return to Andy's Austin Seven Page - Unleaded petrol
NOTE: I HAVE NO CONTROL OVER THE ABOVE BANNERS WHICH APPEAR ON THIS SITE, OR THE CONTENT OF THE SITES TO WHICH THESE BANNERS LINK.
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 Committee also!
A Press Release has recently been issued outlining the composition and aims of the Fuels Committee. Meanwhile this update seeks to review the current situation as faced by the Committee when it was formed and to set the scene for the Committee's perceived tasks. Subsequent updates will be issued as required to advise on progress.
At its inaugural meeting held on 1 July 1997, the Committee agreed the following assumptions:-
a. The sale of leaded petrol at garage forecourts in the UK would be banned with effect from 1January 2000. (Although a mechanism existed within the European Union whereby member countries could seek derogation for a limited number of years, this course of action was judged to be extremely unlikely in the case of the UK; there was not 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 approved motor racing circuits; its cost to the user was likely to be much more than the current retail price of leaded petrol because of its small batch production. it would however allow 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 as Lead Replacement Gasoline (LRG) fell far short of providing full engine protection and was 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 organisations offering products such as pellets which were merely placed in fuel tanks or fitted in small containers to the fuel line. The form of many advertisements for these products was seen by the Committee to be misleading and none would be considered as contributing towards a viable lead substitute, unless of course, any such manufacturer could produce evidence from a recognised independent laboratory that their product worked.
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 exhaust valve seat recession.
b. The best solution to using unleaded fuel in historic engines remained the engineering option; that is the fitting of hardened seats. Since this option often was impossible because of engine design, a lead substitute clearly has to be sought. (The need to ensure that hardened seats were properly fixed - usually by screwing and pilming - was yet again reiterated because of the potentially catastrophic consequences of a seat coming adrift).
c. Whilst agreeing the universal danger of exhaust valve seat recession, there were many other issues which had to be addressed - such as the vulnerability of some fuel injection systems to increased rates of wear, the octane rating of fuels and the risk of blade corrosion in turbochargers - which meant that a valve recession additive which protected valve seats but caused damage elsewhere could enjoy only limited endorsement.
d. There was still much misinformation at large about the use of leaded and unleaded fuel in historic engines. There was no absolute maxim which said that using unleaded fuels in 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 primarily upon the design and manufacture of the engine and thereafter upon the operating temperatures generated in the region of the exhaust valves. Such temperatures could be affected by the way the vehicle was driven (sustained high r.p.m. created high temperatures but so did hard work at lower r.p.m. - conceivably for example through fitting an overdrive - whilst the effectiveness of the cooling system, the setting of the ignition etc. could influence running temperatures). Thus it was quite possible for two engines ostensibly identical in specification to suffer different results from using unleaded fuel fl~ough differences in use and maintenance. Because of the misinformation, the Committee endorsed the advice in the VSCC publication '~Valve Seat 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 conclusions was that the solution to the known problems of using unleaded fuel in older engines lay in the so-called "after market" provision of fuel additives. That is to say additives not blended in the bulk supply of fuel but available at garages in containers, the contents of which 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 the effectiveness of lead substitute additives could be judged, there was currently no hint that the British Government were proposing to do the same. Therefore it was vital to evolve a test protocol which involved testing by wholly independent and accredited test organisations. 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 be available on garage forecourts by 1 January 2000, that the cost to the user was reasonable 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 phosphorus represented technology from which suitable additives of the type envisaged by the Committee would he selected In order to help the Commiflee, to work effectively towards their goal - to have tested viable product for sale on 1 January 2000- the Federation would work closely with motoring organisations, particularly the AA and RAC. An early task was to acquire an accurate data base showing the numbers of vehicles likely to be affected by the withdrawal of leaded petrol.
d. Lastly the Committee would be examining further the implications of the continued need for light piston engined aircraft to use leaded aviation gasoline (AVGAS) and any relevance 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 the Secretary. Please send a C4 s.a.e. when ordering.
Firstly, before the next meeting on the 20th November, a test protocol will have been formulated for use by the FBHVC Fuels Committee. Secondly, manufacturers of additives will be invited to subject their products to the FBHVC criteria, at their own cost, and thirdly members of the Fuels Committee will be researching the market themselves 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 'Fuel News and Update' that it was noted that although a mechanism existed within the European Union whereby member countries could seek derogation for a limited number of years, this course of action was judged to be extremely unlikely in the case of the United Kingdom Your Fuels Committee are of the opinion that a campaign should be mounted to lobby the British Government to consider or reconsider application to the EU to extend the date for discontinuation of supply of leaded fuel, if only to allow sufficient time for substantive research into an effective and meaningful additive to replace the previous lead content in petrol.
Support on this matter is to be generated through a press release and hopefully through co-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 of products being marketed as lead substitutes. This protocol has since been produced and agreed by the Committee. Quotations will now be sought from suitable, accredited, independent test organisations for undertaking the tests. Anti valve seat recession additive manufacturers will then be invited to submit their products for testing at their expense. Those which pass the test would receive a formal endorsement, or approval, from the Federation. The Committee expects that the successful products will be fuel soluble additives, packaged and sold for adding to petrol tanks when "filling up". Sodium, potassium, and phosphorus additives are already in existence and are expected to be submitted for testing. (Metallic pellets for use in tanks or fuel lines are practically insoluble in petrol and are considered to be ineffective in preventing exhaust valve recession: similarly magnets attached to the outside of fuel lines would have no significant effect on exhaust valve recession). However, should any product, despite being of an unexpected nature pass the tests, it would of course receive the Federation's endorsement. All test products should be accompanied by safety data sheets giving details of the composition of the contents, and details of recommended dose rates and wamings for any engine for which it was known to be unsuitable. The process of testing will move ahead as quickly as possible during 1998. Meanwhile the Committee is collecting a data bank of information about all products which are advertised as lead substitutes or other forms of exhaust valve protection.
In a fuels update (The Leaded/Unleaded Saga) written and published in Spring 1996, 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 some forecourts. As LRG does not contain lead, its use in engines with "soft" valve seats could be disastrous. Although LRG was usually labelled 4 star the British Standard logo for leaded motor luel (BS 4040) was not applicable to LRG pumps. The advice was, and still is, always check that the pump you are about to use carries the BS 4040 marking - whether it is labelled 4 star or not. This already slightly confusing situation has now been made more confusing by a British Standards Institute announcement that the 4 star grading is to be removed from leaded fuel (the logic being that since the demise 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 as Lead 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 this ts that the seasonal volatility requirements have now been made mandatory whereas they were formerly recommendations. In brief, this means that those engines prone to misfiring in hot weather because of high volatility fuel, will now benefit from lower volatility fuel for sale during the summer months. This should help to reduce some of the vapour lock problems encountered.
Finally for this Update, the British Standards Instftution (BSl) has prepared a draft British Standard entitled "Specification for high octane unleaded petrol containing valve seat protection additives (Lead Replacement Petrol)". This is the same LRG/LRP cited above as being unsuitable for use in classic car engines. As already explained, this fuel does not contain lead(and therefore could be produced after the leaded ban takes effect) - but does have additives. The point here is that the LRG/LRP specification requires a minimum level of additive unlikely to be sufficient to afford safe exhaust valve protection. Yet if it is proposed that it be retailed in the future with a BSl specification and called "Lead Replacement Petrol" it would obviously be convincing to classic vehicle users who were unaware of its serious shortcomings; if they used it - it could have potentially catastrophic results. It is the view of the Fuels Committee 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 BSI Technical Committee - (On which the Federation and the Vintage Sports-Car Club are represented by a member of the Federation Fuels Committee).
Widespread concern about the possible adverse side effects of using unleaded petrol in vehicles 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 engineering literature published in the USA and in Britain over the last 70 years or so. The study has covered all aspects of the phenomenon known as valve seat recession, which is said to 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 and 1971 in America, when the introduction of exhaust emissions legislation first resulted in the use of exhaust catalyst systems. These devices are incompatible with leaded petrol, 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 seat recession occurs in cast iron engines operated continuously on unleaded petrol. Engine speeds 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 5 thousandths of an inch per hour of operation have been reported, at an engine speed of 4000 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 associated with a 300 valve seat angle, and lower compressed valve spring load. Sodium cooled valves may help in reducing recession. Hardfacing valve seats with Nimonic (80% nickel, 20% chromium) will reduce recession provided the composition of the hardfacing material is closely controlled.
There is ample evidence that exhaust valve seat recession was a problem in America during the nineteen twenties, being associated with truck and motor coach operation on improved main highways, which developed rapidly during this period. Corrosion and wear resistant valve seat inserts were fitted by many American motor manufacturers as original equipment from about 1930 onwards. A contemporary record (1931) indicated that valve seat recession could be prevented by using leaded petrol. In the UK, valve seat recession was much rarer in the twenties and thirties, because of inadequate road development which did not permit sustained high speed, and the predominance of small low powered cars of relatively poor perforinance. Manufacturers of heavy duty engines and quality cars frequently fitted valve seat inserts as original equipment.
Soluble fuel additives, usually based upon organometallic compounds, can reduce valve seat recession in cast iron engines. At low treat rates compatible with exhaust catalyst operation, valve seat recession can still be a problem. Higher treat rates will give improved protection, but may lead to unwanted side effects. Phosphonis based fuel additives have been shown to offer satisfactory protection against 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 additive for 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 a soluble form in petrol, are necessary to protect exhaust valve seats from wear. Metallic pellets introduced into fuel tanks or lines are practically insoluble in petrol, and thus the negligible metal content of the petrol, which results from temporary contact with the pellets, is too low to protect valve seats from wear. Permanent magnets attached to the outside of fuel lines thro~igh which petrol passes will have no significant effect because hydrocarbon fuels are non-polar.
page 19
It is now known that from the first of January 2000, normal sale of leaded petrol will cease in most of Europe, including the UK, as the result of an EEC directive. Some European countries will apply for a concession to be allowed to sell leaded fuel for a further 4 or 5 years, but the UK Governnient is thought unlikely to apply to the EEC for such an extension.
A concession has been offered by the EEC to allow sales of leaded petrol for minority interest groups. This concession would allow sales up to a maximum of one half of one per cent (0.5%) of total fuel sales. However, it is not known how this small amount of leaded petrol would be made available or distributed. Overall, there will in practice 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 prepared for the supply of other fuels.
A British Standard specification is being drawn up (see page 18, paragraph 2 for full details) for a lead replacement petrol containing valve seat recession additives, but there are concerns about the level of protection which this product will offer. Also, it is not known to what extent this product will be available.
The best solution to the problem of valve seat recession is to fit hardened exhaust valve seat inserts. Millions of vehicles world-wide have successfully used such inserts to permit satisfactory continuous operation with unleaded petrol. Insert materials must possess good hot hardness and corrosion resistance to operate satisfactorily. Inserts made of materials rich in cobalt, tungsten, and chromium have given way in recent years to lower alloy content iron-based sintered powder metallurgy materials. These are of lower cost and the sintered matrix can be infiltrated with copper 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 unleaded petrol. Fitting inserts is a skilled engineering job, but there are companies who specialise in this type of work, and who can demonstrate a successful record of valve seat modifications. The work demands engine dismantling, of course, and in some engine types, the combination of long stroke, small cylinder bore, and fixed head design may prevent the fitting of valve seat inserts.
From January 2000, owners unable or unwilling to fit valve seat inserts to vulnerable engines are likely to consider use of a fuel additive for protection against valve seat recession. Additives have been successfully used in several countries to protect against valve seat recession. Work is currently in hand to establish the level of protection provided by various additives or devices.
By 1999, additive solutions offering a known level of protection will be available. Steps are being taken to ensure that suitable products, to be added during refuelling, will be on sale at petrol stations, when leaded petrol is no longer widely available.
page 20
Reports recently produced or reprinted by the Federation are available from the Secretary at the address at the head of this News Sheet.
These reports are titled:
Preserving the Past for the Future' and Valve Seat Recession'
The first a 15 page document deals with the Historic Vehicle Movement in Britain, a survey of the Patterns of Ownership, Employment and Economic Opportunities for Historic vehicles and is available at a price of �5 plus 39p (first class) 3lp~ (second class) postage in the UK.
The second is a document of 20 pages and 26 pages of tables and figures dealing with the use of Unleaded gasoline in older engines, and costs �5.50 plus 60p (1st class), 45p (second class) postage in the UK.
return to Andy's Austin Seven Page - Unleaded petrol
return to Andy's Austin Seven Page
Get your own Free Home Page
Many thanks to 
for sorting out the problems associated with displaying the above date.
since 1st Jan (27 in 2006, 86 in 2005 (516 total), 115 in 2004, 98 in 2003, 117 in 2002, 99 in 2001, 32 in 2000, 55 in 1999)