2.8 to 2.9 swap

Broncoiisafari · Aug 24, 2010

I'm new here and I will introduce myself in a thread tomorrow. I have a 84 bronco 4wd automatic with a 2.8(dead due to your typical cracked head). Well my grandfather's neighbor said he could get it running, so he took out the 2.8 block and put in the 2.9 block. Then preceded to put the carb back on and not use the FI, after that didn't work it they gave up. Now a few months later I decided to ask him why he didn't just leave the 2.9 motor together, and he has no idea why they didn't. My question is we are pulling the carb back off and putting the FI back on. I have been reading around for a 2.8/2.9 swap and haven't found to much. My question is what needs to be done for the electrical other than using the 2.9 disturbutor. Please be as harsh as need be, I have gone and searched, went through the specific motor sections and swap section. I must be missing something.

Inb4: Just do a 4.0 swap (used to have a 4.0 explorer fun as hell, would just want to try the 2.9 swap first)

As much info would help. I will try to answers all the questions you guys have about the swap.

Hahnsb2 · Aug 24, 2010

Well, the 2.9 swap is just as much work as a 4.0 swap..

You need a FI fuel system as well. Personally I'd take the entire harness from a donor B2 and swap it.

Broncoiisafari · Aug 24, 2010

Broncoiisafari said:
(want to try the 2.9 swap first)

I guess by that i mean't I want to try the donor motor first. Yeah I was reading that they both require the same amount of work.

Right now its the 84's wiring harness, are you saying that the 84's wiring harness should work with the 2.9 with a few modifications for the Fuel Injection

Broncoiisafari · Aug 24, 2010

And we do have the wiring harness from the donor ranger. I'm just trying to obtain some more info before we dive to deep in and have to redo it. Tonight we just took off the carb and were moving the alternator and power steering and, from what I have seen and heard is that the alternator mounting is on the right off the 2.9 where as it is on the left with the 2.8.

adsm08 · Aug 24, 2010

If you have access to the entire donor truck I'd grab the:

engine harness
complete dash
the computer
the fuel pumps
the pump harness

That should be everything you need to get it going.

The 2.9 does in fact mount the alternator on the right side.

cammeddrz · Aug 24, 2010

i am totally more curious how they got a carb on a 2.9 :icon_confused:

i would really like to see pics

because:

Mudhound said:
The heads will not interchange, since the 2.9 has the center ports on ech side "swapped": intake and exhuast are switched with each other, compared to the 2.8

Broncoiisafari · Aug 24, 2010

Yeah we have to complete donor rangers so wiring I guess shouldn't be a problem.

As far as the carb on the 2.9 goes, the 2.8's top end match perfectly. Other than the whole timing gear and timing chain difference.

cammeddrz · Aug 24, 2010

Broncoiisafari said:
As far as the carb on the 2.9 goes, the 2.8's top end match perfectly. Other than the whole timing gear and timing chain difference.

ok so i am totally intrigued here. so the 2.8 heads bolted to the 2.9 with the not only the head bolts , but the water jackets lining up too? what about firing order? there is another user on this board that i literally told the complete opposite to (because i had been told as much). so now i am intrigued. it sounds like all your ducks are in a row. so why won't it work? is it because the 2.8's cam spins the opposite direction?

Broncoiisafari · Aug 24, 2010

cammeddrz said:
ok so i am totally intrigued here. so the 2.8 heads bolted to the 2.9 with the not only the head bolts , but the water jackets lining up too? what about firing order? there is another user on this board that i literally told the complete opposite to (because i had been told as much). so now i am intrigued. it sounds like all your ducks are in a row. so why won't it work? is it because the 2.8's cam spins the opposite direction?

Yes everything bolted up just fine he said. Firing order was the same. Distributor won't work with interchange and yes the cam spins the opposite direction.

cammeddrz · Aug 24, 2010

Broncoiisafari said:
Yes everything bolted up just fine he said. Firing order was the same. Distributor won't work with interchange and yes the cam spins the opposite direction.

sorry to pick your brain so much. so the problem was that the distributor was too long or too short or something? it would stand to reason that the cam spinning backwards woudn't matter as long as the firing order stayed the same :icon_confused:

Broncoiisafari · Aug 25, 2010

with the dash can I just replace the instrument panel from the donor and leave my dash in? it has an aftermarket audio system so shouldn't the radio have the same wiring from the donor engine harness? how much difference is there between the 2.8/2.9 harness other than the fuel injection system?

Hahnsb2 · Aug 25, 2010

You probably only have to replace the wiring harnesses under the hood (the power distribution harness and engine harness) for it to work. May want to double check some wiring diagrams and make sure the P/D harness has the same pin-out as the plug on the firewall.

adsm08 · Aug 25, 2010

I think the dash harnesses are very different, the AUDIO section should be the same though.

Also, I am very interested in the same thing cam is. I've always been told the same thing about the 2.8 and 2.9 tops ends not interchanging.

Broncoiisafari · Aug 25, 2010

I'm planning on working on it tomorrow so I shall take pictures although we have the whole 2.8 intake manifold of but we still have the cylinder heads on so I can get a picture of that for you.

2.8 to 2.9 swap

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