| Description | Date | Identifier | |
| Method for stress testing valve gear on new engines by adjusting the valve lash. | 23th Nov 1915 | Box 35 \ 3 scan 001 | |
| Engine design considerations for the 'After-The-War Chassis'. | 3rd Oct 1916 | Box 35 \ 3 scan 002 | |
| Extract regarding the specification for valves and valve springs on the 40/50 HP chassis. | 26th Nov 1918 | Box 35 \ 3 scan 003 | |
| Extract detailing an order for light type valves, stronger springs, and a higher lift cam for a 45/50 HP Chassis. | 29th Nov 1918 | Box 35 \ 3 scan 004 | |
| Alterations to be made to the 40/50 HP chassis for a batch of 500 units. | 8th Jan 1919 | Box 35 \ 3 scan 005 | |
| Index outlining alterations and experimental work for the 40/50 HP present type chassis. | 18th Dec 1918 | Box 35 \ 3 scan 006 | |
| Design and materials for valves, valve gear, and related engine components. | 18th Dec 1918 | Box 35 \ 3 scan 007 | |
| List of components used in the assembly of chassis 1. E.X. X.2565. | 30th Jun 1919 | Box 35 \ 3 scan 008 | |
| Instruction to produce valve grinding tools for the 40/50 chassis for experimental trials and production quotations. | 18th Aug 1919 | Box 35 \ 3 scan 009 | |
| Recurring failures of valve springs and requesting a plan to address the potential weakness. | 13th Nov 1919 | Box 35 \ 3 scan 010 | |
| Cases of broken valve springs and tappet springs in post-war cars. | 20th Apr 1920 | Box 35 \ 3 scan 011 | |
| Comparison of the turning evenness between a 12-cylinder Packard camshaft and a standard 6-cylinder camshaft. | 20th Apr 1920 | Box 35 \ 3 scan 012 | |
| Investigation into the cause of engine rattles, focusing on the camshaft, crankshaft and timing gears. | 20th Apr 1920 | Box 35 \ 3 scan 013 | |
| Standard dimensions and limits for oversize valves. | 12th Jun 1920 | Box 35 \ 3 scan 014 | |
| Different patterns of lubricators and felt-like glands for valve guides. | 21th Jul 1920 | Box 35 \ 3 scan 015 | |
| Wear, noise, and required clearances in the tappet mechanism. | 6th Aug 1920 | Box 35 \ 3 scan 016 | |
| Letter forwarding a circular about the 'Apex' Priming & Compression Valve from W. Edward Storey. | 12th Oct 1920 | Box 35 \ 3 scan 017 | |
| Sales letter from W. Edward Storey proposing the 'APEX' Priming & Compression Valve. | 11th Oct 1920 | Box 35 \ 3 scan 018 | |
| Product information sheet for 'The Apex' priming and compression valve. | 22th Nov 1920 | Box 35 \ 3 scan 019 | |
| Valve guide wear on the 40/50 engine and potential lubrication solutions. | 22th Nov 1920 | Box 35 \ 3 scan 020 | |
| Recurring tappet spring breakages and proposals for investigation. | 4th Dec 1920 | Box 35 \ 3 scan 021 | |
| The applications and potential of Bakelite for various car components. | 21th Dec 1920 | Box 35 \ 3 scan 022 | |
| The serious issue of faulty tappets being manufactured with faces that are out of square. | 1st Jan 1922 | Box 35 \ 3 scan 023 | |
| Valve mechanism noise caused by valve spring vibration. | 8th Jan 1921 | Box 35 \ 3 scan 024 | |
| New machining and inspection methods to address faulty tappets. | 11th Jan 1922 | Box 35 \ 3 scan 025 | |
| Instruction detailing modifications to the Air Valve Cover, including machining and polishing. | 18th Jul 1921 | Box 35 \ 3 scan 026 | |
| Incorrect valve timing due to camshaft variations, with a proposal to inspect the mechanism and establish standard limits. | 24th Aug 1921 | Box 35 \ 3 scan 027 | |
| Valve longevity issues related to seat angles and clearance settings for Goshawk & 40/50 models. | 27th Dec 1922 | Box 35 \ 3 scan 028 | |
| Engine valve performance, pre-ignition causes, and spark plugs. | 29th Dec 1922 | Box 35 \ 3 scan 029 | |
| The practice of pinning piston rings, comparing American methods with the company's 40/50 and Hawk engines. | 30th Dec 1922 | Box 35 \ 3 scan 030 | |
| Return of a 'Nesthill' Valve Spring Compresser tool. | 30th Dec 1922 | Box 35 \ 3 scan 031 | |
| Query from Hs. to Roy. regarding the intended function of a valve spring extractor. | 19th Feb 1923 | Box 35 \ 3 scan 032 | |
| Standardisation of a modified valve spring washer for a chassis. | 28th Feb 1923 | Box 35 \ 3 scan 033 | |
| Investigation into broken valve springs on chassis 4-YG. | 20th Mar 1923 | Box 35 \ 3 scan 034 | |
| Correspondence concerning broken valve springs and a burnt exhaust valve on chassis 9-YG, arranging for the replacement and investigation of the cylinder blocks. | 23th May 1923 | Box 35 \ 3 scan 035 | |
| Investigating six broken valve springs and one burnt exhaust valve on chassis 9-YG. | 26th Apr 1923 | Box 35 \ 3 scan 036 | |
| The investigation of burnt valves from a 40/50 chassis and the arrangement for further testing. | 7th Jun 1923 | Box 35 \ 3 scan 037 | |
| Investigation into the distortion of exhaust valve heads on the 40/50 chassis. | 11th Jun 1923 | Box 35 \ 3 scan 038 | |
| Design and material for improved engine valves, suggesting a 30° face angle and experiments with monel metal. | 20th Jun 1923 | Box 35 \ 3 scan 039 | |
| Causes of burning exhaust valves and proposing changes to valve seat angles. | 6th Jul 1923 | Box 35 \ 3 scan 040 | |
| The cause and cure for the failure of exhaust valves on post-war 40/50 HP cars. | 15th Aug 1923 | Box 35 \ 3 scan 041 | |
| The failures of 40/50 exhaust valves, comparing post-war and pre-war designs. | 15th Aug 1923 | Box 35 \ 3 scan 042 | |
| The causes of valve burning, particularly comparing post-war and pre-war designs with different valve seat angles. | 12th Jul 1923 | Box 35 \ 3 scan 043 | |
| Engine valve seating angles, head shape, and material comparisons. | 15th Aug 1923 | Box 35 \ 3 scan 044 | |
| Exhaust valve pre-ignition issues and recommendations for valve shape and material. | 15th Aug 1923 | Box 35 \ 3 scan 045 | |
| Tappet clearances and weights for different exhaust valve types. | 15th Aug 1923 | Box 35 \ 3 scan 046 | |
| Urgent modification regarding the use of existing valves as inlet valves. | 31th Aug 1923 | Box 35 \ 3 scan 047 | |
| Standardisation proposal for chassis valves to overcome exhaust valve failures. | 16th Aug 1923 | Box 35 \ 3 scan 048 | |
| The cost and stock value of valves. | 22th Aug 1923 | Box 35 \ 3 scan 049 | |
| Standardisation of valves to overcome exhaust valve failures. | 16th Aug 1923 | Box 35 \ 3 scan 050 | |
| Returning a standard sheet with filled-in costs for valves and the total stock value. | 22th Aug 1923 | Box 35 \ 3 scan 051 | |
| Approval, testing, and sourcing of a new high-silicon valve steel for chassis and aero work. | 19th Nov 1923 | Box 35 \ 3 scan 052 | |
| Material for valves, referencing mileage data from Springfield. | 23th Nov 1923 | Box 35 \ 3 scan 053 | |
| Standardisation sheet for valve material for the 40/50 HP and 20 HP models. | 28th Nov 1923 | Box 35 \ 3 scan 054 | |
| Standardisation of valve material for 40 HP and 20 HP chassis to increase life. | 30th Oct 1923 | Box 35 \ 3 scan 055 | |
| Faulty 40/50 HP valve spring that broke during a test, referencing a previous issue with 20-HP springs. | 17th Jan 1924 | Box 35 \ 3 scan 056 | |
| Repeated 40/50 HP valve spring failures due to faulty material, with a recommendation for replacement. | 30th Jan 1924 | Box 35 \ 3 scan 057 | |
| Private memo regarding valve stems and guides for the 40/50 model car. | 9th May 1924 | Box 35 \ 3 scan 058 | |
| Forwarding a note about slow running on 40/50 HP engines to other departments. | 18th Sep 1924 | Box 35 \ 3 scan 059 | |
| Improving slow running on 40-50 HP engines by fitting air-tight washers to the valves. | 17th Sep 1924 | Box 35 \ 3 scan 060 | |
| On addressing wear on 40/50 HP valve guides by standardizing bronze guides in place of cast iron. | 24th Sep 1924 | Box 35 \ 3 scan 061 | |
| Testing and feedback on a 40/50 HP engine fitted with cylinders for completely enclosed valves. | 1st Nov 1924 | Box 35 \ 3 scan 062 | |
| Modification to prevent oil being drawn up the valve stem on the 40/50 HP engine. | 25th Aug 1925 | Box 35 \ 3 scan 063 | |
| Valve seat trouble in Phantom and other engines, posing several questions for investigation. | 16th Apr 1926 | Box 35 \ 3 scan 064 | |
| Booklet on the Midgley Scholey lighting system, sent for interest. | 17th Nov 1922 | Box 35 \ 3 scan 065 | |
| Letter discussing the Midgley-Scholey chassis electrical equipment, its control method, and a critique of its battery charging system. | 30th Jan 1922 | Box 35 \ 3 scan 066 | |
| Critique of car electrical systems, including vibrator regulators, the Midgley-Scholey system and junction boxes. | 30th Jan 1922 | Box 35 \ 3 scan 067 | |
| Letter from the Spanish representative regarding new electrical starter equipment from Messrs. Scholey. | 4th Mar 1922 | Box 35 \ 3 scan 068 | |
| Report on new electrical equipment from Scholey & Co. | 5th Mar 1922 | Box 35 \ 3 scan 069 | |
| Requesting the return of a booklet on Midgley-Scholey chassis electrical equipment. | 8th Mar 1922 | Box 35 \ 3 scan 070 | |
| The Midgley-Scholey chassis electrical equipment, including the dynamo and control units. | 18th Mar 1922 | Box 35 \ 3 scan 071 | |
| Critique of a dynamo's voltage regulator and a starter motor unit with a Bendix drive. | 18th Mar 1922 | Box 35 \ 3 scan 072 | |
| Continued report on an electrical system, critiquing the switchboard, junction box, and wiring. | 18th Mar 1922 | Box 35 \ 3 scan 073 | |
| Requesting the return of a booklet about the Midgeley-Scholey Electrical System. | 13th Nov 1923 | Box 35 \ 3 scan 074 | |
| Letter from Midgley Car Lighting Company Limited proposing their electrical lighting and starting equipment. | 12th Feb 1925 | Box 35 \ 3 scan 075 | |
| Letter from Midgley Car Lighting Company proposing a meeting in Derby to demonstrate components. | 17th Feb 1925 | Box 35 \ 3 scan 076 | |
| Letter to The Midgley Car Lighting Co. Ltd. regarding their electrical equipment. | 17th Feb 1925 | Box 35 \ 3 scan 077 | |
| Continued letter discussing the principles and objections to dynamo machines. | 2nd Mar 1925 | Box 35 \ 3 scan 078 | |
| Letter from Midgley Car Lighting Company regarding a Controller unit being sent for examination. | 2nd Mar 1925 | Box 35 \ 3 scan 079 | |
| Letter from Midgley Car Lighting Company regarding a visit and tests for their M.C.L. Controller. | 7th Mar 1925 | Box 35 \ 3 scan 080 | |
| Letter from Midgley Car Lighting Company Limited regarding their Cut out and Controller, offering a Dynamo for testing. | 29th Apr 1925 | Box 35 \ 3 scan 081 | |
| Blueprint of a 5-inch Saddle & Saddle Mag Dynamo with dimensions. | 29th Apr 1925 | Box 35 \ 3 scan 082 | |
| Blueprint graph showing the output curve for a Standard 5' Dynamo. | 30th Apr 1925 | Box 35 \ 3 scan 083 | |
| Letter to Midgley Car Lighting Co. Ltd. concerning a delay in testing their Cutout and Controller. | 30th Apr 1925 | Box 35 \ 3 scan 084 | |
| Follow-up letter from Midgley Car Lighting Company regarding tests on a Cut out and Controller. | 4th Jan 1926 | Box 35 \ 3 scan 085 | |
| Letter to Messrs. Midgley Car Lighting Co. Ltd. regarding a delay in testing a cutout and controller. | 5th Jan 1925 | Box 35 \ 3 scan 086 | |
| Midgley cutout and controller, referencing an attached report and diagram. | 24th Jun 1926 | Box 35 \ 3 scan 087 | |
| Investigation into the operation of a Midgley cutout and controller for dynamo control. | 21th May 1926 | Box 35 \ 3 scan 088 | |
| The operation and electrical tests of a controller armature and cutout unit. | 21th May 1926 | Box 35 \ 3 scan 089 | |
| Test results and electrical specifications for a controller, including shunt and series measurements. | 21th May 1926 | Box 35 \ 3 scan 090 | |
| Dynamo output characteristics with a discharged battery and various field circuit resistances. | 21th May 1926 | Box 35 \ 3 scan 091 | |
| Wiring diagram for a vehicle dynamo controller and cut-out unit. | 24th Jun 1936 | Box 35 \ 3 scan 092 | |
| Blank page with a Print Room stamp from the Derby facility. | 24th Jun 1936 | Box 35 \ 3 scan 093 | |
| Methods of controlling field resistance, comparing the Remy method with a voltage method and a ballast resistance unit. | 30th Aug 1926 | Box 35 \ 3 scan 094 | |
| Hand-drawn wiring diagram for a Midgley controller and cut-out unit. | 18th Aug 1926 | Box 35 \ 3 scan 095 | |
| Reverse of a document showing a 'Print Room' stamp from the Derby facility. | 18th Aug 1926 | Box 35 \ 3 scan 096 | |
| Patent specification for an Automatic Charge Reducing Switch, known as the Midgley Patent. | 16th May 1927 | Box 35 \ 3 scan 097 | |
| Missing specification copy for the Midgley Patent Automatic Charge Reducing Switch. | 28th Jun 1927 | Box 35 \ 3 scan 098 | |
| The specification for an Automatic Charge Reducing Switch, Midgley Patent. | 30th Jun 1927 | Box 35 \ 3 scan 099 | |
| The return of a patent specification and various Bosch components. | 21th Oct 1927 | Box 35 \ 3 scan 100 | |
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