This may be an unusual question.

I'm thinking of converting my '91 460FI based motorhome to liquified natural gas. You know, the stuff you use to fry pancakes on your stove (US). In a perfect world, it would be dual fuel and could use gasoline assuming I can't find a refuelling station enroute. What would it take? Is there a conversion kit available anywhere? Is there one that can pass California ARB sillyness?

It's an F53 chassis and is big enough that I can mount a lot of fuel tanks. It is even big enough that I could mount a fueling compressor that could tap anyone's lng home service and refuel for next to nothing. Of course I would pay them.

It is good for the environment and good for my budget.

(I voted for "gonna have issues")

 

Your biggest problem is going to be fuel capacity. Most LNG and CNG tanks are not very big.

 

Good point, but this is a 28' long chassis with a box strapped to the top of it. I have room for a LOT of tanks chained together. My biggest problem is California law that does not permit interfering with the operation of the on board diagnostic system.

 

http://franzh.home.texas.net/

This guy posts often on an alt fuel forum with others. he is the go to guy for anything and everything.


http://www.propaneguy.com/ Another cool link

http://www.dualcurve.com/

 

I am thinking of LP gas, I suspect Natural gas is similar, so if I am off base, forgive me. I have seen many a conversion done south of the border when it was economical to do so. However, after observing some engine failures due to hanging a propane tank over a gasoline engine, I have to mention this may not be economical in the long run. I have pulled the heads of a baddly running engine to see the valves beat through the seats into the head, destroying the heads, due to lack of lubrication. Propane is dry. Most gasoline engines have valve rotators, at least on the exhaust valve. If I recall correctly, they must have special hardened seats and (maybe) valves and have the rotators removed to survive. (correct me if I am wrong, as I am doing this from memory). Then, if you wish to go back to gasoline, you have to reinstall the rotators. You will also lose power from the lower BTU's of LP - may not be very good on a long mountain pull.

Short term, you may save money, long term, you will likely destroy the heads. Ever pull heads on a motorhome???

Just my own experiance and thoughts ...

 

I have heard somewhat identical claims by a few people. However, I do know a few companies make a valve saving additive that lubricates especially during a lpg system.

Off the top of my head I would say Flash Lube which can be googled up easily. They do have a North american Distributor, so you can get a hold of it.

I forgot, some people claim any hardened set of valves for unleaded would work fine with the gas. Don't know If it is true, but has been said a few times to me.

 

On most of the "unleaded engines valve seat damage is not as much of an issue. The key just like gasoline is to keep it in proper adjustment and tune. Dual Curve (MSD) units eliminate most of the timing issues that destroyed a lot of heads. But as mentioned earlier on modern engine if you do not have an approved kit most of the time you cannot change them over.

 

I've been in contact with the California ARB. It has not been very helpful, but I'm not done yet. The problem is that they are all about electric and hydrogen fuel cell vehicles. They don't pay much attention to big old motorhomes.

As to the valve seats, I don't think that is a worrisome issue. There are a lot of fleet vehicles that run for a whole big bunch of miles on natural gas. Oh, and in the US, natural gas == propane. In Mexico, you are likely to get butane. Different stuff, so be prepared. They do not interchange. It is the equivalent of gasoline vs. diesel fuel.

 

You might inquire directly of gas companies to see what they run in their own fleets.
If you could limp through inspection on a small tank of hydrogen, then switch back to "whatever" that would also be interesting...
"My biggest problem is California law that does not permit interfering with the operation of the on board diagnostic system."
Hence, any alternate system should be an almost complete workaround that you can convert back for the eco-***** to inspect each year.

For the suffering involved, it might be wise to choose a much older vehicle you can modify to your hearts content.

 

If you use certified equipment for your model (assuming it exists) and can show the EO
numbers to the inspectors, it can be done in California.

i'm converting my '82 E350 van to propane using Impco equipment. My application is different from the OP's tho, as mine is carburated, open-loop and non-catalyst, whereas the OP's rig is (i'm assuming as a '91) fuel injected with catalytic converter and OEM feedback systems.

Subject Top Page: ARB Executive Orders
Subject Top Page: Aftermarket, Performance and Add-On Parts Regulations
http://www.arb.ca.gov/msprog/aftermk...s93_022607.pdf

 

There is too much confusion here and it is common on this subject. CNG, LNG and LPG are NOT the same, or even close.

LPG (Propane and Butane) are easy, but the fuel is just as expensive as gasoline in many markets, much cheaper in some. It still comes from crude oil.

LNG is what is shipped in big tankers across the oceans, not what you can buy at the pump. It is hundreds of degrees below zero.

CNG is what T. Boone Pickens is pushing because he can make money off of it. Pickens Fuels owns a good percentage of the fueling stations. Conversions are more complicated because it is dispensed and stored at 3200-3600psi. The home compressor thing sounds attractive until you actually try to get the permits and run the numbers on lifetime costs.

I didnt PM you because Im not clear on which one you really meant.

"Oh, and in the US, natural gas == propane. In Mexico, you are likely to get butane. Different stuff, so be prepared. They do not interchange. It is the equivalent of gasoline vs. diesel fuel."

I think you have it a little mixed up. Propane and Butane are both liquid at room temperature and low pressure. LPG can be a mixture of both. Methane (Natural Gas) is still a gas at very high pressures and down to very low temps.

Jim

 

Forget cng or lng and go with lpg i,ve had hundreds of thousands miles burning lpg . Contact gotpropane.com.