Anyone have any info on natural gas (dual fuel) conversion to go with a carburated rover V8.

basically i am looking for info on the vapourisers and any information on what camshaft would be best suited for dual fuel.

Before you ask, its cheap where i am and I have the whole system to work with except for the vapourisers.

I will be using Dual SU carbs on a 3.5 V8, can an LPG propane vapouriser be modified to work with CNG? since the LPG vapurisers for SU carbs are readily available..

Has anyone tried to modify the SU carb needle jet to plumb in a vapouriser at the jet to eliminate any restriction at the throat of the carb by placing the vapouriser in front of the carb as done with LPG conversions? basically having the cas coming up the jet past the needle as you would have fuel...or placing a secondary jet beside the fuel jet in the carb body and having the gas plumbed into the body to it..

I've got a dual fuel setup in my carbed V8 also. imo it's not very important where you inject the mixture. With petrol the carb creates the mixture but with LPG the carb only functions as a valve.

here's a picture of a setup simular to mine:

http://www.fatboyz4x4.nl/NL/fotos/div/2002/2/Motor2.JPG

As you can see the lpg is injected into the airducts from the airbox. This setup works excellent on my rig. I'm using the standard camshaft and ignition. A dual fuel ignition probably gives you some more horsepower, but the difference with petrol isn't very noticable with the standard setup.

I don't know much about natural gas. Is this still stored as a liquid?

Just noticed this thread on the gen. 4x4 forum:

link (http://www.pirate4x4.com/forum/showthread.php?t=582838)

It seems CNG isn't a good replacement for LPG.

thanks for the info. need more though.
CNG tanks run at over 3000psi storage gas, compared to low pressure propane. the regulator brings the feed pressure down to atmosphere.

I am Not trying to replace LPG with CNG, i am adding CNG to the truck, That one guys opinion on CNG on the link you gave me was not very sufficient to make me think he had a clue regarding his opinion ( he says he drove 1 truck and has based an opinion on it) , you can get some great results with camshaft and timing changes running on natural gas. I just want to hear if anyone has actually done it on a rover V8.

How well does your setup do with controlling air/LPG mixture with the propane being injected so far up the intake??

How well does your setup do with controlling air/LPG mixture with the propane being injected so far up the intake??

It does fine. Why would it be a problem?

I was under the impression that the mixer also acted as a valve for the gas. at idle or low RPM it would draw less LPG and at higher RPM would allow more LPG into the carbs. this way you do not have a constant rate flow of LPG going in.

do you have a valve set up further back on your system between the regulator and intake that i cannot see in the picture?

The vaporizer is also the regulator. It is vacuum operated. There are no other valves other then the carburator itself in the system. The screw you see on the Y-splitter is used for the mixture adjustment. It really is a very simple but effective system. And when I run out of LPG I flip a switch and it runs on petrol.

edit, youy do need to run it on petrol every now and then to keep the carburettor seals etc. from drying out