| Description | Date | Identifier | |
| Letter from English Racing Automobiles Ltd. discussing Bosch spark plugs, cylinder head performance, and sticking exhaust valves. | 11th May 1938 | Box 162 \ 3 img118 | |
| Letter discussing exhaust valve sticking, nitriding stems, and alternative materials. | 12th May 1938 | Box 162 \ 3 img119 | |
| Letter to P. Berthon of E.R.A. Ltd. arranging a visit to Bourne. | 13th May 1938 | Box 162 \ 3 img120 | |
| Letter to Champion Sparking Plug Co., Ltd. referring to previous correspondence. | 13th May 1938 | Box 162 \ 3 img121 | |
| Letter following up on 'Nu-Able' sparking plug adaptors and notifying a change of address. | 19th Jun 1938 | Box 162 \ 3 img122 | |
| Technical explanation of Hermiss Spark Plug Adaptors and their principle of operation. | 19th Jun 1938 | Box 162 \ 3 img124 | |
| Test of 'Permiss' spark plug adaptors designed to cure engine misfiring. | 15th Jan 1932 | Box 162 \ 3 img127 | |
| Testing 'Hemiss' spark plug adaptors, concluding they offered no advantage. | 15th Jan 1932 | Box 162 \ 3 img128 | |
| Requesting the return of six 'Nermiss' plug adaptors to Mr. A.R. Milton after testing. | 24th Jun 1938 | Box 162 \ 3 img129 | |
| Letter arguing the benefits of 'NER-MIS' sparking plug adaptors. | 24th Jul 1938 | Box 162 \ 3 img130 | |
| Letter discussing the benefits and testing of spark plug adaptors and acknowledging returned parts. | 24th Jun 1938 | Box 162 \ 3 img131 | |
| Letter regarding the testing of adaptors for engines with leaky spark plugs. | 24th Jun 1938 | Box 162 \ 3 img132 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding the upcoming production and supply of British-made Type NA.8 spark plugs for testing. | 29th Jul 1938 | Box 162 \ 3 img133 | |
| Requesting photographs and mileage data for Lodge & K.L.G. sparking plugs under test. | 4th Aug 1938 | Box 162 \ 3 img134 | |
| Requesting the purchase of 3 dozen LBB type sparking plugs from the Champion Sparking Plug Co. | 8th Sep 1938 | Box 162 \ 3 img135 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding the dispatch of miniature sparking plugs and a race ticket. | 21th Oct 1938 | Box 162 \ 3 img136 | |
| Receipt from Champion Sparking Plug Co. Ltd. for Champion Plugs. | 21th Oct 1938 | Box 162 \ 3 img137 | |
| Letter to Champion Sparking Plug Co. Ltd. requesting different specification spark plugs for a Phantom III engine. | 24th Oct 1938 | Box 162 \ 3 img138 | |
| Letter from Champion Sparking Plug Co. Ltd. confirming the dispatch of 24 Champion NA.10 spark plugs. | 27th Oct 1939 | Box 162 \ 3 img139 | |
| Invoice from Champion Sparking Plug Co. Ltd. | 14th Nov 1938 | Box 162 \ 3 img140 | |
| Covering order for 24 NA.10 type sparking plugs from Champion Sparking Plug Co. Ltd. | 17th Nov 1938 | Box 162 \ 3 img141 | |
| Request to obtain 3 dozen Champion LB8 type sparking plugs. | 13th Dec 1938 | Box 162 \ 3 img142 | |
| Request to obtain NA.8 type sparking plugs from Champion Sparking Plug Co. Ltd. | 11th Jan 1939 | Box 162 \ 3 img143 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding an order for spark plugs, discussing model numbers and pricing. | 17th Jan 1939 | Box 162 \ 3 img144 | |
| Letter to Champion Sparking Plug Co. acknowledging receipt of 48 N8 type plugs for use on experimental engines. | 21th Jan 1939 | Box 162 \ 3 img145 | |
| The performance of the KLG FLB50X sparking plug, focusing on electrode wear. | 23th Jan 1939 | Box 162 \ 3 img146 | |
| Photograph of a disassembled spark plug, labelled 'A'. | 23th Jan 1939 | Box 162 \ 3 img147 | |
| Photograph of a fractured spark plug. | 25th Jan 1939 | Box 162 \ 3 img148 | |
| Letter from Champion Sparking Plug Co. Ltd. discussing the supply of N.8 and LB.8 spark plugs as original equipment. | 25th Jan 1939 | Box 162 \ 3 img149 | |
| Letter from Champion Sparking Plug Company Limited regarding their production and supply of spark plugs. | 25th Jan 1939 | Box 162 \ 3 img150 | |
| Letter from Champion Sparking Plug Co. Ltd. following up on a previous letter regarding the supply of spark plugs. | 24th Feb 1939 | Box 162 \ 3 img151 | |
| Letter to Champion Sparking Plug Co. Ltd. regarding the performance and potential standardisation of their plugs. | 27th Feb 1939 | Box 162 \ 3 img152 | |
| Letter from Champion Sparking Plug Co. Ltd. acknowledging receipt of a letter and forwarding it to their Managing Director. | 2nd Mar 1939 | Box 162 \ 3 img153 | |
| Letter to Champion Sparking Plug Co. Ltd. from the Experimental Department requesting to trial a set of 10mm sparking plugs. | 16th Mar 1939 | Box 162 \ 3 img154 | |
| Letter from Champion Sparking Plug Co. Ltd. arranging a supply of 10mm spark plugs for testing. | 17th Mar 1939 | Box 162 \ 3 img155 | |
| Request to obtain four dozen NA.10 type sparking plugs for stock from the Champion Sparking Plug Co.Ltd. | 19th Apr 1939 | Box 162 \ 3 img156 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding the development of new spark plug types N8 and L8.8. | 4th May 1939 | Box 162 \ 3 img157 | |
| Receipt of experimental 10 m/m Champion sparking plugs and inserts. | 13th May 1939 | Box 162 \ 3 img158 | |
| Letter to Champion Sparking Plug Co., Ltd. regarding the company's policy on spark plug suppliers. | 15th May 1939 | Box 162 \ 3 img159 | |
| The procurement of 6 dozen sparking plug terminals from Champion. | 18th May 1939 | Box 162 \ 3 img160 | |
| Requesting the purchase of various Champion spark plugs. | 23th May 1939 | Box 162 \ 3 img161 | |
| Internal memorandum requesting an order for two types of Champion spark plugs. | 11th Dec 1939 | Box 162 \ 3 img162 | |
| The procurement of 2 dozen L.B.8 sparking plugs. | 9th Jan 1940 | Box 162 \ 3 img163 | |
| To R.M/R.Child regarding the thread length of Champion Y4 spark plugs. | 30th Jan 1940 | Box 162 \ 3 img164 | |
| The purchase of sparking plugs for stock from Champion Sparking Plugs Ltd. | 10th Feb 1940 | Box 162 \ 3 img165 | |
| Request to obtain KD7 type spark plugs and insulated plug terminals from the A.C. Sphinx Sparking Plug Co. Ltd. | 14th Feb 1940 | Box 162 \ 3 img166 | |
| Technical letter discussing spark plug issues on Bentley chassis due to poor quality fuel and recommending alternatives. | 15th Feb 1940 | Box 162 \ 3 img167 | |
| Patent specification for a sparking plug, noting the design has been abandoned. | 19th Feb 1940 | Box 162 \ 3 img168 | |
| Outlining the need to adjust carburation on service cars for experimental plug deterioration tests. | 22th Feb 1940 | Box 162 \ 3 img169 | |
| Experimental plug tests on service cars and adjusting carburation. | 22th Feb 1940 | Box 162 \ 3 img170 | |
| Letter to Lucas Ltd. requesting research assistance with spark plug problems in car and aviation work. | 22th Feb 1940 | Box 162 \ 3 img171 | |
| The second page of a letter requesting a research staff member be assigned to a problem. | 23th Feb 1940 | Box 162 \ 3 img172 | |
| Discussion document outlining proposed tests to resolve ignition issues on weak mixtures caused by deteriorating spark plugs. | 23th Feb 1940 | Box 162 \ 3 img173 | |
| Page of instructions detailing testing procedures for diagnosing engine trouble related to spark plugs and carburation. | 24th Feb 1940 | Box 162 \ 3 img174 | |
| Letter to Champion Sparking Plug Co. Ltd. about misfiring and bad starting due to poor quality petrol, requesting a hotter running spark plug. | 24th Feb 1940 | Box 162 \ 3 img175 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding starting and misfiring difficulties and arranging a technical visit. | 27th Feb 1940 | Box 162 \ 3 img176 | |
| Letter from Joseph Lucas Limited regarding spark plug performance, oxydisation of points, and engineer availability. | 27th Feb 1940 | Box 162 \ 3 img177 | |
| Letter to Joseph Lucas Ltd. regarding co-operation on a long-standing problem possibly related to oxidation. | 28th Feb 1940 | Box 162 \ 3 img178 | |
| Plug tests carried out on transport cars with carburetter modifications for fuel economy. | 29th Feb 1940 | Box 162 \ 3 img179 | |
| Carburetter modifications and plug tests for fuel economy on two transport cars. | 29th Feb 1940 | Box 162 \ 3 img180 | |
| Letter to A.C. Sphinx Plug Co. Ltd regarding the testing of their KD.7.A. type spark plugs. | 6th Mar 1940 | Box 162 \ 3 img181 | |
| Requesting to obtain 12 KD.7.A. type A.C. Sphinx Sparking Plugs. | 6th Mar 1940 | Box 162 \ 3 img182 | |
| Letter from Champion Sparking Plug Co. Ltd. sending a paper on ceramic insulators for sparking plugs. | 12th Mar 1940 | Box 162 \ 3 img183 | |
| Visit from a Champion technical representative to discuss spark plug troubles and trial new plugs. | 12th Mar 1940 | Box 162 \ 3 img184 | |
| Letter to Champion Sparking Plug Co. regarding a paper on ceramics and sparking plug troubles. | 16th Mar 1940 | Box 162 \ 3 img185 | |
| Letter to Champion Sparking Plug Co. regarding sparking plug troubles and ceramics. | 16th Mar 1940 | Box 162 \ 3 img186 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding a visit from their engineer to the Experimental Department. | 20th Mar 1940 | Box 162 \ 3 img187 | |
| Letter from Joseph Lucas Ltd. to W.A. Robotham regarding misfiring troubles. | 1st Apr 1940 | Box 162 \ 3 img188 | |
| Letter to Messrs J. Lucas about a poor demonstration of a fault and arranging to send a car as an example. | 3rd Apr 1940 | Box 162 \ 3 img189 | |
| Letter to Champion Sparking Plug Co. Ltd. correcting misleading statements about spark plug development and selection. | 11th Apr 1940 | Box 162 \ 3 img190 | |
| Page 2 of a letter discussing the confidentiality of comparative test reports for four types under supervision. | 11th Apr 1940 | Box 162 \ 3 img191 | |
| Order of Vulcanite protected Busby Terminals from the Champion Sparking Plug Co. | 11th Apr 1940 | Box 162 \ 3 img192 | |
| Letter from Champion Spark Plug Co. discussing ignition system troubles and spark plug performance. | 15th Apr 1940 | Box 162 \ 3 img193 | |
| Letter from Champion Sparking Plug Co. Ltd. addressing misinterpretations and performance issues with their plugs. | 23th Apr 1940 | Box 162 \ 3 img194 | |
| Letter of apology from Champion Sparking Plug Company regarding a misunderstanding over comparative test reports. | 23th Apr 1940 | Box 162 \ 3 img195 | |
| Letter to Champion Sparking Plug Co. Ltd. regarding the development of spark plugs for experimental units. | 30th Apr 1940 | Box 162 \ 3 img196 | |
| Request to obtain six 18mm type 8 Champion sparking plugs as fitted to a Studebaker. | 4th May 1940 | Box 162 \ 3 img197 | |
| Cover letter from Champion Sparking Plug Co. Ltd. enclosing a report on the oxidation of electrodes. | 8th May 1940 | Box 162 \ 3 img198 | |
| Letter to the Champion Sparking Plug Company regarding ignition systems and spark plug development. | 8th May 1940 | Box 162 \ 3 img199 | |
| Letter inquiring about work done on a new insulator marketed by the Batelle Institute. | 8th May 1940 | Box 162 \ 3 img200 | |
| Letter to Champion Sparking Plug Co. discussing ignition systems and improvements to sparking plugs, including experiments with metallic cores. | 8th May 1940 | Box 162 \ 3 img201 | |
| Page 2 of a letter inquiring about a new insulator material from the Batelle Institute. | 17th May 1940 | Box 162 \ 3 img202 | |
| Letter from Champion Sparking Plug Co. regarding a laboratory report and an insulator from Batelle Institute. | 17th May 1940 | Box 162 \ 3 img203 | |
| Development and testing of various sparking plugs for different car engines. | 22th Aug 1940 | Box 162 \ 3 img204 | |
| The suitability of various cars and engine combinations for spark plug testing. | 22th Aug 1940 | Box 162 \ 3 img205 | |
| Querying if KLG spark plugs were responsible for engine 'running on' and preparing to test Lodge plugs as an alternative. | 26th Aug 1940 | Box 162 \ 3 img206 | |
| Investigating the cause of an engine 'running on after switching off' and the role of spark plugs. | 11th Sep 1940 | Box 162 \ 3 img207 | |
| Comparative tests on engine running-on issues, spark plugs, and valve types. | 11th Sep 1940 | Box 162 \ 3 img208 | |
| Correcting a previous statement regarding the engine number fitted with a specific part. | 12th Sep 1940 | Box 162 \ 3 img209 | |
| Chevrolet's ignition system advancements noted in 'The Motor' magazine. | 28th Oct 1940 | Box 162 \ 3 img210 | |
| Requesting the purchase of 4 dozen, 14 mm, N.8 type Champion Sparking Plugs. | 11th Nov 1940 | Box 162 \ 3 img211 | |
| Substitute for a discontinued Champion Sparking Plug. | 27th Dec 1940 | Box 162 \ 3 img212 | |
| Internal request to purchase Champion sparking plugs for a Studebaker. | 20th Dec 1940 | Box 162 \ 3 img213 | |
| Correcting a previous statement regarding the fitment of a part to an engine. | 12th Sep 1940 | Box 162 \ 3 img214 | |
| Blueprint detailing a cross-section of a component, comparing a 'usual reach' with a 'suggested reach'. | 12th Sep 1940 | Box 162 \ 3 img215 | |
| Blueprint showing a cross-section of a component with annotations for 'suggested reach' and 'usual reach'. | 12th Sep 1940 | Box 162 \ 3 img216 | |
| Drawing comparing the 'suggested reach' and 'usual reach' of a component within a cylinder head. | 2nd May 1941 | Box 162 \ 3 img217 | |
| Letter to Champion Sparking Plug Co. requesting samples of different spark plugs for an experimental test. | 2nd May 1941 | Box 162 \ 3 img218 | |
| Letter from Champion Sparking Plug Co. Ltd. regarding a request for sample plugs for testing. | 5th May 1941 | Box 162 \ 3 img219 | |
| Suitability of experimental Super Reach Spark Plugs for different cylinder heads. | 14th May 1941 | Box 162 \ 3 img220 | |
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