Engine swap into 86 Bronco 2

Nightsun · Oct 8, 2016

Hello. I have an opportunity to obtain an 86 bronco 2 with 2.9 fi engine, 5 spd Trans and 4x4. It's at a buddy's ranch that is about 16 miles down the road from my hunting property. Unfortunately it isn't running correctly at the moment and has been sitting for roughly 3 years. Everything is intact however we suspect the motor may be bad. I've read that the 4.0 engine swap is easy however since this truck will only be used on our property it will never see public road. Because of this I'm wondering if the 4.0 is still the easiest swap (aside from another 2.9 swap) what our other swap options. I don't care about ac, gauges aside from water temp and oil pressure which can be mechanical. Just need very basic stuff. Can someone help me out with this? I'm going to be trailering it to my home about 2.5 hrs away to start working on this. Before I do so just trying to get a better idea of what it's gonna take and cost. Thank you for the help. Regards

wildbill23c · Oct 8, 2016

Depends on what you actually want to do. A 2.9L would be the easiest as its already got one in it. Anything different and you'll have to do some modifications of course. The 4.0L swap isn't exactly just a drop in especially if you want gauges and stuff to work but in your case may not be that big of a deal, of course you'll need the wiring harness and computer too. Another option is a 302 V8 swap.

JerryC · Oct 9, 2016

I agree with wildbill keep the 2.9.
Imho, if I did a swap to a different engine for off-road only I'd go 302, and scrap the computer controls.

cammeddrz · Oct 9, 2016

On a 2.9 rig, it's actually harder to "scrap the computer controls"

You can solder 2 additional injector connectors onto the 2.9 harness, and use a truck 5.0 ECM, at that point a TFI 5.0 is literally plug-n-play. From a purely wiring standpoint it's about 20 times easier than a 4.0 swap.

So don't "scrap the computer controls" that'd be a bad move

85_Ranger4x4 · Oct 10, 2016

cammeddrz said:
On a 2.9 rig, it's actually harder to "scrap the computer controls"

You can solder 2 additional injector connectors onto the 2.9 harness, and use a truck 5.0 ECM, at that point a TFI 5.0 is literally plug-n-play. From a purely wiring standpoint it's about 20 times easier than a 4.0 swap.

So don't "scrap the computer controls" that'd be a bad move

4.0 would have the perk of fitting into the existing powertrain though. T-case, driveshafts, cooling system... even the trans if you play nice.

Wiringwise though, yeah, the 5.0 would be easier.

JerryC · Oct 10, 2016

I'd scrap the computer controls so I could build the 302 how I like. From mild to wild as the build progresses. I'd probably start with an old school carb and ignition and move onto one of the new tbi/ignition systems.
Unless I come into more money than I know what do with that probably isn't going to happen.

AllanD · Oct 14, 2016

Disregarding several of the replies above I'll simply say that "mechanically" putting a 4.0 where a 2.9 has been is the easiest engine swap going....

Mostly because the 4.0 is a specifically designed engine to replace the 2.9
The 4.0 uses the same bell-housing pattern and motor mounts, there are other differences, but...

For the wiring it is quite a difficult swap, I did this swap on my '87 Ranger, so I know
this swap fairly well...

On a 1989-92 the swap from a 2.9 to a 4.0 is much easier, IF you grab the wiring harness from the donor, but 89-up Rangers & B2's are wired differently...

Engine swap into 86 Bronco 2

Nightsun

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wildbill23c

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JerryC

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cammeddrz

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85_Ranger4x4

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JerryC

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AllanD

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