LPG Conversion on Cavalier

Yes its me again ....

The Cavalier with the heater matrix problem .... well, I want to consider
something else as well

I drive almost 3000 miles a month in the car, and I want to think about LPG
conversion.

Mk 3 1.8i Single Point Injection, "L" Reg
The car is a saloon, not a hatchback so can house the tank at the back of
the boot.

Can anybody tell me how much this is liable to cost, and anybody know who
can tackle such a job.

I live in Glasgow (ish) area, so anywhere near (ish) me would be good

 

Unless you are going to keep the car for ages are you going to get your
money's worth?
I am sure there are plenty of places you can find on the internet to give
you a quote but try to speak to one of their customers to make sure they do
a "proper" job - seen some scary add on fitted kits. Another option is buy
a car with it factory fitted - least you know it will do what it should.

 

A quick Google suggests likely conversion costs of £1k - £1.5K. I
suspect it would be more cost effective to swap the car for the 1.7
diesel version, or an older pre-catalytic petrol one. Until recently I
was doing 35K per year in my 90H 1.8 petrol Cav Mk3 and averaging 45
mpg.

 

Ask yourself how much money you spend on fuel per week. if its over about
£50-£60 then probably worthit. I had it done to a range rover 3.5 1986
manual a few years back. cost 1k, but paid for itself in 10 months.
currently run a 4.0 litre (non rangey) which I bought already gassed, works
ok.

quality of installers out there is very variable, so shop around.

if you buy a motor already converted, make sure you get a certificate of
conformity (basically a piece of paper with companys name, installers name,
serial number of rank and sometimes other components like the vapouriser.
without one, insurance companies might get a bit iffy, but you shoudnt have
any bother with lpg as long as you declare it. never had any premium rises
over it.

you also need an engine and ignition system in good nick, as gas will find
any weaknesses. if it breathes much, then forget it! if your HT is dodgy
then replace the lot with quality gear.

Also check out prices of gas. avoid garages. usual prices are @ 40p litre.
look for bottled gas suppliers. most sell lpg as well (also labelled
autogas). I use one on Bury, lancs at 34p/litre. downside is limited opening
hours, but at those prices, I just fill up. you tend not to bother with just
putting a tenner in to keep you going.

I have heard that some omega V6's do not take well to gas (dunno why) and my
local installer did a 1.8 vectra old style once and swore never again, but
would not come up with why.

and finally, if you do have one done, get the biggest tank that will fit.
dont get a doughnut shaped tank that fits in the spare wheel well. you loose
the spare and they are bloody expensive compared to a cylender. and dont
have the filler at the back. (think about rear end shunts). get it near the
existing filler.

hope some of this drivel helps.

Mike

 

Yeah Mike thanks

I do spend roughly £50 per week on fuel - car does circa 3K miles per month.
This is why I was considering the change.

Shall do my homework now and see who is best, although Im thinking maybe
buying a pre done car might be better.

The only niggle I have is - "if its so good why did they get rid of it".

Thanks again

Steve

 

If you are spending 50 quid a week to cover 750 miles then that's
around 57 mpg??? ( assuming £3.80 a gallon) That can't be right; I
would expect about 42 mpg out of your 1.8i.

So, assuming 42 mpg that's 275 quid per month on petrol. With an lpg
conversion the economy will drop a bit, I am led to believe, so let's
say 40 mpg. Assuming 35p per litre for LPG then you fuel bill will drop
to 125 quid. SO 150 quid per month saving, best case. So the system
should pay for itself in about a year, by my calculations.

 

Hehehe

so all i need to do is find someone to fund my LPG conversion .......
[/QUOTE][/QUOTE][/QUOTE]
If you are spending 50 quid a week to cover 750 miles then that's
around 57 mpg??? ( assuming £3.80 a gallon) That can't be right; I
would expect about 42 mpg out of your 1.8i.

So, assuming 42 mpg that's 275 quid per month on petrol. With an lpg
conversion the economy will drop a bit, I am led to believe, so let's
say 40 mpg. Assuming 35p per litre for LPG then you fuel bill will drop
to 125 quid. SO 150 quid per month saving, best case. So the system
should pay for itself in about a year, by my calculations.

 

Ok, what I'm about to say will bore some people. If you arent interested in
lpg, stop reading now.

LPG, aka propane (UN number 1978), also comes in bottles. in fact, they are
the red ones you see powering temporary roadworks sign illuminations usually
on motorways. they are also to be found strapped to the back of a lot of
fork lift trucks. reason for this is that they can power a piece of
machinery indoors. the exhaust is non toxic. however, it is an asphyxiant,
so beware!

Note: the stuff you see in blue bottles is butane. it is technically LPG,
the working definition of which is a (hydrocarbon) gas that can be liquified
with a modest amount of compression, but no refrigeration. butane-the stuff
lighters run on-contains less energy per kg than propane, hence propanes
choice as a fuel. even so, (liquid) propane contains less energy than the
same mass of petrol, which is -partly- why it will not sent your wheeled
pride and joy as far as a gallon of the good stuff. (also partly explains
diesels economy, as a litre of diesel contains more energy than a similar
amount of petrol. yes, I know theres more to it than that, but this is a
simplified explanation) you can also expect a mild drop off in performance,
but nothing too dramatic. expect 10-15 mph drop off the top speed.

It also burns slower than petrol. Slower here is a relative term. propane
will still produce a healthy bang!!! because it takes longer for the flame
front to travel the full expance of the cylinder, the spark has to fire a
little earlier. figure 10-12 degrees earlier than the settings for petrol.
you can get little boxes that switch the timing automatically when the
system changes from one fuel to another. costs vary.

propane also burns hotter than petrol. not so you would notice, but it will
nicely burn off any carbon deposits in the combustion chmber area. this can
also mean around valve seats, uncovering hidden problems. hotter
temperatures also mean its a good idea to slightly shorten the intervals
between oil changes.

The electrical resistance across the spark plug gap is greater with a
propane/air mix than with a petrol/air mix. this means that your ignition
system has to work harder to fire that plug. The practical implications of
this are that the spark will find the easiest way out. if you have an old,
damp or even just oily set of leads, then at some point they will be bunched
up and touching. this is a paticular problem around the distributor of V8's!
this means that the spark will jump from one lead to another and fire the
wrong plug at the wrong time. especially if the gaps are a bit uneven. if
you are lucky, this will result in a missing cylinder. if you are unlucky,
it will fire a plug that is in the middle of an induction stroke, and the
flame front will travel backwards out of the engine. you wouldnt believe
what this will do to an air flow meter!. and if you happen to have your head
under the bonnet investigating when a 'mate' decides to gun it a bit to see
if he can clear it, then I guarentee that this will loosen any earwax you
may have!

I'm not trying to frighten you or put you off, but you need to know that it
isnt all plain sailing. usually you find out the above details only after
you have parted with lots of wonga. I would advise getting to know some
people-at least more than 1- and ask their experinces.

Mike

Oh, BTW, LPG cars are currently (I believe) exempt from comrade Kens
congestion charge.