| Description | Date | Identifier | |
| Bentley clutch slip, wear allowances, and pressure loss. | 10th Nov 1938 | Box 103 \ 3 scan0203 | |
| Performance and wear characteristics of graphite bronze clutch facings. | 19th Feb 1938 | Box 103 \ 3 scan0204 | |
| Potential wear on a clutch bush for the 20/25 HP and Bentley models. | 25th Feb 1938 | Box 103 \ 3 scan0205 | |
| On curing clutch judder in 25/30 HP & Bentley clutches by fitting a new bronze bush bearing. | 21th Feb 1938 | Box 103 \ 3 scan0206 | |
| Owner's complaint of clutch judder with graphite bronze clutch faces on a 3½-litre Bentley. | 17th Feb 1938 | Box 103 \ 3 scan0207 | |
| Synchro rattle and judder issues related to graphite bronze clutch facings. | 25th Feb 1938 | Box 103 \ 3 scan0208 | |
| Technical drawing of a clutch for a 20/25 Bentley, highlighting wear on the bronze bush. | 17th Feb 1938 | Box 103 \ 3 scan0209 | |
| Slack in a bronze bush for 20/25 HP and Bentley clutches, and subsequent owner satisfaction after replacement. | 3rd Mar 1938 | Box 103 \ 3 scan0210 | |
| Slight clutch judder complaint concerning graphite bronze clutch faces on a 3 1/2-litre Bentley. | 17th Feb 1938 | Box 103 \ 3 scan0211 | |
| Customer complaints and potential driver fault regarding Borg & Beck clutches. | 18th Feb 1938 | Box 103 \ 3 scan0212 | |
| Examining clutch friction plates and increasing clearance to extend service life. | 20th Aug 1937 | Box 103 \ 3 scan0213 | |
| Alterations to address rattles in Bentley clutch and brake pedals. | 20th Aug 1937 | Box 103 \ 3 scan0214 | |
| Modifying Bentley clutch and brake pedals to address rattling issues by adopting a new joint type. | 3rd Jun 1937 | Box 103 \ 3 scan0215 | |
| Blueprint of a corrugated or bellows-like component with dimensions. | 29th Jun 1937 | Box 103 \ 3 scan0216 | |
| Correction notice for a drawing reference related to Bentley Clutch and Brake Pedal rattles. | 29th Jun 1937 | Box 103 \ 3 scan0217 | |
| Rattles in Bentley clutch and brake pedals, proposing a modification to standardize parts with other models. | 3rd Jun 1937 | Box 103 \ 3 scan0218 | |
| Querying if the spring for the Bentley pedal anti-rattle device can be made with a larger diameter. | 7th Jun 1937 | Box 103 \ 3 scan0219 | |
| Modification to a gas tight joint for the brake and clutch pedals on a Bentley II. | 7th Jun 1937 | Box 103 \ 3 scan0220 | |
| Blueprint for a distance piece for a gas-tight joint on a pedal stem. | 18th Jun 1937 | Box 103 \ 3 scan0221 | |
| The fitting and performance of graphite bronze clutch faces on two 3 1/2-litre Bentley cars. | 10th Nov 1937 | Box 103 \ 3 scan0222 | |
| Complaint and new procedure for setting 25/30.HP & Bentley clutches made by Borg & Beck. | 15th Apr 1937 | Box 103 \ 3 scan0223 | |
| Correspondence regarding the return of a lined friction plate from a 4 1/4-litre Bentley chassis for examination due to a clutch slipping complaint. | 2nd Jan 1937 | Box 103 \ 3 scan0224 | |
| Bentley clutch complaints and potential solutions. | 4th Dec 1936 | Box 103 \ 3 scan0225 | |
| Recurring clutch failures on Bentleys and the comparative cost of repair versus replacement with a Borg & Beck clutch. | 25th Nov 1935 | Box 103 \ 3 scan0226 | |
| Technical note on the introduction of castellated nuts on Bentley 25/30 clutches and the required adjustment process. | 17th Dec 1933 | Box 103 \ 3 scan0227 | |
| Clutch complaint for a Bentley 3.5-litre, chassis B.130 CR. | 30th Nov 1936 | Box 103 \ 3 scan0228 | |
| Enquiry into Bentley flywheels and the argument for a solid ring-out type. | 22th Oct 1936 | Box 103 \ 3 scan0229 | |
| Clutch complaint for a Bentley B102FB, detailing its failure and suspected cause. | 2nd Nov 1936 | Box 103 \ 3 scan0230 | |
| The correct procedure for clutch erection and timing markings for 25/30 HP and Bentley models. | 2nd Nov 1936 | Box 103 \ 3 scan0231 | |
| Investigation into uneven clutch operation and distortion of the clutch housing on a Bentley. | 6th Oct 1936 | Box 103 \ 3 scan0232 | |
| Faulty clutch plate from a Bentley (B-3-GP) causing excessive vibration. | 6th Oct 1936 | Box 103 \ 3 scan0233 | |
| Clutch complaint and subsequent examination for a Bentley B-102-FB. | 8th Oct 1936 | Box 103 \ 3 scan0234 | |
| Complaint regarding transmission rattle and clutch engagement on a Bentley B.226.GA. | 27th Aug 1936 | Box 103 \ 3 scan0235 | |
| The performance of a Bentley clutch after a 500-mile test in London traffic. | 27th Jun 1936 | Box 103 \ 3 scan0236 | |
| Poor flywheel finish on Bentley and 20/25 models causing clutch judder. | 27th Jun 1936 | Box 103 \ 3 scan0237 | |
| Monthly report on customer complaints regarding the Bentley 4.1/4 Litre Borg & Beck clutch. | 18th Aug 1936 | Box 103 \ 3 scan0238 | |
| Standardisation proposal to use copper tubes in place of steel for the cylinder and cylinder head. | 14th Jul 1925 | Box 103 \ 4 scan0001 | |
| Ongoing issues with water found in the engine sumps of several 20-HP cars. | 27th Mar 1926 | Box 103 \ 4 scan0002 | |
| Page two of a typed letter requesting serious consideration for an unresolved vehicle fault. | 30th Mar 1926 | Box 103 \ 4 scan0003 | |
| Issue of water in the engine sump of 20 HP cars, referencing specific chassis numbers. | 30th Mar 1926 | Box 103 \ 4 scan0004 | |
| Requesting a new cylinder head casting for a 20 HP engine with specific component placements. | 8th Nov 1926 | Box 103 \ 4 scan0005 | |
| Request for a blueprint of the 20HP cylinder head made for use with larger valves. | 26th May 1927 | Box 103 \ 4 scan0006 | |
| Modified 20 HP cylinder head with larger diameter valves. | 30th May 1927 | Box 103 \ 4 scan0007 | |
| Blueprint for an experimental 20 HP cylinder head with larger valves for power development experiments. | 30th May 1927 | Box 103 \ 4 scan0008 | |
| Investigation into engine knocks on 20-HP engines, with data on cylinder distortion and a recommendation for a new gudgeon pin fixing method. | 8th Aug 1927 | Box 103 \ 4 scan0009 | |
| Improvements to Phantom cylinder blocks to avoid distortion and piston knocks. | 25th Jun 1927 | Box 103 \ 4 scan0010 | |
| Engine knocks and cylinder distortion issues found in the 20HP model. | 21th Dec 1927 | Box 103 \ 4 scan0011 | |
| Modification of the 20 HP chassis cylinder block to prevent distortion. | 23th Dec 1927 | Box 103 \ 4 scan0012 | |
| Proposed modifications to the cylinder head and induction pipe arrangement for the India Chassis. | 15th Mar 1928 | Box 103 \ 4 scan0013 | |
| Outlining four engineering proposals for modifying the 20 HP engine for the India Chassis. | 15th Mar 1928 | Box 103 \ 4 scan0014 | |
| Design choices and urgent requirements for the India 3 engine. | 21th Mar 1928 | Box 103 \ 4 scan0015 | |
| Modifications for the India 3 cylinder head and induction pipe arrangement. | 2nd Apr 1928 | Box 103 \ 4 scan0016 | |
| Confirming a drawing has been sent for the arrangement of the cylinder head and induction pipe. | 4th May 1928 | Box 103 \ 4 scan0017 | |
| Suggestion to improve iron castings by adding nickel and chromium for car components like cylinders and flywheels. | 23th May 1928 | Box 103 \ 4 scan0018 | |
| Dispatch of a new aluminium turbulent head to achieve a 30% power increase. | 20th Jun 1928 | Box 103 \ 4 scan0019 | |
| Drawing Lec.2566 for the India 3 cylinder head and valve rockers, with particulars of the cylinder block to follow. | 23th Jun 1928 | Box 103 \ 4 scan0020 | |
| Modifications to an India 3-cylinder block pattern to accommodate larger valves. | 29th Jun 1928 | Box 103 \ 4 scan0021 | |
| Instructing a design change for the water pipe connection flange on the India 3 cylinder block. | 13th Jul 1928 | Box 103 \ 4 scan0022 | |
| Performance of 4 pinned rings in 20 HP pistons, despite ending trials on cross web pistons. | 19th Sep 1923 | Box 103 \ 4 scan0023 | |
| Engine issues related to valve clearances and the reuse of cylinder gaskets. | 10th Oct 1928 | Box 103 \ 4 scan0024 | |
| Variable collapse of gaskets for 2GHP valves and proposing standardization. | 6th Nov 1928 | Box 103 \ 4 scan0025 | |
| Cylinder head gaskets, complaints, and the need for proper tappet adjustment after fitting. | 6th Nov 1928 | Box 103 \ 4 scan0026 | |
| Design considerations for the bosses on a cast elbow pipe for the water pump connection. | 1st Dec 1928 | Box 103 \ 4 scan0027 | |
| Pre-ignition issues related to ignition plug temperature and water cooling in a 20 HP aluminium cylinder head. | 10th Apr 1929 | Box 103 \ 4 scan0028 | |
| Proposed modifications to an engine's cylinder head, including compression ratio, plug cooling, and ignition timing. | 10th Apr 1929 | Box 103 \ 4 scan0029 | |
| List of conclusions and proposed modifications for a cylinder head regarding hot spots, compression ratio, and ignition plugs. | 8th Apr 1929 | Box 103 \ 4 scan0030 | |
| Brief internal note from 'R' (at Le Canadel) agreeing to N. scheme 2560 for India 3. | 8th Apr 1929 | Box 103 \ 4 scan0031 | |
| Secret memo discussing performance improvements for the 20 HP car, including engine modifications. | 15th Apr 1929 | Box 103 \ 4 scan0032 | |
| Page 2 of a performance calculation document comparing a 20 HP vehicle with an SS model. | 17th Apr 1929 | Box 103 \ 4 scan0033 | |
| Proposal to increase the bore of the 20 HP engine to 3.250 inches. | 17th Apr 1929 | Box 103 \ 4 scan0034 | |
| Essential improvements for the future 20 HP chassis, specifically increasing the cylinder bore. | 17th Apr 1929 | Box 103 \ 4 scan0035 | |
| Proposed alterations for a 3.200' bore, focusing on cylinder stud design and stress. | 18th Apr 1929 | Box 103 \ 4 scan0036 | |
| Modifications to the 20 HP model, including increasing engine size and horsepower to compete with other manufacturers. | 18th Apr 1929 | Box 103 \ 4 scan0037 | |
| Page outlining hopes for vehicle improvements regarding chassis length, engine performance, and gearing. | 18th Apr 1929 | Box 103 \ 4 scan0038 | |
| Proposed alterations for a 3.250' bore engine, focusing on cylinder stud design and stress calculations. | 18th Apr 1929 | Box 103 \ 4 scan0039 | |
| Cover note for blueprint LEC.2695 shewing the 3.250' cylinders for the 20 HP chassis. | 20th Apr 1929 | Box 103 \ 4 scan0040 | |
| Engine modifications for the 20 HP chassis, specifically increasing the bore to 3.25 inches. | 21th Apr 1929 | Box 103 \ 4 scan0041 | |
| Pattern alterations for a series of 'twenty's' and a delay caused by a visitor. | 22th Apr 1929 | Box 103 \ 4 scan0042 | |
| Performance of a 20 HP turbulent head engine, comparing on-road trial results to test bed data. | 22th Apr 1929 | Box 103 \ 4 scan0043 | |
| Modifications to a 20 HP engine, specifically increasing the bore size for improved power and performance. | 1st Apr 1929 | Box 103 \ 4 scan0044 | |
| Performance report for the 20 HP engine, comparing the standard compression ratio with a new turbulent head design. | 1st Apr 1929 | Box 103 \ 4 scan0045 | |
| Proposed engine modifications to increase horsepower and performance. | 27th Apr 1929 | Box 103 \ 4 scan0046 | |
| Continued list of reasons for a change, with an observation on a broken 3rd speed wheel and a diagram of the gear tooth. | 27th Apr 1929 | Box 103 \ 4 scan0047 | |
| Secret memo regarding alterations required for a 20 HP G.3 engine to accommodate a 3.250' bore, referencing drawing LeC. 2696. | 27th Apr 1929 | Box 103 \ 4 scan0048 | |
| Comparing the machined cylinder for car 12-G4 with the standard cylinder from car 17-G3. | 30th Apr 1929 | Box 103 \ 4 scan0049 | |
| Outlining the 20 HP Programme, detailing specifications for G.4, G.5, and G.6 series cars. | 30th Apr 1929 | Box 103 \ 4 scan0050 | |
| Throttle valve diameter and venturi passageway for a 20 HP carburetter. | 2nd May 1929 | Box 103 \ 4 scan0051 | |
| Secret memorandum discussing improvements and issues with the 20HP model, using codenames 'India', 'China', and 'Japan' for different versions. | 9th May 1929 | Box 103 \ 4 scan0052 | |
| Modifications to the exhaust system, radiator movement, and frame stiffness. | 25th May 1929 | Box 103 \ 4 scan0053 | |
| Instruction to delete the light flywheel G.53434 on all engines using larger bores. | 25th May 1929 | Box 103 \ 4 scan0054 | |
| Arrangements for testing SS and 20 HP cars at Elstree and in France. | 29th May 1929 | Box 103 \ 4 scan0055 | |
| Tests conducted for an extra lubrication scheme for cylinders, scheme Hs.222. | 19th Jul 1929 | Box 103 \ 4 scan0056 | |
| Test report on modifying and observing oil pressure, delivery, and jet performance using different oil types and temperatures. | 29th May 1929 | Box 103 \ 4 scan0057 | |
| Confirmation of a wire concerning fitting a turbulent head to a Sixteen-G-Four engine. | 29th May 1929 | Box 103 \ 4 scan0058 | |
| Testing a one-piece cast iron cylinder block and crankcase for a 20 HP engine. | 29th Aug 1930 | Box 103 \ 4 scan0059 | |
| The progress of an experiment on the 20-HP cast iron cylinder block and crankcase and requesting its completion. | 23th Sep 1930 | Box 103 \ 4 scan0060 | |
| Questioning the standardisation of R.R.50 Alloy for pistons in Phantom and 20/25 chassis. | 9th Sep 1930 | Box 103 \ 4 scan0061 | |
| Proposing a production test of 20 sets of pistons made from R.R.50 alloy to assess their durability. | 3rd Oct 1930 | Box 103 \ 4 scan0062 | |
| Standardisation of chassis parts, proposing a change of piston material from alloy No. 221 to RR.53 alloy. | 4th Sep 1930 | Box 103 \ 4 scan0063 | |
| Benefits of a single-unit cast iron cylinder block and crankcase for the 20 HP engine. | 3rd Nov 1930 | Box 103 \ 4 scan0064 | |
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