| Description | Date | Identifier | |
| Provisional weight analysis and comparison of the H.V. prototype chassis against previous Bentley and Wraith models. | 14th Nov 1938 | Box 88 \ 3 scan0273 | |
| Weight reduction strategies for the sports chassis and the continental Bentley to improve performance. | 14th Nov 1938 | Box 88 \ 3 scan0274 | |
| Comparative weight analysis of B.V and 'W' Series Bentley chassis. | 14th Nov 1938 | Box 88 \ 3 scan0275 | |
| Weight analysis listing the increase and excess weights of various components for S.V. and MX series vehicles. | 14th Nov 1938 | Box 88 \ 3 scan0276 | |
| Comparison of the chassis weights for the 25/30 and Wraith models. | 14th Nov 1938 | Box 88 \ 3 scan0277 | |
| Weight analysis comparing a Humber Snipe Saloon with a standard 4¼ Bentley all-steel body. | 10th May 1939 | Box 88 \ 3 scan0278 | |
| Issues with Bensport exhaust valves, including stretching and overheating, and proposing alternative port designs. | 26th May 1932 | Box 88 \ 4 scan0001 | |
| Technical discussion on the practicality of different engine arrangements, specifically regarding valve gear and port spacing. | 26th May 1932 | Box 88 \ 4 scan0002 | |
| Hand-drawn sketch comparing seven different design arrangements for a Bensport cylinder head. | 30th May 1932 | Box 88 \ 4 scan0003 | |
| Alternative arrangements for Bensport exhaust valves. | 30th May 1932 | Box 88 \ 4 scan0004 | |
| Providing Inlet and Exhaust Valve Lift Curves for the Bensport J.1. engine. | 2nd Nov 1932 | Box 88 \ 4 scan0005 | |
| Instruction to ensure the new type of exhaust valve is used for the Bensport engine. | 15th Dec 1932 | Box 88 \ 4 scan0006 | |
| Proposed production specification for the Valves and Fittings section for the Bensport J.I. chassis. | 10th Feb 1933 | Box 88 \ 4 scan0007 | |
| Table comparing component part numbers fitted to a unit against those proposed for production. | 10th Feb 1933 | Box 88 \ 4 scan0008 | |
| Request to manufacture a modified set of valve wedges to test on valve spring noise. | 29th Apr 1933 | Box 88 \ 4 scan0009 | |
| Request for the manufacture of two sets of inlet and exhaust valves for a Bentley. | 25th Aug 1933 | Box 88 \ 4 scan0010 | |
| On Bentley exhaust valve failure due to leaded fuel and a request for replacements made from Firth's crown steel. | 30th Aug 1933 | Box 88 \ 4 scan0011 | |
| Improved car engine performance by analysing and adopting Bentley's two-inlet-valve design. | 30th Aug 1933 | Box 88 \ 4 scan0012 | |
| Tests comparing the valving efficiency of Phantom II and Bentley engines. | 1st Sep 1933 | Box 88 \ 4 scan0013 | |
| List of engine tests including compression pressure, volumetric efficiency, and air flow across various valve configurations. | 24th Aug 1933 | Box 88 \ 4 scan0014 | |
| Air flow and pressure difference tests on various cylinder heads and valves. | 24th Aug 1933 | Box 88 \ 4 scan0015 | |
| Summary of airflow and pressure difference tests on various engine valve and cylinder head configurations. | 24th Aug 1933 | Box 88 \ 4 scan0016 | |
| Deductions from tests on a Phantom model regarding valve lift, efficiency, and size. | 24th Aug 1933 | Box 88 \ 4 scan0017 | |
| Comparison of Phantom and Bentley engine head designs, focusing on port shape, valve size, and airflow. | 24th Aug 1933 | Box 88 \ 4 scan0018 | |
| Port and valve shape design tests using experimental wooden models. | 24th Aug 1933 | Box 88 \ 4 scan0019 | |
| Summary of performance comparisons between Phantom and Bentley engine heads, based on air flow and power curves. | 24th Aug 1933 | Box 88 \ 4 scan0020 | |
| Potential engine performance improvements for Phantom and R.R. Bentley models. | 24th Aug 1933 | Box 88 \ 4 scan0021 | |
| Appendix detailing the method of procedure for comparing the volumetric efficiency of various cylinder heads. | 24th Aug 1933 | Box 88 \ 4 scan0022 | |
| Description of the method for estimating engine velocities, volumetric efficiency and air flow. | 24th Aug 1933 | Box 88 \ 4 scan0023 | |
| Description of the test rig and general methods of working for airflow experiments. | 24th Aug 1933 | Box 88 \ 4 scan0024 | |
| Calculations for compression pressures, volumetric efficiency, and air flows with test data for a large inlet valve head. | 24th Aug 1933 | Box 88 \ 4 scan0025 | |
| The estimation of air velocity through inlet ports, including formulas and calculated air flows for a Phantom engine at various RPMs and valve lifts. | 24th Aug 1933 | Box 88 \ 4 scan0026 | |
| Calculations for air flow and mass flow for Bentley engines, with comparisons to Phantom engines. | 24th Aug 1933 | Box 88 \ 4 scan0027 | |
| Page detailing formulas for calculating volume flow, with variable definitions and notes for ensuring reliable measurements. | 8th Sep 1933 | Box 88 \ 4 scan0028 | |
| Mysterious exhaust valve failures in car units, suspecting leaded fuel as the cause. | 8th Sep 1933 | Box 88 \ 4 scan0029 | |
| High-speed endurance test of pistons, detailing an exhaust valve failure and subsequent analysis. | 23th Sep 1933 | Box 88 \ 4 scan0030 | |
| Addendum to a report on tests concerning the efficiency of valving for Phantom and Bentley engines. | 25th Sep 1933 | Box 88 \ 4 scan0031 | |
| Conclusions from tests on engine cylinder head components, including induction ports and combustion chambers. | 25th Sep 1933 | Box 88 \ 4 scan0032 | |
| Summary of tests comparing cylinder head designs to improve volumetric efficiency by using two inlet valves. | 25th Sep 1933 | Box 88 \ 4 scan0033 | |
| Sectional elevation and horizontal plane view of an engine inlet port and seating plug mechanism. | 5th Oct 1933 | Box 88 \ 4 scan0034 | |
| Bentley valve stretching during high speed endurance running and the requested modifications. | 5th Oct 1933 | Box 88 \ 4 scan0035 | |
| Design points for experimental exhaust valve seats in a Bentley aluminium cylinder head, based on Kestrel aero engine research. | 7th Nov 1933 | Box 88 \ 4 scan0036 | |
| Blueprint for an exhaust valve seat. | 7th Nov 1933 | Box 88 \ 4 scan0037 | |
| Inadvisability of using a larger diameter thread for Bentley exhaust valve seats. | 15th Nov 1933 | Box 88 \ 4 scan0038 | |
| Request to fit future Bentley units with strengthened exhaust valves and to supply sets for endurance testing. | 27th Nov 1933 | Box 88 \ 4 scan0039 | |
| Use of austenitic steel for Bentley chassis valves and the required tappet clearances. | 18th Dec 1933 | Box 88 \ 4 scan0040 | |
| Standardisation of exhaust valves made from K.E. 965 material with Stellite tips to prevent stretching and fractures. | 20th Dec 1933 | Box 88 \ 4 scan0041 | |
| Request for a set of special tappet springs to be made with modifications to part E.83405. | 12th Feb 1934 | Box 88 \ 4 scan0042 | |
| Comparing the oil feed to the Bentley valve mechanism with the 20/25 HP model. | 20th Feb 1934 | Box 88 \ 4 scan0043 | |
| Experiment to improve rocker shaft lubrication by drilling holes, comparing Bentley and 20/25 HP methods. | 20th Feb 1934 | Box 88 \ 4 scan0044 | |
| Risk of valve spring failure on Bentley cars and preventing the valve from dropping into the cylinder. | 12th Mar 1934 | Box 88 \ 4 scan0045 | |
| Standardisation of parts for a rocker shaft to resolve insufficient lubrication. | 19th Feb 1934 | Box 88 \ 4 scan0046 | |
| Design of Bentley valves to prevent them from dropping into the engine cylinder. | 14th Mar 1934 | Box 88 \ 4 scan0047 | |
| Proposal to fit retaining rings to Bentley valves to prevent them from dropping into the cylinder. | 20th Mar 1934 | Box 88 \ 4 scan0048 | |
| Silent tappet design, departing from Cadillac recommendations, and proposing a die for rockers for the 20/25 and Bentley models. | 19th Apr 1934 | Box 88 \ 4 scan0049 | |
| Instructions for new experimental valve and fitting drawings for a 3 1/2 Litre Bentley. | 1st May 1934 | Box 88 \ 4 scan0050 | |
| Exhaust valve spring failures, testing methods, and potential solutions. | 26th Apr 1934 | Box 88 \ 4 scan0051 | |
| Engine failure due to valve springs and proposals for double valve springs and a locking ring scheme. | 26th Apr 1934 | Box 88 \ 4 scan0052 | |
| Engine failure due to a broken exhaust valve spring on Chassis No. B-54-AH. | 26th Apr 1934 | Box 88 \ 4 scan0053 | |
| Broken valve spring on a new Bentley, leading to a proposal to use double valve springs for prevention. | 30th Apr 1934 | Box 88 \ 4 scan0054 | |
| Micro-examination report on broken 3 1/2 litre Bentley valve springs. | 3rd May 1934 | Box 88 \ 4 scan0055 | |
| Comparison of properties and structures between chrome vanadium and American plain carbon steel springs. | 3rd May 1934 | Box 88 \ 4 scan0056 | |
| Comparison of S/CV and American springs, focusing on dimensions, wire properties, and performance in low temperatures. | 3rd May 1934 | Box 88 \ 4 scan0057 | |
| Comparison of American plain carbon steel springs with chrome vanadium steel springs and English piano wire. | 5th May 1934 | Box 88 \ 4 scan0058 | |
| Cases of valve spring failures and the resulting engine issues. | 5th May 1934 | Box 88 \ 4 scan0059 | |
| Request to prepare a Bentley Cylinder Head with Double Valve Springs to be fitted to a chassis. | 7th May 1934 | Box 88 \ 4 scan0060 | |
| Failure of 3 1/2 Litre Bentley valve springs and recommending a design improvement. | 11th May 1934 | Box 88 \ 4 scan0061 | |
| Experimental department report on a scheme to prevent valves from dropping into a Bentley cylinder. | 16th May 1934 | Box 88 \ 4 scan0062 | |
| Test report on a scheme to prevent a valve dropping into the cylinder upon spring failure, with results and proposed modifications. | 16th May 1934 | Box 88 \ 4 scan0063 | |
| Modifications for preventing valves from dropping into the Bentley cylinder. | 17th May 1934 | Box 88 \ 4 scan0064 | |
| Request to modify a Cylinder Head to fit a Double Valve Spring for endurance tests on a B.6 unit. | 25th May 1934 | Box 88 \ 4 scan0065 | |
| Proposal to bush and test a set of Bentley Rocker Arms on vehicle 21-G-IV. | 17th May 1934 | Box 88 \ 4 scan0066 | |
| Approval to use Bentley type rocker arm bushing on the 20/25 car following successful experimental tests. | 15th May 1934 | Box 88 \ 4 scan0067 | |
| Difficulties in bushing rocker arms for the 20/25 HP model compared to other models. | 1st May 1934 | Box 88 \ 4 scan0068 | |
| Scheme for preventing valves from dropping into the cylinder. | 28th May 1934 | Box 88 \ 4 scan0069 | |
| Scheme for preventing valves dropping in the cylinders. | 30th May 1934 | Box 88 \ 4 scan0070 | |
| Urgent modifications to a Bentley set of self-adjusting tappets. | 5th Jun 1934 | Box 88 \ 4 scan0071 | |
| Rocker shaft modifications for Bentley and 25 HP self-adjusting tappets. | 9th Jun 1934 | Box 88 \ 4 scan0072 | |
| Request to manufacture a new set of Bentley valve springs with specified free lengths to address valve bounce issues. | 14th Jun 1934 | Box 88 \ 4 scan0073 | |
| Request to prepare stellited exhaust valves and seats for Phantom and Bentley models due to testing with lead fuel. | 21th Jun 1934 | Box 88 \ 4 scan0074 | |
| Request to produce two trial Bentley tappets with a new weight-reduced design without a roller. | 2nd Jul 1934 | Box 88 \ 4 scan0075 | |
| Request to manufacture specific Bentley valves as part of an effort to lighten the valve gear. | 3rd Jul 1934 | Box 88 \ 4 scan0076 | |
| Premature valve bounce using Halford Tappets on a Bentley engine, comparing single and double valve springs. | 3rd Jul 1934 | Box 88 \ 4 scan0077 | |
| Lightening valve gear to compensate for the extra weight of automatic tappets. | 3rd Jul 1934 | Box 88 \ 4 scan0078 | |
| Blueprint drawing of an engine inlet valve with dimensions. | 27th Jun 1934 | Box 88 \ 4 scan0079 | |
| Technical drawing of an exhaust valve with detailed dimensions. | 3rd Jul 1934 | Box 88 \ 4 scan0080 | |
| Standardisation document for a scheme to prevent valves dropping in the cylinder head. | 29th May 1934 | Box 88 \ 4 scan0081 | |
| Cost estimate for extra equipment and scrap costs for 'B' series items. | 29th May 1934 | Box 88 \ 4 scan0082 | |
| Letter from Frank B. Halford to E. W. Hives proposing a meeting in Derby. | 17th Jul 1934 | Box 88 \ 4 scan0083 | |
| Letter to Major F.B. Halford confirming a meeting for the following Monday. | 18th Jul 1934 | Box 88 \ 4 scan0084 | |
| Outlining issues with a sample cast Bentley rocker cover and recommending further testing. | 25th Jul 1934 | Box 88 \ 4 scan0085 | |
| Letter forwarding blueprints and detailing weights for various Bentley valve gear components. | 26th Jul 1934 | Box 88 \ 4 scan0086 | |
| Weight and bouncing speeds of different valve gear configurations. | 26th Jul 1934 | Box 88 \ 4 scan0087 | |
| Letter from Frank B. Halford regarding modifications to the Bentley valve gear and hydraulic rocker. | 28th Jul 1934 | Box 88 \ 4 scan0088 | |
| Concluding portion of a letter signed by Frank B. Halford promising suggestions. | 30th Jul 1934 | Box 88 \ 4 scan0089 | |
| Letter responding to queries about engine specifications, including valve bounce and spring loadings. | 30th Jul 1934 | Box 88 \ 4 scan0090 | |
| Letter from Frank B. Halford requesting technical data on valve acceleration for a hydraulic rocker. | 30th Jul 1934 | Box 88 \ 4 scan0091 | |
| Letter from aero-engine designer Frank B. Halford requesting details on a tappet return spring and a hydraulic rocker. | 31th Jul 1934 | Box 88 \ 4 scan0092 | |
| Letter to Major F.B. Halford enclosing blueprints for a hydraulic rocker and tappet return spring. | 1st Aug 1934 | Box 88 \ 4 scan0093 | |
| Letter from Frank B. Halford discussing proposed modifications to a hydraulic rocker and push rod to increase engine RPM. | 1st Aug 1934 | Box 88 \ 4 scan0094 | |
| | | | |
