Questions: FJ60 6BT Cummins NV4500

[roma042987]

im getting 430miles between fillups on my 60 with a 12h-t and stock tank. That's not being super conservative with the skinny pedal and running ac to boot. I really think if I ran it dry I could squeeze out 500 miles.....i still want a bigger tank

12 valve cummins is going to be considerably quieter than a 24 valve something else to consider.

 

[jakerudy]

Just to be clear, you're saying that in addition to the 12-valve Cummins in your FJ60, you also have a 2001 Dodge with a 24-valve engine, right?

Correct. I have an '85 FJ60 with a 6BT and a 2001 Dodge 3/4 ton with a 24V Cummins.

 

[MrK]

I'm running 4bt without soa, let me know if you need pics of the setup.

 

[Will Van]

I'm running 4bt without soa, let me know if you need pics of the setup.

Yeah, that would be great! Can you post the pics here? Really interested in the oil pan clearance.

 

[MrK]

Yeah, that would be great! Can you post the pics here? Really interested in the oil pan clearance.

Don't mind an injector line missing lol out of commission until new one gets it.

 

[MrK]

Btw I'm running 2.5 ome

 

[Will Van]

@MrK - Awesome! Thanks for the pics! So, the reason you're able to run a Cummins without a SOA and just a 2.5" OME lift is because the 4BT is shorter (minus two cylinders)? Essentially the front of the 4BT "ends" before the oil pan begins to interfere with the front axle?

Whereas with a 6BT, because it's longer, you have to go SOA to get the oil-pan to clear the front axle?

Do I have that correct?

 

[MrK]

@MrK - Awesome! Thanks for the pics! So, the reason you're able to run a Cummins without a SOA and just a 2.5" OME lift is because the 4BT is shorter (minus two cylinders)? Essentially the front of the 4BT "ends" before the oil pan begins to interfere with the front axle?

Whereas with a 6BT, because it's longer, you have to go SOA to get the oil-pan to clear the front axle?

Do I have that correct?

Yes, just keep in mind 4bt is louder then 6bt so insulation will be key, also both engines are heavier then 3f so front is going to lean down a bit(add on leaf or really heavy duty leafs will keep the weight up). I know a guy who put 6bt in but he cut up his oil pan and had a 90degree drop pad behind axle instead of slanted. There are always options that you can take but just know for more mods more will you will have to cough up.

 

[Will Van]

Yes, just keep in mind 4bt is louder then 6bt so insulation will be key, also both engines are heavier then 3f so front is going to lean down a bit (add on leaf or really heavy duty leafs will keep the weight up). I know a guy who put 6bt in but he cut up his oil pan and had a 90degree drop pad behind axle instead of slanted. There are always options that you can take but just know for more mods more will you will have to cough up.

Yeah, I'm probably set on the 6BT with SOA just because it's a standard OEM engine. I just want to make an informed decision about all of my options. Thanks for your help!

 

[jakerudy]

Yeah, I'm probably set on the 6BT with SOA just because it's a standard OEM engine. I just want to make an informed decision about all of my options. Thanks for your help!

I've never owned a vehicle and thought "that is too much power". The 4BT is a reliable engine. The 6BT is just more. Both are a great conversion.

You can tear up anything if you try hard enough. My 60 is kind of loud and sits higher than I really wanted but I would be confident driving it anywhere. I can run 70+ mph with no problem on the highway and lug it up a hill off road as slow as I need.

 

[Will Van]

I've never owned a vehicle and thought "that is too much power." The 4BT is a reliable engine. The 6BT is just more. Both are a great conversion.

You can tear up anything if you try hard enough. My 60 is kind of loud and sits higher than I really wanted but I would be confident driving it anywhere. I can run 70+ mph with no problem on the highway and lug it up a hill off road as slow as I need.

I often take road-trips across the western United States just to explore and camp. On one of them, I had mechanical trouble in the middle of nowhere. I had to stop in Cuba, NM and get my vehicle repaired. Luckily, it was a simple fuel filter and we got it replaced and I was on my way. But I use that experience as a measuring stick for future vehicles. I always ask myself, "Could I repair this vehicle on the side of the road in Cuba, NM?"

The 6BT appeals to me because of that. They're stupid-simple, which makes them ultra-reliable and easy to work on. Because the 6BT was put into so many Dodge trucks, parts for them are ubiquitous. Literally millions of Dodge trucks came with the 5.9L 6BT, and a lot of the various iterations have interchangeable parts (some 24 valve parts work on the 12 valve, etc.).

The fact that it's a diesel also appeals to me. A few weeks ago, after Hurricane Harvey, we had a run on fuel. Everybody randomly started to fill up their vehicles. Between Austin and the Texas coast, nobody had any gasoline. But EVERYWHERE still had diesel. When sh*t hits the fan, you'll probably be able to find fuel for your oil-burner. Not to mention, the diesel 6BT has gobs of low-end torque, which is perfect for low speed 4WD, and cruising on the highway. Even the earliest and lowest powered 6BT versions had 400 lb-ft of torque.

The drawbacks to the 6BT are that it's dimensionally really tall, really heavy, and really loud. That means it requires a large suspension lift with extra springs to make it work. I'm with jakerudy - ideally I would just use a 2.5" OME suspension lift with some 33" tires, and be good to go. But any engine has drawbacks. For me, the drawbacks are acceptable for my goals with the truck.

My worthless $0.02.

 

[Will Van]

Sorry, double post.

 

[jakerudy]

I often take road-trips across the western United States just to explore and camp. On one of them, I had mechanical trouble in the middle of nowhere. I had to stop in Cuba, NM and get my vehicle repaired. Luckily, it was a simple fuel filter and we got it replaced and I was on my way. But I use that experience as a measuring stick for future vehicles. I always ask myself, "Could I repair this vehicle on the side of the road in Cuba, NM?"

The 6BT appeals to me because of that. They're stupid-simple, which makes them ultra-reliable and easy to work on. Because the 6BT was put into so many Dodge trucks, parts for them are ubiquitous. Literally millions of Dodge trucks came with the 5.9L 6BT, and a lot of the various iterations have interchangeable parts (some 24 valve parts work on the 12 valve, etc.).

The fact that it's a diesel also appeals to me. A few weeks ago, after Hurricane Harvey, we had a run on fuel. Everybody randomly started to fill up their vehicles. Between Austin and the Texas coast, nobody had any gasoline. But EVERYWHERE still had diesel. When sh*t hits the fan, you'll probably be able to find fuel for your oil-burner. Not to mention, the diesel 6BT has gobs of low-end torque, which is perfect for low speed 4WD, and cruising on the highway. Even the earliest and lowest powered 6BT versions had 400 lb-ft of torque.

The drawbacks to the 6BT are that it's dimensionally really tall, really heavy, and really loud. That means it requires a large suspension lift with extra springs to make it work. I'm with jakerudy - ideally I would just use a 2.5" OME suspension lift with some 33" tires, and be good to go. But any engine has drawbacks. For me, the drawbacks are acceptable for my goals with the truck.

My worthless $0.02.

Yep. If luxury is your goal the FJ60 isn't the best choice to start. If you want a zombie apocalypse proof vehicle a 6BT FJ60 is hard to beat.

I live in the sticks and Land Cruiser parts are hard to find - and then the cost hurts every time. 5.9 Cummins parts are almost like Chevy 350 parts around here. I've said it before on this site, the 6BT is loud, heavy, reliable, powerful, economical, and proven.

This summer due to flight cancellations I had to rent a new Ford Expedition that retails around $70k. Wouldn't trade my 60 for it.

 

[the gimpey one]

Trollhole cruisers in South Carolina would be another recommendation.

 

[GLTHFJ60]

@MrK 's 60 is the first one I've seen (in person) with a SUA cummins conversion. It's not real common and I don't think you could do it with a 6BT because you can't move the engine around as much in the bay, there's just not as much room.

EDIT: "cummins conversion" meaning cummins B-Series conversion (4BT, 6BT, QSB3.9, QSB4.5, ISB5.9, etc.)

 

[jakerudy]

@MrK 's 60 is the first one I've seen (in person) with a SUA cummins conversion. It's not real common and I don't think you could do it with a 6BT because you can't move the engine around as much in the bay, there's just not as much room.

Well said. My 6BT fits like a glove but maybe like an OJ Simpson glove. You couldn't fit much more in there lengthwise. On the sides it is actually cleaner than the 2F because of all the emissions crap.

 

[Will Van]

I'm also looking at a GM 6.2 diesel.

Advantages:

• "Bolt-On" - Has the same basic architecture of a SBC, so all of the adapters, engine mounts, and swap kits readily available would work with the motor.
• No Lift Required - Dimensionally speaking, you could essentially do the swap without a SOA or suspension lift (ignoring the weight factor).
• Cost - Fairly cheap to find a donor-motor and parts.
• Availability - It's a General Motors product, so parts and know-how are readily available.
• Diesel - All of the advantages of a diesel, like low-end torque and decent fuel mileage.
• Simple - Mechanical fuel pump and simple design.

Disadvantages:

• Makes a measly 130 hp and 240 lb-ft of torque in its most modest form (6BT makes 160 hp and 400 lb-ft of torque in its most modest form).
• Essentially the same power and torque as the stock Toyota motor.
• Requires aftermarket mods for decent power and torque.
• Hidden costs of performance upgrades like a turbo kit.
• Questionable reliability.
• It's not a 5.9 liter Cummins 6BT

I'm pretty set on the 6BT, but I'd love to hear your thoughts and input on the Detroit Diesel 6.2 liter GM motor.

 

[jakerudy]

I've never driven a GM 6.2 diesel but the guys I've talked to about them were not overly impressed. It seems like they aren't a bad engine but they don't compare to the 5.9 Cummins in either power or longevity. Given the expense of a swap my feeling is you might as well go with the superior engine.

Between my '91 3/4 ton Dodge 12V (now in the FJ60) and my '01 3/4 ton Dodge truck I've put a fair number of miles on the 5.9L Cummins and they just pull and run. A few years ago my wife drove my '01 about 350 miles in 105 degree weather. When she got home the water pump was shot, as in you could wobble the shaft, but it got her home without overheating. A mechanic I know was 4 wheeling a 24V and dropped it into water to the point it sucked enough water into the engine to lock it (beer involved). He towed it home, drained the water, and changed the oil several times. This was several years ago and the truck has almost 300k on it and is still going strong.

 

[Will Van]

I'm running 4bt without soa, let me know if you need pics of the setup.

I have a few more questions for you @MrK - Who did the 4BT swap for you? Do you ever touch the oil-pan with the front diff when flexing? How commons is the 4BT with the SUA?

 

[MrK]

I have a few more questions for you @MrK - Who did the 4BT swap for you? Do you ever touch the oil-pan with the front diff when flexing? How commons is the 4BT with the SUA?

I have done plenty swaps before but unfortunately didn't swap this one. No my oil pan doesn't touch the diff when flexed. SUA 4bt swaps are not common because of clearance issues and from all the owners with 4bts I have talked to it seems that they did SOA first and never dealt with SUA clearance.correct me if I'm wrong fellas