Converting small petrol engine to run on propane

[Woodworks]

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?

[Dan Maynard]

Did you find a conversion kit? Might be interested if cheaper to run as I have a Honda engine chipper.

Could catch on with all these petrol chippers around.

[Woodworks]

1 minute ago, Dan Maynard said:

Did you find a conversion kit? Might be interested if cheaper to run as I have a Honda engine chipper.

Could catch on with all these petrol chippers around.

Here you go 

LPG Kits | Honda Engines and Generators | Gear GB

WWW.GEARGB.CO.UK

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LPG Kits | Honda Engines and Generators | Gear GB

 

[openspaceman]

37 minutes ago, Woodworks said:

Here you go 

LPG Kits | Honda Engines and Generators | Gear GB

WWW.GEARGB.CO.UK

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LPG Kits | Honda Engines and Generators | Gear GB

 

That's not the name of the conversion I remember. A firm called arboreater (I think @Mick Dempsey may remember better) equipped some small chippers about 15 years ago and it seemed such a good idea but never took off.

 

The thing is that a cylinder of propane weighs a lot more than a tank of the same calories of petrol.

 

Also back then the only economic size to buy was 47kg ( or a liquid draw off tank to fuel a hot air balloon, thius being the cheapest propane I'm told). Otherwise you can fill a portable tank at an autogas pump for just under 70p/litre. Thereby lies a problem, a litre of lpg only contains 70% of the calories of petrol whereas a kilo of lpg contains more calories than a kilo of petrol.

 

Once you draw off more than a few kW of power the propane freezes in the tank, this is why propane converted cars have a liquid draw off which is then vapourised by the coolant. So a 13hp air cooled engine may draw a bit much, I wonder if an exhaust heated vaporiser exists.

 

There are advantages in that the oil will stay golden, I ran a V8 LR 110  for nealy two  decades on LPG and only changed the oil at 20k mile intervals and it was still gold. A chap on a forum I belonged to sent his oil to be analysed and it was in spec at 25k miles but the detergent level had dropped and it was a bit more acid.

 

The thing I never got round to doing was increasing the compression ratio, thermal conversion efficiency is directly proportional to compression ratio and as lpg has a high octane equivalent it should pay to up the compression ratio.

 

What you are looking at is what I would like to do at home but running on natural gas and a small water cooled Honda 420cc  lawnmower engine

[Mick Dempsey]

No sorry, no idea.

 

 

I converted a 4 litre petrol Jeep to gas once (well I paid someone to)
 

£1600 it cost me......that buys a lot of petrol.

Edited January 6, 2020 by Mick Dempsey

[openspaceman]

3 minutes ago, Mick Dempsey said:

No sorry, no idea.

 

 

I converted a 4 litre petrol Jeep to gas once (well I paid someone to)
 

£1600 it cost me......that buys a lot of petrol.

My LR cost £1200 but I was asking if you remembered the name of Lucy's chippers

[Mick Dempsey]

I was unaware of them, but in fairness I’ve been here 15 years.

[openspaceman]

29 minutes ago, Mick Dempsey said:

I was unaware of them, but in fairness I’ve been here 15 years.

My bad I thought you were in the area when the firm diversified into chippers.

[openspaceman]

Edge Technology Power Ltd

WWW.EDGETECHNOLOGY.CO.UK

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Edge Technology are a recommended authorised Honda dealership by Honda UK. Suppliers of portable and standby...

I think this was the conversion used

[lux]

I have a large Honda generator on lpg. Thinks something like the eu3000 in the current Honda range. Very powerful. Very reliable. Cost about 3 or 4 k mind.
No longer in use so possibly for sale if any interest