Classic conversion to deticated CNG

[dillonkbase]

Hi
I'm the proud owner of a 1965 mercedes I use as a daily driver. In reading through the forums I still cannot find any specific detailed information about converting Classic cards to cng.

I understand their are laws related to the EPA and some odp11 thing, but it doesn't sound like they apply to old vehicals, DO THEY?

What does an old vehical need to be converted legaly?

and second

Where can kits to convert old vehicals be found that safley convert them, either as a deticated or bi-fuel design---
deticated seems to have the advantage that timing can be permanently adjusted so my points still work?

[CraziFuzzy]

Re: Classic conversion to deticated CNG

I douby you will find a 'kit' specifically for that old vehicle. Also, is this a diesel Mercedes? If so, conversion would be considerably more complicated. Your best bet wouldbe going with one of the generic kits, which would still require a lot of custom 'design' work to apply it to your specific vehicle.

[topaz420]

Re: Classic conversion to deticated CNG

Or, just use homemade biodiesel, probably cheaper than CNG!

[dillonkbase]

Re: Classic conversion to deticated CNG

converting to diesel would be harder than converting to gas.

Okay so they make generic kits for gas engines?

for carburated engines?

Whats the legality?

[larrycng]

Re: Classic conversion to deticated CNG

Hi all,* lets see if I can be of some help.First someone hit a nerve -- Bi fuel.* Bifuel vehicle is a vehicle that has 2 separate fuel system and operates on one OR the other -- separately.* Dual fuel vehicle is a vehicle is a vehicle with two separate fuel systems and can operate on both systems simultaneously.* The source for these definations is 49 CFR 571.303 otherwise known as FMVSS 303.* Yes, located right before FMVSS 304 which pertains to CNG cylinder construction and under some conditions CNG cylinder inspection.

[larrycng]

Re: Classic conversion to deticated CNG

Hi again, hit the wrong buttons -- to continue

To my knowledge, 1966 was the first year light duty vehicles were required to have exhaust emission controls (1968 federal) This is taken from Calif emission requirements (and I've had a SMOG license since '65). At that time, the the Feds forced Calif to have exhaust emission controls on all new vehicles sold in the state (along with reto-fit garbage back to the '55 my). So, your 1965 Benz is probably exempt from exhaust emission controls and you can you can probably use any CNG system that will work and let the vehicle operate with clean exhaust.

A couple suggestion. Find a mixer that will provide enough air flow for the engine based on CID at what-ever RPM the engine will be expected to turn (say 4,000 to 5,000 RPM). Don't worry about volumetric efficiency, it will give you a little extra air flow capacity. Try Impco, they have something for everything. If you can, find an "off road" unit with an adjustable power screw, grab it (an old 300A might work??)

Find a positive pressure regulator that will provide enough gas flow (read BTU converted to horsepower) to fuel the engine (remember you loose 10 to 20% HP because of the natrue of the fuel system). Again Impco has a one for every occasion. Get something that will you allow to adjust the low pressure side of the regulator, (a model E might be a little big).

You can increase engine ignition advance to increase efficiency and optimise cylinder pressure. To find the right setting use a chassis dyno the old tach-timing might work) Make sure the ignition is in good condition, you might want to go a CD system or maybe "Nology hot wires" (capacitive secondary ignition). Find someone who can chemically decarbonize the cylinder (I use to use water and coke bottle) BG makes some good stuff or the old GM top engine cleaner.

When setting the thing up use a 5 gas analyzer. Set idle for a "lean best idle" If the engine is in good shape you should be below .5% CO (carbon monoxide). For full power use a dyno and set the CO setting to around 1% for full power . That will give you a mixture slightly rich of stoichiometric for best power without melting down pistons. Remember, there is no liquid fuel vaporizing to cool the cylinder, so the more fuel you add (richer you go) the hotter it gets --opposite of gasoline.

And of course use NFPA 52 as guide line to set up the fuel system. You might want to consider running the high pressure lock-off though an oil pressure switch so when the engine is off and ignition is on fuel will be shut off to the engine. Make sure you also have low pressure lock-off (Impco makes a good vacuum unit) so fuel won't flow to the engine when there is no manifold vacuum (another safety thing)

That is the down and dirty version. Take a good conversion class and a good engine performance course from your local community college that covers combustion theory, and exhust analysis as it relates to gaseous fuels (there is a difference between liquid and gas)

OK AFV Man, what did I miss?

Larrycng

[younkin]

Re: Classic conversion to deticated CNG

I am no expert but if you may need a fuel shut off when running on CNG and maybe a CNG Filter in the high pressure CNG line somewhere? Jim

[kimm]

Re: Classic conversion to deticated CNG

in terms of what is legal there are no "illegal" CNG kits period! the issue is tampering and the statute says you may not remove or render inoperative any device or element of design. As a result if you do not do so you have violated no law.

[larrycng]

Re: Classic conversion to deticated CNG

You are correct on the tampering question. I believe the questions are; 1) When did the law take effect? 2) Was it retroactive, and if so how, far back does it go? I believe this will lead to some very lively and educational discussions we can all learn from.

I know when I first started doing Calif Smog anything 1954 and older was not smogged and no one cared what was done to the vehicle. I will have to check my 1965 Smog installers handbook when I get back to Calif around the middle of Oct. and see what I can find. Otherwise I will do some searching on the Federal clean air acts, on line, in the next couple of days. Of course, I almost forgot that state law can be more strict that federal law (i.e., CARB). We also need to know what state we are dealing with.

Larrycng

[larrycng]

Re: Classic conversion to deticated CNG

I am no expert but if you may need a fuel shut off when running on CNG and maybe a CNG Filter in the high pressure CNG line somewhere? Jim

You're right on the money on both counts. The biggest problem he will encounter will be on switch over. If he shuts off the fuel first and waits a couple of seconds then turns on the NG It won't go way rich, flood out and die, especially if the vehicle is at idle. He should make any changes in fuel going down the road or on start up. The mechanical fuel pumps will just back up against fuel pressure like they do when the float valve is closed, so that shouldn't be a problem. He should turn on the fuel for a couple of seconds before shutting off the NG high pressure off. If he uses an air valve mixer (like impco) there won't be any problem with restriction, venturi mixers no concern.

later

Larrycng

[CraziFuzzy]

Re: Classic conversion to deticated CNG

switching between fuels on these 'frankenkits' is never smooth. When the gasoline fuel gets cut from the carb, it will continue to fuel the engine until the bowls are empty, as well as the CNG flowing in (unless JUST the right amount of delay is put in, which is virtually impossible to figure out), making it run way too rich. Then, on the switch back, the CNG will be shut off, and the gasoline turned back on, but until the gas gets back IN the dry carb bowls, you're getting NO fuel, so it will run way lean.

[dillonkbase]

Re: Classic conversion to deticated CNG

If i switched over I wouldn't be switching back and forth back and forth, it would be a pure cng vehicle, I just need a walkthrough on what parts i would need, or a good place here in WA to get this done. It sounds like once you get this stuff installed, and adjust your timing the engine runs very similar(maybe less power,maybe hotter).

[Yroc]

Re: Classic conversion to deticated CNG

There are diesel kits that are duel fuel. They run a mixture of both, usually 30% diesel and 70% CNG. They are cheaper and easier to install. There are many companies in Utah installing them and manufacturing the kits. They are out there. Again, if this get popular, which it will, the EPA will be all over it and try to STOP THIS CLEAN REVOLUTION.

[dillonkbase]

Re: Classic conversion to deticated CNG

I DO NOT HAVE A DIESEL.

I don't want a car that runs on 20 fuels at once just CNG forever. Now it sounds like as long as I don't tamper with my emissions equipment(which is nonexistent on my car) its legal. SO I am looking at somebody to offer advise on what parts I need or where I can get the conversion done In WA specifically. IF all i need is a mechanic to tune the engine after installing the parts thats fine also, but i do not see a generic thread on what parts people need to install cng stuff o non fuel injectedc car engines.

[larrycng]

Re: Classic conversion to deticated CNG

Ok, first go back an read my previous post #6.

Before you can find components that can be assembled into a functioning system, we need to know what is being worked on; year and make we know, what model, what engine, what engine displacement, number of carburetors, ignition system type (probably break point , you should consider a capacitive discharge system).

With that information, you can determine what mixer and regulator will be suitable for the engine. The old carbureted gaseous fuel systems are the simplest. A port injection system would be better, however it will cost more and there need to be a way controling fuel delivery and mixture.

Lets get the basics first, then we can move on to a list of components that you will need to do the job safely and with least problems on change over between fuels.

As was mentioned, change over can be a little rough, but it wasn't bad on the old mechanical propane system that use to be installed on vehicles. "frankensystem" is a bit strong for a term. This is an older vehicle and I am drawing from the older technology as a starting point. By the way if you use a air valve carburetor (impco style) you need to manually raise the air valve during gasoline operation or you will flood out.

Where are you located in Washington? I'll be in the Birch Bay area until about the 1st of October.

Larrycng