| Description | Date | Identifier | |
| Piston ring leakage tests, noting issues with 'gumming' and equipment failure at high pressures. | 2nd Nov 1926 | Box 66 \ 1 scan0117 | |
| Graph showing 'New Phantom' piston leakage versus compression pressure at two different engine speeds. | 2nd Nov 1926 | Box 66 \ 1 scan0118 | |
| Blueprint of an apparatus designed for measuring gas leakage past pistons. | 6th Oct 1926 | Box 66 \ 1 scan0119 | |
| Test report on the effect of piston ring clearance on gumming in a standard Phantom engine. | 18th Nov 1926 | Box 66 \ 1 scan0120 | |
| Tests on piston ring gumming and the effect of groove clearance. | 19th Nov 1926 | Box 66 \ 1 scan0121 | |
| Piston gumming experiments testing the influence of stiff versus weak piston rings on a Phantom engine. | 19th Nov 1926 | Box 66 \ 1 scan0122 | |
| Page from a report detailing test conclusions on piston ring gumming tendency and oil passage. | 22th Nov 1926 | Box 66 \ 1 scan0123 | |
| Cure for gummed pistons by increasing the piston ring wall pressure. | 22th Nov 1926 | Box 66 \ 1 scan0124 | |
| Piston materials for aero and car engines, including trials of magnesium on the Phantom. | 22th Dec 1926 | Box 66 \ 1 scan0125 | |
| Outlining design points and recommendations for pistons in aero engines. | 22th Jan 1927 | Box 66 \ 1 scan0126 | |
| Issues with piston knocks, comparing different piston designs and outlining testing methods. | 1st Feb 1927 | Box 66 \ 1 scan0127 | |
| Piston knock issues and the testing of horizontally slotted pistons as a potential solution. | 23th Feb 1927 | Box 66 \ 1 scan0128 | |
| Blueprint of a piston with an additional sawcut for a Phantom model. | 23th Feb 1927 | Box 66 \ 1 scan0129 | |
| The performance and weight comparison of magnesium pistons fitted to a Phantom car. | 25th Feb 1927 | Box 66 \ 1 scan0130 | |
| Issues with Maxium pistons containing 10% copper, specifically their tendency to collapse and knock. | 28th Feb 1927 | Box 66 \ 1 scan0131 | |
| Performance and potential modifications of Phantom pistons, recommending further experimentation. | 28th Feb 1927 | Box 66 \ 1 scan0132 | |
| Piston design modifications for the Phantom engine to address knocking and improve performance. | 5th Mar 1927 | Box 66 \ 1 scan0133 | |
| Technical discussion on the issue of piston ring gumming due to increased clearances in reground cylinders. | 9th Mar 1927 | Box 66 \ 1 scan0134 | |
| Improvements for gummed pistons in aero and car engines. | 10th Mar 1927 | Box 66 \ 1 scan0135 | |
| Design of piston rings, including tapered, faked, and lapped rings, and their effect on oil consumption. | 1st May 1927 | Box 66 \ 1 scan0136 | |
| Failure of magnesium pedestal pistons and the need for a design alteration. | 18th May 1927 | Box 66 \ 1 scan0137 | |
| Investigation of inertia and temperature stresses in pedestal type pistons E.75540. | 18th May 1927 | Box 66 \ 1 scan0138 | |
| Design instructions and issues related to gummed pistons and car work. | 23th May 1927 | Box 66 \ 1 scan0139 | |
| Stress calculations and proposed modifications for pedestal pistons. | 1st Jun 1927 | Box 66 \ 1 scan0140 | |
| Defect in Phantom cylinder block castings and proposing corrective actions to eliminate piston knock. | 25th Jun 1927 | Box 66 \ 1 scan0141 | |
| Investigation into Phantom piston knocks caused by cylinder distortion, with proposed solutions. | 11th Jul 1927 | Box 66 \ 1 scan0142 | |
| Establishing standard dimensions for pistons for the 20-HP engine, including two diagrams. | 11th Jul 1927 | Box 66 \ 1 scan0143 | |
| Short typed note regarding investigations into the issue of Phantom piston knocks. | 15th Jul 1927 | Box 66 \ 1 scan0144 | |
| Discrepancy in blueprints for a modified cylinder head and piston for Blue Sports Chassis. | 16th Aug 1927 | Box 66 \ 1 scan0145 | |
| Operating temperatures of aluminium and cast iron pistons in petrol and diesel engines. | 6th Sep 1927 | Box 66 \ 1 scan0146 | |
| Machining operations for a Sports Phantom piston made of 'Y' metal alloy. | 10th Apr 1927 | Box 66 \ 1 scan0147 | |
| Test report on a Phantom engine investigating whether piston friction causes overrun vibrations. | 10th Oct 1927 | Box 66 \ 1 scan0148 | |
| Urgent memo requesting the modification of cases and pistons, and the production of new parts from sketches. | 15th Oct 1927 | Box 66 \ 1 scan0149 | |
| Modified design for a Sports Phantom Piston, referencing drawing LeC.2476. | 8th Oct 1927 | Box 66 \ 1 scan0150 | |
| Instructing the fitting of plain rectangular piston rings to Phantom chassis engines with honed cylinders. | 21th Oct 1927 | Box 66 \ 1 scan0151 | |
| Test results for car 14-EX fitted with 1400 lbs rear springs and modified hydraulic dampers. | 11th Nov 1927 | Box 66 \ 1 scan0152 | |
| Issues with 'Y' metal pistons and potential new designs for Phantom and Sports Cars. | 23th Nov 1927 | Box 66 \ 1 scan0153 | |
| Drawings for 'Y' metal pistons for models EAC.10 and 14. | 28th Nov 1927 | Box 66 \ 1 scan0154 | |
| Stiffener for piston LeC.2476 to address flexibility and rattling, with a discussion on material choice. | 28th Nov 1927 | Box 66 \ 1 scan0155 | |
| EAC.10 & 14 die-cast type pistons for production and sporting editions of the Phantom. | 29th Nov 1927 | Box 66 \ 1 scan0156 | |
| New cast aluminium piston design with 'H' webs as an alternative to a previous design. | 30th Nov 1927 | Box 66 \ 1 scan0157 | |
| Technical memo discussing the lubrication of the piston pin and suggesting modifications for experimental sets. | 9th Dec 1927 | Box 66 \ 1 scan0158 | |
| Modifications to the cross web piston design and lubrication system. | 13th Dec 1927 | Box 66 \ 1 scan0159 | |
| Prints of piston parts and instructions for their modification for Sports' Chassis. | 16th Dec 1927 | Box 66 \ 1 scan0160 | |
| Comparing 'Y' alloy with a proposed 'T50' alloy for use in forged aluminium pistons. | 19th Dec 1927 | Box 66 \ 1 scan0161 | |
| Testing of die-cast car pistons in Halls alloy for 20 HP and 40/50 models. | 1st Feb 1928 | Box 66 \ 1 scan0162 | |
| Production of 40/50 HP Sports Type chassis pistons as die castings and questioning the need for 20 HP pistons. | 3rd Feb 1928 | Box 66 \ 1 scan0163 | |
| Mechanical test results for T50 alloy forgings and casts, comparing them to 'Y' alloy and Duralumin. | 2nd Feb 1928 | Box 66 \ 1 scan0164 | |
| Laboratory report discussing die-cast piston materials and urging tests on new types of valve steel. | 1st Feb 1928 | Box 66 \ 1 scan0165 | |
| The metallurgical properties of experimental T50 alloy pistons compared to 'Y' alloy, with a note on 'Condor' valve failure. | 2nd Feb 1928 | Box 66 \ 1 scan0166 | |
| Comparing cross web and diagonal web piston designs, concluding the diagonal web is the superior design for car work. | 18th Feb 1928 | Box 66 \ 1 scan0167 | |
| Directive to change the material for piston pins from casehardened steel to a high-duty alloy steel. | 15th Mar 1928 | Box 66 \ 1 scan0168 | |
| Proposal to change the material for gudgeon pins and the associated concerns regarding wear and hardness. | 21th Mar 1928 | Box 66 \ 1 scan0169 | |
| The benefits of reducing lubricating grooves in aero and car engines. | 1st Mar 1928 | Box 66 \ 1 scan0170 | |
| Material composition of piston pins and recommending further fatigue testing. | 7th Apr 1928 | Box 66 \ 1 scan0171 | |
| Drawing for single bolt pedestal pistons with lower scraper rings for the Phantom and EAC.10. | 2nd May 1928 | Box 66 \ 1 scan0172 | |
| Heat treatment and hardness testing of various pistons. | 11th May 1928 | Box 66 \ 1 scan0173 | |
| Two compression ratios for the 40/50 engine and general chassis improvements. | 29th May 1929 | Box 66 \ 1 scan0174 | |
| Piston gudgeon pin distortion and proposing a series of tests to resolve it. | 31th May 1928 | Box 66 \ 1 scan0175 | |
| Telegram from Royce regarding a dangerous piston design, suggesting it be scrapped and replaced with a strengthened version. | 17th Jul 1928 | Box 66 \ 1 scan0176 | |
| Issue of piston knocks in engines, particularly when starting from cold. | 19th Jul 1928 | Box 66 \ 1 scan0177 | |
| Inquiry to The Automotive Engineering Co. Ltd. about the weight of BHB pistons for a 40/50 HP car. | 16th Oct 1928 | Box 66 \ 1 scan0178 | |
| Piston design, focusing on ring type, quantity, and manufacturing for various chassis. | 18th Oct 1928 | Box 66 \ 1 scan0179 | |
| Piston specifications and design modifications for Phantom and 20 HP models. | 18th Oct 1928 | Box 66 \ 1 scan0180 | |
| Cross-section drawing of a piston and connecting rod assembly with dimensional annotations. | 19th Oct 1928 | Box 66 \ 1 scan0181 | |
| Proposal to have the top of the piston eccentric with the skirt to keep the piston head axial with the cylinder centre line. | 19th Oct 1928 | Box 66 \ 1 scan0182 | |
| Layout drawing for Phantom chassis pistons, seeking approval before proceeding with detailed drawings. | 29th Oct 1928 | Box 66 \ 1 scan0183 | |
| Pistons seizing up in new 40/50 HP and 20-HP cars. | 24th Jan 1929 | Box 66 \ 1 scan0184 | |
| Pistons seizing on new cars and the need to establish a routine test. | 25th Jan 1929 | Box 66 \ 1 scan0185 | |
| Problem of seized pistons on new 40/50 HP and 20 HP cars. | 25th Jan 1929 | Box 66 \ 1 scan0186 | |
| Technical memo discussing seized pistons in New Phantom engines and proposing a modification to the starter carburetter. | 6th Feb 1929 | Box 66 \ 1 scan0187 | |
| Cover memorandum clarifying that the company is not working to finer limits on piston clearances, contrary to a recent suggestion. | 7th Feb 1929 | Box 66 \ 1 scan0188 | |
| Phantom piston seizures due to over-priming and the proposal to circulate a warning leaflet to owners. | 14th Jun 1929 | Box 66 \ 1 scan0189 | |
| Piston seizure and over-priming issues in Phantom cars, and the attachment of a new label. | 17th Jun 1929 | Box 66 \ 1 scan0190 | |
| Instructions and warnings for the use of the starter carburetter for cold engine starts. | 18th Jun 1929 | Box 66 \ 1 scan0191 | |
| Whether to issue a pamphlet regarding Phantom piston seizures. | 18th Jun 1929 | Box 66 \ 1 scan0192 | |
| Proposed trial of a new strutted piston design, referencing Chevrolet's success with a similar type. | 28th Aug 1929 | Box 66 \ 1 scan0193 | |
| Performance test sheet for component 46 P.R. E.A.C. IIE with the cut-out open. | 14th Aug 1924 | Box 66 \ 2 scan0001 | |
| Design changes for induction and exhaust pipes, referencing specific drawings and modifications to joints and heat jackets. | 23th May 1924 | Box 66 \ 2 scan0002 | |
| Secret memo regarding the design and drawings for an exhaust system, detailing a new silencer and a cut-out valve. | 31th May 1924 | Box 66 \ 2 scan0003 | |
| Secret memo regarding proposed modifications to an exhaust system, including the re-introduction of a front silencer. | 8th Sep 1924 | Box 66 \ 2 scan0004 | |
| Dispatch of a blueprint for an E.A.C.II. exhaust system. | 12th Sep 1924 | Box 66 \ 2 scan0005 | |
| Exhaust noise issues and potential modifications to the silencer system. | 23th Oct 1924 | Box 66 \ 2 scan0006 | |
| Redesign of the exhaust system for an E.A.U. engine to fit a sequence starter motor. | 29th Nov 1924 | Box 66 \ 2 scan0007 | |
| Design alterations for the 'V' series exhaust system. | 8th Dec 1924 | Box 66 \ 2 scan0008 | |
| Query regarding the possibility of removing the exhaust choke valve connected to the accelerator pedal. | 12th Aug 1924 | Box 66 \ 2 scan0009 | |
| The necessity of retaining the exhaust choke valve on the 'V' series chassis until distribution is improved. | 15th Dec 1924 | Box 66 \ 2 scan0010 | |
| Secret memo regarding the design of exhaust fittings and silencer brackets for the 'V' series. | 20th Dec 1924 | Box 66 \ 2 scan0011 | |
| Secret memo regarding the design and controls for the 'V' Series rear exhaust silencer and cut-out, with drawings sent for approval. | 7th Jan 1925 | Box 66 \ 2 scan0012 | |
| Secret memo discussing the design of a rear silencer support using sheet steel for 'V' series exhaust fittings. | 22th Jan 1925 | Box 66 \ 2 scan0013 | |
| Confirming a drawing has been made for an exhaust silencer bracket from Mr. Royce's sketch and a blueprint sent to him. | 22th Jan 1925 | Box 66 \ 2 scan0014 | |
| The power losses and modifications of an exhaust system. | 1st Feb 1925 | Box 66 \ 2 scan0015 | |
| The analysis of power losses due to the latest exhaust system. | 10th Feb 1925 | Box 66 \ 2 scan0016 | |
| The efficiency and condition of a silencer system after testing. | 10th Feb 1925 | Box 66 \ 2 scan0017 | |
| Alterations and performance tests of an exhaust system. | 10th Feb 1925 | Box 66 \ 2 scan0018 | |
| Diagram illustrating the components of the E.A.C. exhaust system. | 10th Feb 1925 | Box 66 \ 2 scan0019 | |
| Data table showing the loss of power due to the temperature of a hot spot at various RPMs. | 10th Feb 1925 | Box 66 \ 2 scan0020 | |
| Analysis of exhaust system power output with various parts, showing horsepower at the flywheel for different RPMs. | 10th Feb 1925 | Box 66 \ 2 scan0021 | |
| Table detailing HP loss at the flywheel due to specific system components at varying R.P.M. | 10th Feb 1925 | Box 66 \ 2 scan0022 | |
| Silencer experiments showing performance figures after system alterations. | 7th Feb 1925 | Box 66 \ 2 scan0023 | |
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