| Description | Date | Identifier | |
| Foreword explaining the function and efficiency of the Smith Oil Filter and its use with colloidal graphite. | 27th Aug 1937 | Box 135 \ 3 scan0217 | |
| Article on a new oil filter by Smith Accessory, reprinted from The Automobile Engineer. | 27th Aug 1937 | Box 135 \ 3 scan0218 | |
| Diagrams and explanation of an oil filter's function and the properties of filtered oil. | 27th Aug 1937 | Box 135 \ 3 scan0219 | |
| The comparative performance of oil filters, using paper spot tests to analyse oil cleanliness on the bench and during road tests. | 27th Aug 1937 | Box 135 \ 3 scan0220 | |
| Analysis of an oil filter's components and its performance in removing contaminants and acidity from sump oil. | 8th Jan 1938 | Box 135 \ 3 scan0221 | |
| Letter to Messrs. Smith & Sons Ltd. discussing the principles and performance of the General oil filter. | 8th Jan 1938 | Box 135 \ 3 scan0222 | |
| Letter from S. Smith & Sons to Mr. Robotham regarding the operation of a filter and arranging a meeting to discuss its principle with the designer. | 11th Jan 1938 | Box 135 \ 3 scan0223 | |
| Request to order 2 dozen Tecalemit filters for use on the experimental chassis unit test beds. | 11th Jan 1938 | Box 135 \ 3 scan0224 | |
| Letter to S. Smith & Sons (Motor Accessories) Ltd. requesting a filter for testing. | 13th Jan 1938 | Box 135 \ 3 scan0225 | |
| Letter from S. Smith & Sons arranging to send a filter sample for comparative testing. | 14th Jan 1938 | Box 135 \ 3 scan0226 | |
| Letter from S. Smith & Sons regarding a No.2 Smith Oil Filter sent for testing purposes. | 17th Jan 1938 | Box 135 \ 3 scan0227 | |
| Letter detailing the disappointing test results of a Luber-Finer oil filter and returning it for investigation. | 21th Jan 1938 | Box 135 \ 3 scan0228 | |
| Letter regarding a test on a Luber-Finer unit, questioning its dispatch and installation. | 25th Jan 1938 | Box 135 \ 3 scan0229 | |
| The despatch of a trial oil filter to R.H. Collier Co. Ltd. | 27th Jan 1938 | Box 135 \ 3 scan0230 | |
| Letter to R.H. Collier regarding the testing and failure of a 'Luber-Finer' filter. | 27th Jan 1938 | Box 135 \ 3 scan0231 | |
| Letter from Jervis B. Webb Company regarding a previous correspondence about an oil filter proposition. | 15th Feb 1938 | Box 135 \ 3 scan0232 | |
| Translated article discussing the causes of oil degradation and the requirements for effective oil filters. | 16th Feb 1938 | Box 135 \ 3 scan0233 | |
| The benefits of oil filters, particularly the 'FRAM' brand, in reducing engine wear and oil consumption. | 16th Feb 1938 | Box 135 \ 3 scan0234 | |
| French article discussing the elimination of regular engine oil changes through the use of advanced filtration systems. | 23th Feb 1938 | Box 135 \ 3 scan0235 | |
| Letter to Dick Taylor regarding a ventilation scheme, camera results, and a General Filter. | 23th Feb 1938 | Box 135 \ 3 scan0236 | |
| Letter regarding a leaking and underperforming oil filter returned for investigation. | 25th Feb 1938 | Box 135 \ 3 scan0237 | |
| The concluding page of a letter. | 25th Feb 1938 | Box 135 \ 3 scan0238 | |
| Request to dispatch an AC filter to The AC-Sphinx Sparking Plug Co. Ltd. | 25th Feb 1938 | Box 135 \ 3 scan0239 | |
| Cover letter to R.G.H. Taylor forwarding a copy of a letter from Jervis B. Webb. | 28th Feb 1938 | Box 135 \ 3 scan0240 | |
| Letter from AC-Sphinx Sparking Plug Co. regarding a faulty AC Oil Filter and an Oil Sediment Meter. | 1st Mar 1938 | Box 135 \ 3 scan0241 | |
| Letter from R.H. Collier & Co. Ltd. regarding test results and issues with a Luber-Finer oil filter unit. | 4th Mar 1938 | Box 135 \ 3 scan0242 | |
| Continuation of a letter from R. H. Collier & Co. Ltd. proposing a test of a larger refiner unit. | 4th Mar 1938 | Box 135 \ 3 scan0243 | |
| Follow-up letter from S. Smith & Sons regarding an oil filter sent for testing and a potential invoice. | 4th Mar 1938 | Box 135 \ 3 scan0244 | |
| Request to dispatch a loaned oil filter back to S. Smith & Son Ltd. after a trial. | 9th Mar 1938 | Box 135 \ 3 scan0245 | |
| Letter to S. Smith & Sons regarding the return and test results of a trial oil filter. | 9th Mar 1938 | Box 135 \ 3 scan0246 | |
| Request for an opinion on a Luber oil refiner for chassis B.139.BL. | 9th Mar 1938 | Box 135 \ 3 scan0247 | |
| Advertising brochure for the Luber-finer miniature oil refinery for motors. | 1st Jan 1937 | Box 135 \ 3 scan0248 | |
| Promotional leaflet for the 'Luber-finer' oil refining system and its various models. | 1st Jan 1937 | Box 135 \ 3 scan0249 | |
| Comparative test for by-pass filters for Chassis No. B.139-BL. | 10th Mar 1938 | Box 135 \ 3 scan0250 | |
| Oil reconditioner tests for 'Luber-Finer', 'A.C.', and 'Smith' units. | 10th Mar 1938 | Box 135 \ 3 scan0251 | |
| Test report comparing the performance and characteristics of different oil purification units. | 10th Mar 1938 | Box 135 \ 3 scan0252 | |
| Comparative tests on various oil reconditioner units. | 10th Mar 1938 | Box 135 \ 3 scan0253 | |
| Comparison of the performance and limitations of various oil purification units under test. | 11th Mar 1938 | Box 135 \ 3 scan0254 | |
| Series of graphs comparing the performance of 'Luber-Finer', 'General', 'AC', and 'Smith' oil reconditioners over time. | 11th Mar 1938 | Box 135 \ 3 scan0255 | |
| Graph comparing the performance of different brands of oil reconditioners over time. | 11th Mar 1938 | Box 135 \ 3 scan0256 | |
| Letter from S. Smith & Sons regarding a sample oil filter test and arranging a specialist meeting. | 16th Mar 1938 | Box 135 \ 3 scan0257 | |
| Letter to S. Smith & Sons regarding a future discussion about filters. | 17th Mar 1938 | Box 135 \ 3 scan0258 | |
| Letter to AC-Sphinx Spark Plug Co. Ltd. concerning a recurring leak in an AC oil filter. | 21th Mar 1938 | Box 135 \ 3 scan0259 | |
| Letter to AC-Sphinx Sparking Plug Co. Ltd. discussing filter failures and proposed solutions. | 4th Mar 1938 | Box 135 \ 3 scan0260 | |
| Letter discussing filter functionality, material flaws, connection unions and washer types. | 4th Apr 1938 | Box 135 \ 3 scan0261 | |
| Comparison of bye-pass oil filters from various manufacturers. | 23th Mar 1938 | Box 135 \ 3 scan0262 | |
| Comparative report on the performance and cost of Smiths and Luber-Finer oil filters. | 23th Mar 1938 | Box 135 \ 3 scan0263 | |
| Visual comparison of by-pass filter performance using blotter spot tests over time. | 6th Apr 1938 | Box 135 \ 3 scan0264 | |
| Letter from AC-Sphinx Sparking Plug Co. Ltd. about the test results of a clogged and split oil filter. | 6th Apr 1938 | Box 135 \ 3 scan0265 | |
| Continuation sheet to AC-Sphinx discussing material stress tests, filter mounting, and leak-proofing solutions. | 6th Apr 1938 | Box 135 \ 3 scan0266 | |
| Continuation sheet from AC-Sphinx Sparking Plug Co. Ltd. responding to criticisms. | 9th Apr 1938 | Box 135 \ 3 scan0267 | |
| Two proposed design modifications for an 'A.C.' bye-pass filter mounting to address failures. | 9th Apr 1938 | Box 135 \ 3 scan0268 | |
| Modifications to a Phantom III suction oil filter to suit the revised Wraith III type steering gear. | 22th Apr 1938 | Box 135 \ 3 scan0269 | |
| Attaching a copy of a letter to the AC. Co. regarding oil filter transfers. | 27th Apr 1938 | Box 135 \ 3 scan0270 | |
| Letter to the AC-Sphinx Spark Plug Co. regarding the fitting of transfers on oil filters and enclosing a new drawing. | 27th Apr 1938 | Box 135 \ 3 scan0271 | |
| Cover letter from S. Smith & Sons regarding an enclosed booklet on filtration and lubrication. | 27th Apr 1938 | Box 135 \ 3 scan0272 | |
| Letter from R.H. Collier & Co. Ltd. regarding an unsatisfactory test of a Luber-Finer Oil Refiner and a proposal for a new demonstration. | 2nd May 1938 | Box 135 \ 3 scan0273 | |
| Letter from AC-Sphinx Sparking Plug Co. Ltd. regarding a blue print for the AC ZS-1 type oil filter. | 30th May 1938 | Box 135 \ 3 scan0274 | |
| Blueprint detailing an oil filter installation. | 21th May 1938 | Box 135 \ 3 scan0275 | |
| 'General' type bye-pass oil filter for the Phantom III engine. | 9th Jun 1938 | Box 135 \ 3 scan0276 | |
| Letter from Luber-Finer (England) Ltd. proposing the testing of their oil refiner and a meeting to present data. | 24th Jun 1938 | Box 135 \ 3 scan0277 | |
| Promotional leaflet for the Luber-finer on-board oil refinery system for vehicle engines. | 24th Jun 1938 | Box 135 \ 3 scan0278 | |
| Advertisement for Luber-finer oil refining products, detailing their function, models, pricing, and a guarantee. | 3rd Aug 1935 | Box 135 \ 3 scan0279 | |
| The benefits and functions of automobile oil filters, featuring a reprint from the National Bureau of Standards and an advertisement for Luber-finer. | 3rd Aug 1935 | Box 135 \ 3 scan0280 | |
| The principles of oil filtration and the problems associated with engine oil degradation. | 18th Jan 1938 | Box 135 \ 3 scan0281 | |
| Advertisement for the Luber-finer oil refiner, using quotes from various sources to argue that oil does not wear out. | 18th Jan 1938 | Box 135 \ 3 scan0282 | |
| Promotional document for the Luber-finer oil filter, arguing for its benefits over traditional oil changes. | 27th Jun 1938 | Box 135 \ 3 scan0283 | |
| Letter from British Filters Ltd. to arrange a meeting with a Mr. Swindall to discuss the General Filter. | 27th Jun 1938 | Box 135 \ 3 scan0284 | |
| Letter to Luber-Finer (England) Ltd. concerning the testing of a new filter unit after a previous one was found faulty. | 27th Jun 1938 | Box 135 \ 3 scan0285 | |
| Letter to British Filters Ltd. arranging a meeting to discuss a 'General' oil filter. | 28th Jun 1938 | Box 135 \ 3 scan0286 | |
| Letter from Luber-Finer detailing test parameters for a model 300 oil filter. | 29th Jun 1938 | Box 135 \ 3 scan0287 | |
| Request to British Filters Ltd. to send two filters to Paris for a trial on customer vehicles. | 5th Jul 1938 | Box 135 \ 3 scan0288 | |
| Request for the return of oil samples to Mr. T. Worth at British Filters Ltd. | 6th Jul 1938 | Box 135 \ 3 scan0289 | |
| Letter to British Filters Ltd. discussing the performance of their 'General' oil filter based on oil samples. | 6th Jul 1938 | Box 135 \ 3 scan0290 | |
| Follow-up inquiry regarding the return of an AC Filter sent for examination to the AC-Sphinx Sparking Plug Co. Ltd. | 7th Jul 1938 | Box 135 \ 3 scan0291 | |
| Letter from British Filters Ltd. confirming the dispatch of two filters to Paris. | 8th Jul 1938 | Box 135 \ 3 scan0292 | |
| Letter from British Filters Ltd. regarding the dispatch of four filter cases, a 'sale or return' invoice, and a detailed drawing of the filter body. | 8th Jul 1938 | Box 135 \ 3 scan0293 | |
| Requesting the manufacture of pipes and a bracket for a 'General' type oil filter. | 9th Jul 1938 | Box 135 \ 3 scan0294 | |
| Choked and leaking AC oil filter returned for examination. | 11th Jul 1938 | Box 135 \ 3 scan0295 | |
| Official order be placed with British Filters Ltd for four 'General' filters. | 11th Jul 1938 | Box 135 \ 3 scan0296 | |
| Despatch of trial parts, including oil filters, pistons and rings for Bentley engines. | 15th Jul 1938 | Box 135 \ 3 scan0297 | |
| Modifications and fitting instructions for a 'General' Bye-Pass Filter on Wraith III & Bentley III cars. | 16th Jul 1938 | Box 135 \ 3 scan0298 | |
| Letter from Luber-finer (England) Ltd. proposing a meeting with their European Representative, Mr. Solomon. | 4th Aug 1938 | Box 135 \ 3 scan0299 | |
| Customer testimonial letter regarding the performance and benefits of a 'Luber-finer' oil filter. | 13th Jul 1938 | Box 135 \ 3 scan0300 | |
| Letter to British Filters Ltd. regarding the requirements for a 'General' filter housing, requesting a sample and quotation. | 12th Aug 1938 | Box 135 \ 3 scan0301 | |
| Letter from British Filters Ltd. regarding the production of a General Filter and requesting estimated order quantities for calculating discounts. | 15th Aug 1938 | Box 135 \ 3 scan0302 | |
| Requesting comparative tests on two types of oil filters. | 18th Aug 1938 | Box 135 \ 3 scan0303 | |
| Letter to British Filters Ltd. regarding a model filter, its testing, requested modifications, and a request for quotations. | 30th Aug 1938 | Box 135 \ 3 scan0304 | |
| Letter to British Filters Ltd. requesting the supply of 3 filters with specific modifications to the design. | 2nd Sep 1938 | Box 135 \ 3 scan0305 | |
| Letter from British Filters Ltd. confirming a change to the text on a filter lid. | 2nd Sep 1938 | Box 135 \ 3 scan0306 | |
| Internal memorandum requesting an official order be placed for filters for experimental B.60 engines. | 2nd Sep 1938 | Box 135 \ 3 scan0307 | |
| Proposed design to stiffen the Phantom III pressure oil filter element to prevent collapse, with a request for experiments on different reinforcement options. | 8th Sep 1938 | Box 135 \ 3 scan0308 | |
| Invitation from Luber-Finer (England) Ltd. to visit their stand at the Motor Exhibition at Earls Court. | 21th Sep 1938 | Box 135 \ 3 scan0309 | |
| Letter to Goodyear Tyre & Rubber Co. declining further tests on their belts. | 10th Jan 1939 | Box 135 \ 4 scan0001 | |
| Letter to Ferodo Ltd. regarding a measurement discrepancy on a V.165 belt mould, concluding the matter is closed. | 12th Jan 1939 | Box 135 \ 4 scan0002 | |
| Letter to Gates Rubber Co. Ltd. regarding the successful testing of a Ferogrip fan belt. | 12th Jan 1939 | Box 135 \ 4 scan0003 | |
| Sourcing of fan belts for the Paulin Continental Bentley car. | 20th Jan 1939 | Box 135 \ 4 scan0004 | |
| Internal request to send an official order to Ferodo Ltd for 3 Ferogrip fan belts. | 26th Jan 1939 | Box 135 \ 4 scan0005 | |
| Order of Ferogrip fan belts from Messrs. Ferodo Ltd. | 3rd Feb 1939 | Box 135 \ 4 scan0006 | |
| Letter from The Gates Rubber Company discussing a fan belt drive problem and proposing competitive testing. | 14th Feb 1939 | Box 135 \ 4 scan0007 | |
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