| Description | Date | Identifier | |
| Extract detailing a persistent noise issue from the engine tappets during warm-up on the S.S. Chassis. | 8th Aug 1929 | Box 17 \ 6 Scan100 | |
| Exhaust and inlet valve design and materials for all aero and car engines. | 19th Aug 1929 | Box 17 \ 6 Scan101 | |
| Testing and proposed modifications for the Phantom II valve spring removing tackle. | 23th Sep 1929 | Box 17 \ 6 Scan102 | |
| Valve noise issues with new open-ended valve springs and recommending a return to the previous design. | 16th Dec 1929 | Box 17 \ 6 Scan103 | |
| Drawing detailing modifications to S.S. type valve guides, including the use of asbestos packings. | 21th Aug 1929 | Box 17 \ 6 Scan104 | |
| Standardisation of chassis parts, specifically asbestos valve guide packings. | 13th Mar 1930 | Box 17 \ 6 Scan105 | |
| Standardisation of Chassis Parts for Asbestos Valve Gland Packing. | 7th Jun 1930 | Box 17 \ 6 Scan106 | |
| Depot sheet regarding 40/50 valve guide washers, recommending asbestos grummits to prevent fouled sparking plugs. | 13th Aug 1930 | Box 17 \ 6 Scan107 | |
| Solution to over-oiling during slow running by replacing felt valve guide washers with new asbestos ones. | 30th Aug 1930 | Box 17 \ 6 Scan108 | |
| Instruction to minimise the stock of valve guides and modify their future manufacture to take asbestos valve washers. | 30th Aug 1930 | Box 17 \ 6 Scan109 | |
| Improved exhaust and inlet valves, discussing their increased weight and the potential impact on valve spring load. | 1st Aug 1931 | Box 17 \ 6 Scan110 | |
| Request to make one set of experimental Double Tapered Valve Springs and washers for the Phantom II. | 2nd Jul 1932 | Box 17 \ 6 Scan111 | |
| Blueprint for Continental Phantom double tapered valve springs. | 2nd Jul 1932 | Box 17 \ 6 Scan112 | |
| Exhaust valve failure during an endurance test on a Phantom II, Unit 25. | 27th May 1932 | Box 17 \ 6 Scan113 | |
| The fitting and standardization of valve springs for various car models. | 22th Sep 1932 | Box 17 \ 6 Scan114 | |
| Fitting and testing heavy exhaust valves on a Phantom II, including modifications. | 22th Sep 1932 | Box 17 \ 6 Scan115 | |
| Customer complaints of stretching exhaust valves and the testing of new heavy-type valves as a solution. | 23th Sep 1932 | Box 17 \ 6 Scan116 | |
| Standardisation sheet detailing modifications to fit new type exhaust valves to the Phantom II. | 1st Jan 1932 | Box 17 \ 6 Scan117 | |
| Valve guide failures and rattling issues on a Phantom model. | 14th Oct 1932 | Box 17 \ 6 Scan118 | |
| Instructions on fitting a new exhaust valve and modifying the valve guides to prevent rattles caused by stretching. | 14th Oct 1932 | Box 17 \ 6 Scan119 | |
| Standardisation of chassis parts, specifically exhaust valves Lec.3303 and guides Lec.3240. | 2nd Mar 1933 | Box 17 \ 6 Scan120 | |
| Form for the standardisation of chassis parts, detailing implementation and associated costs. | 31th May 1933 | Box 17 \ 6 Scan121 | |
| Requesting an experimental set of 12 rockers for Phantom II Automatic Tappets, based on blueprint Lec.3501. | 31th May 1933 | Box 17 \ 6 Scan122 | |
| Requesting the conversion of large inlet valve head springs to a double taper valve spring assembly. | 9th Jun 1933 | Box 17 \ 6 Scan123 | |
| Request to manufacture one set of Phantom II taper outer valve springs with a modified length. | 1st Jul 1933 | Box 17 \ 6 Scan124 | |
| New design for the plunger in the valve rocker for the Phantom II Automatic Tappets, due to issues with air trapping. | 7th Jul 1933 | Box 17 \ 6 Scan125 | |
| Requesting the production of a new set of steel high lift rockers for a P.II, as the phosphor bronze set failed. | 28th Jul 1933 | Box 17 \ 6 Scan126 | |
| Weight specifications and comparisons for various types of large inlet valves. | 8th Aug 1933 | Box 17 \ 6 Scan127 | |
| Request to manufacture a ball end for the Phantom II silent tappets to specific requirements. | 8th Aug 1933 | Box 17 \ 6 Scan128 | |
| Weight reduction of Phantom II inlet valves through various modifications. | 10th Aug 1933 | Box 17 \ 6 Scan129 | |
| Query regarding the production possibility of reducing the weight of large inlet valves by drilling a hole in the stem. | 24th Aug 1933 | Box 17 \ 6 Scan130 | |
| Performance and issues with larger inlet valves for the Phantom engine. | 25th Aug 1933 | Box 17 \ 6 Scan131 | |
| The weight reduction of Phantom II inlet valves through various modifications. | 26th Aug 1933 | Box 17 \ 6 Scan132 | |
| Test on exhaust valve size modifications. | 26th Aug 1933 | Box 17 \ 6 Scan133 | |
| Improved car engine performance by analysing and potentially adopting Bentley's twin inlet valve design. | 30th Aug 1933 | Box 17 \ 6 Scan134 | |
| Tests conducted on the efficiency of valving for Phantom II and Bentley engines. | 24th Aug 1933 | Box 17 \ 6 Scan135 | |
| Compression pressure, volumetric efficiency, and airflow tests on Phantom II cylinder heads. | 24th Aug 1933 | Box 17 \ 6 Scan136 | |
| Descriptions of air flow and pressure difference tests for various cylinder heads and valves. | 24th Aug 1933 | Box 17 \ 6 Scan137 | |
| Air flow and pressure difference tests on various engine valve and head configurations. | 24th Aug 1933 | Box 17 \ 6 Scan138 | |
| Deductions from tests on a Phantom engine, focusing on valve lift, efficiency, and size. | 24th Aug 1933 | Box 17 \ 6 Scan139 | |
| Analysis of engine port shape, valve size, and valve seat angles, comparing Phantom and Bentley heads. | 24th Aug 1933 | Box 17 \ 6 Scan140 | |
| Experiments with port and valve shape designs using wooden models. | 24th Aug 1933 | Box 17 \ 6 Scan141 | |
| Analysis of engine head and valve performance based on flow curves, with a summary of findings. | 24th Aug 1933 | Box 17 \ 6 Scan142 | |
| Analysis of potential improvements to engine head, valve, and camshaft design for increased power and efficiency. | 24th Aug 1933 | Box 17 \ 6 Scan143 | |
| Appendix detailing the method of procedure for testing the volumetric efficiency of various cylinder heads. | 24th Aug 1933 | Box 17 \ 6 Scan144 | |
| The method for estimating air flow velocities in an engine cylinder, including assumptions and calculations. | 24th Aug 1933 | Box 17 \ 6 Scan145 | |
| Description of the rig used and general methods of working for air flow tests. | 24th Aug 1933 | Box 17 \ 6 Scan146 | |
| Calculations relating to Compression Pressures, Volumetric Efficiency and air flows. | 24th Aug 1933 | Box 17 \ 6 Scan147 | |
| Estimation of air velocity through inlet ports, with calculations for required air flows at various RPMs and valve lifts. | 24th Aug 1933 | Box 17 \ 6 Scan148 | |
| Page of airflow calculations and formulas for a Bentley engine. | 24th Aug 1933 | Box 17 \ 6 Scan149 | |
| Formula for calculating volume flow with notes on reliable gas flow comparison. | 30th Aug 1933 | Box 17 \ 6 Scan150 | |
| 8 Litre Phantom exhaust valve failure during power tests. | 30th Aug 1933 | Box 17 \ 6 Scan151 | |
| Investigation into exhaust valve failures on car engines, suspected to be caused by leaded fuel. | 5th Sep 1933 | Box 17 \ 6 Scan152 | |
| Temporary loan of a Bentley 8 litre/cylinder block for inspection. | 5th Sep 1933 | Box 17 \ 6 Scan153 | |
| The design, function, and testing of a self-adjusting tappet mechanism for the Phantom II model. | 14th Sep 1933 | Box 17 \ 6 Scan154 | |
| Troubleshooting tappet clatter issues related to oil temperature and system aeration. | 14th Sep 1933 | Box 17 \ 6 Scan155 | |
| Comparison table of silent tappet systems, considering spring loads only. | 25th Sep 1933 | Box 17 \ 6 Scan156 | |
| Additional report on tests comparing the efficiency of valving on Phantom and Bentley engines. | 25th Sep 1933 | Box 17 \ 6 Scan157 | |
| Conclusions from tests investigating air flow and pressure differentials for inlet ports, induction ports, and combustion chambers. | 25th Sep 1933 | Box 17 \ 6 Scan158 | |
| Summary of tests on improving volumetric efficiency by fitting two inlet valves per cylinder instead of a single valve. | 25th Sep 1933 | Box 17 \ 6 Scan159 | |
| Blueprint showing a sectional elevation and a head cutaway for a rotating port valve design. | 25th Sep 1933 | Box 17 \ 6 Scan160 | |
| Extremely faint and illegible page with a purple stamp in the bottom right corner. | 28th Sep 1933 | Box 17 \ 6 Scan161 | |
| Comparative tests between the Large Inlet Valve Head and the Standard Head for the 8 Litre Phantom engine. | 28th Sep 1933 | Box 17 \ 6 Scan162 | |
| Power test results comparing different sized inlet valves for an 8.1 litre Phantom engine. | 8th Sep 1933 | Box 17 \ 6 Scan163 | |
| Specification for double valve springs for oil adjusted tappets on the Phantom engine. | 23th Oct 1933 | Box 17 \ 6 Scan164 | |
| Letter requesting two sets of an improved self-adjusting tappet from 'Self Adjusting Tappets Ltd.' for experimental testing. | 26th Oct 1933 | Box 17 \ 6 Scan165 | |
| Letter to Self-Adjusting Tappets Ltd. concerning tappet push rods, valve clearances for a Phantom engine, and a blueprint for a 20/25 engine. | 31th Oct 1933 | Box 17 \ 6 Scan166 | |
| Requesting tappet push rods to be supplied for an experiment on self-adjusting tappets for the Phantom car. | 31th Oct 1933 | Box 17 \ 6 Scan167 | |
| Request to manufacture a set of Phantom exhaust valves and valve seats to modification Hs.1197. | 7th Nov 1933 | Box 17 \ 6 Scan168 | |
| Technical comparison of silent tappet specifications for various engines. | 29th Nov 1933 | Box 17 \ 6 Scan169 | |
| Requesting modifications to parts for experiments on Phantom II tappet noise. | 16th Dec 1933 | Box 17 \ 6 Scan170 | |
| Requesting a specific machining clearance for the plungers and casings of silent tappets for model 28-EX. | 31th Jan 1934 | Box 17 \ 6 Scan171 | |
| The description and testing of self-adjusting tappets supplied by Self-Adjusting Tappets Ltd. | 31th Jan 1934 | Box 17 \ 6 Scan172 | |
| The reliability and wear of a self-adjusting valve mechanism after road tests. | 31th Jan 1934 | Box 17 \ 6 Scan173 | |
| Sketch of a self-adjusting tappet of the mechanical type. | 1st Feb 1934 | Box 17 \ 6 Scan174 | |
| Experimental rockers designed to eliminate clicking valve noise by ensuring concentric seating. | 30th Jan 1924 | Box 17 \ 6 Scan175 | |
| Instructions for fitting self-adjusting tappets to overhead valve engines. | 30th Jan 1924 | Box 17 \ 6 Scan176 | |
| Rough sketch of an O.H.V. self-adjusting tappet. | 5th Feb 1934 | Box 17 \ 6 Scan177 | |
| Unsatisfactory performance of tappets from a supplier and seeking information on previously used alternatives and future implementation plans. | 5th Feb 1934 | Box 17 \ 6 Scan178 | |
| Persistent issues with automatic tappet adjustments, specifically a plunger fault and valves being held open at high speeds. | 5th Feb 1934 | Box 17 \ 6 Scan179 | |
| Urgent request for two sets of valve springs for trial on Phantom and Vulture cylinder heads. | 6th Feb 1934 | Box 17 \ 6 Scan180 | |
| Standardization and application of self-adjusting tappets on various engine models. | 6th Feb 1934 | Box 17 \ 6 Scan181 | |
| Letter from Frank B. Halford to E. W. Hives regarding an automatic tappet and arranging a visit. | 21th Feb 1934 | Box 17 \ 6 Scan182 | |
| Modification of worn Phantom Automatic Tappet Plungers. | 27th Feb 1934 | Box 17 \ 6 Scan183 | |
| Letter from Ethyl Export Corporation discussing the condition of a Phantom engine valve and promoting the use of leaded fuel. | 6th Feb 1934 | Box 17 \ 6 Scan184 | |
| Request to manufacture 12 distance pieces for converting Phantom II automatic tappets to solid type. | 21th Mar 1934 | Box 17 \ 6 Scan185 | |
| Request for a pair of hardened Phantom II Automatic Tappet Rocker Shafts to be manufactured. | 27th Mar 1934 | Box 17 \ 6 Scan186 | |
| From 'Sg' to 'Hs' detailing a visit from Major Halford regarding his patent hydraulic self-adjusting valve tappet. | 13th Apr 1934 | Box 17 \ 6 Scan187 | |
| Automatic tappets, comparing the Halford and Cadillac schemes for car and aero engines. | 14th Apr 1934 | Box 17 \ 6 Scan188 | |
| Hydraulic automatic valve tappets, referencing their use on the Napier 'Dagger' engine. | 16th Apr 1934 | Box 17 \ 6 Scan189 | |
| Request for the manufacture of parts for Cadillac type automatic tappets (P.II). | 17th Apr 1934 | Box 17 \ 6 Scan190 | |
| Letter from Frank B. Halford arranging a visit to Derby to check on the progress of hydraulic tests. | 19th Apr 1934 | Box 17 \ 6 Scan191 | |
| Short typed communication to Halford regarding a discussion about silent tappets. | 20th Apr 1934 | Box 17 \ 6 Scan192 | |
| The testing of Cadillac-type automatic tappets for Vulture and Phantom cylinder heads. | 20th Feb 1934 | Box 17 \ 6 Scan193 | |
| Issues and solutions related to engine push-rod mechanisms, valve bounce, and tappet lubrication. | 20th Feb 1934 | Box 17 \ 6 Scan194 | |
| Tappet and valve bounce issues on the Phantom engine, with conclusions and proposed solutions. | 20th Feb 1934 | Box 17 \ 6 Scan195 | |
| Page discussing proposals for improving eccentric bearings and oil supply. | 20th Feb 1934 | Box 17 \ 6 Scan196 | |
| Requirement for a separate oil filter for rockers and proposing a test rig for tappets. | 20th Feb 1934 | Box 17 \ 6 Scan197 | |
| Addition to a report summarising suggested alterations and re-designs for automatic tappets. | 27th Feb 1934 | Box 17 \ 6 Scan198 | |
| Request for three solid steel push rods for valve gear deflection tests on Phantom II engines. | 24th Apr 1934 | Box 17 \ 6 Scan199 | |
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