CNG or LNG Conversion

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Might want to PM DudleyFJ40. He has done this on his '68.

Tony
 
mybluetoy said:
I have a 1972 FJ40 with an early 80's chevy 350 motor. I would like to change over to compressed natural gas or liquid natural gas, could someone list a link or give some detailed info on where to go for this.
Click to expand...

Hello, LPG is way better than CNG. The LPG (or propane) is stored in a liquid state which allows you to carry fuel per volume.

You will first need to decide if you want a dual fuel or propane only. I chose dual fuel because I drive on the road alot. I would hate to run out of propane away from home and not have a "reserve tank" to get me home.
 
There are a couple of good threads on both cng and lpg conversions down in the alternative fuel section. I am considering a cng conversion myself.
 
Propane filling stations are more common than CNG fill stations where I am.

Matter of fact I have never seen a CNG fill station.

I have a CNG line running to my house but I can't tap into it to fill my tank.

Now for the LPG barrel at the farm that is a different story. :D
 
Dudleyfj40 said:
Propane filling stations are more common than CNG fill stations where I am.

Matter of fact I have never seen a CNG fill station.

I have a CNG line running to my house but I can't tap into it to fill my tank.

Now for the LPG barrel at the farm that is a different story. :D
Click to expand...

I am putting a fill station in my carport off the Southwest Gas line coming to the house. I am probably not going to convert my cruiser, but my wife's pickup truck. She never leaves town in it, but puts a lot of local miles on it.
 
Think about the issues. CNG is not a great fuel to use - propane is better - I've used both inj several vehicles.

CNG cons are:
approx 70% of the power and range of petrol.
Very heavy tanks - and to get a decent range you need bigger than for propane.

Also, CNG is very dry - you may need to consider some form of upper cyclinder lubrication - like a Morey's kit or similar...

And because of the difference in ignition curves, it's much harder to set up for dual fuel without some form of dual curve ignitiuon system. Propane is much easier to get a single compromise that works for both fuels.

Having said that for many years I ran a large 4 litre van on CNG with no problems but having since used propane on my cruiser I'd not go back to CNG.

The other issue - CNG is much more prone to icing up the regulator and mixer than propane. How cold does it get where you are?

I'd get icing problems (as in so much ice the vehicle would stop) once the temp got down to around 5 degrees C. Thius was under sustained full throttle - less throttle makes this less of a problem. But more cold makes it much worse!!

HTH
 
I had forgotten all about this thread, glad I am still looking to do the LPG conversion. I had to do some other conversions first. Now with the winter on its way here in Michigan and the price of gas going up I will be doing a LP conversion. I see that there is a dual conversion that you can run gasoline or LP? Could someone explain this and I was wondering is it more economical to run LP as this will be my daily driver from April through October and then back to storage, Michigan winters are rough on any vehicle with all the salt that the road commission throws down. I have a 350 sbc and was wondering what type of milage I would get, also what is the typical size tank I would want to have. Where is the best place to purchase the kit, as far as quality, customer service, price, and so forth. Thanks and sorry it took so long to get back to this thread.
 
I bought most of my stuff in Minn at Acme Alternate Fuel Systems.

ACME Alternate Fuel Systems Homepage

I had great luck with them, I bought partial stuff other places then what was left that I needed they had it and then helped me through set up. Give them a call.

Search for Impco on Ebay and other places, these are the most popular. Impco 300 50-60 is what I am running on my 350. The 50-60 has more CFM's. It is a dual fuel. You can see a basic pix in my "Garage".

Hope this helps. :cheers:


 
one question where do you all mount the Propane tank and how many liters does it hold .
i would love to convert mine to LPG only ,but am concerned with size and location of tank?
any body got pics. also what kind of mileage do you get out of the tank.
most converted vehicles here have these huge tanks.
 
I have a 43# (10 gallon) Fork Truck cylinder mounted underneath. It fit really good.

0726091241a.jpg

Being you have to remove it to refill this would not be the tank you would want. It works great for dual fuel but wouldn't for straight LPG.

I get 7 mpg with petro and 7 mpg with LPG.
0726091241a.jpg
 
I have run propane systems for years - until I discovered diesel, I even converted a chev caprice to propane took about half a day with all the parts, I ran my last F250 with a 351w on propane only, There are alot of drawbacks to propane , Things like the mixer freezing up ( if your coolant is even a little low ) Needing your distributor adavanced, running hotter plugs , Make sure you have a decent secondary ignition sysytem as well, a Msd box and coil thicker plug wires . one thing that will suprise you is how clean your oil is you can go six months and the oil will still be clean, If you intend for the motor to last I would consider getting the heads rebuilt with hardened valve seats .

Lastly you are going to spend quite abit for all the parts new, where as you can purchase a propane vehicle from craigs list and transfer every thing over for 1/2 the price or less. Just search craigslist for "propane". I would consider purchasing my tanks new. You may need to get it inspected in order to fuel up .
 
Dudleyfj40 said:
Propane filling stations are more common than CNG fill stations where I am.

Matter of fact I have never seen a CNG fill station.

I have a CNG line running to my house but I can't tap into it to fill my tank.

Now for the LPG barrel at the farm that is a different story. :D
Click to expand...

The solution is is as far away as your carport and the CNG line running to your house. MyPhil is the at home CNG filing solution

lc69hunter said:
I am putting a fill station in my carport off the Southwest Gas line coming to the house. I am probably not going to convert my cruiser, but my wife's pickup truck. She never leaves town in it, but puts a lot of local miles on it.
Click to expand...

X2,

For me the trick is finding a bi-fuel solution for CNG/diesel. Just like the guys who run a bi-fuel propane setups, flip a switch, CNG, flip a switch diesel.

I´d run CNG for around town and daily commutes.
 
Last edited:
two 10gal fork lift tanks on rear tire gate? 72 fj40

Has anyone heard of propane tanks being mounted on the rear bumper tire carrier? I have a 1972 fj40 with a 1968 chevy 327, im going to convert to dual fuel and i run a hard top, so in the bed mount is out. I have a 22 gal gas tank that i want to keep under the bed. so my thought was to build a rear gate to hold 2 - 10 gal tanks. my thought was that if i mount the bottom of the tanks higer than the average hood height i should be ok from a rear end collision? any in put welcome. if any one has done this or seen it done i would love to see some pics. thanks
 
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