The Pianoman 1,535 Posted July 26, 2016 Report Share Posted July 26, 2016 The only criteria for a petrol engine to run on LPG is that the engine needs to be unleaded friendly as there is no lubrication available with LPG. Therein lies the problem running a diesel on it because a diesel needs the 'oilyness' of diesel fuel to provide lubrication to the engine and injector pump. Otherwise a diesel will run perfectly well on LPG but there will be little or no gain in MPG. Cost of fuel may be less. 1 Quote Link to post Share on other sites
DJ360 6,738 Posted July 26, 2016 Report Share Posted July 26, 2016 Later in life I decided that I wouldn't have minded being an airline pilot, but it was too late for me by then. Had an aquaintance who was a pilot for BA. Started out on 707s and finally ended up pushing a 747 around by the time he retired. He got in there via the RAF. Hard for a working class kid to get in there. I think you needed a university education and a private pilot's license before they'd even take you on as a trainee. Over a 30 year 'Career' as a Careers Adviser, I noted how demand for Airline Pilots changed over time. It went from feast to famine on a fairly regular basis, but the overall numbers increased steadily. It follows that as Civil Aviation continues to expand, so will the demand for pilots. The link is to the National Careers Service web site. The National Careers Service is a pretty poor substitute for the 1:1/ Face to Face guidance which it attempts to replace. (All done away with by that nice Mr Gove. ) But I suppose even they can manage to collect the facts competently. https://nationalcareersservice.direct.gov.uk/advice/planning/jobprofiles/Pages/airlinepilot.aspx Col 1 Quote Link to post Share on other sites
DJ360 6,738 Posted July 26, 2016 Report Share Posted July 26, 2016 The only criteria for a petrol engine to run on LPG is that the engine needs to be unleaded friendly as there is no lubrication available with LPG. Therein lies the problem running a diesel on it because a diesel needs the 'oilyness' of diesel fuel to provide lubrication to the engine and injector pump. Otherwise a diesel will run perfectly well on LPG but there will be little or no gain in MPG. Cost of fuel may be less. I'm confused. What does unleaded have to do with lubrication? Lead was added in the form of Tetraethyl Lead to prevent 'knocking' or 'pre ignition' . 'Unleaded' engines overcome this through different ignition timing AIUI. They still rely on oil for cylinder lubrication. Col Quote Link to post Share on other sites
DJ360 6,738 Posted July 26, 2016 Report Share Posted July 26, 2016 I didn't mention any political persuation ! You don't have to Mick. Public policy and the spending of public money are by defintion, political issues. Party positions don't need to be mentioned. I'm not taking sides in this debate though except to say one thing. The value of any system of public transport cannot, IMHO be determined on a simple profit/loss basis. This because much of the real value exists in the 'lubrication' of the whole 'socio economic' environment. In other words, without public transport, the economy is far less efficient. Even the Americans.. arch capitalists.. recognise the need for public funding for some transport. The US government heavily subsidises Rail and Air transport, as well as the Interstate Highway system. Col Quote Link to post Share on other sites
catfan 14,793 Posted July 26, 2016 Report Share Posted July 26, 2016 It could be that gas engined vehicles run much hotter. Quote Link to post Share on other sites
The Pianoman 1,535 Posted July 26, 2016 Report Share Posted July 26, 2016 Tetraethyl Lead was also added to petrol not JUST to prevent knocking but also to prevent excessive wear to valves and valve seats particularly exhaust valves. It is nothing to do with cylinder lubrication. I have a 1971 Rover 2000TC. The exhaust valves are Nimonic 80A (Basically Jet heat) which is fine with unleaded but the valve seats are not suitable with unleaded (they are cast iron in an alloy head) so without the tetra lead in the petrol or a suitable additive I get valve seat recession. This engine IS NOT suitable for LPG conversion as there would be no lubrication for the valve seats. As an aside when I was using that car as my daily transport I got 22,000 miles out of a cylinder head until my tappet clearances disappeared. I just stuck another cylinder head on and off I went again. It is now on its third cylinder head but as these things are no longer as readily available as they were I shall have hardened seats fitted to the cars original head which I have retained and continue carry on as normal. Quote Link to post Share on other sites
DJ360 6,738 Posted July 26, 2016 Report Share Posted July 26, 2016 But it was you who mentioned lubrication! engine needs to be unleaded friendly as there is no lubrication available with LPG. You are correct that the leaded petrol also reduced excessive exhaust valve wear, but as I understand it, the excessive wear was itself caused by the knocking. In effect, the closed valve took a 'hammering' so severe that it 'micro welded' to the seat which caused progressive damage as the valve opened, closed, welded, opened etc. So, cure the knocking and you cure the wear. That's my understanding anyway. But, I could be wrong. (This is a very rare occurrence, but has been known.. ) I'm trying to establish whether the lead provided any 'direct' protection to the valves, in addition to preventing knocking. If it did, I'm wrong, and happy to admit it. Col Quote Link to post Share on other sites
The Pianoman 1,535 Posted July 26, 2016 Report Share Posted July 26, 2016 The valves spin as they seat. As in they don't just open and shut. The tetra lead prevents wear as they seat. Knocking occurs on top of the piston. Quote Link to post Share on other sites
DJ360 6,738 Posted July 26, 2016 Report Share Posted July 26, 2016 Knocking exerts equal force on all components enclosing the combustion chamber. It cannot be otherwise, because the 'knock' or explosion occurs within a gas, and gases under pressure exert equal force at all points. So, whilst much of the noise may be transmitted, or generated by a rattlng of the piston/pin/con rod/ big end assembly, there is also a knock which hits any closed valve and can cause microwelds. Not heard about the spinning valves, but I'd be interested to know what mechanism causes it. Quote Link to post Share on other sites
DJ360 6,738 Posted July 26, 2016 Report Share Posted July 26, 2016 Old, but informative. Lead and Lead Substitutes - The FactsThe lead in petrol is known as Tetra Ethyl Lead (TEL) or Tetra Methyl Lead (TML) and was originally developedin the 1920’s by a joint venture between General Motors and Standard Oil (now known as Exxon - Esso inEurope).The original reasons for adding lead in petrol was not to prevent Valve Seat Recession (VSR) but to raise theoctane of the petrol. This octane gain allowed engine designers to increase compression ratios and hencepower without any dangers of engine damage. These more modern high compression engines were now ableto run at higher revolutions without experiencing knocking or pinking.Before the development and introduction of lead to fuel, engines were successfully run without lead, albeitat low compression ratios which gave low power and low fuel economy. As engines of the period were nothighly stressed valve seat recession did not appear to be a major problem.The world-wide use of lead and the discovery that lead compounds formed during the combustion of leadalkyls prevented valve seat recession (VSR) by forming thin layers of lead oxides and sulphates on criticalvalve/seat interfaces was a bonus. This led to the world-wide practice of machining valve seats directly intothe cast iron head.Problems occur with these engines once lead is removed from the petrol and the protection is lost, which iswhen recession starts. The combustion of the petrol in the cyliders generates extreme heat on the exhaustvalve seats as the burnt gases pass through. Each time the valve is hammered open and shut, it momentarilywelds itself to the valve seat at the hottest points. This localised welding of the exhaust valves to their seatstends to be followed by ‘tearing out’ of small fragments of metal from the seat, ie. the valve sticks to its seatand as it is lifted off by the valve gear, it ‘rips’ away from its micro-welded condition. Small particles of valveseat material are thus embedded in the valve face and are likely to be further oxidised forming ‘warts’ of hardiron oxide.The continuous repeated impact of these hard materials on the soft valve seat causes further damage and,if the valve seat rotates, a degree of ‘grinding in’ will also occur. From this moment on, valve seat wear is bothrapid and inexplorable leading to engine failure as the valve and seats burn away.Other than the actual material from which the valve seat is made, the next most important factor in determiningwhether VSR will take place, is the driving condition. All the technical data produced indicates that enginespeed and load are significant factors. VSR has been found to be an exponential function of speed but therelationship with engine load is believed to also be a factor.The actual occurrence of VSR is related to seat temperature which increases with speed and load 9eg.acceleration, climbing hills, motorway driving and towing).The demise of lead from petrol which is set for 1st January 2000, (but will probably become more and moredifficult to find from mid 1999), will cause premature failure to those engines which have ‘soft’ valve seatswhen used under modern road conditions. Competition use, continental touring and high speed driving willexacerbate the problem.Development and TestingIt is widely accepted that lead is the best material for VSR protection and octane response when used at theUK maximum permitted treatment of 150 mg/ltr. Typically however, the current BS 4040 4 star leaded fuel hasa concentration in the range of 80-120 mg/ltr or a minimum lead content of 50 mg/ltr. So what are the optionsfor owners of pre 1990 and classic cars and how are these verified?Additive ChemistryThe move to unleaded petrol around the world stimulated the development of additives to prevent VSR. Theresearch has led to the availability of several technologies all of which are based on metallic salts:SodiumPotassiumPhosphorusManganeseMetal PelletsSodiumThis type of product was one of the initial materials tested in the US when Pb levels in leaded gasoline werereduced to 26mg per litre. Because of these moves a programme was run jointly by the US EnvironmentalProtection Agency (EPA) and the US Department of Agriculture (USDA) on two basic chemistries, Sodium beingone.Testing in various engines showed that at the recommended treatment some degree of protection againstVSR was provided. However, at four times the recommended treatment VSR was eliminated. A negative findingduring the testing was that oil black deposits were found in the inlet tracks.Sodium is also known to form low melting point eutectics in very hot regions. This is known to result in erosionproblems, particularly with turbochargers. As a consequence of these findings, Sodium has been withdrawnfrom the list of chemistries being considered for use in Lead Replacement Petrol (LRP).PhosphorousThis material was also included in the original EPA/USDA study. The treatment was tested at about doublethe recommended treatment and reduced VSR although a wear rate value of 0.022ins/100 hours still signifiesfuture problems.Additionally, this additive caused deposits to form in the inlet valve area of the engine to the extent that onevalve was unable to close fully and was starting to burn at the test completion - 200 hours.In these tests the fuel treatments (Sodium/Phosphorous) were found to contaminate the crankcase oil. Suchcontamination has a deleterious effect on the oil normally causing it to thicken. Phosphorous is also knownto be a severe poison for catalytic converters which could cause additional problems if mis-applied whenfilling a car with petrol.PotassiumWith the demise of Sodium, Potassium has become its natural replacement since test work has shown thatPotassium will provide similar levels of VSR protection to Sodium. There is a large body of evidence whichdemonstrates that potassium in the presence of lead alkyls or associated halogen chemistry scavengers leadsto inlet valve burning. While leaded fuel is still available any mis-fuelling and the use of after treatmentscontaining this type of product will remain a concern.Potassium as a fuel additive has been previously used, not as a VSR treatment but as a fuel performanceenhancer. Many motorists may possibly recall the major problems which many cars, and the models of onemajor car producer in particular, encountered when their cars were run on a well known brand of petrol.Metal PelletsThere have been claims over many years that using metal pellets either in the fuel tank or fuel lines reducesVSR. One such device which uses tin pellets was tested and reported in a Classic Car magazine in 1989/90period.The published results indicated that VSR protection was not achieved which is hardly surprising since thesolubility of metallic tin or lead in petrol is very low, in the order of one part in 10 million (VSCC !((!). This isin contrast to the 30-50ppm of lead concentration generally considered as the minimum for protection.ManganeseManganese in the form of Methylcyclopentadienyl Tricabonyl (MMT) has been used in virtually all Canadianunleaded petrol without any problems for well over 20 years. Its original use was for the self same reasonsthat lead was first used - namely to increase octane.Like the lead it can replace, MMT also protects soft valve seats from recession so it can be said that MMT isthe closest alternative to lead.With MMT being available since the early 1970’s it has been subjected to the most vigorous testing of any fueladditive in history with extensive test data to support its important feature:Helps reduce intake valve deposits in conjunction with fuel detergents.Does not contribute to valve stick either alone or in combination with detergents.Completely safe in turbo-charged engines.No adverse engine deposits formed.Compatible with all construction materials including plastics and elastomers.Insoluble in water preventing any interaction problems.MMT has gained US EPA Waiver for use in unleaded gasoline along with Pipeline distribution approval dueto its non-surfactant properties.Toxicity of VSR MaterialsAny product which is added to fuel to be burnt in engines and expelled through the exhaust will have an effecton emissions. Of all the treatment chemicals examined, only MMT has been subject to in-depth studies. Thesehave shown that no problems are posed in respect of emissions, hence the approval of US EPA.For catalytically equipped vehicles statistically significant reductions in carbon monoxide (CO) and oxides ofnitrogen (NOx) have been observed.Manganese is a naturally ocurring element found in soil, water, food and all living organisms. In the combustionprocess the Manganese forms Manganese Oxide (Mn3 O4) and only about 0.1% Manganese is emitted fromthe exhaust. Very high concentrations of Manganese (30,000 mg/m3) can have side effects (Parkinson likesymptoms) but a recent study conducted by Research Triangle Institute in Toronto, Canada, showed that nocitizens of that city are even exposed to the safe recognised scientific level which is set at 0.025μg/m3.Little or no toxicology data is available for other metallic systems but it is considered that phosphorouscompounds can lead to highly toxic emissions similar in nature to organo-phosphates which are highly toxicie. Gulf war syndrome and the use of sheep dip on farms.So how do we prevent Valve Seat Recession in most pre-1990 and Classic Cars?It depends on how long you wish your car engine to last. You can retard the ignition and lose power and thendrive your car at very low speeds; never accelerate quickly, slow down when climbing a hill and alwaysdecelerate immediately the engine starts to ‘pink’.Your engine may last several years more, but it is a potential risk. Speed and higher engine temperatures willseverely damage the valve seats when running on unleaded petrol.Can I have the soft seats replaced with hardened valve seats?It is possible to replace valve seats in aluminium cylinder heads by machining out the old soft seats andreplacing them with hardened seats. However, with cast iron heads it is sometimes impossible or excessivelyexpensive to do so. The cost for valve seat replacement in aluminium or cast iron cylinder heads can be severalhundred pounds for a 4 cylinder engine and 2, 3 or 4 times that amount for V6’s, V8’s or V12 engines.Even then you will still have to retrd the ignition to prevent pinking because 4 star leaded petrol is 97 octanewhereas premium unleaded is only 95 octane. Consequently you will lose power unless you use an OctaneBooster. If you retard the ignition by only 2 degrees you could lose in the region of 5% power at the wheels -more degrees lose even more power. Remember as engines build up deposits with use, there is a requirementfor increased octane.Will the oil companies offer a lead substitute petrol on their forecourts?Prior to and after January 2000 some petrol companies may provide a lead substitute fuel at selected fillingstations. (One has already stated they won’t and older cars should be driven off the road). It is likely to beexpensive due to the low demand and the protection given to valve seats may be lower than required for highengine load conditions. The lead substitute content of the fuel is expected to be low to prevent accidentalcross contamination of fuels at filling stations as some types of lead substitute fuels will severely damagethe modern catalytic converter equipped cars or to avoid any problems from sticking inlet valves.Are lead substitute fuel additives the answer?In many countries where leaded petrol is banned, bottled lead substitutes are on sale at filling stations. Anumber of alternative lead substitute fuel treatments have been developed for this application but at thepresent time these have potential drawbacks.Millers VSP Plus, Lead Substitute and Octane Booster - Endorsed by the FB HVCMillers VSP Plus is different, being based on proven manganese additive technology with US EnvironmentalProtection Agency (EPA) waiver for unleaded gasoline.Millers VSP Plus treatment utilises MMT additive chemistry which mimics the properties provided by lead. Itgives a protective lubricant film on valve faces and seats while also increasing octane by 2-3 numbers,something which other treatments have difficulty in acheiving in a single treatment. Col Quote Link to post Share on other sites
Merthyr Imp 729 Posted July 26, 2016 Report Share Posted July 26, 2016 As the kids say these days - 'Too much information!' 3 Quote Link to post Share on other sites
DJ360 6,738 Posted July 27, 2016 Report Share Posted July 27, 2016 Nobody made you read it! Col 1 Quote Link to post Share on other sites
Merthyr Imp 729 Posted July 27, 2016 Report Share Posted July 27, 2016 I was afraid questions may have been asked later. 2 Quote Link to post Share on other sites
Guest Posted July 27, 2016 Report Share Posted July 27, 2016 I hope Catfan knew all that...tearing around in his reknown! Quote Link to post Share on other sites
catfan 14,793 Posted July 27, 2016 Report Share Posted July 27, 2016 We only drove em Ian, we didn't know or want to know what made em tick ! Quote Link to post Share on other sites
DJ360 6,738 Posted July 27, 2016 Report Share Posted July 27, 2016 But it was you who mentioned lubrication! You are correct that the leaded petrol also reduced excessive exhaust valve wear, but as I understand it, the excessive wear was itself caused by the knocking. In effect, the closed valve took a 'hammering' so severe that it 'micro welded' to the seat which caused progressive damage as the valve opened, closed, welded, opened etc. So, cure the knocking and you cure the wear. That's my understanding anyway. But, I could be wrong. (This is a very rare occurrence, but has been known.. ) I'm trying to establish whether the lead provided any 'direct' protection to the valves, in addition to preventing knocking. If it did, I'm wrong, and happy to admit it. Col Comes to summat when you are quoting yourself. But I assured Pianoman that I would admit it if I was wrong. It seems I was wrong. Valves do indeed turn. From what I can gather it is not a deliberate thing but a function of the forces involved etc. But , nothing is done to stop it. Also seems the lead in petrol does afford some sort of lubrication/protection to 'soft' valve seats, but not needed for anything much other than old direct cut seats in Iron heads. I'm going into the garden to eat worms.... He said... Graciously... Col 1 Quote Link to post Share on other sites
The Pianoman 1,535 Posted July 27, 2016 Report Share Posted July 27, 2016 Sorry I didn't get back to this as a result of doing something else. As I understand it the valve turns as it moves its length of travel with the opening and closing movement of the valve spring. A coil spring is a torsion bar coiled up and as a coil spring is compressed the wire it is made of also twists. I am saying no more on the subject purely because that is about as far as I went in my research to find out which car will and will not run on unleaded petrol and why. Quote Link to post Share on other sites
Enigma. 1,533 Posted August 17, 2016 Report Share Posted August 17, 2016 Highbury Road , Bulwell 1963 Looking down towards Bulwell Market Place  6 Quote Link to post Share on other sites
FLY2 10,109 Posted August 18, 2016 Report Share Posted August 18, 2016 Is the bloke to the right of the bus with his back to the camera having a pee up against the wall? Quote Link to post Share on other sites
Merthyr Imp 729 Posted August 20, 2016 Report Share Posted August 20, 2016 Maybe he's spying out a good place to build a supermarket. Â Here's a thought for DJ360 if he sees this - do you think that's one of Eric Shepherd's cars behind the trolleybus? Quote Link to post Share on other sites
DJ360 6,738 Posted September 2, 2016 Report Share Posted September 2, 2016 Just looking again at the bloke to the right of the bus. I wondered what he was standing on, but close inspection appears to show he was standing on one of the large 'coping' stones from the top of the wall in front of him. Somehow a couple of stones have been dislodged and he's standing on one to look through the gap. Could be looking at the railway I suppose.  I don't remember that gap. Is the wall still there since the area was re-developed for access to Tesco etc? I can't recall, but if the wall is still there it would be interesting for someone to have a look when passiing to see if there are signs of repair.  Edit: Hve a look at this Google Maps image: https://www.google.co.uk/maps/place/Highbury+Rd,+Nottingham+NG6+9AT/@53.0002226,-1.1953327,3a,75y,352.59h,82.82t/data=!3m7!1e1!3m5!1sDFnk53oAAk-Wnr3iYJjKoQ!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3DDFnk53oAAk-Wnr3iYJjKoQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D215.85739%26pitch%3D0!7i13312!8i6656!4m5!3m4!1s0x4879c1d2c17529f3:0x446124c3377c74fd!8m2!3d52.9956118!4d-1.1913038 Seems to show the same wall with a more recent repair from about the same point.  I'm confused though. He seems to be at Spring Lane, so the railway would be behind him between Spring Lane and Church Lane..... or summat..  And yes MI, I reckon that car could well have been one of Eric's.   On that subject, I recall the young science teacher Steele,(the one with the albino streak in his hair) had a mini. (Mini Van I think) Somebody had a Standard summat or other (Standard 8?) and Bert Dodd had a blue BSA Bantam.  Col Quote Link to post Share on other sites
Merthyr Imp 729 Posted September 2, 2016 Report Share Posted September 2, 2016 DJ360 - yes, the man is standing on the corner shown in the Google Maps image. My first thought was also that he might be trainspotting, then I realised the railway is below where the photographer is standing.  I remember Eric Shepherd did have a car at least similar to that one - a Wolseley? Austin? (others will know). In my earlier days at High Pavement (1961/62) I used to get the no. 6 bus to school from the stop on Hucknall Road near to Haydn Road, and if Eric saw High Pavement boys waiting there he would usually stop and give us a lift. It was sometimes that one or more usually his little old Baby Austin (ANG732???).  The name Steele seems vaguely familiar but I can't bring him to mind. I think it was Bloom (John?) who had a Standard 8. The only other masters' car I remember is Ray Caulton's Standard estate which had all the foreign 'Tiger in Your Tank' stickers on it.   Quote Link to post Share on other sites
DJ360 6,738 Posted September 3, 2016 Report Share Posted September 3, 2016 You got me there MI.  I recall that the Standard car had the little 'two flag' badge somewhere on it. It was greyish. That's al I recall.  Bloom. Yes, Curly haired chap I think. Didn't he teach Physics?  This memory loss is a bugger... Quote Link to post Share on other sites
Bubblewrap 3,815 Posted September 3, 2016 Report Share Posted September 3, 2016 #4119 I think he appears to be standing on something, but not having a "Jimmy" There appears to be some bricks missing off the top of the wall and our man looks like he is standing on them? Quote Link to post Share on other sites
FLY2 10,109 Posted September 3, 2016 Report Share Posted September 3, 2016 The chap is looking into what is now the car park behind Wilkos. The little road to the right leads to the Argos car park and ultimately Tescos car park. The railway / tram tracks ar behind the man. Ill check on the brickwork next week. Quote Link to post Share on other sites
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