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Ian Edmunds. (Chairman) An engineer in the motor industry.
Peter Glover. Chairman of the Federation.
Rosie Good. General Manger of the TR Register.
Peter Henley. The FBHVC appointed fuels expert.
Tom Ryland. An FBHVC Committee member and recent retired from the oil industry.
Matthew Vincent. A fuels expert in the petroleum industry.
with the Secretary to the Federation, for his sins, being the Secretary to this Committeealso!
A Press Release has recently been issued outlining the composition and aims of the FuelsCommittee. Meanwhile this update seeks to review the current situation as faced by the Committeewhen it was formed and to set the scene for the Committee's perceived tasks. Subsequent updates willbe issued as required to advise on progress.
At its inaugural meeting held on 1 July 1997, the Committee agreed the followingassumptions:-
a. The sale of leaded petrol at garage forecourts in the UK would be banned with effectfrom 1January 2000. (Although a mechanism existed within the European Unionwhereby member countries could seek derogation for a limited number of years, thiscourse of action was judged to be extremely unlikely in the case of the UK; there wasnot the political will nor the commercial imperative to make a convincing case) -
b. Leaded ruel in limited quantities would continue to be blended for sale at approvedmotor racing circuits; its cost to the user was likely to be much more than the currentretail price of leaded petrol because of its small batch production. it would howeverallow historic racing to continue with the lull protection of leaded fuel.
c. The fuel being made available at the pumps in some European countries and known asLead Replacement Gasoline (LRG) fell far short of providing full engine protection andwas unlikely, in any case, to be widely marketed in the UK for commercial reasons
d. There was no scientific evidence to support the marketing claims of organisationsoffering products such as pellets which were merely placed in fuel tanks or fitted insmall containers to the fuel line. The form of many advertisements for these productswas seen by the Committee to be misleading and none would be considered ascontributing towards a viable lead substitute, unless of course, any such manufacturercould produce evidence from a recognised independent laboratory that their productworked.
Based on these assumptions, the Committee agreed the following conclusions:-
a The single most important risk to engines no longer able to use leaded fuel was exhaustvalve seat recession.
b. The best solution to using unleaded fuel in historic engines remained the engineeringoption; that is the fitting of hardened seats. Since this option often was impossiblebecause of engine design, a lead substitute clearly has to be sought. (The need to ensurethat hardened seats were properly fixed - usually by screwing and pilming - was yetagain reiterated because of the potentially catastrophic consequences of a seat comingadrift).
c. Whilst agreeing the universal danger of exhaust valve seat recession, there weremany other issues which had to be addressed - such as the vulnerability of some fuelinjection systems to increased rates of wear, the octane rating of fuels and the risk ofblade corrosion in turbochargers - which meant that a valve recession additive whichprotected valve seats but caused damage elsewhere could enjoy only limitedendorsement.
d. There was still much misinformation at large about the use of leaded and unleaded fuelin historic engines. There was no absolute maxim which said that using unleaded fuelsin historic engines would inevitably result in valve dan~ge - and there never had been,The point was that there was a significant risk. The level of that risk depended primarilyupon the design and manufacture of the engine and thereafter upon the operatingtemperatures generated in the region of the exhaust valves. Such temperatures could beaffected by the way the vehicle was driven (sustained high r.p.m. created hightemperatures but so did hard work at lower r.p.m. - conceivably for example throughfitting an overdrive - whilst the effectiveness of the cooling system, the setting of theignition etc. could influence running temperatures). Thus it was quite possible for twoengines ostensibly identical in specification to suffer different results from usingunleaded fuel fl~ough differences in use and maintenance. Because of themisinformation, the Committee endorsed the advice in the VSCC publication '~ValveSeat Recession, Use of Unleaded Gasoline in Older engines" which provided an in-depth review of the historic and current aspects of the problem.
e. The overall conclusion to be drawn from all these assumptions and other conclusionswas that the solution to the known problems of using unleaded fuel in older engines layin the so-called "after market" provision of fuel additives. That is to say additives notblended in the bulk supply of fuel but available at garages in containers, the contents ofwhich would be added to unleaded fuel when the vehicle tank was being replenished.
Finally the Committee made the following decisions:-
a. Although it was understood that Australia was defining a standard by which theeffectiveness of lead substitute additives could be judged, there was currently no hintthat the British Government were proposing to do the same. Therefore it was vital toevolve a test protocol which involved testing by wholly independent and accredited testorganisations. The cost of such testing should be borne by the additive manufacturer.The Federation would endorse such tested products but not others.
b. To liaise with the oil industry to ensure, if possible, that suitable products would beavailable on garage forecourts by 1 January 2000, that the cost to the user wasreasonable and that the product had clear unequivocal instructions for its use,including dose rates, for different vehicle users and listed engines for which it would NOT be suitable.
c. The current range of available additives which used potassium, sodium or phosphorusrepresented technology from which suitable additives of the type envisaged by theCommittee would he selected In order to help the Commiflee, to work effectivelytowards their goal - to have tested viable product for sale on 1 January 2000- theFederation would work closely with motoring organisations, particularly the AA andRAC. An early task was to acquire an accurate data base showing the numbers ofvehicles likely to be affected by the withdrawal of leaded petrol.
d. Lastly the Committee would be examining further the implications of the continuedneed for light piston engined aircraft to use leaded aviation gasoline (AVGAS) and anyrelevance there might be to the future use of older road vehicles.
A copy of the aforementioned VSCC document is available in limited quantity, price £5.50, from theSecretary. Please send a C4 s.a.e. when ordering.
Firstly, before the next meeting on the 20th November, a test protocol will have beenformulated for use by the FBHVC Fuels Committee. Secondly, manufacturers ofadditives will be invited to subject their products to the FBHVC criteria, at their owncost, and thirdly members of the Fuels Committee will be researching the marketthemselves to provide data on additives currently on offer in the marketplace.
In News Sheet Issue number 30 you may remember that in the article headed 'FuelNews and Update' that it was noted that although a mechanism existed within theEuropean Union whereby member countries could seek derogation for a limitednumber of years, this course of action was judged to be extremely unlikely in the caseof the United Kingdom Your Fuels Committee are of the opinion that a campaignshould be mounted to lobby the British Government to consider or reconsiderapplication to the EU to extend the date for discontinuation of supply of leaded fuel, ifonly to allow sufficient time for substantive research into an effective and meaningfuladditive to replace the previous lead content in petrol.
Support on this matter is to be generated through a press release and hopefully throughco-operation with the specialist motoring press.
The brief update in News Sheet 31 (October 1997) explained that a test protocol(i.e. a schedule of relevant tests) would be designed for the independent testing ofproducts being marketed as lead substitutes. This protocol has since been produced andagreed by the Committee. Quotations will now be sought from suitable, accredited,independent test organisations for undertaking the tests. Anti valve seat recessionadditive manufacturers will then be invited to submit their products for testing at theirexpense. Those which pass the test would receive a formal endorsement, or approval,from the Federation. The Committee expects that the successful products will be fuelsoluble additives, packaged and sold for adding to petrol tanks when "filling up".Sodium, potassium, and phosphorus additives are already in existence and are expectedto be submitted for testing. (Metallic pellets for use in tanks or fuel lines are practicallyinsoluble in petrol and are considered to be ineffective in preventing exhaust valverecession: similarly magnets attached to the outside of fuel lines would have nosignificant effect on exhaust valve recession). However, should any product, despitebeing of an unexpected nature pass the tests, it would of course receive theFederation's endorsement. All test products should be accompanied by safety datasheets giving details of the composition of the contents, and details of recommendeddose rates and wamings for any engine for which it was known to be unsuitable. Theprocess of testing will move ahead as quickly as possible during 1998. Meanwhile theCommittee is collecting a data bank of information about all products which areadvertised as lead substitutes or other forms of exhaust valve protection.
In a fuels update (The Leaded/Unleaded Saga) written and published in Spring1996, before the Federation Committee had been formed, it was explained that a fuel,graded "4 star" and called Lead Replacement Gasoline (LRG) was being sold on someforecourts. As LRG does not contain lead, its use in engines with "soft" valve seatscould be disastrous. Although LRG was usually labelled 4 star the British Standardlogo for leaded motor luel (BS 4040) was not applicable to LRG pumps. The advicewas, and still is, always check that the pump you are about to use carries the BS 4040marking - whether it is labelled 4 star or not. This already slightly confusing situationhas now been made more confusing by a British Standards Institute announcement thatthe 4 star grading is to be removed from leaded fuel (the logic being that since thedemise of 2 star and 5 star there is now only one grade of leaded fuel).
page 17
There could however still be cases of LRG (often now referred to and marketed asLead Replacement Petrol (LRP)) being sold. The golden rule therefore still applies:check for the BS 4040 logo before buying the fuel. The good news arising from all thists that the seasonal volatility requirements have now been made mandatory whereasthey were formerly recommendations. In brief, this means that those engines prone tomisfiring in hot weather because of high volatility fuel, will now benefit from lowervolatility fuel for sale during the summer months. This should help to reduce some ofthe vapour lock problems encountered.
Finally for this Update, the British Standards Instftution (BSl) has prepared adraft British Standard entitled "Specification for high octane unleaded petrolcontaining valve seat protection additives (Lead Replacement Petrol)". This is the sameLRG/LRP cited above as being unsuitable for use in classic car engines. As alreadyexplained, this fuel does not contain lead(and therefore could be produced after theleaded ban takes effect) - but does have additives. The point here is that the LRG/LRPspecification requires a minimum level of additive unlikely to be sufficient to affordsafe exhaust valve protection. Yet if it is proposed that it be retailed in the future with aBSl specification and called "Lead Replacement Petrol" it would obviously beconvincing to classic vehicle users who were unaware of its serious shortcomings; ifthey used it - it could have potentially catastrophic results. It is the view of the FuelsCommittee that LRP is unlikely to be made and sold extensively in the UK.Nevertheless a comment highlighting the dangers of giving a BSI endorsement to LRP,(in effect masking its inadequacies) has been sent by the Federation to the relevant BSITechnical Committee - (On which the Federation and the Vintage Sports-Car Club arerepresented by a member of the Federation Fuels Committee).
Widespread concern about the possible adverse side effects of using unleaded petrol invehicles having engines with cast iron cylinder blocks (side valve) or heads (OHY),has resulted in the execution of a detailed study of the scientific and engineeringliterature published in the USA and in Britain over the last 70 years or so. The studyhas covered all aspects of the phenomenon known as valve seat recession, which is saidto occur when an engine valve "sinks", under the pressure exened by its return spring,into the cylinder head or block. Much investigative work was carried out in 1970 and1971 in America, when the introduction of exhaust emissions legislation first resultedin the use of exhaust catalyst systems. These devices are incompatible with leadedpetrol, and so unleaded petrol was re-introduced into the market in America at this time.
There is much evidence from reported scientific literature that valve seatrecession occurs in cast iron engines operated continuously on unleaded petrol. Enginespeeds and loads do not necessarily have to be high for valve seat recession to occur,although seat wear rates increase rapidly with engine speed. Wear rates of over 5thousandths of an inch per hour of operation have been reported, at an engine speed of4000 rpm.
page 18
When leaded petrol is burnt in an engine, lead compounds, mainly lead sulphate and lead oxide, are deposited in the combustion chamber. There compounds, laid down in the valve seat area, act as a solid lubricant, preventing metal to metal contact between valve and seat. As a result, serious valve seat wear with leaded petrol is almost unknown. By contrast, continuous use of unleaded petrol in cast iron engines allows metal to metal contact, with consequent adhesion between valve and seat. Particles of the seat material, removed by the valve as it opens, are oxidised by hot exhaust gases. Hard lumps of iron oxide form on the surface of the valve face; valve rotation grinds away at the valve seat producing recession or 'sinkage'.
Valve seat recession with unleaded petrol increases rapidly with engine speed.At sustained speeds below 2000 rpm, the risk of wear is low, while above 3500 rpm, catastrophic wear can result. Valve rotation speed is closely linked with engine speed,and is seen as the factor pnmarily influencing wear. Reduced wear rates are associatedwith a 300 valve seat angle, and lower compressed valve spring load. Sodium cooledvalves may help in reducing recession. Hardfacing valve seats with Nimonic(80% nickel, 20% chromium) will reduce recession provided the composition of thehardfacing material is closely controlled.
There is ample evidence that exhaust valve seat recession was a problem inAmerica during the nineteen twenties, being associated with truck and motor coachoperation on improved main highways, which developed rapidly during this period.Corrosion and wear resistant valve seat inserts were fitted by many American motormanufacturers as original equipment from about 1930 onwards. A contemporary record(1931) indicated that valve seat recession could be prevented by using leaded petrol. Inthe UK, valve seat recession was much rarer in the twenties and thirties, because ofinadequate road development which did not permit sustained high speed, and thepredominance of small low powered cars of relatively poor perforinance.Manufacturers of heavy duty engines and quality cars frequently fitted valve seatinserts as original equipment.
Soluble fuel additives, usually based upon organometallic compounds, canreduce valve seat recession in cast iron engines. At low treat rates compatible withexhaust catalyst operation, valve seat recession can still be a problem. Higher treatrates will give improved protection, but may lead to unwanted side effects. Phosphonis based fuel additives have been shown to offer satisfactory protectionagainst valve seat recession in a range of engines and under most operating conditions.An additive of this type is in widespread use in New Zealand as an aftermarket additivefor use at the petrol station forecourt, at the time of refuelling.
Treatment rates of between 30 and 50 parts per million minimum of lead in asoluble form in petrol, are necessary to protect exhaust valve seats from wear. Metallicpellets introduced into fuel tanks or lines are practically insoluble in petrol, and thusthe negligible metal content of the petrol, which results from temporary contact withthe pellets, is too low to protect valve seats from wear. Permanent magnets attached tothe outside of fuel lines thro~igh which petrol passes will have no significant effectbecause hydrocarbon fuels are non-polar.
page 19
It is now known that from the first of January 2000, normal sale of leaded petrolwill cease in most of Europe, including the UK, as the result of an EEC directive. SomeEuropean countries will apply for a concession to be allowed to sell leaded fuel for afurther 4 or 5 years, but the UK Governnient is thought unlikely to apply to the EECfor such an extension.
A concession has been offered by the EEC to allow sales of leaded petrol forminority interest groups. This concession would allow sales up to a maximum of onehalf of one per cent (0.5%) of total fuel sales. However, it is not known how this smallamount of leaded petrol would be made available or distributed. Overall, there will inpractice be almost no leaded petrol available for road vehicles after the end of 1999.Leaded petrol will probably be harder to find from about the middle of 1999 onwards,as petrol station pumps, tanks and other dispensing items are progressively preparedfor the supply of other fuels.
A British Standard specification is being drawn up (see page 18, paragraph 2 forfull details) for a lead replacement petrol containing valve seat recession additives, butthere are concerns about the level of protection which this product will offer. Also, it isnot known to what extent this product will be available.
The best solution to the problem of valve seat recession is to fit hardenedexhaust valve seat inserts. Millions of vehicles world-wide have successfully used suchinserts to permit satisfactory continuous operation with unleaded petrol. Insertmaterials must possess good hot hardness and corrosion resistance to operatesatisfactorily. Inserts made of materials rich in cobalt, tungsten, and chromium havegiven way in recent years to lower alloy content iron-based sintered powder metallurgymaterials. These are of lower cost and the sintered matrix can be infiltrated withcopper to give improved heat transfer and to provide a solid lubricant effect.
Valve seat inserts can be fitted to older cars to prevent recession with unleadedpetrol. Fitting inserts is a skilled engineering job, but there are companies whospecialise in this type of work, and who can demonstrate a successful record of valveseat modifications. The work demands engine dismantling, of course, and in someengine types, the combination of long stroke, small cylinder bore, and fixed headdesign may prevent the fitting of valve seat inserts.
From January 2000, owners unable or unwilling to fit valve seat inserts tovulnerable engines are likely to consider use of a fuel additive for protection againstvalve seat recession. Additives have been successfully used in several countries toprotect against valve seat recession. Work is currently in hand to establish the level ofprotection provided by various additives or devices.
By 1999, additive solutions offering a known level of protection will beavailable. Steps are being taken to ensure that suitable products, to be added duringrefuelling, will be on sale at petrol stations, when leaded petrol is no longer widelyavailable.
page 20
Reports recently produced or reprinted by the Federation are available from theSecretary at the address at the head of this News Sheet.
These reports are titled:
Preserving the Past for the Future'andValve Seat Recession'
The first a 15 page document deals with the Historic Vehicle Movement inBritain, a survey of the Patterns of Ownership, Employment and EconomicOpportunities for Historic vehicles and is available at a price of £5 plus 39p (firstclass) 3lp~ (second class) postage in the UK.
The second is a document of 20 pages and 26 pages of tables and figures dealingwith the use of Unleaded gasoline in older engines, and costs £5.50 plus 60p (1stclass), 45p (second class) postage in the UK.
