| Description | Date | Identifier | |
| Engineering committee meeting report on engine lubrication and piston issues. | 10th Mar 1926 | Box 16 \ 1 Scan102 | |
| Engine performance issues including wristpin fits, city driving complaints, and oil suitability. | 10th Mar 1926 | Box 16 \ 1 Scan103 | |
| Engine adjustments relating to pilot jets, oil pressure, and extra oil supply. | 10th Mar 1926 | Box 16 \ 1 Scan104 | |
| The factors controlling overoiling on Phantom engines compared to Silver Ghost engines. | 4th May 1926 | Box 16 \ 1 Scan105 | |
| Report analyzing oil consumption in relation to oil flow through bearings, with comparative data for Silver Ghost and Phantom cars. | 4th May 1926 | Box 16 \ 1 Scan106 | |
| Comparison of oil consumption and pressure between the Silver Ghost and Phantom models, attributing differences to bearing clearances. | 4th May 1926 | Box 16 \ 1 Scan107 | |
| Comparison of oil flow between the Silver Ghost and Phantom models and the methods for reducing excessive oil flow. | 4th May 1926 | Box 16 \ 1 Scan108 | |
| Engine testing results, focusing on oil flow, piston lubrication, and the effectiveness of 'L' section piston rings. | 4th May 1926 | Box 16 \ 1 Scan109 | |
| Summary of findings on engine oil consumption, exhaust smoke, and potential solutions. | 4th May 1926 | Box 16 \ 1 Scan110 | |
| High oil consumption in the Phantom engine, attributing the issue to the fit of bearings and piston rings. | 28th Jul 1930 | Box 16 \ 1 Scan111 | |
| Overoiling issue on PII S pistons and a potential solution. | 28th Jul 1930 | Box 16 \ 1 Scan112 | |
| Issue of over-oiling in English-built Phantom II chassis and the effectiveness of new piston rings and bleeder holes. | 2nd Jul 1930 | Box 16 \ 1 Scan113 | |
| Piston oil consumption improvements and the potential contributing factors. | 8th Jul 1930 | Box 16 \ 1 Scan114 | |
| Fitting Perfect Circle piston rings and drilling holes to address overoiling issues. | 30th Aug 1930 | Box 16 \ 1 Scan115 | |
| New scheme to prevent over-oiling during slow running by fitting improved Asbestos washers. | 30th Aug 1930 | Box 16 \ 1 Scan116 | |
| Dimensional changes to channel scraper rings to resolve an overoiling problem on Phantom II and 20/25HP chassis. | 7th Jan 1931 | Box 16 \ 1 Scan117 | |
| Page 2 of a letter from a customer, Stanley Johnson, detailing ongoing engine trouble and contrasting it with another vehicle. | 13th Jun 1910 | Box 16 \ 1 Scan118 | |
| Experiment card to determine the standard for piston rings, comparing plain versus double-ring types. | 13th Jun 1910 | Box 16 \ 1 Scan119 | |
| Departmental memo regarding a procedure to fix sticking piston rings using parrafin. | 16th Jul 1912 | Box 16 \ 1 Scan120 | |
| Departmental memo from E.P. suggesting a point be brought before other departments of the Company. | 3rd May 1912 | Box 16 \ 1 Scan121 | |
| Article from 'The Autocar' magazine discussing the design, manufacture, and efficiency of different types of piston rings. | 7th Sep 1912 | Box 16 \ 1 Scan122 | |
| Newspaper clipping detailing a pinned piston ring design and a custom wire tool for removal. | 21th Sep 1912 | Box 16 \ 1 Scan123 | |
| Potential fault with a piston ring pin in Lord Portarlington's car, number 2107. | 2nd Apr 1913 | Box 16 \ 1 Scan124 | |
| Chassis 2301, detailing the special double piston rings with a new locking device. | 22th Apr 1913 | Box 16 \ 1 Scan125 | |
| Works order memo regarding production cards and instruction sheets for Piston Rings. | 25th Apr 1913 | Box 16 \ 1 Scan126 | |
| Brake leverage, piston design, engine rings, and balance weights for a new car series. | 5th May 1913 | Box 16 \ 1 Scan127 | |
| Remark regarding the production of pip locking piston rings for pistons X.294. | 10th Jun 1913 | Box 16 \ 1 Scan128 | |
| Adoption of parallel piston rings for aero and car engines. | 31th Dec 1914 | Box 16 \ 1 Scan129 | |
| Query regarding the best type of piston rings to use. | 5th Oct 1915 | Box 16 \ 1 Scan130 | |
| Extract concerning a 10,000-mile bench test for piston rings. | 21th Jul 1914 | Box 16 \ 1 Scan131 | |
| Alteration to a piston ring drawing to specify clearance for shop practice. | 21th Jul 1914 | Box 16 \ 1 Scan132 | |
| Suitability of engine oil for the Australian climate, based on a report. | 13th Oct 1915 | Box 16 \ 1 Scan133 | |
| Letter from L.C. Harvey regarding the supply and testing of 'Wedgerite' piston rings. | 23th Mar 1921 | Box 16 \ 1 Scan134 | |
| Advertisement for Wedgerite Piston Rings which expand in width as well as in diameter. | 23th Mar 1921 | Box 16 \ 1 Scan135 | |
| Retail price list and promotional leaflet for WedgeRite Piston Rings, including a diagram of its function. | 2nd Aug 1921 | Box 16 \ 1 Scan136 | |
| Letter from supplier Morris, Russell about a new patented scraper piston ring. | 2nd Aug 1921 | Box 16 \ 1 Scan137 | |
| Letter from Wellworthy Ltd. to the Technical Dept. regarding their patented piston rings, enclosing a small pamphlet and a newspaper clipping. | 11th Nov 1921 | Box 16 \ 1 Scan138 | |
| Advertisement for Wellworthy Universal Radially Direct Pressure Piston Rings. | 11th Nov 1921 | Box 16 \ 1 Scan139 | |
| From Wellworthy Limited detailing the importance, manufacturing challenges, and development of the piston ring. | 15th Sep 1922 | Box 16 \ 1 Scan140 | |
| New method from the American division for dealing with piston ring stops on the 40/50 chassis. | 15th Sep 1922 | Box 16 \ 1 Scan141 | |
| Springfield plant's decision to stop pinning pistons, contrasting it with the standard Derby practice. | 28th Nov 1922 | Box 16 \ 1 Scan142 | |
| The American practice of fixing piston ring stops to resolve over-oiling issues. | 29th Dec 1922 | Box 16 \ 1 Scan143 | |
| Springfield's return to the standard system for pinning piston rings and demanding an inquiry into the unauthorized deviation. | 1st Feb 1923 | Box 16 \ 1 Scan144 | |
| Letter discussing the trial of a special piston ring for the 40/50 chassis, manufactured by Clews Peterson & Co. | 4th Apr 1923 | Box 16 \ 1 Scan145 | |
| Customer complaint letter detailing a recurring ring trouble issue and extensive repair history for Chassis No. 23-PB. | 30th Aug 1923 | Box 16 \ 1 Scan146 | |
| Piston ring knocks on pre-war chassis and the compatibility of pre-war pistons with post-war rings. | 4th Sep 1923 | Box 16 \ 1 Scan147 | |
| Experiments and solutions for piston ring knock on a pre-war chassis. | 4th Sep 1923 | Box 16 \ 1 Scan148 | |
| French language bulletin on piston modifications for the installation of R.H. oil control rings, with diagrams and a table of dimensions. | 5th Sep 1923 | Box 16 \ 1 Scan149 | |
| Proposing experiments to investigate and resolve piston ring knock issues. | 5th Sep 1923 | Box 16 \ 1 Scan150 | |
| Experiments with post-war piston rings to resolve ring clap issues on pre-war pistons. | 24th Sep 1923 | Box 16 \ 1 Scan151 | |
| The incompatibility of post-war aluminium pistons with pre-war connecting rods to cure piston ring clap for Chassis 41-NA. | 17th Nov 1923 | Box 16 \ 1 Scan152 | |
| Piston clap issues and various component breakages in pre-war and post-war cars. | 14th Nov 1923 | Box 16 \ 1 Scan153 | |
| The causes of troubles with aluminium pistons versus cast iron pistons, focusing on gas leakage. | 7th Nov 1923 | Box 16 \ 1 Scan154 | |
| Chasing a decision from an individual regarding 'Piston Ring Clap'. | 7th Nov 1923 | Box 16 \ 1 Scan155 | |
| Customer complaint regarding piston ring clap on Chassis 23-PB. | 22th Oct 1923 | Box 16 \ 1 Scan156 | |
| Chasing a reply from CJ regarding a proposal on 'Piston Ring Clap'. | 11th Oct 1923 | Box 16 \ 1 Scan157 | |
| Chasing for instructions regarding a 'Piston Ring Clap' issue due to pressure from car owners. | 6th Oct 1923 | Box 16 \ 1 Scan158 | |
| Proposal to resolve piston ring clap issues in pre-war engines by fitting post-war narrow rings. | 26th Sep 1923 | Box 16 \ 1 Scan159 | |
| Experiments on post-war piston rings fitted to pre-war pistons to resolve complaints about ring clap. | 24th Sep 1923 | Box 16 \ 1 Scan160 | |
| Proposal for a series of experiments to investigate and resolve the issue of piston ring knocks. | 5th Sep 1923 | Box 16 \ 1 Scan161 | |
| Piston knocks on pre-war chassis, specifically about using pre-war cast-iron pistons. | 4th Sep 1923 | Box 16 \ 1 Scan162 | |
| Issue of piston ring knock in pre-war engines after an overhaul. | 29th Aug 1923 | Box 16 \ 1 Scan163 | |
| Roy to Hs seeking confirmation on a draft reply to the British Piston Ring Company. | 7th Jan 1924 | Box 16 \ 1 Scan164 | |
| Letter to The British Piston Ring Co. Ltd. regarding the supply and testing of heat-formed lapped rings. | 7th Jan 1924 | Box 16 \ 1 Scan165 | |
| From B.J. to Hs. requesting an update on issues with lubricating oils. | 1st Oct 1924 | Box 16 \ 1 Scan166 | |
| Promotional letter from R. A. Rothermel, Ltd. regarding their PERFECT CIRCLE Oil Regulating Ring. | 24th Nov 1924 | Box 16 \ 1 Scan167 | |
| Page 2 of a letter from R. A. Rothermel, Ltd. offering sample engine rings and guaranteeing improved performance. | 18th Dec 1924 | Box 16 \ 1 Scan168 | |
| Procurement and testing of 'Perfect Circle Scraper Rings' on car and aero engines. | 18th Dec 1924 | Box 16 \ 1 Scan169 | |
| Piston design, oil consumption, and potential solutions for component failure. | 23th Mar 1925 | Box 16 \ 1 Scan170 | |
| Patent application for oil scraper rings, particularly the attribution of the 'L' section ring design. | 27th Mar 1925 | Box 16 \ 1 Scan171 | |
| Laboratory report on engine lubrication, detailing experiments with mineral oils and fatty acids. | 24th Jun 1925 | Box 16 \ 1 Scan172 | |
| Letter to Messrs. R.A. Rothermel Ltd. requesting a quotation and availability for 'Perfect Circle Scraper rings'. | 18th Sep 1925 | Box 16 \ 1 Scan173 | |
| Letter from a supplier confirming the manufacture of 'Perfect Circle Oil Regulating Rings' based on provided blueprints. | 21th Sep 1925 | Box 16 \ 1 Scan174 | |
| Comparing the oil scraping performance and accuracy of Wellworthy and Brico piston rings. | 21th Oct 1925 | Box 16 \ 1 Scan175 | |
| Comparing the poor performance of 'Wellworthy' piston rings with the superior 'Brico' rings, and recommending a change in supply. | 21th Oct 1925 | Box 16 \ 1 Scan176 | |
| Proposal to modify the grinding of Wellworthy piston rings, with a comparison to Brico rings. | 21th Oct 1925 | Box 16 \ 1 Scan177 | |
| Clear marking of components fitted with 'Wellworthy' rings for testing. | 21th Oct 1925 | Box 16 \ 1 Scan178 | |
| Advice note from R. A. Rothermel, Ltd. for the supply of oil regulating and compression piston rings. | 7th Dec 1925 | Box 16 \ 1 Scan179 | |
| Order for oil regulating and compression piston rings. | 3rd Mar 1926 | Box 16 \ 1 Scan180 | |
| Tests investigating the effect of piston ring clearance on gumming up tendencies in a Phantom engine. | 18th Nov 1926 | Box 16 \ 1 Scan181 | |
| Test results on piston ring groove clearance and carbon build-up. | 19th Nov 1926 | Box 16 \ 1 Scan182 | |
| The influence of stiff versus weak piston rings on 'gumming up' within the grooves of a Phantom engine. | 19th Nov 1926 | Box 16 \ 1 Scan183 | |
| Page concluding the results of tests on piston ring gumming tendency and stiffness. | 31th Mar 1927 | Box 16 \ 1 Scan184 | |
| Design of scraper rings for engines. | 31th Mar 1927 | Box 16 \ 1 Scan185 | |
| Graph plotting oil flow through bearings against engine RPM for car 12.EX. | 2nd May 1927 | Box 16 \ 1 Scan186 | |
| Use of tapered piston rings as oil scrapers and their effect on oil consumption. | 2nd May 1927 | Box 16 \ 1 Scan187 | |
| Oil consumption experiment on a Phantom test bench engine comparing standard versus upward sloping drain holes. | 9th May 1927 | Box 16 \ 1 Scan188 | |
| Instructions and considerations for piston design, addressing issues like gummed pistons and oil consumption. | 23th May 1927 | Box 16 \ 1 Scan189 | |
| Instructions for the correct fitting of piston rings for automobile and aviation engines, by Amédée Bollée. | 23th May 1927 | Box 16 \ 1 Scan190 | |
| Advertisement for the Amédée Bollée special vice for adjusting oblique-cut piston rings. | 23th May 1927 | Box 16 \ 1 Scan191 | |
| Advertisement leaflet for Amédée Bollée double scraper piston rings. | 23th May 1927 | Box 16 \ 1 Scan192 | |
| Technical leaflet for Amédée Bollée scraper piston rings, detailing different types, their advantages, and a list of clients. | 1st Apr 1927 | Box 16 \ 1 Scan193 | |
| French product sheet for 'Amédée Bollée' piston rings, detailing specifications and fitting instructions. | 1st Apr 1927 | Box 16 \ 1 Scan194 | |
| 'Perfect Circle Piston Rings' and arranging an interview with Mr. Potter. | 15th Jul 1927 | Box 16 \ 1 Scan195 | |
| Letter asking for clarification on the standardization of Perfect Circle piston rings. | 20th Oct 1927 | Box 16 \ 1 Scan196 | |
| Use and effectiveness of 'The Perfect Circle' piston rings on aero and Phantom engines. | 22th Oct 1927 | Box 16 \ 1 Scan197 | |
| The trial and potential adoption of Perfect Circle piston rings. | 7th Nov 1927 | Box 16 \ 1 Scan198 | |
| Installation instructions for Dubois Oilproof Rings on pistons. | 9th Nov 1927 | Box 16 \ 1 Scan199 | |
| Letter from DuBois Machine Company to the Chief Engineer proposing their new Combination Oilproof Ring. | 9th Nov 1927 | Box 16 \ 1 Scan200 | |
| Concluding page of a letter from DuBois Machine Company. | 11th Sep 1927 | Box 16 \ 1 Scan201 | |
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