W124 300TE LPG Conversion

[mark.porthouse]

Hi All,

I'm just getting my 1988 W124 300TE auto converted to LPG (autogas) (Liquid Petroleum Gas).

The car will be dual fuel and will run on either petrol (with the KE-Jetronic) or LPG using a very simple gas mixer (carburettor) without computer feedback from a lambda exhaust probe.

I'm getting a toroidal tank (625mm diameter, 225 width - not huge) fitted where the old spare tyre was (upright on the left hand side (nearside) of the estate load bay). The gas filler will be mounted in the bodywork next to the petrol filler on the offside.

I've just purchased an unused space saver wheel/tyre (genuine Mercedes) 125/80 x 17 for £35 (!!) including delivery which I believe is from a C Coupé which I must secure to the other side of the load bay (upright on the offside). Saying that the conversion people reckon I should just have a can of gunge to fill and seal a punctured tyre and not have a spare. They say that the AA or RAC just transport you if you don't carry a spare!

Has anyone had a puncture that they reckon a can of gunge wouldn't fix temporarily?

The supplier is in Exeter, Devon:
http://www.gaspoweruk.co.uk/
who appear to be very good, but I'll tell you more once I get the car back.

I'll post some photos once I have the car back - hopefully today or tomorrow.

Cheers,

Mark

 

[Sp!ke]

It'll be interesting how you get on with this. Your using a single point mixer I take it?

How much for the conversion if you dont mind me asking?

 

[Vlad]

Second that question...how much

 

[mark.porthouse]

Yes, single point mixer. He commented that this would actually sit inside the air filter box - but photos will come.

Now, as for price, it seems that it is more common to convert W124 saloons because the wheel well is in the floor of the boot - making it a simple conversion. Some people with estates just go for big tanks bolted in the load area(!), but for what I'm doing - an upright toroidal they have to design and fabricate a custom cradle for it. This means that the price is £1,385 which isn't cheap in my view.

It might be worth noting that once the cradle has been designed/made once it might be easier and cheaper to copy.

I've just been on the phone to the chap and they are just getting the final adjustments on the gas pressure sorted - so I should have it back this afternoon (Friday).

Cheers,

Mark

 

[mark.porthouse]

Hi 'all of those interested',

Here is a link to a page of photos and notes.
http://www.markporthouse.net/merc/w124lpg.php

Stako toroidal tank, Romano evaporator. Gas filler in wing just next to the existing petrol filler flap. Fuel control switch mounted on side of centre console just near the ignition lock.

I'm intending to cut away some of the plastic webbing inside the spare wheel cover panel so that it closes better - it currently interferes with the new tank.

I would say that there is a small loss of power in LPG mode. I haven't really tried it in petrol mode since the conversion - I wonder if the mixer is artificially throttling the air intake. I'll give it petrol test drive to see.

I'm going to run the car out of gas and then see how much gas I can put in to fill the tank.

Cheers,

Mark

 

[glojo]

What I can never understand is why this idea has never taken off? It is even getting to the stage where cars that have had a conversion are not an attractive buy (are Range Rovers the exception?)

For years I have heard sceptics saying how the Chancellor might raise the tax on this fuel, but this suggestion has been doing the rounds for a good few few years?

Good luck and I hope it works out for you.


Regards
John

 

[grober]

Neat Install

How does the evaporator heat exchanger tie into the coolant system? does it use any of the heater plumbing or what? Forgive the curiosity! Looks a neat installation. Single point injection systems used to be criticised for blowback problems but I guess the more modern systems have overcome that. Installation seems quite neat but £1385 seems a trifle expensive for a single point injection system if you don't mind my saying so.

 

[Mercedes cozy]

Spare wheel

My mate had a 300te converted to gas and he had one of those roof boxes from halford and put his spare wheel in side.
So the spare wheel problem was finished.

hope this helps:bannana:

 

[Howard]

Surely the extra drag of having a roof box negates any savings made by running on LPG ?

 

[Mercedes cozy]

The boxes now days are made from a light weight material and the 300te already has roof bars in which it claps on to.

 

[Howard]

Doesn't matter what they are made of , they will still create aerodynamic drag ....

As an example, it was calculated that if you run around in a normal family saloon , and are too lazy to take your roof rack off in between using it, your fuel consumption will rise by between 5 and 10% ...

So, having a box on the roof, even if it is shaped like a missile, will still create drag ....

When we had our 300te , the box always came off the moment we had finished using it ....

 

[Mercedes cozy]

Doesn't matter what they are made of , they will still create aerodynamic drag ....

As an example, it was calculated that if you run around in a normal family saloon , and are too lazy to take your roof rack off in between using it, your fuel consumption will rise by between 5 and 10% ...

So, having a box on the roof, even if it is shaped like a missile, will still create drag ....

When we had our 300te , the box always came off the moment we had finished using it ....

Your right.

My friends car ran on gas it barley made a differance as the gas was cheap compared to petrol.

He did have a blow out once and he waited for the RAC to come out and when they came in the van, they inspected his tyre which could not be sorted out and they said you will have to until recovery lorry comes and he ended up waiting 4 hours and his family, ruined the whole day.
So the it comes down to choice spare wheel or no spare wheel.

 

[mark.porthouse]

Hi grober,

No, it is using the main engine water plumbing. In the third photo down - the first engine compartment photo you can just see one of the T junctions in the existing hot water plumbing where hot water is taken off to the evaporator. If you look at the evaporator itself there are two round blue stickers on it. By the right hand sticker you can see one of the T junctions - there is another rubber hose above it which you have to ignore which is for something entirely different! You can just see all three jubilee clips for the T.

The other T is shown in the first photo under 'engine bay connections' where you can see a small black plastic box with 'Stop K-J' written on it. This is by the bulkhead at the back of the engine bay near the top.

Perhaps I need to take better photos?

The first thing that I did when I came away from the garage was accelerate to 40mph in first gear - no sign of a misfire/blowback. My Range Rover only misfired after I started fiddling with the mixture! As long as your mixture isn't too lean and your ignition is good then you shouldn't get a misfire.

Yes. It wasn't cheap! Where I am I didn't have a great deal of choice and I was particularly impressed with these people. They throw in four free services up to 2 years/24,000 miles.

Mark

 

[mark.porthouse]

Hi glojo,

The good thing about the Range Rover Classic with LPG that I just got rid of is that you didn't lose any interior space. That is certainly key. I will lose some with the space saver in the 300TE, but it won't be too much and the 300TE has more boot space than the RR anyway. I can always leave the spare at home if I absolutely have to.

I guess there are just too many barriers to entry for LPG to take off: Boot space, spare tyre, extra maintenance, installation cost, slower refuelling, fewer refuelling stations, rubbish grant system for installations, few converted cars qualify for lower road fund tax or zero congestion charge, slightly higher insurance, not allowed in the Channel Tunnel...

But the savings are fantastic, especially if you do high mileage - which I don't!

Cheers,

Mark

 

[grober]

Pictures Are Fine!

Hi grober,

No, it is using the main engine water plumbing. In the third photo down - the first engine compartment photo you can just see one of the T junctions in the existing hot water plumbing where hot water is taken off to the evaporator. If you look at the evaporator itself there are two round blue stickers on it. By the right hand sticker you can see one of the T junctions - there is another rubber hose above it which you have to ignore which is for something entirely different! You can just see all three jubilee clips for the T.

The other T is shown in the first photo under 'engine bay connections' where you can see a small black plastic box with 'Stop K-J' written on it. This is by the bulkhead at the back of the engine bay near the top.

Perhaps I need to take better photos?

The first thing that I did when I came away from the garage was accelerate to 40mph in first gear - no sign of a misfire/blowback. My Range Rover only misfired after I started fiddling with the mixture! As long as your mixture isn't too lean and your ignition is good then you shouldn't get a misfire.

Yes. It wasn't cheap! Where I am I didn't have a great deal of choice and I was particularly impressed with these people. They throw in four free services up to 2 years/24,000 miles.

Mark

Thanks Mark for the guided tour. It would appear that your supply to the evaporator is Tee'd off the heater feed from the rear of the cylinder head/block then runs round to the front offside where it feeds the evaporator. The return pipe from the evaporator is then Tee'd back into heater return pipe before it goes to the water pump assembly. Thats how I read it anyway. Thanks for sharing the details of your installation with the forum . Sounds if the installers will provide good backup. Remember to run on petrol periodically to keep the conventional fuel system up to scratch and stop the petrol from going off.
One ML OWNER on the forum had evaporator difficulties in very cold weather but I think his tank was under the car rather than inside. You probably know all this already if you ran a Rangie with LPG . Hope it turns out to be a good investment.

 

[devonian]

I had my E200K Estate converted by the same people about 20,000 miles ago (Prinz multipoint system) and so far have been very pleased with it

 

[mark.porthouse]

Hi grober,

Yes, sorry, you are right - off the heater feed and return.

Mark

 

[mark.porthouse]

Hi devonian,

I'm pleased to hear of your experience with them. That sounds like a much more sophisticated system. Do you have a big tank in one side of the boot?

Cheers,

Mark

 

[devonian]

Hi devonian,

I'm pleased to hear of your experience with them. That sounds like a much more sophisticated system. Do you have a big tank in one side of the boot?

Cheers,

Mark

Yes I do.
I had a large tank fitted to give me a decent range however if I were having the job done again I would consider the tank placement more carefully as this is the only thing I'm too happy with on my installation.

 

[mark.porthouse]

I've got my space saver now and using a ratchet strap I've secured it to the side of the load area (opposite the normal spare position). The strap is hooked around some metal pressings on the inside of the rear wing, however, I might put some slots in the plastic internal 'wall' so that I can get a more effective tension and perhaps wrap the strap around a couple of times to spread the load in the strap better. However, space wise it is spot on and it doesn't obscure rear vision as it is against the side window at the back on the driver's side - would be less ideal on a LHD car where the driver can see through that window better normally.

Cheers,

Mark