Gas or not Gas

[Paulo]

I have had my CF for a few months and given my job I do not have much time to actually do anything, other than plan for it, I read the topic on here in regards to converting to LPG. and I have a question, what is the main reason for running an engine on Gas?
  I have had several LPG vehicles my self and the main reason was to save a few cents at the bowser.

[rumax]

running cost is the main reason, but realize if you are on historic rego in SA, you cannot run it on LPG and retain the rego

[Paulo]

thanks,
please excuse my ignorance though when I ask what is historic rego, it's been what seems like forever since I have had a project so a lot of catch up to do

[Paulo]

in regards to the gas or not gas, my personnel preference has to be unleaded, either way there is serious mods to be done to the engine.

[rumax]

In sa, if your vehicle is built pre 31/12/1979, you are eligible for historic rego....but the car must be as it left the factory.... obviously within reason,like spark plugs etc. you can rego up to 3 years and drive a max of 90 days... I just put a car on for 2 years and it cost 188, so $94 per year.....

[Paulo]

thanks Rumax for that information, the plan is for our's is to be a touring van when and if i finally retire
   Paulo
       

[Zeeman]

Gas conversions here in Victoria have dropped right off, as the price difference between gas and petrol has closed up to make the conversion much less economical.  If I was building a van from scratch I would still consider a gas conversion, had a small Impco gas converter on a 350 Chev with a 150 litre gas tank on my old van, was excellent for long trips. This was back when gas was 25 cents a litre!

[wendyh]

Only worth it when petrol is dear....
Engine needs to be set up for LPG.  Like stainless steel  valves...
Best to run straight gas
You do lose a bit of power...but Ray did race a an old falcon on straight lpg
You do use a bit more lpg than petrol,but when  its cheaper its no drama...
All of our vehicles we have had all our life has been on straight lpg except our BA  falcon which has good economy on long runs and we didnt want to loose boot space.
Our beddy is stright lpg and we found a 140 litr tank to put in it as theres heaps of space
So really it depends what engine your running and how many km your goung to be doing in it
And if you want to spend the $$ setting the engine up for lpg or you will burn out valves ETC
Rays a mechanic who has done heaps of conversions....loves impco running gear...

[Marishka]

I love the
Impco systems.
So easy to work on.

[Chucky]

I have full LPG and a Late model 350 / 700R4 / 12 Bolt on 15" rims.  I get 100km for $10.  Range was an issue with a small tank so now I'm adding an APA 306F Toroidal 58 litre external tank from the BF falcon wagon.  With this I will have 100 litres and approximately 600km range for $60 in a V8 bedford.......not bad.

The haters for LPG will argue that its not really worth it, but the physics of LPG make it hard to ignore:

1)   
LPG wants to expand as a gas as much as possible, unlike petrol vapour which is always fighting you to return to liquid form,   for this reason single plane manifolds work exceptionally well if you have the space.
2)
The AFR across the rev range is much more stable compared to carbs, making the vehicle more driveable with less work in my opinion.
3)
Cold/Warm/Hot mornings, an LPG engine will always fire right up.

BUT, you need to set up your engine for this different fuel correctly or you will burn out valve seats, destroy pistons with pre-detonation etc.  A racer sets up their motor for Nitro, Methanol, Dope, or Alcohol.....we should set out motors up for LPG if we are to expect good outcomes.

1) Ensure you have HARDENED valve seats

2) Use LPG SPARK PLUGS because they are the correct heat range for the fuel.

3) Recurve your Dissy (or retune your ignition) so it fully advances at 2000rpm.  I used the moroso HEI recurve kit and the lightest possible springs.

4) Set static timing to 10-14 degrees

5) Add a  variable vacuum advance and set to 12-14 degrees

The goal was to get 14/14/14 degrees of Static/Mechanical/Vacuum advance so at full advance I have around 42 degrees as a starting point.

There we have it.  My van tows well, goes hard, starts every time and costs bugger all to run.  I hope this helps.

Regards,
Chucky