Diesel VS. Gas Which would you suggest

[MoparFreak69]

A GM gas v8 (305/350 ect...) will fit very nicely and perform whatever tasks needed

BOOOOOO!

It always bothers me when someone sticks a bowtie where it doesnt belong............

Say NO to GM! Keep your DODGE all DODGE and you will never regret it!

Hot Rod magazine explained GM best in one sentence. "GM engineers their transmissions to last 100,000 miles under normal operating conditions". Typical GM, 100K (if you are lucky) and toss it away so you can install a new one.

[MasterYota]

On a good day, I can squeak 11-13mpg on the highway. That was in its previous truck, with comparable gearing and weight and a 4spd. turnign about 2400rpm@60mph. Naturally the mileage does go down a little when working it, but thats not a real issue. The mileage for any engine under load will go down when compared to no-load useage.

[Jason Mills]

A GM gas v8 (305/350 ect...) will fit very nicely and perform whatever tasks needed for the minimum amount of dollars - period. Use a Gm 4spd (SM465) and a common splined yoke to connect it to the NP200 tcase. The stock rad will cool it just fine.

The diesel swap is cool, but you'll never get your investment out of it. Unless you plan to drive at least 220000 miles. The average V8 gas engine gets 14 mpg, and Charles Diesel will get somewhere around 20. The mileage difference is basically 6mpg. On a 25 gallon tank, thats 150 miles difference at 25 dollars per tank more operating cost( with diesel being about 1 dollar more per gallon). At 11000 dollars just for the engine you'll need to put 440 tanks of fuel through the truck. At roughly 500 miles per tank x 25 dollars more per gallon x 440 tanks = 220000 miles. After this mileage, the diesel will start to pay for itself, but the rest of the truck will be beyond worn out, and you'll be desparately seeking somthing more comfortable to drive.

I speak from experience, having driven and owned a SB powered M37 - it was a blast, cheap and fun, and reliable. My current M37 has a 7.0L 428ci big block under the hood; with 450hp, and over 500 ftbs, I can out hustle any light duty diesel you could fathom to swap into an M37, and I've done it cheaper. You can have your cake and eat it too...

what MPG do you get out of the 428?

[MasterYota]

A GM gas v8 (305/350 ect...) will fit very nicely and perform whatever tasks needed for the minimum amount of dollars - period. Use a Gm 4spd (SM465) and a common splined yoke to connect it to the NP200 tcase. The stock rad will cool it just fine.

The diesel swap is cool, but you'll never get your investment out of it. Unless you plan to drive at least 220000 miles. The average V8 gas engine gets 14 mpg, and Charles Diesel will get somewhere around 20. The mileage difference is basically 6mpg. On a 25 gallon tank, thats 150 miles difference at 25 dollars per tank more operating cost( with diesel being about 1 dollar more per gallon). At 11000 dollars just for the engine you'll need to put 440 tanks of fuel through the truck. At roughly 500 miles per tank x 440 tanks = 220000 miles. After this mileage, the diesel will start to pay for itself, but the rest of the truck will be beyond worn out, and you'll be desparately seeking somthing more comfortable to drive.

This cost breakdown is just the engine, add in the costs of a 5spd trans, and re-gearing the diffs to 4.88, and the price just goes up and up... From an economical and financial perspective, the diesel swap isn't remotely practical.

I speak from experience, having driven and owned a SB powered M37 - it was a blast, cheap and fun, and reliable. My current M37 has a 7.0L 428ci big block under the hood; with 450hp, and over 500 ftbs, I can out hustle any light duty diesel you could fathom to swap into an M37, and I've done it cheaper. You can have your cake and eat it too...

[maineSS]

If your goals are modest, a six cylinder gas engine can be made to work extremely well. Keep in mind the 230 also powered the 6x6 and the Half Track all through WWII and beyond. While the highway speed of these two were quite low, they got the job done.

The Israelis paid Dodge 1 million to fit the Slant Six into the Export PW chassis, so that can be done, though I believe the rad had to come forward a bit. I think there's enough left in the 230 to make fitting a Slant Six a wash, even though spare parts would be easier to source for the Slant.

Presently I'm getting 12-13 MPG out of a tired 230 in my B1 during summertime driving at 35-40 mph. I have electronic ignition (80's Jacobs Mileagemaster), lockout hubs, semisynthetic lube in the tranny, T-case, and diffs, and Yokohama radial tires (good for 1.5-2 mpg).

The 230 likely has another 30+ hp left in it, from my thinking, and I believe I can shift the torque band up higher with a different cam by improving induction and exhaust. The early cam torque peaked at 1300 rpm, and the later cam (used also in the M37) peaked at 1600 rpm. At 35-40 mph, you're up at 2000 rpm with the 5:81 diff- definitely falling off, as hill climbs in 4th gear will show!

The 230 was limited to 3600 rpm max because of the crank oiling arangement, but cross-drilling has allowed 6000 rpm in antique tractor pulling. The HP peak is actually in the mid 4000 rpm range, but much over 2000 rpm brings on big increases in fuel consumption.

What I intend to do is use the 1959 head, which bumps CR to 8:1 and flows better, do some valve shape and valve seat angle research to gain much needed flow, use the Fenton repro cast iron exhaust manifold, and try my Fish Carb against a triple Harley Davidson Kehein setup. I think I should be able to see 50-55 at a fuel consumption rate that won't break the bank, and still keep enough grunt down low to get things moving.

From what I've heard on the Vintage racing circuit, more attention is being paid to the 230- it's much tougher than the Ford V8, and can make more hp per dollar. Some people are reporting 170 hp dyno pulls- not bad uprating from 94 hp!

[gixxer]

I am newbie too and am interested in do a 4bt conversion as well. I found all the information posted above very informative and a great read. Over the past month I've combed this and other related diesel swap forms trying to get a parts list together of the items needed for the swap. This is something you (Jason) may want to consider as well. It doesn't seem any swap is straight forward, I went from thinking all I had to do was swap in a new motor. Come to find out I need (want) a 5 spd. OD trans too, then I found out it's better (for my intentions) to run a centered rear axle and t-case. So now I am looking at replacing the whole driver train. Just some food for thought.

[Charles Talbert]

No problem

I agree. I simply felt that some of the information provided was excessive for the question posed. I do not disagree with anything you stated, it is all good information, to the right person (it was informative to me as I have been out of the scene for a couple years). Judging by later posts from the original poster I feel that my take was very justified. He was, and seems like he sort of still is, quite overwhelmed with basic information provided, and the addition of information as it pertains to fleets in 2014 was overkill. I took it as showmanship. I understand that something typed on the internet often loses the intention of the person that posted it, and I am sure I overreacted here. I want to applogize for my actions/reactions that I posted on here and I really do hope that the information provided by everybody is helpful to Jason Mills. I think I speak for everybody when I say that is the whole goal of this forum (and all others). To make information much more readily available to anybody who wishes to ask and read.

The original question was concerning a gas or diesel installation. The info I shared should be considered by anyone doing any repower installation, especially if it's diesel. Nothing more was intended. I'm surely not saying I like or agree with the guidelines, and some of it makes no common sense at all as most any later design engine is better in the way of emissions than what came out in a '46 WDX. The guidelines are the law none the less, none of us can change that. What do we do, that's simple; either comply or run the risk of any possible consequences is the only answer I can offer on that one.

I didn't get involved because of any individual take on the matter. We are in a position of being forced into all this if we install new Cummins engines. I just shared the facts they have shared with us.

I'm sure others besides Jason will glean some good out of what has been shared. Many have told me of info they read here that never choose to get into the conversation.

[MoparFreak69]

Small bites is the prescription for this situation.
You are probably best starting with the basic theory of how a diesel engine operates.
Diesel engines do not use spark to ignite the fuel, like a gas engine does. A diesel instead relies on the heat of the compression to cause the fuel to combust (explode), rather than ignite (burn). The fuel is not drawn into the engine on the intake stroke like a gasoline engine. The only thing a diesel engine draws in on the compression stroke is air. At the prescribed point in the compression stroke (generally close to TDC depending on load, engine speed, etc) the injection pump will then squirt a fine mist of diesel fuel into the combustion chamber (in older diesel engines) or the cylinder itself (in newer direct injection engines). The fuel mist then combusts instead of burning like a gas engine.
Another major difference that a diesel engine has over the gas engine is the air to fuel ratio. For a gas engine to run properly the air to fuel ratio needs to be around 14:1 (14 parts air to one part fuel). A diesel on the other hand varies greatly depending on engine speed, load and other factors. You may notice that the majority of diesel engines do not have a throttle butterfly in the intake line (some do so this adds to confusion at times). At low idle a diesel can run somewhere around 100:1 air to fuel ratio. This is how a diesel idles, it basically just has enough fuel to keep it going. At high idle (not working, just revving to top RPM) the ration comes closer to the 14:1 of the gasser, but not quite. Only when the engine is really working will the fuel ratio increase significantly. When working at full power, and depending on tune, a diesel can reach 10:1 air to fuel before smoke becomes significant.

As mentioned earlier, component size is quite different between the two until you start looking at brand new engines that are becoming smaller and lighter to increase efficiency. Diesel engines utilize much larger parts, largely in part because the ignition of the fuel is an explosion rather than a fast burn like gasoline. The components are larger just to handle to added stresses the fuel places on them.

[Jason Mills]

Although I am still not fully "owning" all the information presented, I am learning and growing in depth on this subject as a result of each perspective because it is different from my own.

I take it that each perspective is totally 100% accurate based upon the experience that was required to formulate the ideas behind it.

I DONT have a ton of experience, so I figured I would ask the question, and learn what others experience has taught them.. so I am riding on your coat tails and appreciating everything that is being said..

[MoparFreak69]

Look, the only reason I even got into this thread at all was to make this gentleman aware of certain issues before he spent $$$. What he does is now totally up to him.

I agree. I simply felt that some of the information provided was excessive for the question posed. I do not disagree with anything you stated, it is all good information, to the right person (it was informative to me as I have been out of the scene for a couple years). Judging by later posts from the original poster I feel that my take was very justified. He was, and seems like he sort of still is, quite overwhelmed with basic information provided, and the addition of information as it pertains to fleets in 2014 was overkill. I took it as showmanship. I understand that something typed on the internet often loses the intention of the person that posted it, and I am sure I overreacted here. I want to applogize for my actions/reactions that I posted on here and I really do hope that the information provided by everybody is helpful to Jason Mills. I think I speak for everybody when I say that is the whole goal of this forum (and all others). To make information much more readily available to anybody who wishes to ask and read.

[Charles Talbert]

A couple of our fire dept customers tried it and hated it, they were hauling a heavy load of water, hose reel, other supplies, and equipment. Could not get the low speed crawl they needed for getting around in the woods; too much throttle was required; thus ground speed was more than was desireable for the application. We had nothing to do with either of these V8 installations.

Look, the only reason I even got into this thread at all was to make this gentleman aware of certain issues before he spent $$$. What he does is now totally up to him.

[MoparFreak69]

A diesel is more expensive in the short term.. CAN diesels be set up to run on propane or CNG? is that a spark ignition engine only?

Correct, where diesels return on their investment are when the fuel savings start to pay for itself (4-5 year range depending on investment price). This is why companies like UPS and pretty much all major shippers run diesels. This is also why the majority of locomotive engines are diesel powerplants. They also have very long life expectancies which begin to pay for themselves in the quarter million mile mark, where you would have probably rebuilt a gasser at least once already.

Can a diesel run on just LPG(propane) or CNG? No. The biggest factor is that CNG and LPG are considerably more flammable than diesel fuel is. The diesel engine is designed to run on a fairly slow burning fuel, hence they usually croak when run on straight gasoline. A common power mod is to add LPG and nitrous to the air inlet of a diesel. The nitrous is an oxidizer, which basically means it adds more "air" into the inlet than regular air because it is much more dense (molecules are smaller so they pack together much more tightly than regular air). The LPG is then used as a fuel to re-balance the fuel mixture to avoid a lean condition (which in a diesel only reduces power output unless severely lean).

You can see how it can become very confusing when looking at both, somewhat similar technologies. Even when just speaking of old versions of both a gas and diesel engines, the similarities between the two aren't really that much similar.
Gasoline is a very fast burning fuel, which is a large part of the reason you can rev a gas engine to 5K+ RPMs fairly easily (20K+ in some racing applications). A smaller part of that ability is the lighter components that dont have to be thrown around as much by the crankshaft, which helps tremendously.
Diesel is a slower burning fuel, which is a large part of the reason why diesel engines generally do not come close to the 4K RPM point. Heavier duty components play a part in that as well, heavy parts are harder to sling around, but newer engines are narrowing that gap with more efficient designs.
Diesels never will bridge the RPM gap between gasser, but that really isnt a problem because they produce their power in a much different way. This different way also explains why they are more powerful than their gasoline powered equivelant.

Get into new stuff and the rules change significantly. Technologies like Common rail, HEUI and other injection methods are changing the way diesels run and act. Gas engines on the other hand are benefitting from new technologies as well, such as direct injection (which diesels have been using for a long long time already) which are starting to cut the huge gap between the two down slightly.
If you ever have a couple weeks of free time read up on some of the things mentioned. It can almost take a PhD to understand what is being explained, but if that sort of thing interests you it can be quite fascinating. From what I have seen from posts made by Charles Talbert, he is a good source of information like that (new and emerging technologies) and I am sure he wouldnt mind you picking his brain on the matter if you should choose to. Be warned that unless you have a very very firm grasp on mechanics you are sure to be overwhelmed (which was what I was afraid of with the information that was provided earlier). When I was taking certification course from CAT for their HEUI engine family I saw many a good, very experienced, mechanic struggle to process what is happening inside that big ol chunk of iron (or high tech ceramics/composites/alloys if you are looking at prototype stuff).

Now is the time to research what it is you want and what you can afford. Ideas on paper does not cost a thing so if you screw up on paper you are not out anything but a bit of time. There are always pros and cons to anything. Take you time to wiegh them all out and then you can decide on which is best for you.

Just remember this, a 23cc Weedeater motor WILL push a snow plow. A 23cc Weedeater motor WILL NOT push a snow plow fast nor effectively.

[MoparFreak69]

Be careful with a V8, for the most part they don't offer good low end torque. I've known folks that used them only to learn that their ability to creep around off highway was virtually lost because low end torque just wasn't there. It required more throttle to go than was needed for creeping in order to keep the engine running. After money is sunk into a project is not a good time to realize it was not the better way to go. My advice is to be sure you know what ever you choose will give you the desired end result before you spend $$$.

Your sure about that? While a V engine may not produce as much torque as a similar displacement inline motor, simply due to design, a V8 will provide plenty of torque for almost any application.
The key to a V8, as with any engine, is to set it up properly to run in the range you need it to. If you need a low speed torque monster you need an intake with long runners to get the intake velocity speed up (hence the big keg intakes that magnum truck engines utilize). You will also need a cam that is designed to produce the power down low (something in the RV range, dont have any specs off the top of my head). Headers generally do not do well in low RPM applications as they are made to scavange using one pulse to draw from another port. Stock intake manifolds are generally the ideal way to start an exhaust system for a low down tugger.

The Magnum/LA 318 I swapped into my Wrangler is very handy at idling along up or down an incline. I can putter along trails at about 10MPH in 3rd at about 700RPM and have plenty of grunt to accelerate briskly at will. I am using the keg style truck intake (with quite long runners) along with stock style manifolds. My cam isnt the greatest seeing how it came from a car, but it does quite well. I have experienced similar results from a '77 Cherokee I owned that had an AMC 360 in it. It would creepy crawl all day long at idle. I have even (quite stupidly I might mention, I do NOT recommend anybody do this) spotted myself over an obstacle by jumping out with it running and in gear and watching where it was creeping to. I would then jump back in and adjust and repeat until I was past the obstacle.

[MoparFreak69]

One appealing aspic of diesel is, it can run on a veggie oil. I'm not sure if this is practical for your application or for the engine you may choose to use.

This is entirely possible but you run into the gelling factor really bad in the cold. Common Veggie conversion kits use warm coolant run through a pipe in the veggie tank to keep the oil in liquid form. This isnt a big deal but you run into the situation of where you have to run the engine on diesel to get it warmed up, and depending on engine application (a normal diesel swap is along the 4/6bt lines because of cost factors) the engine may take 20-30 minutes to warm up enough to turn veggie goo into veggie oil. By that time I imagine the driveway would be cleared already, or probably close to it. Winter use for veggie oil isnt terribly economical in a situation like that. Summer use is great, you can just about start up on veggie oil depending on where you live.

[Jason Mills]

Be careful with a V8, for the most part they don't offer good low end torque.

Less than the 230? hummm.. OK I hear your concern.