LNG anyone?

[lat 64]

So,
I've been thinking. What if there's an advantage to convert to Liquified Natural Gas for an old A-4?
I checked around the net for kit suppliers and such. It seems doable.

Benefits as I see it:
Less fire danger,
Same fuel as for cooking,
can be same fuel as heating too,
no more water in fuel,
no more old fuel problems,
clean burning(less CO danger),

This thread is to stir up some thoughts on unforeseen drawbacks, difficulties and such.
Can you all see any besides finding proper design, cost of installation, and availability?

Russ

[Administrator]

Russ:

Is LNG the same as CNG?

Bill

[lat 64]

I don't know for sure, but I think so.
You have to compress it to liquify it I think.


The best comparison for a conversion I found is the forklift kits for propane, but that's heavier than air.

[msmith10]

Great question and I'll be interested in hearing the result.

[Dave Neptune]

Alternate fuels

Russ, there are many conversion kits for fork lifts as you stated. I have worked with quite a few propane applications both for street and racing purposes and have found the carbs to be quite reliable as far as shutting down the fuel. I have not worked with CorLNG but I would think that the engineering in the carbs would be just as good.
Does anyone know how much heat is available with CNG as compared to gas or propane? Also what are the preassures we would be working with?
I have wanted to try to find a CNG operated fridge to try adapting to a boat. CNG could be used for cooking cooling and heating why not add propulsion to the equation.
One big bleep tank and a spare?

Food for thought
Dave Neptune

[lat 64]

This is the best I ame up with for a supplier:

http://www.hendrixsystems.com/

I'm sure there's many more.

In the 80s here, the cab companies used propane. It seemed to wear the exhaust valve seats sooner. We surmised it was the lack of cooling effect of incoming gas droplets on the valve. I guess when they got 200,000 to 300,000 miles on their dodge 318 v-8s, then they didn't worry too much that the seats were worn out at that point.
I know the oil and the rest of the engine stayed much cleaner than gasoline engines.

When we did rebuild the heads for those cabs, we put in hard valve seats and sodium filled vales from truck engines if we could find them in the used parts bin.
I think the spark advance curve was shorter too. Some times this is just a matter of lighter flyweights on the distributer. That might have been the cheepo way anyway.

Russ

[Dave Neptune]

Seats

Russ, I have seen the seats hammered out as well from going to propane however I don't think it would be a problem with the spring preassure on the A-4's. Heck you don't need them since the lead was removed from our fuels. I also saw a lot of cracked heads along the intake runners from the icing affect of the vaporizing fuel. Those were mostly trucks which loaded things up a bit more.
I have been working on a dry lake car that is propane & alchohol fueled with 26 pounds of turbo boost in a 502. It is making 1300 HP and we had a major problem at Bonmneville. Due to the chilling affect of the propane and the alchohol injection the manifold literally iced closed. What we had to do was modify the air coolers on the turbos to be heaters instead. On a 100 degree day the intake runner 6" away from the valve is 68 degrees at 26 psi. The engine runs at 210 and we are running the coolant into the intercoolers to preheat the air. Yes I know it doesn't make sence but otherwise the intake will ice closed. It took along time to figure this out he wasted 3 seasons on the flats. The truck would get half way down the flats and then just start slowing down and almost die. By the time it was towed back the ice would be gone, so the third season Ed got a IR gun and chased the truck down and shot it everywhere to see if he could find something and he found a manifold below freezing and full of ice, now scratch your head after a nap on that one.

Dave Neptune

[Dave Neptune]

Oops seats part II

The hp is actually 1740 at 26 psi however in street trim it is 1300 at 20 psi. It is a fun ride and really turns haeds when it runs. It's a 37 Chevy flat bed witha mid engine hidden under the tool box, The three P/bottles need to flow enough fuel are under the hood.
Out Dave

[ndutton]

I had an El Camino converted to propane in the early 70's right before the petrochemical crunch and as propane is a dry fuel compared to the leaded gas of the era, it was murder on valves and seats. I expect CNG would have been similarly hard on them. Having said that, I have no idea if our A4 valves and seats are comparable to a vintage Chevy.

As to available therms between gasoline and CNG, gasoline is way higher at equal volumes of equal pressure by a factor of at least (I think, not guaranteed) 2X.

I have a client who manufactures custom hot rod wheels. He preheats the aluminum rims prior to welding on an automatic rotating machine that uses propane as a fuel (propane's therms are a little less than gasoline for comparison). His new shop came with a massive natural gas supply and he looked into fueling the preheat machine with nat gas out of convenience. The therms were so low by comparison that the plan was scrapped before the first pipe fitting was purchased and the nat gas pipe was plugged.

[sastanley]

Dave, I read about that very issue (icing up during the run but the ice melted before anyone could figure it out) not too long ago in maybe Car & Driver or something..

I always like reading about cars at Bonneville. Glad you figured it out!

Where I am, at the local race track (Maryland International Raceway) the kids bring bags of ice and lay on top of the valve cover in between runs to cool the motor down...these guys are running regular gasoline...this is at the 'test & tunes'...'run what you brung' and all that. I personally never thought it was a good idea, but the only time I ran my own car was in stock trim and it ran a 17.9 () in the 1/4 mile. If I EVER get my transmission issue fixed, I plan to take it back to the track, as that was my goal to see what I could do with it with a new motor & tranny that I put in myself. Too bad I put in a bad tranny, because now I've cannibalized the slower working tranny, so i have two bad ones and a car I can't get out of my driveway.

[Dave Neptune]

Seats

Neil, the seats in the ole A-4's are better than the old Chevy and most others as well. The A-4 is a hi-nickle block and the seats are in the block not the head. When the lead was removed form our fuels all heck broke loose especially in anything that would be considered a performance engine. Those engines that experienced most of the trouble had two strikes against them the soft cast iron seats and very hi valve spring tension to carry the cam profile and rpm's associated with them. The A-4 with hi-nickle seats and almost no valve spring preassure to speak of and low RPM's the seats should be no problem and haven't been that I am aware of.
I would think that converting would just require a stainless valve and not a sodium filled ones. These engines are a constant duty type as they are not throttled back and forth due to traffic which causes havoc with chilling then heating etc.

However if the heat ratio is close to 2:1 compared to gasoline these little beasties may not make much power on CNG.

Dave Neptune

[ndutton]

However if the heat ratio is close to 2:1 compared to gasoline these little beasties may not make much power on CNG.

Don't rely on the 2:1 figure as gospel, it was drawn from my often faulty memory. Although I'm certain CNG offers less heat than gasoline, I'm not certain as to the exact ratio.

[Dave Neptune]

Heat

Niel, that's why I said if. I'm don't know either although like you I do know it is less.
Dave

[lat 64]

Salt shakers, cool!

Dave, Does your friends hot rod have a blog or web album?

Regarding icing: Thats a familiar story with me, I had an old Mercury Capri all tweaked poor-boy style. It would ice up the carburator venturi on rainy mornings before the engine warmed up. It was the little 2.6L v-6 and I put used valves from a ford 200 six in it. It was breathing lots better now and the pressure drop at the venturi was just enough to make ice on a wet morning. I just built a carb heat duct to warm it up and it ran fine after that.
There have been a few airplane crash mysteries solved by opening up the Bendix fuel injection and finding slush in the intake.

Valve seats: I have read that just having a different melting temp for the valve from the seat is helpful to avoid wear. The valve it seems will weld it self to the seat microscopically each cycle and the repeated weld/break erodes the seat.

Below is from the web (where else?)
Any thoughts on running our engines on dung?

Fuel Energy Content & Conversions

Here are some approximate energy comversion factors. The exact values will vary depending on the quality of the fuel and in some cases the pressure.

Propane

1 gallon = 91,500 BTU
1 cubic foot = 2,500 BTU
1 pound = 21,500 BTU
4.24 lbs = 1 gallon
36.39 cubic feet = 1 gallon

Natural Gas

1 cubic foot = 1,050 BTU

Gasoline

1 pound = 19,000 BTU
1 gallon = 125,000 BTU
1 gallon = 6.1 lbs

Oils

1 gallon kerosene = 135,000 BTU
1 gallon #2 oil = 138,500 BTU
1 gallon diesel = 139,200 BTU
1 gallon #6 oil = 153,200 BTU

Other Fuels (dry)

1 lb hydrogen = 51,892 BTU with steam as product
1 lb coal (anthracite) = 12,700 BTU
1 lb coal (subbituminous) = 8,800 BTU
1 lb coal (bituminous) = 11,500 BTU
1 lb pine wood bark = 9,200 BTU
1 lb hardwood bark = 8,400 BTU
1 lb wood = 7,870 BTU
1 lb dung = 7,500 BTU
1 lb waste paper = 6,500 BTU
1 lb sawdust/shavings = 3,850 BTU
1 kWH electricity = 3,413 BTU
1 therm any fuel = 100,000 BTU

[sastanley]

1 lb dung = 7,500 BTU

LOL - you can see what my warped mind always pays attention to.