box 162 \ 2 img016 | |
| Tests on the relationship between ignition sparking plug voltage and the acceleration performance of a chassis. | 12th Jun 1936 | Box 162 \ 3 img001 | |
| Test results table showing 'steady braking' and 'pick up' performance for a 6-cylinder engine at various speeds. | 31th May 1911 | Box 162 \ 3 img002 | |
| Engine cylinder performance suggesting alterations to the induction pipe and carburettor system. | 12th Jun 1936 | Box 162 \ 3 img003 | |
| Acquisition of faulty spark plugs from Professor Dodds' Bentley for examination. | 29th Jul 1936 | Box 162 \ 3 img004 | |
| Letter regarding the history of faulty spark plugs replaced on Professor Dodd's car, model 34-GA. | 3rd Aug 1936 | Box 162 \ 3 img005 | |
| Letter to the Champion Sparking Plug Co. Ltd. requesting sample plugs for testing on Phantom III and 25/30 chassis. | 3rd Aug 1936 | Box 162 \ 3 img006 | |
| Letter from Champion Sparking Plug Co. Ltd. arranging a visit to Rolls-Royce. | 4th Aug 1936 | Box 162 \ 3 img007 | |
| Letter from Champion Sparking Plug Co. regarding a telegram about plugs sent for testing and arranging a visit. | 6th Aug 1936 | Box 162 \ 3 img008 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding the supply and specification of spark plugs for specific engines. | 6th Aug 1936 | Box 162 \ 3 img009 | |
| Confirming a slowdown in ordering RL.14 Sparking Plugs for the Phantom III Chassis. | 10th Aug 1936 | Box 162 \ 3 img010 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding the supply of N.A.10 and N.A.14 spark plugs for testing on the 'Phantom' model and a racing engine. | 10th Aug 1936 | Box 162 \ 3 img011 | |
| Invoice from Champion Sparking Plug Co. Ltd. for spark plugs. | 13th Aug 1936 | Box 162 \ 3 img012 | |
| Letter to the Champion Sparking Plug Co. Ltd. regarding the unsuitability of their NA.10 plugs due to a high heat factor and a request for a batch designed to run hotter. | 18th Aug 1936 | Box 162 \ 3 img013 | |
| Covering order for Champion Sparking Plugs. | 19th Aug 1936 | Box 162 \ 3 img014 | |
| Letter to Champion Sparking Plug Co. Ltd. regarding the satisfactory performance of their N.A.8 and L.B.8 plugs. | 10th Dec 1937 | Box 162 \ 3 img015 | |
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