| Description | Date | Identifier | |
| Status update on various engine units, including rebuilds, new units, and specifications. | 27th Mar 1940 | Box 148 \ 2 scan0293 | |
| Four outstanding mechanical problems identified on rationalised cars. | 8th Aug 1940 | Box 148 \ 2 scan0294 | |
| Analysis of guarantee account expenditure for various car models for periods in 1939 and 1940. | 15th Aug 1940 | Box 148 \ 2 scan0295 | |
| File copy of a memo discussing four vehicle issues: propellor shaft vibration, clutch failures, steering shocks, and gearbox rattles. | 9th Sep 1940 | Box 148 \ 2 scan0296 | |
| Duplication of the 'PL' prefix used for drawing numbers. | 1st Oct 1940 | Box 148 \ 2 scan0297 | |
| Analysis of expenditure on guarantee accounts for various car models, comparing costs from 1940 and 1939. | 31th Oct 1940 | Box 148 \ 2 scan0298 | |
| Confidential memo discussing the strategy to counter speculation about post-war small car production. | 14th Feb 1941 | Box 148 \ 2 scan0299 | |
| Price list for Wraith and Bentley models detailing pre-war catalogue prices, purchase tax, and total costs for various body types. | 20th Jun 1941 | Box 148 \ 2 scan0300 | |
| The stock levels of chassis components for B.V., Wraith and Phantom III cars. | 20th Jun 1941 | Box 148 \ 2 scan0301 | |
| Stock report detailing parts shortages for building 145 chassis and a total of 100 engines. | 20th Jun 1941 | Box 148 \ 2 scan0302 | |
| Stock levels and component availability for building B.V. Wraith and Phantom III cars. | 20th Jun 1941 | Box 148 \ 2 scan0303 | |
| Component shortages for the construction of 145 chassis and a total of 100 engines. | 20th Jun 1941 | Box 148 \ 2 scan0304 | |
| Stock position of chassis parts for B.V. Wraith and Phantom III models. | 20th Jun 1941 | Box 148 \ 2 scan0305 | |
| Inventory report detailing part shortages for the production of chassis and engines. | 20th Jun 1941 | Box 148 \ 2 scan0306 | |
| Stock list of engine components with availability figures for cars. | 20th Jun 1941 | Box 148 \ 2 scan0307 | |
| Stock list of engine and chassis components, detailing finished and unfinished parts. | 20th Jun 1941 | Box 148 \ 2 scan0308 | |
| Stock list of car parts showing finished, unfinished, and total quantities available. | 20th Jun 1941 | Box 148 \ 2 scan0309 | |
| Stock list detailing quantities of rear axle, brake, and hub components. | 20th Jun 1941 | Box 148 \ 2 scan0310 | |
| Stock list of various car components, detailing quantities and availability. | 20th Jun 1941 | Box 148 \ 2 scan0311 | |
| Inventory list of finished and unfinished car parts and the number of cars for which material is available. | 20th Jun 1941 | Box 148 \ 2 scan0312 | |
| Stock list detailing finished and unfinished parts and their availability for cars. | 3rd Nov 1943 | Box 148 \ 2 scan0313 | |
| Analysing pre-war car sales by price and horse-power to inform post-war car strategy. | 3rd Nov 1943 | Box 148 \ 2 scan0314 | |
| Breakdown of new car registrations by price range for the year ending September 1938, with a focus on high-end competitors. | 15th Feb 1939 | Box 148 \ 2 scan0315 | |
| Statistical analysis of new private car registrations in Great Britain by horse-power class for 1936-1939. | 23th Nov 1943 | Box 148 \ 2 scan0316 | |
| Cover memo for an attached document concerning mass production's effect on cost by Charles R.F. Englebach. | 23th Nov 1943 | Box 148 \ 2 scan0317 | |
| Requesting an analysis of the pre-war running costs for the Chassis Division's Engineering Department. | 23th Dec 1943 | Box 148 \ 2 scan0318 | |
| From 'E' discussing Mr. Royce's feedback on the design of die-cast pistons. | 4th Apr 1921 | Box 148 \ 3 scan0001 | |
| Pistons manufactured by Aluminium Manufacturers Inc. | 13th Apr 1921 | Box 148 \ 3 scan0002 | |
| Cover memo for an attached memo and a letter from America concerning pistons. | 13th Apr 1921 | Box 148 \ 3 scan0003 | |
| Forwarding a query about chassis piston clearance for the gudgeon pin to the Experimental Department. | 25th Apr 1921 | Box 148 \ 3 scan0004 | |
| Letter detailing the design of 'constant clearance' aluminum pistons from a manufacturer for testing purposes. | 24th Mar 1921 | Box 148 \ 3 scan0005 | |
| To Mr. Claude Johnson discussing piston skirt design, thermal expansion, clearances, and issues with gudgeon pin locking screws. | 24th Mar 1921 | Box 148 \ 3 scan0006 | |
| Letter to Mr. Claude Johnson regarding piston design modifications to prevent engine knocking and cramping. | 24th Mar 1921 | Box 148 \ 3 scan0007 | |
| Sketches for an Aluminium Castings Co piston design, detailing clearances and gudgeon pin clamping. | 24th Mar 1921 | Box 148 \ 3 scan0008 | |
| Technical extract comparing the performance of C.I. (Cast Iron) pistons to other types. | 11th Aug 1920 | Box 148 \ 3 scan0009 | |
| Piston performance, modifications, and vibration issues in pre-war and post-war car models. | 11th Aug 1920 | Box 148 \ 3 scan0010 | |
| Extract discussing engine over-oiling complaints from the U.S.A. and the performance of 4-ring versus 6-ring pistons. | 8th Jun 1921 | Box 148 \ 3 scan0011 | |
| Recommendation to fit aluminium pistons over cast iron ones to prevent engine detonation and seizing. | 8th Jun 1921 | Box 148 \ 3 scan0012 | |
| Extract about improving the finish of aluminium castings, like gear boxes and crankcases, by washing them in paraffin after sandblasting. | 28th Jun 1921 | Box 148 \ 3 scan0013 | |
| Proposal to add a fifth ring to pistons on post-war cars to improve slow running and gas tightness. | 18th Jul 1921 | Box 148 \ 3 scan0014 | |
| Agreeing to modify pistons on post-war cars by adding a fifth groove and an extra ring. | 22th Jul 1921 | Box 148 \ 3 scan0015 | |
| Questioning why agreed-upon die-cast pistons for the 40/50 chassis are not being used as standard. | 1st Jan 1922 | Box 148 \ 3 scan0016 | |
| Difference in piston pinning practice between the Springfield and Derby plants. | 28th Nov 1922 | Box 148 \ 3 scan0017 | |
| Letter to Mr. Hives requesting an urgent report on a metal sample. | 5th Mar 1923 | Box 148 \ 3 scan0018 | |
| Letter to Mr. Elias regarding a laboratory report on an aluminium alloy. | 6th Mar 1923 | Box 148 \ 3 scan0019 | |
| Fitting of pistons, comparing different methods and standardizing the practice. | 1st Jun 1923 | Box 148 \ 3 scan0020 | |
| Technical report on piston design, eccentric grinding, performance after dynamometer testing, and service results. | 1st Jun 1923 | Box 148 \ 3 scan0021 | |
| Issues and improvements related to fitting aluminium pistons on 40/50 and 20-HP chassis. | 4th Oct 1923 | Box 148 \ 3 scan0022 | |
| Piston bedding, distortion, and standardizing production procedures. | 4th Oct 1923 | Box 148 \ 3 scan0023 | |
| Standardisation of chassis parts, specifically the grinding of pistons for 40/50 HP and 20 HP chassis. | 4th Oct 1923 | Box 148 \ 3 scan0024 | |
| Recommendation to standardize new pistons with taper grinding on the sides following successful engine testing. | 11th Nov 1923 | Box 148 \ 3 scan0025 | |
| Standardisation of taper eccentric grinding for 40/50 HP chassis pistons. | 7th Nov 1923 | Box 148 \ 3 scan0026 | |
| Cause of broken induction pipes and suggesting the trial of aluminium pistons. | 22th Nov 1923 | Box 148 \ 3 scan0027 | |
| Causes of various broken pipes in postwar cars, attributed to issues with aluminium pistons. | 4th Dec 1923 | Box 148 \ 3 scan0028 | |
| The testing of Aluminium Pistons for pre-war cars, seeking authority for standardisation. | 30th Jan 1924 | Box 148 \ 3 scan0029 | |
| Opinion on a piston from a 40/50 car sent by an owner. | 13th Feb 1924 | Box 148 \ 3 scan0030 | |
| Requesting tests on the effect of heat treating aluminium castings to hasten the ageing process. | 2nd Feb 1924 | Box 148 \ 3 scan0031 | |
| The return of a piston, noting it is more expensive and heavy with no discernible advantages. | 22th Feb 1924 | Box 148 \ 3 scan0032 | |
| Standardisation of chassis parts, specifically aluminium pistons for repair cars. | 31th Jan 1924 | Box 148 \ 3 scan0033 | |
| Quarterly note detailing the procedure for introducing changes to the chassis and warning against unapproved alterations. | 28th Mar 1924 | Box 148 \ 3 scan0034 | |
| Use of various aluminium alloys for weight saving in aero engines and car parts. | 13th Feb 1926 | Box 148 \ 3 scan0035 | |
| Corrosion issues with an aluminium carburetter air valve on a Phantom and considering alternatives. | 1st Jul 1927 | Box 148 \ 3 scan0036 | |
| Piston temperatures for different materials and engine types. | 6th Sep 1927 | Box 148 \ 3 scan0037 | |
| Letter from the American branch discussing Pierce-Arrow piston weights and proposing an experimental order for Duralumin con-rods and Bohnalite pistons. | 25th Jan 1928 | Box 148 \ 3 scan0038 | |
| Use of different alloys like alum-magnesium and alum-bronze for strong and lightweight castings. | 1st Dec 1927 | Box 148 \ 3 scan0039 | |
| Difficulties and ongoing efforts in casting Aluminium Bronze and Hall light alloy. | 3rd Dec 1927 | Box 148 \ 3 scan0040 | |
| Reasons for abandoning aluminium bronze castings due to machining difficulties, supplier bankruptcy, and unsuitability for brazing. | 5th Dec 1927 | Box 148 \ 3 scan0041 | |
| Page 2 of a memo discussing material changes involving aluminium bronze. | 5th Dec 1927 | Box 148 \ 3 scan0042 | |
| Aluminium bronze for its strength and suitability for casting in metal mould gravity castings. | 5th Dec 1927 | Box 148 \ 3 scan0043 | |
| Laboratory report comparing 'Y' alloy pistons with a proposed new 'T50' alloy, detailing the advantages of the new material. | 19th Dec 1927 | Box 148 \ 3 scan0044 | |
| Cover note discussing the weights of Pierce Arrow reciprocating parts and strut piston design. | 1st Feb 1928 | Box 148 \ 3 scan0045 | |
| Letter from the American office to Derby about piston and connecting rod assemblies, suggesting an experimental order for the Phantom. | 25th Jan 1928 | Box 148 \ 3 scan0046 | |
| Laboratory report discussing die-cast pistons in T.50 alloy and the testing of Austenite valve steel. | 2nd Jun 1928 | Box 148 \ 3 scan0047 | |
| Diagnosis and potential cures for piston knock troubles. | 7th Feb 1928 | Box 148 \ 3 scan0048 | |
| Potential causes and tests for piston knocking issues. | 21th Feb 1928 | Box 148 \ 3 scan0049 | |
| Bohnalite steel strut pistons and duralumin connecting rods, citing reliability and material concerns. | 21th Feb 1928 | Box 148 \ 3 scan0050 | |
| Use of magnesium and electron pistons in 6-cylinder car engines. | 27th Mar 1923 | Box 148 \ 3 scan0051 | |
| Inquiry to The Automotive Engineering Co. Ltd. about the weight of BHB pistons for a 40/50 HP car. | 16th Oct 1928 | Box 148 \ 3 scan0052 | |
| Dimensioned drawing showing a cross-section of a piston and connecting rod. | 20th Oct 1928 | Box 148 \ 3 scan0053 | |
| Letter from The Automotive Engineering Company Ltd regarding a drawing for a B.H.B. Piston. | 20th Oct 1928 | Box 148 \ 3 scan0054 | |
| Letter from The Automotive Engineering Company Ltd. regarding a self-adjusting piston for a 40/50 HP engine. | 23th Oct 1928 | Box 148 \ 3 scan0055 | |
| Blueprint showing a cross-sectional drawing of a B.HP Piston with dimensions. | 26th Oct 1928 | Box 148 \ 3 scan0056 | |
| Letter to B.H.B. Pistons regarding the weight of their pistons for a 40/50 HP engine. | 26th Oct 1928 | Box 148 \ 3 scan0057 | |
| Particulars of pistons, including ring configuration, scraper ring design, and material selection. | 8th May 1929 | Box 148 \ 3 scan0058 | |
| The correct material for a bridge repair on an F cylinder. | 1st Jun 1929 | Box 148 \ 3 scan0059 | |
| Attached letter and booklets from the Cork-Sealed Piston Ring Company of Canada. | 3rd Jul 1929 | Box 148 \ 3 scan0060 | |
| Analysis of 'picking up' and pitting issues on S.S. exhaust valves and seatings, attributing the problem to the softness of the Aluminium Bronze used. | 16th Jul 1929 | Box 148 \ 3 scan0061 | |
| Letter from The Cork-Sealed Piston Ring Company of Canada proposing a supply of piston rings for testing. | 1st Jul 1929 | Box 148 \ 3 scan0062 | |
| Letter to The Cork-Sealed Piston Ring Co. of Canada acknowledging their letter and referring the matter to the Works. | 3rd Jul 1929 | Box 148 \ 3 scan0063 | |
| Stating no further interest in piston rings from the Cork Sealed Piston Ring Co. of Canada. | 11th Jul 1929 | Box 148 \ 3 scan0064 | |
| The test results of Invar pistons for the Phantom II engine. | 13th Nov 1929 | Box 148 \ 3 scan0065 | |
| Modifications to improve the flexibility of Phantom II Invar pistons. | 23th Jan 1930 | Box 148 \ 3 scan0066 | |
| Changing the alloy for aero engine pistons from Y. alloy to RR.59. | 19th Sep 1930 | Box 148 \ 3 scan0067 | |
| Comparison of piston performance based on manufacturing method (forged vs. pressed) and material type (RR.59 vs. Y alloy). | 12th Mar 1931 | Box 148 \ 3 scan0068 | |
| New low-expansion piston alloy, '132LoEx', from the Aluminium Co. of America. | 24th Apr 1930 | Box 148 \ 3 scan0069 | |
| Standardization of RR-50 Alloy Pistons in place of Y Alloy for engines. | 31th May 1932 | Box 148 \ 3 scan0070 | |
| Seeking Air Ministry approval to use RR.50/RR.59 alloy for pistons in place of 'Y' alloy. | 6th Jun 1932 | Box 148 \ 3 scan0071 | |
| Use of RR-50 alloy for pistons in place of the standard 'Y' Alloy. | 13th Jun 1932 | Box 148 \ 3 scan0072 | |
| Sourcing pistons for the 'Kestrel' Engine, continuing with Y.Alloy instead of the unavailable RR-50 alloy. | 8th Jul 1932 | Box 148 \ 3 scan0073 | |
| Requesting suggestions for a corrosion-resistant aluminium alloy for engine casting purposes, specifically for a Bentley thermostatic control. | 6th May 1933 | Box 148 \ 3 scan0074 | |
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