"Do not park in gear"

[JCKnife]

We've strayed a little, but how does this backwards-running engine thing happen?

 

[tm america]

Any engine will run backwards. Ussually not to long as there isnt much fuel to be had from the exhaust system. i have seen it several times .

 

[greenjeepster]

The weight of a transmission has always been an issue for snowmobiles. Bombardier solved the weight issue by designing their engines to run backwards so they didn't need a transmission for reverse.

 

[pittdog]

look guy !... Allwasys park in doow! Youse the chock block between the duells ! ..... Parkin brake... Only temp ..ie when you you go top off !... man..d#@$%!

 

[wreckerman893]

Back to the original question.....why should you put the truck in neutral?

Scenario A: You park your deuce in the Wally-World parking lot.

Some kid (who's parents haven't a clue as to where he/she is) jumps up in your truck (which has the steering wheel chained and locked) and flips on the power switch.

The deuce is in High Range, 2nd gear and there is air pressure in the system so no warning buzzer to scare the little cretin off.

Little Dufus hits the Red button and the deuce fires up and starts rolling.....as it moves it starts collecting cars in front of it and they pile up until the sheer weight causes the deuce to stall.

Little Dufus bails and is never seen again.

You come out of Wally-World and start filling out paper work.

Scenario 2: You park your deuce in neutral with the transfer case in neutal and the power switch locked and dont worry about Little Dufus starting your truck.

Your call.

 

[emr]

Nope, not unless you have a Detroit 2 stroke in your Deuce. A 4 stroke isn't going to run backwards.

Oh yes it can and yes they have , a 465 Multi can do it easier than most simply because they start sooo darn easy, and ...running backwards... is part of the answer to the question at hand, ...how easy they start is the culprit, why U or anyone should never park a Multi in gear, but like said , fuel out no start... and wreckerman hits it right on here also, as for us the hobbiest , His is an equal part of the answer to the question at hand, good post though, alot of guys had not heard about this, good timing on asking i think..... and said earlier, any engine can. that i do not know and think would be alot harder, But as Recovery 4x4 says, it is just crazy easy to do with a Multifuel, and happens ,

 

[Flyingvan911]

Lock the doors and come out of Wally-world carrying a baseball bat.

 

[Varyag]

Just a side note and funny story. Some of my old unit went to Germany to help train some units in Armor and were issued M60a3 tanks as OPFOR. On manuvers one of the tanks tried to climb a nasty grade. It stalled and rolled backwards. The guys in the tank found out real quick that the intake spews into the crew compartment.

I also heard of M60s popping on thier own and crawling across the motor pool bumping and starting other friends along the way. Hillarity ensues.

Not a case of piston engined tanks doing this, but we had M1s firing up on occasion in our motor pool in the Cav. They are autos so they don't take a jog, just run till someone notices.

 

[6X6 ALL THE WAY]

The reason I was told by someone who worked for the goverment on vehicle safety is that if you leave it in 1st or
reverse the spring on those two gears can fail and fall into the transmission. he told me about a 5-ton dump that did this,
it caused the tranny lock up. the truck rolled and kill the three guys in it. he also told me never to leave the fuel shut off
pulled out as this can cause air to get in the pump. lastly he said don't leave the parking brake on during long periods of
time as it causes the threaded end on the cable to pull off.

 

[emr]

thats not the reason, it is an assumption, it is actually in a PS Magazine that they will run away and never leave it in gear, it is direct from the Army ups and in print... as for the threads pulling off the park brake, that is a long shot at best and i really think it all was just his opinion on that happening, kinda like guys saying u can get a ticket for useing anti sieze on wheel threads, never happen . do NOT leave the park brake on for long periods because they rust up and stick , period, and that happens alot, cant even belive the threads could ever get that much pressure when parked ,if they did would the handle be almost impossible to move, just wondering... I am only sayin the do not leave in gear rule is because i know this to be true, when i assume I say so, please take it the way I am sayin it, all in conversation... I recently had a Bldg inspector say the block straps were wrong because they should be drilled thru and pulled around the wood, just because he said it does not make it true, I showed him the picture on the box and he walked away, just sayin, to have the correct answer u need it directly from uncle sam in print and it is...

 

[6X6 ALL THE WAY]

No what I ment was the end of the cable with the threads will pull off the cable. not the threads pull through

 

[dittle]

I also heard of M60s popping on thier own and crawling across the motor pool bumping and starting other friends along the way. Hillarity ensues.

Not a case of piston engined tanks doing this, but we had M1s firing up on occasion in our motor pool in the Cav. They are autos so they don't take a jog, just run till someone notices.

M60's are automatics also and if parked in park should not pull start. I know there is a way to pull start a '60 but you have to have it in a cerain state to do so and I don't think park is the proper state.

A member of the museum up here also watch an erdolator engine run backwards as well, just another witness to the wierd multi-fuel backwards running scenerio.

 

[DMaddox]

look guy !... Allwasys park in doow! Youse the chock block between the duells ! ..... Parkin brake... Only temp ..ie when you you go top off !... man..d#@$%!

What the ..... I only get about every other word

 

[army70deuce]

Ok, since it was brought up and not really answered, HOW does a deuce run backward. I mean what actually happens mechanically, there's no turbo on the exhaust so it won't compress the air and will to valves even work that way. I'm not very familiar with multifuels yet, so can someone explain the whole process of how it can run backwards. Thanks

 

[Brentzilla]

Well Im glad I looked at this post.. no more leaving it in 1st for me!

 

[DDoyle]

Ok, since it was brought up and not really answered, HOW does a deuce run backward. I mean what actually happens mechanically, there's no turbo on the exhaust so it won't compress the air and will to valves even work that way. I'm not very familiar with multifuels yet, so can someone explain the whole process of how it can run backwards. Thanks

The turbo really doesn't have that much effect on the operation of the engine - you can take it off and throw it away, and so long as you plug the oil supply that (used to) feed it, the engine won't care.

In most turbosupercharger applications, the idea is to feed more oxygen-containing air to the engine, so that it can burn (oxidize) more fuel, and generate more power. On the LDT, the turbo feeds more oxygen-containing air to the engine, not so it can burn MORE fuel, but rather, so it can burn ALL the fuel that is already being supplied to the engine. This more complete combustion reduces the amount of unburned/partially burned fuel being blown out the stack in the form of a black smoke. This was solely the reason the turbo was installed on the LDT - so that the trucks would then meet emissions requirements.

Moving on to the core of your question - the actual compression that is key to the firing of the engine (multifuel, gas or diesel) is a function of the piston traveling up in the cylinder while both the intake and exhaust valves are closed - compressing the air trapped in the cylinder.

In the case of multifuel and the diesel engines, it is the heat generated by this rapidly compressing air that ignites the fuel (as opposed to a spark plug in a gasoline engine).

The opening and closing of the valves is controlled mechanically by the camshaft, which is geared to the crankshaft. Thus, inherently for any given combination of piston positions the valves are always in a specific relative position.

The piston, nor valves, nor camshaft care if they are being turned "forward" or backward".

Also driven by the crankshaft on the LDT (and LD, and LDS) is the fuel injection pump. Again, a purely mechanical device, it works very much like the engine itself - its piston WILL be in a particular position for any/all given positions of the crankshaft.

Thus, when the motor turns, in either direction, the fuel injection pumps fuel to the injectors, the valves open, allowing air into the cylinders, and other valves open to let exhaust escape from the cylinders.

Now, to run smoothly, effeciently, and economically, there are a number of factors - the timing of the injection sequence can be slightly adjusted, etc., that must be "just so" for you drive down the road comfortably - but to merely RUN - all the LDT needs is fuel (supplied by the mechanical injection pump any time the crankshaft turns), air, supplied every time a valve (either intake or exhaust) opens when the piston is on the down stroke, and heat (or spark) - supplied every time the piston travels up with both valves closed, and a method of exhaust (ideally supplied by an opening valve - BUT with a 22:1 compression ratio, the LDT/LD/LDS WILL find a way to exhaust - valve, head gasket, past the rings or past the valve seals - this is the voice of experience!).

All that is need for this process to begin is for the engine crankshaft to turn oh-so slightly. The starter motor turns it the "right" way - so does moving the the truck in the same direction as the gearshift selector is placed (pushing the truck forward with it in 1-5, or backward with it in R) with the clutch released......however, moving the truck in the direction opposite the gear selected with the clutch released (pushing the truck backward while the transmission is in 1-5 or forward with it in R) WILL start the engine, but in the opposite direction of rotation than the one for which it was designed.

By the way, on the LDT this causes all sorts of lubrication problems. As a point of trivia, I've crossed the Mississippi river many, many times on an old Diesel-powered ferry that was reversed by stopping the engine, and restarting it turning backwards.

Best wishes,
David Doyle

 

[Marcel]

actually not correct, It is due to the fact the these multis start and run so easy, they can jump in only a couple of feet, it was due to the fact that, actuall events of deuces left in gear that had a bump from the rear they would start and drive down the way, so it was a bulletin and then in the PM s also, it clearly states why, Also...these trucks will start so easy u can jump em backwards and the motor will run backwards, exhaust out the air intake and the air sucked in thru the exhaust. Most guys around here in years past always leave the fuel shut off out as an aditional sayfety feature, I do that always in my deuces, no fuel no start, simple.

I was backing up a hill in reverse when my five ton stalled. The truck began to roll forward so I let out the clutch with the gear selector still in reverse to stop the forward momentum and the engine restarted backwards and propelled me down the hill. The rear brake line decided to rupture at that time and I found myself with no brakes. Fortunately it was a short trip for I had two trees to stop me. The bumper looks like a pretzel and the front fenders got bent up some. The passenger (my wife) and I were fine albeit a bit frazzled. Oh yeah did I mention that this all happened with a full load of soil in my 5 ton dump?

 

[USAFSS-ColdWarrior]

Back to the original question.....why should you put the truck in neutral?

Scenario A: You park your deuce in the Wally-World parking lot.

Some kid (who's parents haven't a clue as to where he/she is) jumps up in your truck (which has the steering wheel chained and locked) and flips on the power switch.

The deuce is in High Range, 2nd gear and there is air pressure in the system so no warning buzzer to scare the little cretin off.

Little Dufus hits the Red button and the deuce fires up and starts rolling.....as it moves it starts collecting cars in front of it and they pile up until the sheer weight causes the deuce to stall.

Little Dufus bails and is never seen again.

You come out of Wally-World and start filling out paper work.

Scenario 2: You park your deuce in neutral with the transfer case in neutal and the power switch locked and dont worry about Little Dufus starting your truck.

Your call.

WM,
You have such a fantastic gift for the written word.

This little Rufus... is he one of your biological children or did you 'dopt the little inbred bass-turd

To apply some sound teaching principles here.... Little Rufus has had too much sparing of the rod and now the child is spoiled ROTTEN.... hence he needs a little more ROD applied.....

 

[cbvet]

In my 48 years of working on cars, I've seen carbureted gasoline engines run backwards several times.
They usually run poorly, and with very little power, but they do run.
I think if the timing is off, an engine can "kick back" on starting & run backwards.
I also remember push starting an old Dodge Power Wagon. The driver put it in reverse & the engine ran backwards. Twice!

 

[Westex]

wreckerman has it right. I assume you've found the little dufus's in your truck just like I have. Happened to me in Del Rio, Texas. I come out with oil and what not only to meet "papa" with his little johnny playing with the steering wheel and "papa" explains 'he just wants to be in the army.' Gave me a heart attack. Thing was pointed at the food section of Wal Mart's doors. I now try to park up against the light standards concrete base, lock and chain everything up and shop fast.