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Discussion Starter · #1 ·
Here's the plan: I take my 91 Ford explorer 4x4 with a good straight body, 4.0 gas (sorry) motor and auto tranny and put in a better diesel motor and (hopefully) a 5-speed without having to replace drivetrain components beyond the tranny. How feasible is that? I've heard about adaptor plates for Chevy, and of course Dodge, and about folks putting the 4bt into f-150s, but nothing about Explorers. My question is, how do i make this explorer into a fuel hating diesel powered family hauler without breaking the bank? I have modest ability in pulling motors, trannys, etc., just not the in-depth knowledge prevalent here.

Thank you for any help ya'll can give :)
 

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Honestly, due to the weight of the 4BT3.9, I would consider something smaller...like the 4BT3.3 or a turbo Kubota 3.3 liter
 

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Discussion Starter · #3 ·
A smaller motor would be fine in my eyes; fuel mileage is my main priority. i'm mainly concerned about being able to bolt the motor to my auto tranny, or the yet-to-be-bought 5 speed. Of course, the wife probably would prefer the auto anyway, but can it withstand the torque of the diesel?
 

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I'm mainly concerned about being able to bolt the motor to my auto tranny, or the yet-to-be-bought 5 speed.
I'm sorry to say I can't think of anything that would be that simple. I suppose you could drop in a turbo diesel Isuzu Trooper engine and trans combo. Either way you slice this, it is a full custom swap. Just when you think you'll be able to keep that trans, you'll find one reason or another why it won't work for you.

There are a lot of companies that are making adapter plates, I am sure someone could make what you need.
 

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I'm debating doing the swap into my v8 sexplorer because of thse issues:

- With the current price of diesel the swap will take 5 years to pay off.
- Emissions laws
- The thing is heavy and would probably need a body lift to be easy.

Overall, I don't think I'll do it. I get 17mpg with my explorer now so even if it went up to 25 it wouldn't be that much of an improvement. I'll probably do a 3.3BT instead but it will be way down the road.
 

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Discussion Starter · #6 ·
The MPG increase from 17 to 25 might be bigger than you think if you look at it as number of gallons of fuel saved.; for 100 gallons of fuel you can go either 1700 miles or 2500 miles. With fuel prices as they are, it adds up fast. At 17 mpg, you would spend $529.41 to go 3000 miles, but at 25 mpg, you would spend $360; you would save 169.41 between oil changes (assuming $3.00 per gallon).

How much are you looking to spend on the repower? I've seen price ranges around $1800 for a used 4bt on this forum, so I would think that a DIY job would cost around $3000, unless I am sadly mistaken.......

That being said....
If it cost $3000 to do the repower, and you drive 1500 miles a month, it would take 26 months (18,000 miles) for your repower investment to break even, and that is not considering the lower maintenance costs of a diesel motor vs. a gas motor. If you make your own fuel, it would take a few months to pay off. Not trying to say your wrong; I may not have all the facts.

Re LincTex, I know as far as the motor is concerned, there would have to me several mods to get the fool thing in there and running to begin with, without even hooking up the tranny. Is it a safe assumption that they make an adaptor for just about any tranny/motor combo? If that is the case, i may keep the auto tranny in place to save costs so that i can get a better motor. If I got a different tranny, then I would have to consider whether it would hook to my transfer case, which is a problem I would like to avoid.

What mods would I need to do to the fuel tank to support the needs of a diesel motor? I would hope I could recycle my tank. My assumption is that I would have to modify the fill tube to accept the larger diameter diesel fuel nozzle, as well as a different pickup; possibly even new fuel lines to the motor. Sadly, the only diesel I have had experience with is a Volkswagon Rabbit 1.5 I got running, and it looked like it just had a simple pickup going to a line, to the fuel filter,to the pump and then back again. are things different for a more modern diesel?

I appreciate any insight ya'll can share.
 

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If the engine comes with a SAE flywheel housing, you can get a SAE to trans adapter from several companies. If they need to make a custom one, usually it just requires the parameters and dimensions entered into their CNC program.

If the engine comes with nothing that bolts to the block, you would need the blueprint for the rear block face to get the measurements.

Fuel tank: still using the stock one that came with the '79 from the factory. I just used some new hose: http://www.4btswaps.com/forum/showthread.php?t=2429
and also added a large spin-on fuel filter between the tank and the lift pump.
The return line is plumbed into the filler neck.

I did remove the filler neck to remove the nozzle restrictor....luckily it was just pressed in and not spot welded to the filler tube. I just pounded it out.
 

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Discussion Starter · #8 ·
Many Many thanks for the info.... my project sounds more realistic now.

I assume I cannot use the high pressure gas fuel pump in the tank, and therefore i would need to get an older style pickup for the tank.

I am not familiar with the "lift pump"; the lil VW I had had the fuel line going straight to the injection pump.

My only other concern about hooking up a motor is whether the flywheel whould bolt to the torque convertor, or if I would have to get a custom made job....

Boy I do appreciate the input. I've been wanting a diesel family hauler so long it makes me sick.
 

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Many Many thanks for the info.... my project sounds more realistic now.

I assume I cannot use the high pressure gas fuel pump in the tank, and therefore i would need to get an older style pickup for the tank.

I am not familiar with the "lift pump"; the lil VW I had had the fuel line going straight to the injection pump.

My only other concern about hooking up a motor is whether the flywheel whould bolt to the torque convertor, or if I would have to get a custom made job....

Boy I do appreciate the input. I've been wanting a diesel family hauler so long it makes me sick.
Your trans won't bolt up unless you have a V8. You're correct on the fuel pump thing. Really easy...

But yeah on the trans you'd be better off just buyin a trans for a smallblock ford and getting the adapter. That would be cheapest I think.
 

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...that is not considering the lower maintenance costs of a diesel motor vs. a gas motor....
OK, I get this in fleet service but who is spending all this cash on maintaining their own personal gassers?

Not one of the newer(1995 and up) gasoline powered vehicles I've owned in the past ten years required any engine related maintenance beyond changing the oil, which is cheaper than with the larger oil capacity diesels. I've not had to change fuel filters, injectors, O2 sensors, spark plugs, wires, rotors, etc. I've literally done nothing but change lube oil/filter on the gassers I've owned for the past 10+years. Where's this great expense of maintenance that is so commonly mentioned when comparing diesel to gas?

I see it the other way around with the diesel requiring more oil and fuel filters than the gasser.

Now with the older gassers where plugs/rotors/points/carb etc required regular maintenance I can see it but those days are long gone for the vast majority of gassers on the road.

As an extreme example, a friend of mine has a 1995 F150 with a 351W. He's owned it since 60K miles. It now has 215K miles on it. He has never changed anything but the oil, oil filter and air filter. No sensors, no spark plugs, no plug wires, no cap/rotor, no injectors, no fuel filter, etc. And this truck had to pass emissions testing every year up until this year(no longer required here as of JAN 2007).

So what are these seemingly astronomical maintenance costs of the gassers that are so commonly referred to(they are regularly used to help justify the cost of diesel vs gas engines)?

In this thread's example of 18,000 miles to break even, what gasser is needing anything beyond an oil change in 18,000 miles(in which I assume the diesel would have had a change as well)?

Ken
 

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The MPG increase from 17 to 25 might be bigger than you think if you look at it as number of gallons of fuel saved.; for 100 gallons of fuel you can go either 1700 miles or 2500 miles. With fuel prices as they are, it adds up fast. At 17 mpg, you would spend $529.41 to go 3000 miles, but at 25 mpg, you would spend $360; you would save 169.41 between oil changes (assuming $3.00 per gallon).

How much are you looking to spend on the repower? I've seen price ranges around $1800 for a used 4bt on this forum, so I would think that a DIY job would cost around $3000, unless I am sadly mistaken.......

That being said....
If it cost $3000 to do the repower, and you drive 1500 miles a month, it would take 26 months (18,000 miles) for your repower investment to break even, and that is not considering the lower maintenance costs of a diesel motor vs. a gas motor. If you make your own fuel, it would take a few months to pay off. Not trying to say your wrong; I may not have all the facts.
Uh.. Methinks there's a math error in there. First paragraph looks good, but if you save $169.41 every 3000 miles driven, that means you save $0.05647 every mile. Then, $3000 swap cost / $0.05647 saved per mile = 53126 miles to recoup (rounding up).

Or did I get something backwards?
 

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You have to subtract the cost of what the replacement motor would cost, as well as whatever you sell/part out the old engine for.

I didn't swap just for fun, I needed to replace the 400M that was in it, and was considering the costs to make it a usable truck again.
 

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Uh.. Methinks there's a math error in there. First paragraph looks good, but if you save $169.41 every 3000 miles driven, that means you save $0.05647 every mile. Then, $3000 swap cost / $0.05647 saved per mile = 53126 miles to recoup (rounding up).

Or did I get something backwards?
The 4bt is not an economical swap and I think that is proof. It's for fun mostly. Do what you want but realize you're not going to save much money. Right now diesel is ~$0.60 more than gas around here!
 

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I think the idea of the swap in a small vehicle that already gets good mileage is a waste.

The 4BT shines and the mileage and maintenance difference can be huge in a bigger truck with a bigger gas engine. I strongly dissagree about the 351W going 215K without any maintenance. That's a fluke. A small block is not a truck engine and will not hold up to hard work day in and out.

My '91 F-250 4x4 with speed density 351W, 5 speed and 3.55's gets consistant 13-14 MPG average. Hook a 6K pound trailer on that and not only is it utterly gutless but gets about 4 MPG. The same truck with a 460 would average 10-12 and drop to 8 or so with an even heavier trailer yet. Drop a 4BT in and you'll be averaging low 20's and get 15 around 12K GCVW and you'll have far more useful power than that 351W could ever muster. Not to mention the 4BT will easily outlast the small block by twofold and the 460 by several times over.

The Ford EEC-IV engines are great motors, but They simply don't last 200K+ miles without plugs, cap, rotor and some sensors. They have to be the cheapest EFI motors to work on though. Do the same math for a Vortec GM 350 and the tables turn quite a bit. Those engines average very high maintenance costs past 80K or so. Very poorly designed and expensive injection system, 4 very expensive O2 sensors, 2 cats, corrode your engine apart orange coolant and intake gaskets that don't like to seal make for pretty high maintence costs.
 

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The 4bt is not an economical swap and I think that is proof. It's for fun mostly. Do what you want but realize you're not going to save much money. Right now diesel is ~$0.60 more than gas around here!
Diesel always goes up during the winter cause all you yanks live in the stoneage heating your houses with #2 fuel oil. :p
 

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Discussion Starter · #18 ·
This is an excellent thread.

A gas engine is lucky to make it much past 200,000 miles without needing an overhaul. And not needing to spend money on spark plugs, cap/rotor, burned out coil packs, clogged injectors, plugged up cat convertors, burned up piston due to preignition, etc. in 10+ years makes me deduce 2 things

1) you don't have the displeasure of buying a used vehicle

2) paying extra for the fuel mileage in a large gasser is not a problem because you make pretty good money, hence why you have a 1 owner vehicle.

I've had 14 gassers and 1 motorcycle in 10 years, and all of them had problems of various sorts. None of them made it to 200,000 miles due to engine problems. A modern engine older than 10 years will nickel and dime you to death due to so many things to go wrong. On a 4bt, how many sensors are there that control the running of the motor?

I'm a poor guy who cannot afford a newer vehicle. I often cannot go places because of my truck getting only 15 miles a gallon, despite being in excellent mechanical condition and only being a 4.0L V-6. A simple diesel engine with a mechanical injector pump expected to easily last 500,000 miles and get nearly double the fuel mileage sounds like a sound investment.

After owning a gasser for 10+ years, how do you manage to not have to replace an oxygen sensor (once every 90,000 miles) a timing belt (60,000 miles) spark plugs and wires (at least 100k) and not have a single sensor go out? Unless you don't clock the miles like I do.

Anyone who can deny that a diesel motor is a far superior engine to the highest quality gasser over the long term is lacking all the facts. Sorry.:happyfinger:
 

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And don't forget the elec. high pres. fuel pumps these EFI engines use. Some of them run as high as $750.00. I run a Dedicated propane engine (11 to 1 compression). But the 4bt is looking better to me all the time. Propane is getting higher also and is harder to find on a long road trip. Thats one of the reasons I building my 4bt truck. But most of all I just like to try new and diffrent things.
 

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Just my 2c.

For almost everyone here a diesel swap is done for vehicle improvement, customisation if you will. Taking a vehicle that does most of what they need and spending the time and money to make it exactly what they need.
In most cases that's a vehicle where no off the shelf equivalent exists.

When you're doing such a project the economic decisions go well past what your accountant will come up with. Factors such as reliability and range don't come with a dollar figure, nor does the pleasure of driving a torque monster compared to a petrol engine of the same power but less than half the torque.

You have to decide early on in the planning how much extra use you'll give the vehicle due to the swap and how long you plan to keep it. For most of us resale is completely irrelevant as we'd never intend to sell the finished vehicle.
 
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