Converting small petrol engine to run on propane

[Woodworks]

6 hours ago, Rob_the_Sparky said:

Note: LPG is not the same as Propane.  LPG contains a significant amount of Butane and this is what causes a problem when the tank get cold as it has a boiling point of ~0C.  Propane on the other hand has a boiling point of ~-42C so in the UK I doubt you will have any issues with it remaining liquid.

 

Don't know the details but I know in caravans you have to convert the gas appliances to run specifically on either LPG or Propane so I expect there will be a difference when running an engine on gas as well.

It all seems a bit confusing. I asked for LPG and have had a bottle of Calor Propane delivered? 

 

From the Calor site 

"LPG (Liquefied Petroleum Gas) is a hydrocarbon gas that exists in a liquefied form. LPG is a colourless, low carbon and highly efficient fuel. Supplied in two main forms, propane (C₃H₈) and butane (C₄H₁₀), LPG has a range of uses – from providing fuel for Autogas vehicles, leisure parks, crop-drying, BBQs, heating homes and much more.
"

[spuddog0507]

On 06/01/2020 at 19:17, Woodworks said:

Getting a bit fed up the fumes from my GSX390 Honda on processor. I have been looking at ways to improve this some of which get bonkers expensive like electric motors run of a generator. Then a chap in the local hire place says just run it on propane. Seems that its a very cheap conversion and cheaper to run. 

 

Anyone done this and what are the drawbacks?

Hi had a simular issue a few years ago with a diesel sawbench that i run inside a building looked at other engines and then experimented with a extension to the exhaust, made up an extension and it worked ok, just fixed a stainless bit of flexi pipe to exhaust and then fixed that to a new upright piece of exhaust pipe and works fine.

[Woodworks]

Well today I got it all up and working with exactly the same performance as it has with petrol. Turns out gas is a bit more fussy about the state of spark plugs and air filters but once sorted it works as sweet as a nut. Only  takes second to switch from petrol to gas and back again.

 

Only cut a few cube so far and will report back if there any snags long term but this looks like a no brainer for my set up. 

[AHPP]

24 minutes ago, Woodworks said:

Well today I got it all up and working with exactly the same performance as it has with petrol. Turns out gas is a bit more fussy about the state of spark plugs and air filters but once sorted it works as sweet as a nut. Only  takes second to switch from petrol to gas and back again.

 

Only cut a few cube so far and will report back if there any snags long term but this looks like a no brainer for my set up. 

Have you come across (or done yourself) any numbers on the costs of a diesel engine running on red and a petrol engine running on propane? Which does more work for the same money?

[Woodworks]

2 minutes ago, AHPP said:

Have you come across (or done yourself) any numbers on the costs of a diesel engine running on red and a petrol engine running on propane? Which does more work for the same money?

Diesel on red I am sure would be much cheaper but fitting a diesel engine would be expensive and heavy which would not be ideal on a road tow machine. Plus I dont want to sit in the smell of burning diesel all day any more than I do petrol. No noticeable smell so far but not done any long sessions yet. 

[Justme]

On 07/01/2020 at 17:10, openspaceman said:

They charge 70quid for 47kg near me which works out at £19/day on gas if you currently use 16 litres of petrol.

 

Autogas near me is 60p/litre  the equivalent price is £1.2/kg so 47kg of autogas would cost £56.40 even with road duty.

£70 eeek we pay £42 inc vat.

[eggsarascal]

20 minutes ago, Justme said:

£70 eeek we pay £42 inc vat.

£74:50 in Sudbury, I choose to buy mine off a bloke that fills bottles from his tank.

 

I understand the risk involved.

[Justme]

10 minutes ago, eggsarascal said:

£74:50 in Sudbury, I choose to buy mine off a bloke that fills bottles from his tank.

 

I understand the risk involved.

Mine are from a company and get delivered for that price.

[scbk]

I always mean to come on here and ask, how did you get on with propane in the end Woodworks?

[Woodworks]

5 minutes ago, scbk said:

I always mean to come on here and ask, how did you get on with propane in the end Woodworks?

Tricky to say. The engine ran fine on it and was very convenient with no odour when working. After a while it became harder and harder to start. Carb was checked as was the valve spacing but neither resolved the problem. In the end the engine was a non runner and I ballsed up my shoulder starting it. Bought a new key start engine but have not yet put the gas adapter on it. The old engine is with a local engineer awaiting a post mortem. The machine was not new when I bought it and its done some hard work since so I wont call judgment on the gas conversion just yet. If the old engines problem cant be related to the gas I will convert the new engine in a flash