Silver Spirit 2 LPG

York, UK

#1 Jan 9, 2011
Has anyone had a LPG convertion fitted to their Silver Spirit 2
Jan Forrest

Rotherham, UK

#3 Jan 10, 2011
I've tried to respond to this question twice, but it seems that the site objects to the length of my reply even though it's within the number of characters permitted (?).
I'll split into 2 parts and see what happens.
Part 1:

I had my Shadow 1 converted about 2 years ago. The engines are virtually the same apart from a slight difference in the compression ratio and the use of fuel injection in place of the previous twin SU carbs.

When the tuning is right she does 14mpg on petrol and 11mpg on gas. When it isn't it can go down to 12 and 9 respectively. However this may not be the case with your Rolls. When I had a previous car converted with a sequential system (a Jeep Grand Cherokee with the US-only 5.2 litre V8 engine) I found the mpg to be the same for gas and petrol: 14. Nice!

How long it takes for the fuel savings depends on how much mileage you put on the car annually and, of course, how much you pay for the conversion. As you will have to have a 'sequential' or multi point gas injection system installed this will cost you considerably more than the 1K I paid. Budget for at least 3.5K and think yourself lucky if it comes out at less - assuming that the conversion is perfect from the off. Best check up on the converters in your area to see if they've worked on Rolls' before and what kind of track record they have with larger engines. Not all of them have much experience of engine sizes much over 3 litres or so!

Another important consideration is the siting (and size) of the LPG tank. Many say that the toroidal types that fit inside the spare wheel well are less obtrusive. The down side is that they don't hold a lot of gas with the obvious limitation on the distance you can go between fill ups. Also you will no longer have anywhere to carry a spare wheel.

The two alternatives to this are:
1) Siting the tank underneath the car. This means either the use of a slim, small gas tank or a larger tank with the replacement of the standard petrol tank with a smaller one.
2) A larger tank - 80-100 litres 'water capacity' is possible - in the boot. Obviously this means a loss of almost half the boot space.

Whichever option you go for, bear in mind that the quoted capacities of the various gas tanks is usually rated as the 'water capacity' or notional full volume of the tank. When being filled with LPG they have to be limited to 80% of this volume to give a safety margin between filling up with cold gas and the pressure increases that will occur as the gas warms up.

Occasionally some converters will set the system up so the car will only run on gas and completely eliminate the petrol system. I've found that this can reduce the overall fuel consumption as gas doesn't warm up the engine as quickly as petrol and so much more is used during the warm up period. For the sake of flexibility I think it's better to leave the petrol side in place and have automatic switch over between the two. With this kind of system the car starts on petrol and then switches to gas when the engine reaches a set temperature - often within mile. Also the same kind of system will switch back to petrol when it senses that the gas is about to run out. You have the added advantage that the whole gas system can be removed and put in another car should you decide to sell the car without it or have to replace it after any kind of serious accident damage to the car.
Jan Forrest

Rotherham, UK

#6 Jan 10, 2011
This site is getting on my wick. I add replies, they go missing, I add other replies and then the first ones turn up again.
Annoying? You'd better believe it. Oh, well. If at first you don't succeed get a Boy Scout to do it for you ...

Preston, UK

#7 Jan 10, 2011
Hi Jan , thank you so much for your comments our 1992 Silver Spirit has the Bosch K Motronic fuel injection , I am told that this is not an ideal system for LPG due to it being mechanical ?
Quotes have been 1199 inc VAT fully installed and with 2-3 year warranty .
Jan Forrest

Rotherham, UK

#8 Jan 10, 2011
Bugger. It's done it again.

Here goes, but I bet it finds it once I've posted the same response for a second time.

I wasn't aware what kind of fuel injection was fitted to the Spirit although I knew it wasn't exactly an up-to-date design. Mind you, I suppose that it's at least marginally better than the SU carbs on my Shadow. I really must remember to overhaul them as soon as I can afford the 100+ per side for the rebuild kits.

Obviously the LPG set up that's going to be fitted to your Rolls will have one or two mixers although mine is different (see below). That's why it's so (relatively) cheap. As long as the fitter is accredited and has good word-of-mouth recommendations then it should be a good investment. How he sets it up to stop the mechanical injection system when running on LPG will be very important. I would expect that a lot of the internals are normally lubricated by the petrol passing through them and you don't want them running dry and suffering excessive wear from it. Ask the fitter about this in advance. If the gas is going to routed through the injectors (unlikely, but ...) there will be no such lubricating properties and it's not as if you can add anything to the gas to overcome this, so I doubt it.

Also make sure the heated water supply to the evaporator is in parallel to the cab heater and not in series like mine was installed. Fortunately I noticed it in time and rerouted the plumbing to put it right. Yes, I should have taken it back, but I had it fitted at a place some distance from my home and just didn't fancy going all that way for such a simple fix. A couple of 'T' joints, several Jubilee clips and a few feet of water hose and the job was done. Simples!

The evaporator that turns the liquid gas into gaseous ... gas is important as well. It will need to be a big one. Mine's an "OMVL R90" which is one of the biggest around and it has 2 possible gas outputs for use with 2 separate mixers - although my car runs far better on simple 'spud pipes' which just dump the gas into the air flow on each horn leading from the central 'choke flap' to the mouths of each carb. What can I say? It works for me.

By the way: Don't forget to inform your insurers. It shouldn't make any difference to your premiums although some class it as an 'engine modification' and load the premiums as though you've fitted a nitrous set up. If they do just shop around for a better quote. Please note that Footman James has been sold to the Yanks and isn't as competitive as it used to be. Fortunately Peter James (the James half of the above) has now opened up on his own and is reported to be very competitive. I'll be asking him for a quote when my insurance comes up for renewal in a few months.

Another tip is that you will no longer be able to take your Rolls to the continent through the Chunnel. LPG is completely banned. Even the ferries demand that the gas flow is completely shut off before boarding. Just turning back to petrol should be enough to cover that as long as it's set up that way - as it should be.

Do you go to any of the Classic Car, Steam Engine or similar rallies? I do, but not in the Rolls as I'm the member of the Toyota Estima Owners Club ( ) and go along with them. I use the Toyota as it's a diesel that runs well (and very cheaply) on old veggy oil and happily tows my 1 tonne caravan so I can camp for a long weekend. We 'do' several every year in the warmer months - some of them around the London and Home counties areas. Perhaps I'll see you at one of them.

York, UK

#9 Jan 11, 2011
Jan your a star , thanks for your tips / comments , we traded our Nissan Patrol 4x4 for the Rolls having now retired and did not use it so much and to fulfill a boyhood dream of RR ownership , her indoors was scared of the Patrol so I bought her a new Qashqai diesel .
We used the Patrol to tow our twin axel caravan locally to take the g/kids to the seaside bla bla and hope the Rolls could take on the job of toy / towcar we sourced a flange towbar from waltlings and still need to have it fitted , we also want to audio upgrade with flip up unit with bluetooth / dvd / cd / sat-nav etc all the toys we have become used to and enjoy also we a have firm in the village who will tint the windows for us . the lpg convertion with a selection of tanks come in at 1200 to 1400 with 2 year warranty . we would like your thoughts /comments on any of the intended mods , bearing in mind the Rolls will be used as second car for our enjoyment not for investment . can send you e mail address if you prefer to converse off forum . Thanks Steve
Jan Forrest

Rotherham, UK

#10 Jan 11, 2011
Unfortunately it's not practical to exchange email addys on an open forum like this. There are all too many criminals, perverts and spammers who could pick up on a publicly posted addy for my way of thinking. The most obvious way that comes to mind is for you to register with the LPG forum I mentioned earlier,(always a good idea anyway) then you could send me a PM through it and I could respond with my details for us to continue this conversation in private.
I use the ID of Sir Henry, both on there and on the Estima forum.
Hope to hear from you in the near future.

York, UK

#11 Jan 11, 2011
ok have registered with estima and LPG dont no what to do now ??
Jan Forrest

Rotherham, UK

#12 Jan 11, 2011
On the Estima site you just look at the top right of the forum screen and click on your ID for drop down menu. Select Messenger. A little lower on the same side of the new page you click on the big, black "Compose New" to send a PM. Don't forget to put my ID in "Recipient's Name" and a subject in "Message Subject" or the PM won't be sent.
It's much the same on the LPG site other than you start by clicking on "new messages" at the top left of the forum page and then "compose message" in the fixed menu on the same side.

Saxmundham, UK

#13 Apr 6, 2013
I have lpg on my silver spirit
still drives like a rocket
lpg is 72p petrol 140, which means i get 2 litres to litre petrol, so 18 miles to the gallon petrol = 36 miles to lpg.
lpg keeps the engine clean, and i only use petrol to start my car,1 minuet and 25 seconds and i am full gas.
my lpg v8 system cost 1,500 pounds from
TEL. NO.0178 7376724

off course, smaller the engine the cheaper the price.

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