Diesel Truck for hunting

[Darryl Cassel]

Txhunter

I believe you will find it's the flash point of diesel fuel as compared to gas.

The preheaters on the Dodge heat the fuel and the vehicals with glow plubs heat the cylinders and also the fuel that is being pumped in. Heating the fuel and/or cylinders help the diesels start in cold weather since the flash point of diesel fuel (under pressure or not) is much higher then say a gas engine therefore, heating of the fuel and combustion chamber first, is needed in cold weather.


That's another reason the over the road drivers seldom shut the engines down in cold temps. They may not get them started again if they cool off and a glow plug or two doesn't function correctly.

Your teacher was correct , "if" the engine was gas and had high compression like gas engines do, heating wouldn't be needed in cold temps.
With the flash point being higher in diesel fuel and many times lower compression then a gas engine has, the preheaters and glow plugs are needed to get them started.
If you keep the block heaters plugged in or keep the vehical in a warm garage, no problem at all starting. You don't even have to wait till the warming cycle light goes out.

I think most will find that the flash point of Diesel fuel being higher then it would be for gas engines is the main reason for heating the fuel and chamber "first" in cold temps.

I have a Case backhoe with a diesel. In cold temps that engine won't start at all unless it's heated first. When the temps climb above 30 degrees, it fires right up. Needs glow plugs replaced.

Later
DC

 

[steve smith]

Sorry DC
I'd have to disagree with you there. Diesel engines have a much higher compression ratio than gasoline engines. Most gas engines have a compression ratio somewhere around 9:1 where as a true diesel (like the Cummins) has somewhere around 16.5-17:1.

Though I do agree with you on the flash point of diesel being much higher than gas. And that it remains constant at any pressure. But I still believe that the amount of compression (and the amount of heat generated during compression) has a lot to do with starting troubles in cold weather. Diesel engines with low comression would have trouble starting in cold weather with or without glow plugs. The Onan generator I mentioned earlier has much lower compression and will not start in 101 degree weather without running the glowplugs through the heating cycle. I know be cause I tried.
Looking back at the various gas laws used in chemistry, If you take a given volume of air (the number of molecules is fixed, we'll say one cubic liter)at atmospheric pressure, and ambient temperature. If the volume of air is compressed to half of it's orininal volume (now .5 cu liters, but the mass remaining constant (1cu lt @ 1ATM) the temperature increases accordingly. Now if you compress the air even more (lets say down to .25cu liters, (a 4:1 compression ratio) the temperature increase in a predictable path. The final temperature is entirely dependant upon the initial temp and the amount of compression. So with my experience in my truck @28 degrees F a 17.1:1 compression ratio is enough to raise the air temperature to the flash point of #2 diesel fuel with out the use of the fuel preheat. With the onan generator in 101 degree F the compression ratio is not high enough to raise the temp to the flash point of diesel. Hit the plug heating button for 30sec and it fires right up. The generator is a diesel engine but it is not a true diese engine, in that it requires an external heat source to fire. The Cummins engine is a true diesel in that it requires only the heat generated during compression to fire.

[ 02-09-2004: Message edited by: txhunter ]

 

[ewallace]

I just got my diesel Ford 4x4 F 350 6 speed manual trans

Crow Mag

 

[Matt Regalia]

Eric, VERY VERY nice. Looks like a 1999 model. Let me know if you need any info on where to get great deals on fuel filters and such. Or if you feel like you want a performance chip I can give you some suggestions too. Congrats on the new hunting rig.

Matt

 

[Darryl Cassel]

Txhunter

First, I'm speaking of engine performance at "cold temps" here.

As you mentioned, not "all" diesel engines have high commpression and this is true. Some are designed higher and some lower.

Purpose of the preheaters and glow plugs is to fire up "faster" in cold weather and get the engine running quicker and to smooth it out faster.

Sure my Cummins will fire and run in real cold temps but, it runs like crap for quite a while until it gets warmed up. To preheat the fuel causes a much faster start then if I just turned the key and started it. My Fords wouldn't do that at all in cold weather without the glow plugs at full heat.
When using the block heater and/or just warming the fuel with the preheaters, a much faster start is achieved and you are on the road quicker.


In extreme cold temps like at high altitude in Colordo and without the block heaters pluged in, it was tough getting two Ford diesels started. This could have been because of one and two of the eight glow plugs not functioning correctly.

Again in cold weather The Dodge will fire up fine with the preheater on but it just takes a long time to run smooth until the engine warms up and we all know how long it takes to warm a diesel at idle.

In conclusion;
The main purpose of the fuel preheaters or the glow plugs is to "heat the fuel" in cold temps for "Faster" starts and for quicker and smoother engine performance. This again is because of the high flash point of Diesel fuel compared to gas.
The perheater and glow plugs are there for that purpose and should be used everytime a cold engine is started. That's in every owners manual.

Another example of the heat causing a faster firing is in the summertime. When the engine and fuel is warm it will fire and run just fine without the preheaters being on at all. "Warming the fuel is the key."

I forgot to ask--What diesel do you own?

Later
DC

[ 02-10-2004: Message edited by: Darryl Cassel ]

 

[Darryl Cassel]

Crow Mag

Nice truck.

Be aware though, if your in a backwoods situation in Colorado (like where we go) there is the famous mud known as "Gumbo", just watch out.

Your duelly rear tires will not ride the ruts
well and you will get a fish tailing when the rear end slides around on inclines and going downhill in the terrible mud.
Saw a duelly go over the mountain a few years back, in our area.

We have to put chains on all four wheels and "stay" in the ruts as much as possible when leaving the hard road.

The fellows with the duellys leave them out at the hard road and ride the horses or 4 wheelers back in where we go now. I guess the word spread about the rancher that went over the mountain in his?

Just a thought, be careful and remember, aggressive tires and chains are a must in the Colorado Gumbo.

Later
DC

 

[ewallace]

Thank you Matt
It is a 99 and we will have to talk about performance in a couple weeks the next time we shoot.

Darryl Thank you for the info I have 2 sets of heavy duty chains that will fit on the duelly I may have to get one more for the extra tires in the back or a duelly set I will see how it works

Crow Mag

 

[steve smith]

Nice truck! Looks like winner to me.

Sorry DC, didn't mean to sound like I was trying to argue with ya there. I guess I was trying to say that in cold weather with a Cummins engine if the fuel preheater fails, there is a higher probability of the engine starting up than with a Powerstroke or Duramax with bad glow plugs.

Oh almost forgot! I've a 2002 Ram 2500 4x4 HO Cummins and 6spd manual transmition.

 

[Darryl Cassel]

All right Txhunter.

That's the Dodge I would like to have and it will be my next one when I get 300,000 or 400,000 miles on the one I now have.

I have a friend who has the 6 speed HO and he also put a banks kit on his. It was unreal before the Banks kit but now it's an animal.

His bug shield says--"Powerstroke this"

I know what you mean about the glow plugs. They do fail and they did for me and another friend who use to have Ford diesels.

Thanks for the reply, always good to hear from another Dodge diesel owner.

DC

 

[Matt Regalia]

Eric,

Shoot me an email and let me know when you are planning on hitting the fields again. I am trying to plan an open weekend the end of Feb, beginning of March.

Matt

 

[ewallace]

Where do I start with boosting the power?

 

[Darryl Cassel]

Call "Banks" in California "FIRST". Ask for Pat Delaney 1-800-438-7693

Later
DC

[ 02-11-2004: Message edited by: Darryl Cassel ]

 

[steve smith]

"Power Stroke This" Now that's funny! I gotta get me one of those. hehe

 

[ewallace]

Thank you Darryl I talked to Pat today very knowledgeable.
Crow Mag