| Author | Message | ||
     Bob UK Unregistered guest Posted From: 172.185.221.241 |
I need technical help. Petrol in the uK is £0.77 per litre and rising also there is talk of raising revenue from gas guzzlers, hopefully older cars will be exempt. Or LPG will be exempt. LPG is £0.39 per litre and the Chancellor is holding that price for 5 years. The equipment for the conversion is readily available but no one seem to know what to fit to the Shadow. I have read that a twin stage vapouriser is best and a 4 hole tank complete with valves. I am worried about blow backs I have heard of a merc with a big dent in the bonnet --- Anybody know the details. Merry Christmass | ||
| David Gore Moderator Username: david_gore Post Number: 144 Registered: 4-2003 |
Hi Bob, We have a LPG Shadow in the Club, will track it down and put you in contact with the owner so you can get more info. Dare I say; Australia has been a leader in LPG conversions for many years and has the system and installation practice pretty well sorted out. | ||
| Bill Coburn Prolific User Username: bill_coburn Post Number: 69 Registered: 4-2003 |
Bob/ One of our blokes on Canberra has a gassed Shadow. You might like to correspond with him at peter.smith@dest.gov.au. The only distraction as far as I am aware is a need to prop the back up a bit to cope with the extra weight of the tank. | ||
| Bob Unregistered guest Posted From: 172.186.138.166 |
Cheers me dears. Good point about weight. The extra weight is no problem because my rear springs need replacing so I will take this into account with my spring supplier. I will contact Peter Smith. The Queen's Rolls-Royce are LPG and they run very well on gas. They were coverted by RR. | ||
| Mark Tomlinson Experienced User Username: mark_tomlinson Post Number: 7 Registered: 9-2003 |
Hi Bob, my 66 shadow is full gas with the petrol tank removed (for sale if anyone needs one)it runs like a dream and only pings slightly under full power up hills and the slightly higher running temperature was fixed by putting a second fan between the air conditioner cooling system and the radiator. I would highly recomend anyone thinking about the switch to do so. | ||
| Bob Unregistered guest Posted From: 195.93.33.11 |
Mark Do you still use the carbs or have you fitted a special LPG carb how do you start on gas. | ||
| Mark Tomlinson Experienced User Username: mark_tomlinson Post Number: 8 Registered: 9-2003 |
The carbs have been removed and a gas system put in place. Starting the car is simply turning the key without priming and it turns over for about 5 seconds then it idles perfectly. | ||
| BOB Unregistered guest Posted From: 172.187.54.69 |
Sounds good enough for me. Have you got more details such as makers name and serial numbers. What about the throttle. | ||
| William H. Trovinger II Prolific User Username: bill_trovinger Post Number: 45 Registered: 8-2003 |
Bob; There was an article in the RREC Bulletin, Issue 240 May/June 2000, pages 66 and 67 that might help you if you have not seen it. Regards, Bill | ||
| BOB UK Unregistered guest Posted From: 172.189.140.243 |
Bill, I am not a member of RREC so I couldn't access the info. If it not going to upset RREC property rights would it be possible for someone to post the info on this site. | ||
| William H. Trovinger II Prolific User Username: bill_trovinger Post Number: 46 Registered: 8-2003 |
Bob; As per your wish here is the article from RREC Bulletin Issue 240 May/June 2000. With all credit given and as this is done for no reason of profit I hope the RREC does not object! Due to file size I could not upload as attachment so instead the following is a cut and paste: The Advantages of LPG from Krzys Osuch OVER recent months I have read with interest the various articles and letters written in the magazine regarding the use of unleaded fuel in our cars and have taken some time to decide what to do regarding the effect of fuel changes on my own Silver Shadow II (SRH36478). In the end I decided to convert my vehicle to run on LPG. My decision to do this was based on the fact that approximately two years ago I had my Volvo 850 estate converted to LPG in Poland. Being of Polish origin and having business interests in that country I had the vehicle converted there (at a fraction of the UK price, yet the equipment was identical to that being offered there). My experience of LPG (easier starting, negligible wear on spark plugs, clean engine oil at oil change intervals, little difference in the available power) persuaded me to look at the possibility of converting my Rolls-Royce to this fuel. After several enquiries at several UK garages the lowest price quoted was £1200 for the conversion. To me, like most of us, my Rolls-Royce is a passion, however the price demanded for such a conversion seemed a little high; other options had to be explored. I then made a telephone call to the installer who converted my Volvo in Poland and asked him if his garage could convert the Rolls-Royce. After taking details of my vehicle he went to calculate the required system and the financial damage. My phone call was returned some days later and I was told that the work could be carried out for the princely sum of £350 (the equivalent in Polish currency)! The decision had been made. To undertake such a long journey in a vehicle twenty years old took some preparation. Green cards had to be arranged, which was easy, but also vehicle recovery was a must. I have been a member of the RAC for many years and, using their breakdown assistance service for all my vehicles in the UK and the Volvo for overseas. It was only when I enquired about taking the Rolls-Royce that I learned that their policy did not cover vehicles outside the EU (I was told that 'Europe' does stretch to the Ural Mountains in Russia!) and were apparently unable to help. However, the AA covered me for a week at £50! I arranged to go to Poland in September 1999 and took the usual spares such as top and bottom hoses, fan belts, fuel pumps, spare engine oil and TQF fluid and distributor, as well as a Polish pal of mine who is also a motor engineer (just in case). It was the first time for many months that the vehicle had a good run outside town. Driving down the A1 towards London I noticed in the rear view mirror that on acceleration and deceleration there was some blue smoke showing from the exhaust pipe and I had visions of having to stop and keep topping up with engine oil. However, on arriving at Dover and checking the oil level I found that only approximately half a pint had been used in 142 miles. By the time we arrived in Calais it was getting dark. We fuelled and began our next leg to Poland through the night. We drove the route Calais, Ghent, Brussels, Liege, Achen, Cologne, Frankfurt (just before Frankfurt we took a side road at Limburg and drove across country to just north of Giessen - a saving of some sixty miles), then on through Eisenach, Gotha, Jena, Gera, Chemnitz and Dresden, arriving at the Polish-German border of Zgorzelec (Gorlitz) at lunch time. Along the route we fuelled twice and changed drivers. The car was driven at a steady 130kph (80 mph). It returned 18.23 mpg and used only just over one pint of oil. By the time we got to Cologne all town residues were blown out through the exhaust and no smoke showed on acceleration or deceleration. It just shows that our cars do really need to be used. On reaching the Polish-German border I had to show my vehicle documents. The German guards began laughing, nodding their heads approvingly and looking around the car. Their comments were" Ah! Rolls-Royce." I just smiled as I was in a bit of a hurry and just made the comment: "Not Rolls-Royce but Audi!" This caused more laughter, my papers were given back and I moved ten yards to the Polish side of the border. Again a similar occurence happened, except that I distinctly felt there was going to be a real interrogation, with all my belongings being checked. This would be time-consuming and inconvenient. As luck would have it a German was caught trying to smuggle several cases of whisky through the border, so all interest was transferred to him! I was told to move on. Driving in Poland became interesting, with the local youths overtaking, slowing down to have a look at what the vehicle was, confused looks on their faces as they read the twin RR on the radiator, then with laughter moving on faster. In Poland the speed limit is 90kph on the side roads and this limit is vigorously upheld by the local constabulary with on the spot fines. Digressing a little, a few years ago I was witness to a German having to pay on the spot fines five times in a 2km stretch. However, he was a fool trying to prove how wonderfully powerful his Mercedes was as the fine is up to approximately £100 each time you are stopped for speeding. I arrived at my hotel in Wroclaw by early afternoon and after a welcome shower I visited some friends. Leaving the car outside their house soon made it the celebrity in the street, with most of the children and fathers having a look at it. (In fact the fathers took it upon themselves to guard the car against their offspring's fingers.) Ah, such respect! The next morning I arrived at the garage at 8 am, already a hive of activity converting other vehicles and adjusting settings. There was even a Volvo 850 from Russia being tuned. As I drove in there fell a deathly hush. All the clients and some of the mechanics could not believe their eyes as very few people had been forewarned of my arrival. I was being treated as a celebrity. Eventually my turn arrived. I put on my overalls and began to clear the boot area of my luggage. The first action was to find a suitable size of tank which would fit into the boot without taking up too much room. A 62-litre cylindrical tank was chosen as it fitted neatly between the wheel arches and did not protrude beyond the top lip of the boot area. (My Volvo has a wheel tank, which neatly hides away. Unfortunately this is not possible in the Rolls-Royce as the spare wheel carrier is hung from below the boot externally.) Also the stillage for the tank is usually fixed to the vehicle floor but due to the position of the fuel tank and the rear subframe mountings in the Rolls-Royce a bar had to be made which went through the rear arches and was then screwed tight. This left only enough space for the pipework to go through the floor. One pipe goes to the front of the car, delivering the fuer to the regulator, while the other goes to the rear of the car to the filler position. I decided not to cut through the rear wing and install the filler in the wing but to put it on to a bracket attached to the bumper irons. It fits neatly there and is unobtrusive. While the 'tank boys' were hard at it in the boot area a second team was working out where to instal the regulator and the best position for letting the gas pass into the manifolds to mix with air. It was decided that the regulator would have to be mounted on the suspension leg, it needs to be mounted vertically and in the plane of travel. The only other place would have been in the wheel arch in the front wing. I preferred to have the regulator positioned in the engine compartment as I believe it to be the safer place and also one needs to pre-heat the gas, thus although hot water from the vehicle cooling system is brought to the regulator, the heat from the engine also helps. A rather neat job was beginning to emerge, with just a single rubber pipe emerging from the gas regulator, which then splits up with further rubber pipes connecting to the mixture manifolds. There are mixture. control screws at three points, one for general adjustment and then one for each manifold. One can really finely tune the fuel mixture in this way. The only real problem occurred when the electric fuel pump needed to be switched off so that, when running on gas, petrol was not being delivered to the carburettors. A small relay was installed into the circuit to overcome this. The last problem was where to locate the control switch, which changes the vehicle from running on petrol to gas and vice versa. Normally it would go into the passenger compartment, but as time was moving on and I did not want to take off the dash roll to see where a convenient place would be, I decided to install it in the engine compartment, with a view that at a later date I would move it to a more suitable position. However, I think that I will leave it there as it acts as an extra security measure - who would imagine that one needs to open the bonnet and manually switch over in a Rolls-Royce? But what thief would think that a Rolls-Royce is gas powered? The only drawback is that from cold the vehicle will not start on gas. You have to start the vehicle on petrol then wait until the engine warms up a little. At this point switch over the electronic brain to a midway position while revving up the engine to empty the carburettor pots and then, at just the moment when the engine is about to die, switch over fully to gas. It is a small inconvenience to pay when one considers the economics of running the vehicle on gas. On successful conversion the mechanics enjoyed several of my cigars and a few bottles of whisky were downed by us all in celebration of this successful job. In return I was given a pair of white gloves which were to be used when filling the car with gas or adjusting the mixtures! I have now had time to use the vehicle in various conditions. Firstly I drove back from Poland along the German autobahns, cruising at 80 mph (130kph), returning 12.28 mpg on LPG. Around town on petrol the car returns around 12 mph, but on LPG it returns 10.18. This is wonderful news as most of my driving is in town and LPG costs 39.9p per litre. While in Poland I visited various clients and suppliers, adding about 1000 miles in a week. The savings I made on the fuel costs during that week paid for the installation. There is little difference in the power/performance of the vehicle and the number of petrol stations distributing LPG in the UK is growing daily. On returning to the UK the gas regulator had been 'run in' and required a small adjustment. I therefore made a visit to my local MOT station, where the mechanics were only too pleased to check out the emissions for me, letting me adjust the gas side myself. The emissions on petrol are 2.5%, while on LPG they are below 0.25%! This in itself is interesting as I believe that in the near future vehicles will have road fund licences charged according to the emissions. If this is the case, then this conversion will again be of great benefit to me. Should anyone reading this wish to discuss my experiences and the tangible benefits that I have gained by this conversion, I would be very happy to discuss them. I can be reached by telephone on +44 (0)1234 360318 in the evenings or bye-mail abaco@btinternet.com. I will also be at the Annual Rally in Towcester. The car registration number is WP0214T. Regards, Bill | ||
| Bob UK Unregistered guest Posted From: 172.188.19.65 |
Updated LPG. I have contacted a lad in Wales and he has given me an estimate of £750 for a kit. I don't fancy the drive to Poland ! The cab needles have to be held up so that when running on gas the needles don't run dry. A gas tank and a small 3 gallon petrol tank will fit in place of the 23 gallon std one. The petrol tank is extra and I have found a 16 litre marine one second hand for £10. The gas tank has 4 holes and valves in a gas tight box which has a down ward pointing vent pipe. one of the valves has a device that detects too much gas been delivered --- as in a broken pipe or leak. and shuts down. One pipe to vent one to the filler which now goes under the flap. and one to the front of the car. plus a wiring loom to a 3 position switch --gas-- off-- and petrol. the switch has LEDs to show gas content. another loom goes to a solenoid valve under the bonnet. The feed pipe goes to the solenoid valve. a pipe goes from the solenoid to a 2 stage vapouriser. coolant is circulated around the vapouriser to keep the vapouriser from freezing due to the expansion of a gas. The vapouriser does not need to be warm just not cold. -- evidently. If starting in cold weather is differcult a hot water bottle resting on the vapouriser gets its going. The vapouriser has to be mounted in the correct orinetation to the movement of the car else G force effects the mixture. A pipe goes to a Y piece with a restrictor. The 2 pipes from the Y piece go to 2 mixer which are fitted inside the U bends as close as possible to the carbs. The mixers are what you could call a gas choke. The same pipe that delivers the gas also senses the vacuum in carb intake which moves the vapouriser diaphgram which opens the gas valve. same as a demand valve that Scuba divers use. The needles are held up by vacuum via a soleniod valve which is connect to the lpg switch. I think there are some relays because the switch is small. However because I intend to run on gas only I will forgo the kit for holding the needles up and either remove them or place a short lenght of copper tube over them so the needle and pistons stay up. I reckon I can remove the tubes quicker than I change a wheel in case I have to revert to petrol. Before I can order the kit the bloke from Wales wants measurements of some bits. He is designing the kit for 250 BHP not engine capacity and has said that there no such thing as a unversal kit . An extra maybe the ignition. LPG likes proper sparks where as petrol is less demanding. I may have to go electronic by fitting a kit. Then I can have dual advance one for gas and one for petrol. And super duper plug leads--- Magnicor seems to be all the rage. My leads are 30 years old. Dodgy sparks is the usual reasons for blow backs. Also the ignition is run at 12BTDC which is one reason for not running on petrol the car will pink bad, unless I have the dual advance. I will have retard the ignition as well as taking the tubes of the carbs to run on petrol--- no problem. Evidently the Shadow is an easy car to convert and they run even better on gas. 1.5% less power because of the mixers in the air flow and around 11 mpg instead of 13 mpg but when cruising at 60mph there is no difference and high teens is normal and one Bentley T1 owner I spoke got just about 20 mpg on gas at 50 mph on the motorway over a 100 mile run. which because gas is half the cost of petrol in the UK means 30 mpg plus average in comparision with petrol. Better than a Ford Escort. The only annoying thing is that I should have converted the car when I got it 14 years ago and saved all that wonga. Hopefully I will have the bespoke kit within a month and can start fitting it I reckon 30 hours for a proper job. | ||
| William H. Trovinger II Prolific User Username: bill_trovinger Post Number: 48 Registered: 8-2003 |
Bob; I know I will sound dumb asking this but I have little knowledge of LPG in autos. I see no mention of a gauge for the tank. I know the propane tanks for my barbie have gauges that are about as good as our last president's sworn word. I know that our local power company (5 years ago or so) ran some vehicles on propane but they limit them to the city area as one problem they had was running out of gas. It seems that air temperature and humidity played tricks on the gauges. Have they found a better gauge? Regards, Bill | ||
| Bob Unregistered guest Posted From: 172.185.133.216 |
Bill, Good point. I did hear of a way of connecting the exsisting gauge to the gas tank. Which appears not to work well. Because it appears that the gas tank sensors works in stages of full 3/4 1/2 1/4 and fumes with corresponding LED lights. The LED lights are in the car. There is also a contents gauge on the tank. I guess that a less than careful eye on gas use could lead to a situation were I am low on gas and too far to a gas pump because I forget when the 1/4 LED came on and now the fumes LED is on. Hence the petrol capability--- and a AA card. However if the petrol tank is removed I can fit a 140 litre tank which would be 80% net. approx 125 litres. because petrol is so expensive I have been buying 30 litres a time. So with half price fuel I can buy 60 litres for the same money and travel twice as far. I have also been told that the petrol system will have to be used once a month to keep it working. In the UK there are gas pumps within a 50 mile radius of anywhere. My nearest is 1 mile 40pence a litre (24/7) and 2 miles 35pence. 25 miles 30 pence. Also available are 10 litre gas bottles that can be emptied into the gas tank. | ||
| David Gore Moderator Username: david_gore Post Number: 150 Registered: 4-2003 |
Hi Bob, My apologies for being so slow in coming up with more information on LPG conversions however you might find some interesting information from the following links: http://rroc.org.au/library/lpg_je.html http://www.gasresearch.com.au/productsilverseries.html http://www.gogas.com.au/site/page/15/lang/en http://www.mvria.nsw.gov.au/motorists/mot_sel_lpg.htm http://www.megagas.com.au/products.htm http://www.rta.nsw.gov.au/registration/downloads/vehicinfor_dl1.html - look for VSI 14 LPG fuelled vehicles. | ||
| whunter Prolific User Username: whunter Post Number: 40 Registered: 10-2003 |
Thank you David I will try to dig up information on CNG (Compressed Natural Gas). There are some commercial fleets in the USA running CNG instead of LPG, the cost is slightly lower from what I have seen. The possible bad of CNG is that the tank pressure is 3000 to 6000 psi average. Have agreat day. whunter | ||
| David Gore Moderator Username: david_gore Post Number: 153 Registered: 4-2003 |
We are also using CNG for commercial vehicles mainly bus applications where the cost of the gas compressor installation needed to fill the fuel tanks can be amortised over a large number of vehicles. Commercial CNG filling stations are few and far between for other users. The Government has not taxed LPG in the past on environmental grounds however the last Budget included taxes on alternative fuels with the consequence that conversions have stopped almost completely and our major manufacturer of LPG components has gone into voluntary administration. The tax means the cost of conversion will not be recovered over the life of the vehicle for average users. However, our wise and most learned government is going to legislate the use of ethanol blend fuels despite the problems for owners of older vehicles and marine users - of course there will be no price reduction to compensate for the increased fuel consumption caused by ethanol blend fuel due to its lower energy content. | ||
| whunter Prolific User Username: whunter Post Number: 41 Registered: 10-2003 |
Hello David If it where not the government; I would be waiting for the punch line to that joke. Sorry, we have basically the same thing happening here. First they encourage you to use it; then they PUNISH you for it. A radio talk show in Detroit (USA) uses the following to start and end their show each day: I Love my country, but Fear my Government. I find it most appropriate in situations like LPG and CNG conversion. Have a great day. whunter | ||
| William H. Trovinger II Prolific User Username: bill_trovinger Post Number: 49 Registered: 8-2003 |
David; Here in the States we pay more for ethanol blend fuels currently about 10 cents per gallon, that is at 10%. They are talking about raising it to 20% ethanol (I guess ADM sales are down)which would raise the cost another 10 cents per gallon. Oh, yes that is cost not retail. Of course no one has said how much more this will increase our fuel consumption. Regards, Bill | ||
| Bob Uk Unregistered guest Posted From: 172.189.105.59 |
natural gas unfortunately does not go liquid as easily as PG hence LPG. In the UK CNG is used in vehicles but only in fleets the problem is the very powerful compressor required refuel in a resonable time. It was tried for private cars but the equipement took 1 hr to fill the tank or even longer is you had one installed at home on the gas main. Also the government decided that tax should be paid so the gas companies put different meters in which were charged at a much higher --- 5 times the price. Of course it quickly fell apart and what could have been didn't. That govs for you. Dave Emailed me about tax and LPG and the dangers thereof. However the motorist in the UK is gradually getting what we what. 26 million of us is a big vote plus the other 30 million are sitting in the back seat. The gov is real careful at the moment not to upset us. For the moment that is. Ta for the lpg links info like this is invalueable. | ||
| Brad Clinch Frequent User Username: brad_clinch Post Number: 11 Registered: 11-2004 |
I’ve also been interested in converting to gas (LPG), but would still like to retain my petrol fuel tank. And I do understand that I’d have to upgrade my rear springs, which could do with replacing anyhow. Bill at MegaGas did give me some pricing about a year ago, which involved a tank between the rear rams, but it was too costly for me to get it done at the time due to other priorities, and I then mislaid his contact details having moved house. I’ve recently heard of ‘sequential injection’ gas conversions, which I suspect would involve injecting the gas directly into the manifold near each of the intake ports. Of course this would require a fuel computer. About 4 years ago I installed an injected turbo 13B rotary into an NSU Ro80, which necessitated wiring in a Microtech MT8 (fuel and ignition) computer with which I had no difficulty, so a ‘fuel-only’ (i.e. not requiring ignition control) installation should be quite simple. Though this type of LPG conversion may be more expensive due to requiring injectors and a relatively basic computer, it would also do away with the vaporiser and mixer. The main advantage that appeals to me is that I anticipate injection would improve the efficiency just as petrol fuel injection is superior to carburation. Of course as well as being able to use LPG, which here (on the Gold Coast in Aust.) costs around 0.45 / litre, vs. unleaded at around 0.90 / litre. Anyhow, I will have a look at the various links suggested here. But if anyone has any comments, I would be interested. Regards, Brad C | ||
| David Gore Moderator Username: david_gore Post Number: 374 Registered: 4-2003 |
Hi Brad, If you haven't already done so; I suggest you search this site using "LPG" and "gas conversion" as keywords. The concept of gas injection into the intake manifold raises some interesting technical considerations with mixture uniformity/combustion efficiency in the cylinder as well as injection timing/quantity. The required fuel/air ratio will be subject to the injection of an appropriate volume of fuel gas which will be determined by both gas pressure AND temperature as gas is compressible and subject to Boyle's Law [P1V1/T1=P2V2/T2]. Liquid fuels are effectively incompressible and accordingly can be metered by volume only independent of pressure and temperature considerations. I suspect quite sophisticated monitoring probes, computer hardware and software will be required to allow successful sequential injection and this is the reason it has taken so long for this type of system to appear. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 244 Registered: 9-2004 |
Hi Brad, well i think i need new glasses as i did not know this topic was on here. Regarding the rear springs,fitting heavy duty would be the best long term practice. However as i made and fitted a tow bar and Lpg some time ago,i thought i would test some spring assisters to stiffen up the back end. Well they are still there doing a great job. Handeling is so much better. The ride height when stationery over a period of time does not sag. I forgot all about them so have taken a pix for your interest.  | ||
| Robert Chapman Grand Master Username: shadow Post Number: 152 Registered: 5-2003 |
Brad C, My advice would be forget injection go for the tried and proven simplicity of a conventional system as seen in the pictures supplied by Patrick L. Boemo Engineering (Melbourne) will supply you all you need in a complete kit at a very affordable price. This kit has been used for many years and will work straight out of the box. You will get Converter,mixers, tank, valves, soleniods, pipes, hoses,gauges,wires the lot. And by the way there is a company in Melbourne that can supply uprated springs specifically designed for this job. If you do a few miles in you car I would say go for LPG you wont regret it, not only will it reduce your fuel bill it will prolong the life of you engine and will also perform much smoother(not to mention reduce exhaust emissions). Hey that sounds really good I must convert my own! | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 247 Registered: 9-2004 |
Crums you lot in Oz have some remarkable kit to work straight out of a box. Mine sure needed some time on the set up. To make it worth while doing the kit yourself you need to use the car and clock the miles up,more miles more saveing the kit will soon pay for its self many times over. In the Uk the fitting practice code must be followed and a certfication test cert issued to the passed lpg vehicle. This is needed if the car is used on the Eurotunnel shuttles etc. | ||
| Robert Chapman Grand Master Username: shadow Post Number: 153 Registered: 5-2003 |
Hi Patrick, Yes we are fortunate that a tried and tested kit is ready to bolt on to our cars,this has come about through lots of testing by the supplier and feed back from installers and tuners such as ourselves. LPG regulation is strict in Oz ,you need to attend a course and pass a test to qualify to be licenced to maintain or install,all installations must be performed at a licenced premises and strict levels of equipment must be maintained. The vehicle must fitted with a ID plate supplied by the alternative fuels board and stamped with the regestered installers number and company name.All steel tanks must be tested or replace every 10 years(all tanks are serial numbered and date stamped). | ||
| Robert Wort Prolific User Username: robert_wort Post Number: 58 Registered: 12-2004 |
Hi Robert, Sometime in the future (not too distant I hope), I will probably get you to convert my Spur to LPG. Two questions though. 1/ As I would probably go the whole hog and go exclusively on LPG, Can a large Tank be put in place of the existing petrol tank (say 100ltrs), so as not to impinge on my boot space? 2/ Could the existing petrol guage then be converted to read the LPG levels? | ||
| bob uk Unregistered guest Posted From: 80.4.224.7 |
I have converted my SS1 to gas. I use a OMVL tandem vaporiser (250bhp) and a 90litre tank between the sus in the boot 72l capacity The car is smoother with no real power reduction and does 10.5 mpg(13) on gas around town and 15(18) on a run at 60 mph. petrol in brackets. Intial problems with cold starts was solved by fitting a button to hold the solenoids open longer. before cranking. 10 seconds ensure first time start. once even slightly warm the auto 3 second prime works first time. Next stage I am going to do is to fit a lamda sensor in the exhaust and connect this to a stepper motor that controls the mixture. the kit is £130. The gas conv kit was £600 plus £25 for nuts and bolts etc. I have in 3 months recovered 1/2 the cost of the parts. I am hoping that once the stepper motor is fitted mpg will improve further and pay for stepper motor as well. My goal is to break even by the end of May so I have 1/2 price motoring in time for my holidays. I recomend that you fit a system as above tried and tested by many RR/Bentley cars. apart from one car I know of that had a stalling problem I have never heard of any problems injecting gas has got to be better than my system but I would suggest that with a stepper motor the gap would much closer. A bit like single point and multipoint injection. You know the multipoint is meant to be better but when drive the single point version you can't tell the difference. squential gas injection in my opinion is over complicated for no gain. Whats happens is that it takes time to inject the gas and as the demand rises the injectors end being open while the inlet is shut. The first injected RRs had continous injection and run very well. More responsive than a carb version with more torque. However I will keep an open mind. | ||
| Robert Wort Prolific User Username: robert_wort Post Number: 62 Registered: 12-2004 |
Interesting that it takes longer to start on gas with RR. On my old banger FORD, it always starts instantaneously on LPG and when I had it on petrol, it took a few cranks. Probably because the Ford is a simple engine it doesn't have so many ancillaries to go through. I have driven about 200,000 kilometres on gas exclusively without the dreaded valve seat recession that everyone talks about. The only thing that I do have to watch out for is in winter. Upon starting the engine, sometimes the lines can freeze up, causing the old girl to stop. It doesn't happen very often but I make sure that I keep near the kirbside of the road to avoid holding up peakhour traffic if it does. Since I put a tea cosy (Pure Wool-Fireproof) over it on those cold days, I haven't had any probs since. I wouldn't advise this method as a permanent fix though as there is still always the risk that something nasty could occur. I was thinking of insulating the pipes around it with some sort of exhaust wrapping. This stuff is a good insulator so I think it would be a better long-term solution. | ||
| Robert Chapman Grand Master Username: shadow Post Number: 155 Registered: 5-2003 |
Hi Robert W. Sirit/Spurs are a bit of a problem when it comes to LPG tanks,personally I can't see the advantage of going straight gas only. 1)Why limit yourself to one fuel,there may be occasions when you can't get one or the other. 2) You always have a second fuel system back up if one gives trouble. 3)Fitting a gas carburettor drastically changes the under bonnet appearance,it is true you can fit the gas mixers and leave the redundant carbys in place ,but if you are going to do that then why not have the advantage of duel fuel operation. 4)I costs more because you have to buy a gas carburettor and fittings .(Although you do have the extra cost of the petrol tank). I believe people used to go gas only for 2 reasons. 1)LPG used to be much higher octane,so they could build engines with much higher comp ratio and get higher perforemance ,but this would mean that the advance curve would not suit the much lower octane petrol that was around then. 2)The only way to get some imported cars or cars without all the emission equipment fitted to comply with Australian Design Rules is to fit a gas only system. Personally I think the best bet is to remove the petrol tank,have a small petrol tank made of say 25% capacity and fit the largest gas tank that will fit in the remaining space.The compromise is you may have to fill up slightly more often and have slightly less range but where can you go now where you cant get gas. One other advantage is you don't have to try and convert your petrol gauge to read gas levels (this can be done). | ||
| Robert Wort Prolific User Username: robert_wort Post Number: 71 Registered: 12-2004 |
Thanks Robert, I'm convinced. Now all I have to do is get my piggybank filled. I think it was Patrick who said that the shorter range can be an advantage. More rest stops. By the way! When you stated that LPG is better for the engine as is gives it a longer life, as good old Professer Julius Sumner Miller once asked."Why is it so?" | ||
| Robert Chapman Grand Master Username: shadow Post Number: 156 Registered: 5-2003 |
Hi Robert W, There are a couple of reasons I believe. Firstly,is that LPG is a much cleaner burning fuel and introduces a lot less combustion by-products into the engine oil.It is often noted how long engine oil remains clean in a LPG fueled car.Special gas engine oil is recommended. Secondly ,because it enters the cylinder as a gas(as opposed to petrol that can enter as a liquid) it does not wash oil off the cylinder walls or dilute the oil. Thirdly and particularly pertinent to V8 RR and B carburettor equipped cars,they dont have to be started on petrol thus avoiding the use of the choke.This very rich mixture is necessary because the petrol going into the cylinder condenses on the cold cylinder walls and turns back from vapor to liquid and is very difficult to ignite,in the process washing critically needed oil from the top of the cylinder wall and top rings.The majority of engine wear take place during this period, some suggest as much as 70%. One other area of operation that aviods the use of a very rich petrol mixture is full power,it is noted that a much leaner lpg mixure(compared to petrol) is required to produce maximum power. | ||
| Robert Wort Prolific User Username: robert_wort Post Number: 73 Registered: 12-2004 |
Many thanks Robert C. What you say makes perfect sense. On another tangient, I took the car for a drive today to charge up the accumulators, brought it back, turned off the engine and pumped the brake pedal. I got seven pumps in before the lights came on. It didn't come as much of a surprise as I notice that it takes a good 20 to 30 seconds for the warning lights to extinguish from cold. I understand that these accumulators on Silver Spurs are not rechargeable like the Shadows and are a throwaway item. Are these accumulators easy to replace , as in unscrewing the old ones off and screwing the new ones in, or is it a little more complicated than that? Also, What are the replacement costs of these items please Robert? | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 530 Registered: 4-2003 |
Let's move this one to the Silver Spirit section. | ||
| Robert Wort Prolific User Username: robert_wort Post Number: 75 Registered: 12-2004 |
You're right Richard. Sorry | ||
| Brad Clinch Frequent User Username: brad_clinch Post Number: 13 Registered: 11-2004 |
Hi all, The topic of LPG conversions is most interesting and I thank everyone who has given input advice. Having read everything I can find on this site regarding the topic, I think I'll fit the standard type of system (though I still wouldn't mind sequential injection, as it still appears to me that there are no complications that I regard as a significant obstacle). But I would like to find a suitable gas tank to replace the original petrol fuel tank, leaving sufficient room for a small auxilary petrol tank. Can anyone please advise tanks to suit? MegaGas will probably supply the parts, and I know a good gas fitter who will do the job. Thanks everyone. Regards, Brad C | ||
| Brad Clinch Frequent User Username: brad_clinch Post Number: 14 Registered: 11-2004 |
In addition to what I wrote above, it would seem that those who have replaced their original fuel tank have vehicle models 'for USA and Canada' where the fuel tank is behind the rear seat instead of where mine is, being under the boot floor to the RHS and next to the spare tyre in its cradle underneath. So I withdraw my question above re suitable replacement tank as I doubt there would be one. But I am interested in knowing the impedance of the fuel sender so that I can couple it to the existing gauge. I can't find this information in the manual (Silver Shadow II - 4 door), when I had thought I would have found it under testing procedures. The index that I have states the 'fuel sender unit' to be covered in 'Carburettor and Fuel System, B6', but I can't find it! It also says the 'Gauge' is in K6, whereas the K6 chapter in my manual has 'Air intake systems'. The tank assembly K2, and instrument fault diagnosis M4 chapters, both do not appear to contain this info either. It would seem I'm looking in the wrong index, but it is titled, 'Four-door motor cars 1965 - 1980'. I would probably find it if I continued searching, but considered, why not just ask? So if anyone knows the sender impedance, please advise. Or where I'm going wrong with the index! Though I'll probably work that one out after submitting this and feel a fool! By the way, I think I'll go for an A70 gas tank (700mm x 375mm D, being 54 litres usable). Thank you. Brad C |
