Information added to the following by the CIS Auto Web Editor appears in the color red.

Originally quoted from Morgan Fletcher, posted to the Land Cruiser Mailing List, in regards to a conversation he had with a gentleman who installed a Isuzu 4DB1T into a Toyota Land Cruiser FJ40:

"He says it's a great motor, gobs of torque, starts easily, 23 mpg, does 70 mph comfortably, (He uses SM420 + Ranger OD.) and is very reliable. Only nit is that it doesn't generate enough heat for the cab. He's done four rubicons over five years with it, logged 50K miles." 

Morgan Continues to Write:

• Would look at what Cummins did to put the NV4500 behind the turbo-diesel. (This would be a NV4500HD (heavy duty version of the NV4500). You'd want the non-Chevy NV4500, like out of a dodge pickup.
• He has a 4BDT, custom aluminum bell housing ranger overdrive, SM420, 3spd tcase. 
• Governor and fuel injection pump are differences between automotive and agricultural/marine/generator versions. 
• Filtration is _very_ important on the fuel line. He uses a Racor filter and then two cheap filters after that. (Filtration is very important in all diesels, if anyone is interested in Racor filters I am selling some farily cheap).
• Fuel injection pump is often sending fuel back to the tank, so it circulates fuel through the tank, thus breaking free the crap in the tank. (This is common in all mechanically operated diesel engines).  Therefore, need to use the return line for a diesel. 
• Isuzu 4DB1T has an integral power steering pump. 
• He has had his Isuzu motor in his 40 for over 10 years. 
• There is a Cummins 4BT and an Isuzu 4BD1. He thinks they may share a bolt-pattern and the Cummins NV4500 bell housing may work on the Isuzu. (With the proper adapter, they do).

Morgan Writes: "Here are some messages I got from Jim Littleton about the swap, two years ago: 

Morgan, 
I have said motor and in the process of machining a bell housing to adapt a SM465. Talked to Rob Mullen about factory adapters. He said get a flywheel housing with an SAE #3 bolt pattern. No problem, ordered one, arrived, but about six inches long. The combination of that flywheel housing with a standard GM bell housing adds up to about 12". If you, or the gentleman you talked to with the conversion, have the part #'s please email me. 

Thanks, 
Jim Littleton 

Morgan Writes again: Here's another one from Jim: 

<< Jim, is the 4BD1 the version w/o a turbo? Where/how did you get it? How much was it?>> 

Yes with turbo. 

<<Yesterday I made four calls to places in the SF bay area and found two motors. One recently sold for $2500 as-is, and the other guy is going to give me a call when the truck is sold to him by the insurance company. I also talked to a repair shop in SF specializing in Isuzu commercial trucks, and this guy tried to warn me off the project, saying it wasn't economically advisable. He told me the rebuild kit for the motor runs "$330 a hole.">> 

T 4BD1s with approx. 225K as is about $3K. I was quoted about $500 for bearings and liners for all four cyl. The shop manual was about $125 though. 

<<Bill also gave me a number for Ben's Truck Repair in Red Bluff, CA, where he bought the Isuzu<->GM flywheel and bell housing. He said they've put a couple of these motors in GM pickups. I'll call them today. morgan>> 

Please let me know asap as the machining costs for the bell housing and having the Isuzu flywheel machined and drilled for GM parts will probably cost more than buying these parts. They are at the machinist now and he is waiting for the pressure plate and my go ahead. 

Jim 

This is from an unknown source:  If this is you (or you know who it is), please email me so I can properly cite them.

Isuzu makes a 175 hp 4 cyl for the NPR truck series. These are strong motors 
and the parts are fairly cheap. I see a lot of these trucks rolled or 
otherwise destroyed by renters who don't know how to drive. Might be a 
affordable option. I think they are 4 valve computer controlled. The older 
engines are 135 hp with mech injection. Kind of slow in a 13K truck. 

End QUOTE from Morgan --- Here's another message from an unknown source. 

I've owned half a dozen Isuzu's in the past. The NPR's are OK if you get the 175HP engine. When empty, they will surprise you with their quickness. Loaded not so good. I used to get around 13 mpg average. 

The FSR's are WAY better but pricey. The last one I bought was right at 45K with a 20' box and liftgate. They have a 6 cylinder diesel very similar to the Cummins in every dimension. It got about 11 mpg. I would get the bigger truck again because of the extra-cab and incredible width. I could seat 4 across in that beast. Air brakes helped stop it. When I sold it, it had 300K miles with no problems. 

End QUOTE 

Here is some information from British & Australian Rover guys: 

Turbo Diesel Conversions:
Isuzu 4BDIT 3.9L Turbo Diesel Conversion 

The Isuzu 4BDIT motor is used to power the 6 tonne gross mass 6X6 Land Rovers at respectable speeds. in your Range Rover, at around 2 tonnes, performance is shattering. 

The big four cylinder diesel hits a maximum output of 81kW (110hp) at a modest 3000rpm. Maximum torque of 315Nm is at an incredibly low 1800rpm. All this translates into a 100km cruising speed at a ridiculously low 2000rpm. 

Once mobile, the 4BDIT diesel is at quiet, smooth and responsive as a petrol engine with the benefits of greater fuel efficiency and reliability, and the pulling power of a truck. 

On road, handling is unaffected by the extra weight off the diesel due to the addition of longer, stiffer front springs. Off road, the big four cylinder diesel is unbeatable. Dropped into low range, its tractive effort is more than ample to climb anything your tyres can bite. The conversion comes with a full 12 month/20,000km warranty when a new factory engine is installed. 

This is another conversation: 
Charlie, 

I'm looking for a thread that discussed how easy it was to put an engine out of a US medium duty truck like the Isuzu/Mitsubishi cab forward trucks into a Cruiser. This was a diesel engine and I seem to recall it was surprisingly easy and there's an existing adapter that was discussed. Sound familiar? I'm trying to figure out which model Cruiser and which diesel engine was the 
popular swap. One of the posters on the thread had done a couple and I believe he was from Australia? What say ye? 

And his reply: 

It was an Isuzu 4BD1 (plus/minus turbo). I saw ads in Australian 4X4 magazines about 10 years ago for bolt in kits for Land Cruisers (and Land Rovers) for the 4cyl Isuzu, 3.9L. Land Rover Australia actually speced ALL Australian LRs with a 3.9L Isuzu, turned it into a torque machine. Maybe some of our Australian readers could help out, try the DTLC (diesel LC List) (dtlc@helios.net <mailto:dtlc@helios.net> ). The 4cyl Isuzus are used in the smaller forward control trucks, I think the NPR. I'd grab the trans too, it's a good 5spd. 

I know of no kits currently available, but I don't know everything. It's a good motor, it ranks right in there with the 4BT and Perkins 4 cyls. The Hino W04/W04T is also a superior 4 cyl motor. 

Charlie

Another Unknown Source of Information:
Nissan Diesel The UD 1200 is powered by the FD46TA 4.6L diesel engine rated at 145-hp at 2,800 rpm. The standard transmission is the MES50C five-speed manual. The Aisin A5043L four-speed automatic is optional. 

One more from the Toyota Land Cruiser FAQ by Rob Mullen. (Look for the latest version to be appearing soon).

17.2 Diesel Engine Swaps 
- ------------------------ 
I'm starting here because to me this is the swap that makes the most sense for a rock-crawling machine and is probably the least explored. As you'll figure out shortly, I'm pretty opinionated on this one and I welcome anyone to dispute my views. I believe that diesel engines are superior to gas ones for offroad use 
for many reasons. They tend to make usable torque at much lower engine speed than gas engines. This means you don't need nearly as low a crawl gear. They also feature a much flatter torque curve. There is no ignition system to fail because of moisture. They are not as affected by altitude, in fact, turbocharged diesels are virtually immune to altitude. In most cases, even though they have all the advantages of a fuel injected engine, such as the ability to run at extreme angles, they rely on mechanical injection which is considerably simpler than electronic injection. Diesel engines also tend to get much better fuel economy and greater cruising range than gas engines of similar displacement. 

The best diesel swap into an FJ40 I've ever seen is the Isuzu 3.9l diesel. Two of its applications were in Isuzu NPR series cab-forward trucks, and BELT LS2700CII (4BDIT). 

I also believe it was used in the GM Forward 3000-4000 series trucks. There are two paths for putting an Isuzu diesel into a Land Cruiser. The first involves a factory Isuzu adapter bell housing. It is designed to mate any SAE #3 flywheel cover to a GM manual transmission with a 5.125" bore. The part number is WF 150015. Unfortunately, this bell housing has recently been discontinued. There are still some around--try your local Isuzu dealer. A better option is an adapter ring. I have yet to locate a commercial source for these--the one I've seen was made years back by a company that has since moved/failed. The ring allows a GM bell housing with a 350 bolt pattern to be attached to an SAE #3 flywheel cover. Using the adapter ring, it would be possible to attach the 4BD1T directly to a Toyota transmission with an Advance adapter Chev->Toyota bell housing. 

Please note, these specs are for INDUSTRIAL applications, not automotive.

17.2.1 Isuzu Engine Specs 
- ------------------------- 
DISP (INDUSTRIAL) TORQUE COMP 
MODEL (CC) CYL FUEL BHP* FT-LB RATIO 
4BD1 3856 4 DD 88@2800 181@1600 17.1 
4BD1T 3856 4 TDD 105@2500 240@1600 17.5:1 

*Figures according to SAE J1349 Gross BHP test. "Automotive" BHP of the 4BD1T for instance is actually 121@3000