Re: Quit Being A Goddamn Idiot, Bill Hughes!!

I was running a 50% mix of the correct and new antifreeze (the rad was changed a week before). I looked around the internet and it seemed to be a fairly common phenomenon (especially when starting fork lifts which had been left outside on cold nights). It took a long time to unfreeze as well - several hours.

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

God Bless America, ßill O|||||||O> mailto: snipped-for-privacy@aol.com

L.W. ("ßill") Hughes III did pass the time by typing:

Ted never ran an old propane/diesel tractor in cool and humid weather. They ice up and stick without a heat riser or hot air intake and can literally run away till things warm up.

Propane similar to NO is stored as a liquid under pressure. NO is stored at a much higher pressure than propane. P1V1/T1 = P2V2/T2 i.e. the greater the pressure drop the greater the temperature drop. Part of the boost caused by NO is due to the cooling effect and resulting increased density of the air/fuel charge. For almost all NO installations the injection is under the TB or carb. For a propane retrofit it is always before the TB or carb. That's the issue. Given the right conditions a propane vehicle will cool the intake air enough to cause ice to form on the butterfly.

Propane vehicles feed the Propane under pressure to a vaporizer, which uses engine coolant to heat the propane. If it's going to freeze up anywhere, it's going to be here-where propane takes the heat of vaporization.

Frozen throttle bodies just haven't been a problem with propane installations. Frozen coolant passages in vaporizers, evidently yes. Carb fires in dual fuel installations, definitely. But no one in the LP vehicle industry I have been able to find has ever heard of frozen throttles.

Propane in short has problems-problems that can be solved, just like gasoline has. Gasoline is not necessarily the best fuel, it's just the one that's been the most available. If alcohols, kerosenes, heavy fuel oils, or condensable gases were available much cheaper, and the government didn't get in the way, we'd find ways to burn them and be happy. Indeed, people have.

(I'm not sure what you mean by a propane-diesel tractor. Compression ignition engines cannot burn propane as a primary fuel,because diesel injection systems aren't capable of handling what is essentially a cryofuel and because propane is a very low cetane fuel. (Low cetane~=high octane). Either it's used as a fumigant auxilliary fuel for power augmentation and smoke abatement (which works well if not overdone) or you drop the compression, put in a spark plug, and fit a throttled propane mixer and run it as a spark ignition engine.)

But then you get these fat pompous channelmasters who think they know everything and they just like to badmouth anything that isn't the status quo. I think it's because they are really afraid if they had to go back and work out anything from first principles they'd be shown up for what they are.

Perfect for when you want rooster tails of dirt while plowing your field.

Matt Macchiarolo did pass the time by typing:

Or tractor pulls. :)

Now where did I put that link for the 4x4 tearing down the drag strip....

Foo. It was here but it went bye bye. :(

God Bless America, ßill O|||||||Omailto: snipped-for-privacy@aol.com

L.W. ("ßill") Hughes III did pass the time by typing:

That was it. :)

Still wonder just how long the engine will last before barfing its guts all over the road.

[snip fore and aft]

Given the right weather conditions (cool and humid) the previous engine in my `79 CJ-5 would occasionally ice up the throttle butterfly. It was always a little exciting when it would happen, because I'd only notice when I was trying to take _off_ speed and the gas pedal would stay where it was. I'd have to give it more throttle to get it unstuck.

Hardly the fault of propane then,was it? (Shades of Monty Python's stunned parrot....)

Yes, it happens, more often a linkage problem than anything else. But this was about propane specific throttle freezeups.

Aside from the cold why do carbureted airplane engines freeze up at high altitude? I thought at high altitude there was very little moisture?

-Bill (remove "botizer" to reply via email)

Wblane did pass the time by typing:

Depends on the definition of "high" but for private(unpressurized) there is a lot of humidity from sea level up to 8-9000ft. The pressurized craft that fly up higher are usually turbofan or jet and aren't susceptible to ice like a piston aircraft. (the control surfaces just get too cold and ice upon decent causing loss of control) Which by the way is fixed somewhat by having the fuel actually warmed in the wings as part of the heat management system.

Keep in mind the cooling effect is from the venturi in the carb and the addition of liquid fuel that takes heat to vaporize. The fuel is injected just before the venturi opens up, then the charge gets room to expand. Expanding gas cools and if it's cold enough it will start to cool the whole carb until the whole shooting match is at freezing, then bad shit happens.

.. Yea, I hung around aircraft for a few years, but learned most from the private pilots at work..

Wblane proclaimed:

There is enough moisture to condense due to nothing more than the turbulence from passing aircraft...aka contrails or more formally condensation trails.

The absolute humidity will drop off as you go up in a standard atmosphere, but the relative humidity may still be near 100%.

The planes most in danger of carb icing don't fly very high...