| Description | Date | Identifier | |
| Request to test a cam (D.71342) to see if it allows time for the distributor points to cool. | 25th Mar 1927 | Box 61b \ 1 scan0029 | |
| Request to produce two experimental condensers with the maximum possible turns for the 20 & 40/50 chassis. | 31th Mar 1927 | Box 61b \ 1 scan0030 | |
| Instructions for experimental tests on a battery ignition system. | 1st Apr 1927 | Box 61b \ 1 scan0031 | |
| Tests and modifications to ignition system components, including the coil, condenser, and contact breaker. | 1st Apr 1927 | Box 61b \ 1 scan0032 | |
| Continued note on the primary object of a stronger spring for improving the running condition of contact points. | 31th Mar 1927 | Box 61b \ 1 scan0033 | |
| Graph of Make Ratio-Speed curves for a standard contact breaker using standard and increased rated springs at various gaps. | 31th Mar 1927 | Box 61b \ 1 scan0034 | |
| The experimental results of using stronger contact breaker lever springs for battery ignition systems. | 25th Apr 1927 | Box 61b \ 1 scan0035 | |
| Ignition system tests, focusing on pivot reaction and the performance of platinum and tungsten points over 10,000 miles. | 25th Apr 1927 | Box 61b \ 1 scan0036 | |
| The unsatisfactory performance of stronger springs on the battery ignition contact breaker lever during a 10,000-mile bench test. | 25th Apr 1927 | Box 61b \ 1 scan0037 | |
| Pressure on battery ignition contact points. | 29th Apr 1927 | Box 61b \ 1 scan0038 | |
| Battery ignition, focusing on improving the life of tungsten points compared to platinum points. | 16th May 1927 | Box 61b \ 1 scan0039 | |
| Listing various suggestions and test results for the improvement of ignition contact points. | 18th May 1927 | Box 61b \ 1 scan0040 | |
| Report page detailing the results of various electrical ignition component tests. | 18th May 1927 | Box 61b \ 1 scan0041 | |
| Progress report on various experiments concerning engine components like cams, coils, and contact points. | 18th May 1927 | Box 61b \ 1 scan0042 | |
| Request for three sets of experimental parts to create a semi-rigid mounting for the fixed contact point in an ignition distributor. | 25th May 1927 | Box 61b \ 1 scan0043 | |
| Requesting parts for the semi-rigid mounting of contact points on test distributors. | 1st Jun 1927 | Box 61b \ 1 scan0044 | |
| Proposed improvements to a battery ignition contact maker. | 10th Jun 1927 | Box 61b \ 1 scan0045 | |
| Specifications for the doming of platinum and tungsten battery ignition contact points. | 21th Jun 1927 | Box 61b \ 1 scan0046 | |
| The order of precedence for experimental tests on battery ignition contact points. | 14th Jul 1927 | Box 61b \ 1 scan0047 | |
| Continued report on experimental testing delays and the noise levels of Bosch and Delco-Remy electrical parts for the Phantom. | 5th Jul 1927 | Box 61b \ 1 scan0048 | |
| Instructions for modifying Distributor Schemes 259 & 260 by fitting new parts. | 22th Jul 1927 | Box 61b \ 1 scan0049 | |
| Request for a new set of ignition distributor parts with a more flexible spring made from spring steel. | 8th Sep 1927 | Box 61b \ 1 scan0050 | |
| List of suggestions for the improvement of the operation of platinum or tungsten contact points. | 23th Sep 1927 | Box 61b \ 1 scan0051 | |
| Continuation of a numbered list detailing component modifications and tests. | 24th Sep 1927 | Box 61b \ 1 scan0052 | |
| Battery ignition systems, plugs, and potential improvements to distributor components. | 28th Nov 1927 | Box 61b \ 1 scan0053 | |
| Instruction to halt production of the current make & break mechanism due to the development of an improved design. | 8th Dec 1927 | Box 61b \ 1 scan0054 | |
| Extract from a memo criticizing unauthorized and wasteful experiments conducted at the Derby facility. | 9th Dec 1927 | Box 61b \ 1 scan0055 | |
| List of suggestions for improving the operation of platinum or tungsten contact points. | 13th Dec 1927 | Box 61b \ 1 scan0056 | |
| Numbered list detailing modifications and tests on ignition system components. | 17th Sep 1928 | Box 61b \ 1 scan0057 | |
| EFC to RHC urging the fitting of six contact points to six N.S. levers. | 17th Sep 1928 | Box 61b \ 1 scan0058 | |
| Fitting of rubbing blocks and spring anchor pins to five N.S. ignition levers. | 18th Sep 1928 | Box 61b \ 1 scan0059 | |
| Recommendation to include carborundum in the kit for touching up tungsten points and to update the instruction book. | 18th Dec 1928 | Box 61b \ 1 scan0060 | |
| Maintenance of tungsten contact points, suggesting replacement over repair. | 8th Jan 1929 | Box 61b \ 1 scan0061 | |
| Letter regarding a complaint of misfiring due to faulty battery ignition tungsten contact breaker points on a 10,000-mile test chassis. | 11th Apr 1929 | Box 61b \ 1 scan0062 | |
| Examination of battery ignition contact breaker points from a 10,000-mile test chassis. | 11th Apr 1929 | Box 61b \ 1 scan0063 | |
| Battery ignition issues and burnt contact points on a 10,000-mile test chassis. | 29th May 1929 | Box 61b \ 1 scan0064 | |
| Extract from Mr. Hancock's report regarding misfires caused by burnt tungsten contacts in a distributor. | 30th May 1929 | Box 61b \ 1 scan0065 | |
| Extract from H.E. West's report on battery ignition contact breakers at the 1929 Olympia Motor Show. | 21th Oct 1929 | Box 61b \ 1 scan0066 | |
| The eccentric screw adjustment mechanism for ignition contact breakers. | 31th Oct 1929 | Box 61b \ 1 scan0067 | |
| The modification of a contact breaker arm for the 23-EX distributor. | 10th Feb 1930 | Box 61b \ 1 scan0068 | |
| Letter of complaint regarding persistent issues with the ignition points on a 20 HP car. | 13th Feb 1930 | Box 61b \ 1 scan0069 | |
| Letter responding to an issue with malfunctioning tungsten points in an ignition system. | 17th Feb 1930 | Box 61b \ 1 scan0070 | |
| Letter from Peto & Radford to E. Fowler Clark regarding continuous trouble with a 20 HP car. | 18th Feb 1930 | Box 61b \ 1 scan0071 | |
| The performance and maintenance history of tungsten contact breaker points for battery ignition systems on experimental cars. | 28th Feb 1930 | Box 61b \ 1 scan0072 | |
| Recommendations for the maintenance, trimming, and replacement of ignition contact points. | 28th Feb 1930 | Box 61b \ 1 scan0073 | |
| The necessity of ensuring correct bedding and location when replacing contact points. | 3rd Mar 1930 | Box 61b \ 1 scan0074 | |
| Maintenance schedule and replacement policy for tungsten battery ignition contact points. | 3rd Mar 1930 | Box 61b \ 1 scan0075 | |
| Re-evaluation of experimental domed surfaces on contact points. | 1st Apr 1930 | Box 61b \ 1 scan0076 | |
| Design considerations for ignition coils and magneto armatures using tungsten points on the contact breaker. | 1st Apr 1930 | Box 61b \ 1 scan0077 | |
| Letter to E. Fowler Clark regarding engine misfiring issues in 20 HP cars and discussions with Mr. Royce on potential solutions. | 5th May 1930 | Box 61b \ 1 scan0078 | |
| Letter to Mr. Minchin of Peto & Radford regarding tungsten point trouble on 20 HP cars. | 9th May 1930 | Box 61b \ 1 scan0079 | |
| Letter from an accumulator manufacturer discussing ignition system performance, maintenance, and potential improvements. | 10th May 1930 | Box 61b \ 1 scan0080 | |
| Internal request to dome the surface of six tungsten contact breaker point screws. | 2nd May 1930 | Box 61b \ 1 scan0081 | |
| Cover letter regarding tungsten battery ignition contact points, referencing two attached letters. | 3rd May 1930 | Box 61b \ 1 scan0082 | |
| Information on the necessity for replacing tungsten contact points and distributor rotors. | 14th May 1930 | Box 61b \ 1 scan0083 | |
| Letter to Mr. G.R.N. Minchin of Messrs. Peto & Radford concerning issues with tungsten contact points. | 14th May 1930 | Box 61b \ 1 scan0084 | |
| Analysis of battery ignition troubles and replacements for the two quarters ending 31st March 1930. | 15th May 1930 | Box 61b \ 1 scan0085 | |
| Ignition troubles for Phantom and 20 HP models for quarters ending December 1929 and March 1930. | 31th Mar 1930 | Box 61b \ 1 scan0086 | |
| Replacement of battery ignition components, specifically tungsten contact points and distributor rotors. | 15th May 1930 | Box 61b \ 1 scan0087 | |
| Letter from an accumulator manufacturer discussing a persistent ignition problem with 20 HP cars, and the instruction manual's detail on points. | 15th May 1930 | Box 61b \ 1 scan0088 | |
| Experiment on battery ignition contact breaker tungsten points, by fitting a contact screw with a domed surface to specific chassis. | 6th May 1930 | Box 61b \ 1 scan0089 | |
| Response to a query about the life of the tungsten contact points for a battery ignition replacement. | 16th May 1930 | Box 61b \ 1 scan0090 | |
| Customer complaints about tungsten contact points and requesting a detailed investigation. | 7th May 1930 | Box 61b \ 1 scan0091 | |
| Requesting further information on the replacement frequency and mileage of Tungsten Contact Points. | 20th May 1930 | Box 61b \ 1 scan0092 | |
| Tungsten Contact Points and an offer to investigate a customer's car. | 20th May 1930 | Box 61b \ 1 scan0093 | |
| Letter to a customer regarding an investigation into a complaint about tungsten points. | 20th May 1930 | Box 61b \ 1 scan0094 | |
| Customer complaint about the renewal of Tungsten Contact Points. | 22th May 1930 | Box 61b \ 1 scan0095 | |
| Responding to an enquiry about the status of a Depot Sheet for Battery Ignition Contact Points. | 22th May 1930 | Box 61b \ 1 scan0096 | |
| Letter discussing a persistent engine misfire issue at low speeds in 20hp models. | 26th May 1930 | Box 61b \ 1 scan0097 | |
| The irregular action of battery ignition tungsten contact points and a proposal for investigation on experimental cars. | 27th May 1930 | Box 61b \ 1 scan0098 | |
| Returned parts for chassis GYL-61 and clarifying an addressee error. | 29th May 1930 | Box 61b \ 1 scan0099 | |
| List of seven single variations from the standard for tungsten contact point experiments. | 29th May 1930 | Box 61b \ 1 scan0100 | |
| Investigative report on faulty battery ignition parts from a 20 HP Chassis GYL-61. | 30th May 1930 | Box 61b \ 1 scan0101 | |
| Tungsten ignition contact points, recommending an updated design to address performance complaints. | 31th May 1930 | Box 61b \ 1 scan0102 | |
| The condition and testing of faulty battery ignition parts from a 20 HP Chassis GYL-61. | 2nd Jun 1930 | Box 61b \ 1 scan0103 | |
| Recurring faults with the battery ignition system on chassis GYL-61. | 3rd Jun 1930 | Box 61b \ 1 scan0104 | |
| Potential causes of faulty battery ignition parts on a 20 HP Chassis, GYL-61. | 5th Jun 1930 | Box 61b \ 1 scan0105 | |
| Engine misfire caused by a closing contact gap, with a proposal to modify the distributor on chassis GYL-61. | 5th Jun 1930 | Box 61b \ 1 scan0106 | |
| Letter from the Bombay office to Derby regarding experience with Tungsten points and distributor rotor replacements in India. | 12th Jun 1930 | Box 61b \ 1 scan0107 | |
| Request to experiment with a 50% stronger contact breaker spring for the battery ignition tungsten contact point. | 6th Jun 1930 | Box 61b \ 1 scan0108 | |
| Test report on the variation of battery ignition contact breaker gap with temperature. | 17th Jun 1930 | Box 61b \ 1 scan0109 | |
| Tungsten contact point trouble and oxide formation on a 20 HP chassis. | 9th Jun 1930 | Box 61b \ 1 scan0110 | |
| Replacement of 'points' due to wear and requesting detailed information on specific trouble cases. | 9th Jun 1930 | Box 61b \ 1 scan0111 | |
| Query regarding the omission of instructions for cleaning ignition contact breaker points in the 20/25 HP Instruction Book. | 24th Jun 1930 | Box 61b \ 1 scan0112 | |
| The instruction book for the 20/25 HP model, regarding the use of a carborundum strip for cleaning ignition contact points. | 25th Jun 1930 | Box 61b \ 1 scan0113 | |
| Follow-up letter to a customer regarding a car inspection at the Cricklewood location. | 27th Jun 1930 | Box 61b \ 1 scan0114 | |
| Letter from accumulator manufacturers Peto & Radford regarding a query. | 28th Jun 1930 | Box 61b \ 1 scan0115 | |
| Tungsten Contact Points and issues with them quickly burning. | 4th Jul 1930 | Box 61b \ 1 scan0116 | |
| The testing of battery ignition contact breaker cams hardened by the 'Cloudburst' process. | 5th Sep 1930 | Box 61b \ 1 scan0117 | |
| Super-hardening battery ignition contact breaker cams using the 'Cloudburst' process. | 15th Sep 1930 | Box 61b \ 1 scan0118 | |
| Requesting two Delco-Remy contact breaker levers for comparative testing. | 3rd Oct 1930 | Box 61b \ 1 scan0119 | |
| Record of experiments on an ignition contact breaker to improve the performance and life of tungsten contact points. | 30th Sep 1930 | Box 61b \ 1 scan0120 | |
| List of single variations from standard for tungsten contact point experiments. | 9th Oct 1930 | Box 61b \ 1 scan0121 | |
| Test report on various electrical contact point configurations and materials. | 9th Oct 1930 | Box 61b \ 1 scan0122 | |
| Report summarizing test results for ignition system components like contact screws, contact breakers, and condensers. | 19th Aug 1930 | Box 61b \ 1 scan0123 | |
| Examination of battery ignition tungsten contact points from chassis 24EX after 15,000 miles running. | 19th Aug 1930 | Box 61b \ 1 scan0124 | |
| Experiments to improve the working life of tungsten contact breaker points by using various capacity condensers. | 8th Oct 1930 | Box 61b \ 1 scan0125 | |
| Test report on condenser capacity effects on screw point oxidation and arcing during bench rig running. | 8th Oct 1930 | Box 61b \ 1 scan0126 | |
| Testing Delco-Remy distributor condensers and the effect of their capacity on contact point oxidation. | 8th Oct 1930 | Box 61b \ 1 scan0127 | |
| Condenser capacity and ignition coil inductance to prevent tungsten point oxidation. | 10th Oct 1930 | Box 61b \ 1 scan0128 | |
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