Cyril's progress

[frugg]

Anyway, await a future episode of Cyril's progress for this paint project..

Why don't you paint it like the one on ebay germany:

[mat_fenwick]

Hi Graeme,
I've kept the variable mixer as I do intend to fit it someday... Although what I would like to do is fit a switchable supercharger to raise the compression on LPG, and then develop a liquid LPG injection so that the transformation to vapour cools the inlet charge. From what I understand the problem is getting injectors to control the very small amounts of liquid phase LPG. Can't see it happing any time soon!
I'm getting between 14 and 20 mpg on gas (down to 10ish towing anything heavy), which I don't think is too bad. Never done a petrol mpg calculation to compare it to, as I've never filled the 20 gallon tank. At the moment round here petrol is about 90p/litre, LPG 45p, although did peak at 137p/52p respectively, so was actually giving me the equivalent of mid 40s mpg at one point.
The LPG garage were (I'm sure) trying to rip me off. Criticising the kit and saying they had to replace parts to get it to work. Cutting off the coolant temperature sensor from the gas ECU, leaving the cut wire bare and dangling. Making a soldered joint that looked like they hadn't turned the iron on, which cause no end of rough running - can't see why they even meddled with it. Then charging me £600 to get it back!

[velosolex50]

Hi. The exhaust probe is a length of strong steel tube, approx half inch diameter, sealed at the far end, inserted through a compression fitting you weld onto the silencer. On the end sticking out is a 1.5 inch diameter steel manifold arrangement which feeds liquid gas along a smaller tube within the first tube, and allows warmed liquid gas/vapour back out to the evaporator feed pipe. There are armoured flexi pipes connecting the gas to & from.
Although it sounds a bit hair raising to feed lpg into the hot exhaust, it is a very strongly built item, and I had no problem with it at all over several thousand miles.
The reason the water heating system didnt work very well was mainly due to the little water pumps not being up to the job of pumping continuously. If it stopped, the first I knew was that the car would die a few minutes later, and I would then find the evaporator frozen solid and have to wait hours for it to thaw. Even a thermos of hot water wasn't enough to melt it.
I guess on a 2cv, you could coil the gas pipe round the exhaust close to the head which might work for the small gas consumption it would have--but I think you would need very good contact, & soft copper pipe might not be durable enough. Maybe a carefully designed thermosyphon or a heat pipe would work.
There is an alternative, using engine oil, but I think the risks of wrecking the engine due to a leak, and also the warmup time would put me off. My vote would be for the exhaust probe every time, but as I said in the other post, you might have a problem with certification as the gas feed is meant to stay well away from the exhaust.
Great blog BTW, its nice to see an early BX being cared for properly. I had a series 1 19gt many years ago, it was a lovely car. Now got a 19tzi estate auto with aircon, which is even better! Perhaps I'll get round to gassing it too...

[jonathan_dyane]

I wonder why the coils of pipe round the hot exhaust doesn't move enough heat to stop the freezing - maybe too much loss or too low a rate of heat transfer?

An idea that Jonathan had was to fit a water- oil heat exchanger in place of the 2CV or GSA oil cooler but he ran into some trouble with this.

The late Jeroen Cats sucessfully converted several A and G series Cits using the copper pipe method, which in the 2CV is best fitted around the exhaust pipe within the heat exchanger and circulated by a proper VAG or Merc electric water pump (not a washer pump.)

Online description here, select LPG/GPL from the left-hand menu. He did *many* troublefree miles in the Ami 8 van he converted.


The water-oil hear exchanger was David R's excellent idea, and although it is not possible on the G series due to the shape of the engine casting, it should work well on a 2CV, I would have no hesitation going down this route...

I will have an LPG GS eventually, time and money are the principal barriers...

[Aerodynamica]

Interesting replies guys!

Will look into the ideas.

Mild update: after a long wait the adapters I needed to fit the 'normal' ring type of mixer arrived - they are barry boy style coloured silicone tubes! they were not cheap but actually fit very well and look suitably odd that pleases.

Packet had arrived:

The 70mm straight pipe, aluminium gas mixer and the 70-80mm reducer


Checking the fitments



Adapting to the intake



Fitted:



How does it run with the standard ring mixer (originally off an Astra) ? not very well! It does start and run but after some time the idling drops to a rough tickover and the driving is sluggish. It might be because the 2 adjustments on the evapourator have been untouched - you leave them screwed in for the BLOS mixer but with the ring mixer you need to adjust them - I don't know how to! I didn't get any instruction with my new evapourator and the one on the CX was S/H and I left the settings as they were. Unfortunately the LPG supplier is away so might just need to have a fiddle with the dials..

[velosolex50]

Make sure the holes visible on the flat surface of the mixer are plugged, or you will not be drawing the right amount of gas through & getting a weak mixture. It looks like a mixer designed to sit on a carb top, with float chamber vents etc. I will try to find some instructions I have for tuning with this type of mixer/evaporator and send them on.
Regards
Huw

[velosolex50]

Also look out for airleaks on the engine side of the mixer......it looks like the silicone tube is just pushed in, which would almost certainly leak unless it's a really tight fit
Huw

[Aerodynamica]

Cheers Huw, it was a mixer previously fitted to an Astra. I'd thought that the holes in the mixer were calibration holes - so they should be plugged? I think I'll give that a go this evening. I was concerned that plugging the holes would restrict the flow too much - the area of the 2 carb throats together is much greater than the diameter of the mixer center hole and the area of the gas slits together.

The tube is just pressed into the mixer and is a tight push fit - it's also held in by the air filter housing pushing against it (i'd made it a deliberate tight fit) but ideally the push in part would be on the other (airfilter)side of the intake as it's less critical but looking at the shape of the venturi in the mixer and the side the gas slits are located I concluded that the direction was right. However it DID come slightly adrift going up a hill! and started bucking - could be brought under control by reducing speed to 20mph and then I stopped and refitted it. I have made a mistake it seems! the air filter housing is seperate from the engine and there was a flex section on the air intake (I even included the flex part when using the BLOS mixer!) but somehow I'd forgotten about it.. I need to come up with a solution. Duct tape is helping just now.

I've been out in the car today and it ran ok but a bit sluggish - drives like an old diesel. It restarted after a park (<15mins) and when it started again it caught but was barely running - I turned one of the 2 adjustments on the vapo and immediately it raised the revs and smoothed out so I think I found which one does the idle! - still I'd be really appreciative of an instruction guide if you have one.

I'm tempted to just fit the BLOS thing back on as it worked so well.

[velosolex50]

In my fairly limited experience the mixers have to be small to get enough 'suck' on the gas supply. I think this contributes a lot to the loss of performance usually experienced. I found my 1.9 TRS was pretty dull after conversion, having been quite quick before. Probably the variable mixer is a better solution, as it will open up when you need a bit of power. Ideally, injection of course, but expensive+++. Megasquirt (home grown EFI) might be worth a look, although you would stil need to buy expensive injectors. I've found the LPG tuning instructions and can send you a scan if you send me your email.
Regards
Huw

[Aerodynamica]

Thanks very much Huw, it's cx@citroencarclub.org.uk

Definitely going to block those holes and see what happens!

[Aerodynamica]

Thanks Huw, got scans.

Also just returned from the garage: first thing done was to try the mixer the other way "just in case" but it ran like a bag of spanners.

Refitted right way and covered up the holes in the mixer and RUNS VERY WELL NOW!!!

thanks for the advice - not quite as smooth or flexible to drive as with the variable mixer but after a run (in the snow!) it now rolls pretty well - not like an old diesel!

Thanks again

[velosolex50]

[Aerodynamica]

Thanks to Mark Dunmore at Louth Citroen I now am in possession of a new HP pump - it arrived less than 24 hr after putting the telephone down! excellent delivery.

So this evening while waiting for the paint of a CX rear subframe to dry ( you don't want to know!) I swapped the HP pump over.

It took just over an hour but the new pump is in, primed and running! Initially, I'd say there was no noticable difference - it raised the rear suspension after first starting no quicker than before and the constant Hisss seemed still there.

BUT! after a few short local journeys it steadily improved and now the hiss seems to have gone (after I retightened the drive belt) and the PAS is smooth as silk now! the crappy feel to it has gone!! joy.

So I'll need to be off out early tomorrow so can report as to its 'from cold' performance..

It seems that even with your best attempts to prime the new pump - it never fully primes first time and takes several miles to purge the air. It's also quieter so bonuses all round.

Here's a little pic of Cyril for good measure:


TTFN

[Aerodynamica]

Well, out at half nine this morning and this afternoon I returned to declare that the new HP pump has bedded in and is performing very well. The steering is most noticable: it's a lot lighter at parking speeds as a call in to Asda on the way back revealed. The car seems to rise up a bit quicker and the constant hissing has improved but not vanished - before you had to raise the revs to get the regulator to cut out and the hissssss to cease but now, generally it doesn't do it but there's the odd occasion where is seems to be doing it still but all it takes is a minor tap of the throttle and it instantly stops it. It seems to make a louder less frequent hiss now.

Anyway, i think the pump has really improved the PAS and it's so quiet! the other improvement is that the steering seems to self center on the move better than before where it felt dead and never straightened itself. It does now.

Overall, a fairly easy improvement that has made a big difference.

[CitroXim]

My "sinker" Xantia hisses Graeme. I wonder if it's inherent in the use of an FDV in these vehicles.

Mine has always hissed, much to the amusement of others but the hydraulics otherwise work absolutely perfectly...

Something to be lived with I guess and all part of the "Character"