Thinking of a 4bt or 6bt swap?? help

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fj62max

fj62max

Wildlife Customs
Joined
Oct 31, 2007
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Hello everyone. I have a fj62 with 240k and iam thinking of doing a diesel swap 4bt or 6bt. The reason why iam thinking of the doing the swap because i have some oil leaks. i know most cruiser do, I need a alternator, tranny has worn outshaft. i have a extra tranny just need to swap it. I just dont want to keep wasting money into the 3fe. what do you guys think? I have a new rondavis aluminum rad. hope i can still use, two stainless battery trays. i have 2.5 ome lift. I was reading may need more of a lift. I would like to use my trafercase. iam no racer just would like to keep to simple to cruise with the family and do some offroading with my sons. thanks
 
Just to give you an idea as to what needs to be done with a diesel engine swap:

1. Fuel system redesign
2. Electrical system redesign ( VE pumped 4 and 6BTs are pretty simple, but 3FE wiring needs to be cut out )
3. Cooling system redesign
4. Fabricate motor and transmission mounts
5. Decide on transmission + transfercase

Couple more points:
1. If you want to drive on the highway, you'll need an overdrive transmission
2. Plan on the swap taking at least twice as long as you estimate
3. Plan on spending $10k all said and done


I fully support the decision to swap out your motor for a Cummins ( I just did ), I just want you to have realistic expectations before jumping into a project of this size.

Let me know if you have any other questions!
 
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Do it! It will take much longer than you think (I thought mine would take 3-4 weeks, that was June, and I'm still piecing mine together). It will also take more money than you thought.

I'd be willing to pm you some of the costs to help you get an idea if that helps. You will need to lift the truck, pretty much agreed that an SOA is the only way to go. The guys above really know their stuff too, so listen to them and check their build threads.

I also want to say that I've never heard of someone doing the swap and wishing they hadn't, I'd give it a try if you've got time and some money.
 
Dam i feel like ripping out the 3fe already.lol. i have now a 2.5 ome can i use my same leaf springs? how hard is the wiring part??
 
fj62max said:
Dam i feel like ripping out the 3fe already.lol. i have now a 2.5 ome can i use my same leaf springs? how hard is the wiring part??
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You can use them, but they will give the truck a pretty big lift.
Do a search on "SOA with ome springs" it should give you an idea of how much lift it will net you.

The wiring is very basic if you use a mechanically injected 4BT or 6BT (VE or P pumps)
The engine I swapped in is basically a 3 wire motor. I was able to easily tie it into the stock wiring harness.
 
Gumby said:
You will never come close to the cost of replacing or repairing your engine even with fuel cost savings. Diesels are cool, but they will cost a lot more to do than fixing what you have.
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True. Diesels are just so much cooler to me.

You can still use your OME leafs, wiring from my experience is a little time consuming.
 
Gumby said:
You will never come close to the cost of replacing or repairing your engine even with fuel cost savings. Diesels are cool, but they will cost a lot more to do than fixing what you have.
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it all depends on what youre replacing it with. if youre replacing it with an imported diesel that costs 2x that of an off the shelf 2F then i guess youre right. if we're talkin a used 4bt vs rebuilding the 2f THAT HE HAS (some of the 2f long/short block prices ive seen are outrageous), the cost is comparable. and, the mileage with the 4bt will be 2x that of the 2f (or more). 5,000 lbs, OD, and a STOCK 4bt is a formula for 20-25 mpg avg. modify the 4bt for mileage (i.e. head porting, exhaust/turbo porting, boost tube mods, mild aftermarket injectors) and upper 20's are achievable. youll spend more on carb kits, headers, head milling, ignition parts, and rebuild kits on a 2f in a quest for max mileage than you will modifying a 4bt.

if you can pull a 2f and reinstall it, and own a welder, chances are you can install a 4bt and enjoy close to or over 2x the mileage of even the *best* setup 2f (for mileage). at that rate it will pay off rather quickly, not including longevity.

im not saying diesel builds dont get pricey quickly, because they often do. however, if you do your homework and are patient and diligent in parts collection you can find everything you need without draining your bank account replacing a tired 2f that still wont make any power.

before it seems like im bashing anyones decision to keep a 2f over a diesel, i LOVE the 2f and there is nothing wrong with keeping it 2f power. in addition, if we are talking a minor repair on a 2f vs a 4bt swap then you *probably* wont be able to save money in the long run in fuel jumping straight to a diesel swap. the dependant variable in this equation is the overall health of the 2f besides the repair. if you repair the 2f, just to blow the motor 6t months down the road, it would have proven (in hindsight) not to be an economical repair. this argument is often moot, considering *anything* mechanical can fail at any given time, so your only option is to maximize your chances of longevity in anything by proper maintenance and analysis of overall condition.
 
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Cruzerman said:
2x the mileage? Really?
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That's what people before us have said. Figure my 2F got 10-12mpg. It's not unrealistic to expect 20-24mpg out of the same truck with a turbo diesel.

I'll report my accurate mileage once I get my speedo hooked up and my truck is on the road.
 
For me I was getting ~10mpg in stock form on the 2F. During my conversion I lifted it (aerodynamic drag), run bigger tires (surface drag) and travel a constant higher speed because I now can (wallet drag) and I get ~19-20mpg. If all I had done was swap the engine and left the other dynamics alone mid 20's would be easy. I have power with amazing torque, I can run alternative fuels if wanted, and my mileage doubled.
 
I recently swapped gears and tires, and hope to improve my mileage to the mid 20's with the upgrade, but with my previous setup on 35's I never got worse than 18 MPG. The 4bt noise and vibration should also be taken into account. It's funny how often random parts will vibrate loose on my truck.
 
MagicBeans said:
I recently swapped gears and tires, and hope to improve my mileage to the mid 20's with the upgrade, but with my previous setup on 35's I never got worse than 18 MPG. The 4bt noise and vibration should also be taken into account. It's funny how often random parts will vibrate loose on my truck.
Click to expand...

You have a build thread on your truck?

I'm hoping my fluid vibration dampener will help with the vibes at idle.
 
GLTHFJ, I don't. I wish I had started one from the beginning, but can't seem to find the time to even check up on MUD regularly. I do plan to do a thread on some of my more recent mods in the near future though.

Edit: I do have the liquid filled motor mounts, and do think they help, but they aren't a miracle. I have also noticed they allow the engine to turn under torque quite a lot, which has occasionally wreaked havoc on the hard lines connected to the body, like oil pressure, fuel pressure, etc. I would really like to have another liquid mount for the transmission crossmember. I have noticed a lot of vibration still comes through via the transmission.
 
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MagicBeans said:
GLTHFJ, I don't. I wish I had started one from the beginning, but can't seem to find the time to even check up on MUD regularly. I do plan to do a thread on some of my more recent mods in the near future though.

Edit: I do have the liquid filled motor mounts, and do think they help, but they aren't a miracle. I have also noticed they allow the engine to turn under torque quite a lot, which has occasionally wreaked havoc on the hard lines connected to the body, like oil pressure, fuel pressure, etc. I would really like to have another liquid mount for the transmission crossmember. I have noticed a lot of vibration still comes through via the transmission.
Click to expand...

Well you've got to have some pictures at least!
 
What do you guys think would it be better to get a 6bt with a transmission and transfercase together. Instaed of getting advace adapter for transfercase? What would be a cheaper way? Maybe try to buy whole truck!??
 
fj62max said:
What do you guys think would it be better to get a 6bt with a transmission and transfercase together. Instaed of getting advace adapter for transfercase? What would be a cheaper way? Maybe try to buy whole truck!??
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There is no cheaper way to do it. If you want to run the centered rear output transfer case, you'd be better off running a centered rear axle, although it can work with the offset rear.

Buying a whole truck with some major components you intend to run ( motor, transmission, transfer case ) would be better as it would have a lot of the bits and pieces you don't think about until you're neck deep in the swap, if you have the space that is.
 
Whats a good auto w od transmisson and transfercase setup??
 
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