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Discussion Starter · #1 ·
I have heard the argument over and over by non-diesel drivers who constantly trash our engines. Their theory is that diesels aren't worth owning, because the increased economy is offset by increased costs of fuel. I have a sister in law who constantly trashes diesels because they are just too expensive. Here are some numbers I threw together, based on estimated, but very realistic, figures.

I'm basing these figures assuming the same vehicle, but comparing diesel vs. gas engines. The diesel is assuming a swapped-in 4bt in a midsize to small fullsize vehicle (for example, a 1/2 ton 4x4 pickup). Prices will be errored on the side of caution, showing worse case examples (using aproximate numbers for my area).

-Gas: $2.75/gal.
-Diesel: $3.05/gal.

-Gas: 15mpg.
-Diesel: 25mpg.

Yearly mileage: 25k miles.
Cost of gas for 25k miles: $4583.33
Cost of diesel for 25k miles: $3050
Yearly savings: $1533.33.

That doesn't take into account the higher cost of maintenance for a gas engine. I don't know of many $200 sensors on a 4bt. ;-)

Jim
 

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I diesel engine will last longer than a gas as long as it's taken care of ,the high cost of the gas parts ( newer engine ) it will make you want to change .

The up front price of doing a conversion is high but in the end it pay's off .

Just my .02

Scott
 

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A few months ago in "Diesel Power Magazine" there was an article called "Gas vs. Diesel"
They test drove an 08 ford diesel and v10 gas, a range of test from highway, city, and towing, all under identical conditions.

the results were the diesel paid for its self (the extra money the diesel option cost) in about 40-50 thousand miles. This was assuming that both gas and diesel cost exactly the same.

To me it says the diesel is a getter buy, it pays for the higher purchase price rather quickly,
Last longer
Fuel savings will continue even after the 50,000 mile break even point.
Truck is worth more for resale.

On the other hand, a diesel swap generally cost lots, so the pay off could be way beyond 50,000 miles, and not realistic.
So, do a diesel swap because you want to, don't mind the initial investment, but don't count on your bank account being fatter in the long run because of it.

Grigg
 

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I owned a isuzu diesel pickup as a teenager, A mercedes 300CD, Mercedes 240D, a Mitsubishi delica 4wd minivan with turbodiesel (in japan), a VW rabbit diesel, and now I have a 4bt in my 71 chevy. With all my diesels I never had one that ran rough until it warmed up. Start missing because of a vacumn leak. Start missing because of a bad spark plug. Start missing because of a plug wire burned by the header. Start missing because it needed a new set of points. Start missing because the coil wire worked loose.
With my diesels I never worried about how much the fuel would cost. With my 71 chevy and a 400 under the hood I used to decide not to go ride my ATV in the national forest 2 hours away because I didn't want to spend the $30 on gas round trip. Now I go if I want.
Your time spent working on a vehicle or taking it to be repaired when you aren't enjoying it is worth something. Not having to be stressed out by your engine not running on all cylinders is worth something. Having fun without worrying how much it's going to cost for gas is worth something.
Lots of things you can't put a price tag on. If you tend to buy a new vehicle and keep it for 5 years before buying new again and you don't do your own work then none of the above applies to you. As for me I like the diesels better.
 

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i did the calculations on the clevo in my F100 before i pulled it. it gives me 15-ish mpg on lpg. driving up and down the highway near where i live, it was cheap enough. however, lpg here is around $1/litre. ( it is 55c in the nearest town, 120 mi. away. ) the problem i had is when i want to drive anywhere off the highway, i didn't have enough lpg to get there and back. if i start running on petrol ( dual fuel setup. ) at $1.60- odd per litre at 15 mpg adds up fast. the clevo was up for a major rebuild. $3k easy by the time i did it all. i have always liked turbo diesel stuff, and everywhere i go diesel is available. on one trip i had some lpg issues and burnt the boosters out of the carby ! 400 miles from civilisation ! at least it still sort of ran on petrol and i was able to get out ok. so yeah, diesel seems like a good option to me. i have learnt a heap of new stuff as well.
 

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The people who claim that diesel doesn't make financial sense, are usually terrible with both maths and money.
 

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I figure if I break even in 3-4 years the 4BT swap was worth it. As a side bonus I can afford to drive my toy on my WVO blend. 50c a gallon never hurts.
 

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another plus with the diesel swap is they will run on all sorts of stuff.
 

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Lots of things you can't put a price tag on.
Yes. I had no intentions of giving up my beloved '79 F-250 4x4. I was with my dad when we drove it home from the dealer in December 1978. I learned to drive in it.

the clevo was up for a major rebuild. $3k easy by the time i did it all.
Me too, the 400M was still running good and smooth but way down on power and mileage. I had to replace it no matter what. My first options I was looking at were either an EFI 302 or 300 six. I wanted better mileage than those engine would deliver, so started thinking about diesels.

I knew I would be forced to drop AT LEAST $1500 USD to either rebuild the 400M or install an EFI 300 or 302, so that can't be added into the conversion price of going diesel.

another plus with the diesel swap is they will run on all sorts of stuff.
ANOTHER HUGE plus! Waste veggie oil, waste hydraulic and ATF, etc.

The up front price of doing a conversion is high but in the end it pays off
It depends on the vehicle. The 4BT I bought ($1750) already had a NP435 trans attached to it, so I just unbolted the big-block bell from the NP435 already in my truck and bolted the Cummins in. Everything else needed to do the swap came from the miscellaneous bits of junk around the place, like the exhaust system and air cleaner from a '93 Dodge Cummins truck. The most expensive thing I bought new was an air filter for $50. I think I might be able get $200 for the old 400M, and still have the NP435 that came with the engine that I need to sell.
 

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My experience with diesel vehicles has been that the total costs of a diesel tend to be front-loaded, where a gas-powered vehicle is back-loaded. In other words, a diesel vehicle requires you to invest in the vehicle up front. Gas-powered vehicles cost more money to keep on the road as the miles pile up.

Most diesel opponents can't get past that front-loaded expense and often do not figure trade-in value into their cost analysis. Diesel opponents will merrily "trade-up" when their gasser starts to nickel-and-dime them. The premature "trade-up" is hard to put a dollar value on, as well.

Why is my old '98 Dodge truck worth $3-4K more than a gasser with less miles? It is the magic of supply and demand. Diesels are in high demand and in relatively short supply.

My argument would be, "Name a sizeable commercial fleet that has not made the switch to diesel power?" Even the gas-powered service vans in my part of the country are rapidly being replaced with diesel Sprinters. Advantage: Diesel.
 

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Discussion Starter · #11 ·
It looks like I got some people's interest with this thread. For my own particular case, I had more to consider financially, and the Cummins really made sense. Our Durango has a bad 5.9 in it, and I'm not going with another used engine. My cost for a brand new 5.9 short block is $1700. Add in the cost of assembled heads and gaskets. On top of that, I'm still tracking down electrical gremlins with the PCM/TPS circuit. I already have almost $1000 into that fiasco, and have gotten nowhere. So I'm guessing at least $2500+ if I replace the 5.9, plus the cost of the electrical issues.

In comparison, I'm planning a total of $4000 max. for the 4bt swap, and that includes the NV4500 swap. $700 for a low mileage NV4500 with bellhousing, $400 for a new clutch assembly including Dodge Cumins flywheel and all bolts (Napa), $200 for an ebay Dodge P/S/Vacuum pump assembly, and I'm planning $1000 for the 4bt bread truck. I'm guessing $1000 in misc. parts.

In the end I'll have a motor I know will last a long, long time, and actually is worth rebuilding when the time comes. I'll have a transmission that is MUCH more reliable than the Dodge auto. And when the Durango wears out, I can swap the motor into something else, so it will continue to pay for itself. With the mileage we drive, I'm planning on the Cummins paying for itself in about a year or a little more. Until its paid for, It will be paying for itself with the added peace of mind that I have an extremely reliable vehicle.

Jim
 

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In the beginning I asked myself these same questions comparing the Ford 300 six to the 4bt. But apparently the step van operators felt it was worth the swap. And some of these late model gas vehicles have fuel pumps that cost more that a rebuilt diesel injection pump and go out much more often, and thats just one of many electrical components. Besides I just wanted to learn about diesels. A few years ago I built a full time propane veh for my 140 mi. per day commute and it has worked out very well and will still be a little cheaper to operate than the 4bt that I am doing but I want something different. I will still drive the propane veh most of the time.
 

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I have heard the argument over and over by non-diesel drivers who constantly trash our engines. Their theory is that diesels aren't worth owning, because the increased economy is offset by increased costs of fuel. I have a sister in law who constantly trashes diesels because they are just too expensive.
Never argue with an idiot. You won't change their mind and they won't make any sense.

I'm not sure there are any gas motors worth owning anymore. The just don't put out the power and they consume too much fuel! As stated, the diesels can run pretty nicely on WVO - I've got 15k miles on WVO in my 3/4 ton Dodge - and I get that for free. I may spend $0.05/gallon on materials for cleaning the WVO up, but that sure beats the price of gas or diesel at the pump. I get 20+ mpg anyway - and I can drag any gasser along with everything it can carry and everything it can tow. We haven't even covered the topic of rebuilding an engine - most of the gas motors will make it to 200+k miles nowadays - but be pretty tired. A decent diesel is just about broken in by then.

Even smaller vehicles benefit from diesel power. I had a VW Golf TDI - it pulled 48 mpg out of an automatic. The gas models are lucky to do 30 mpg.

I don't think the value of the use of WVO can be ignored. My truck has a 34 gallon fuel tank and it runs around $80 to fill it from a comfortable level. I can make that tank of fuel last for months by switching to WVO once it is warmed up. I also have the option of making my own biodiesel (~ $0.80/gallon) to fill the main tank. The more I drive, the greater the savings over a gas engine.

Now - what were the advantages to a gas engine again? :happyfinger: ;)
 

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I can sort of directly compare a Ford f250 with Auto and 5.4 to my Ram 2500 Cummins auto. I get 7-8 better MPG with both empty and not towing.

Hook up to ANYTHING and the f250 becomes a SLUG. And at the same weights my MPG advantage goes up to 10 or more.

So I also ask, what were the advantages to a gas engine again?
 

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I am by no means anyone who should be giving advice since I just joined the forum, however I have been thinking about this and can safely say this...

I think I could craigslist to cash a running 4bt on a trailer faster than I could any small block gas engine assuming the same condition. Heck... I'm out there looking for a good deal on one now ;)

That may not help you, but that argument is swaying me from going 4.3 Chevy as I speak. :grinpimp:
 

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Discussion Starter · #18 ·
Lemme know when you find one for that! :D
I just did. Well, not exactly, but it will be in the end. I scored my truck at today's auction for $1725. Thats about $500 more than I was planning to use for my limit, but this truck as 6 good tires (which I believe to be 19.5...at least I hope so) which will go on my Ram, which needs tires. That will save me at least $500, which doesn't count the bonus of moving up to the size I want, and converting to dually.

Next, it has the Hydroboost I need for my trail Cherokee. And finally, I'll sell off the aluminum for at least $500 (scrap metal is low in our area). In the end, I consider that I'm paying less than $1000 for the engine.

Oh, and one last bonus- The truck is drivable, so I won't have to tow it home. I'm planning to ride my bike down, load it in the back, and drive it home. Of course my bike's luggage will be filled with tools.

Wahoo!!!! I bought my 4bt!!!! (and I bought the NV4500 last night for $600)

Jim
 
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