Well, it starts like this, i got an 89 bronco II 4X4 with a 5 speed Mazda R-1 tranny and a 2.9 with only 47 grand on the clock when i was 16, (first truck, 3rd month driveing and someone ran a stop sign and i t-boned 'em) i'm almost 18 now and it just so happens that its a bit rusty and the frames tweaked something hardcore but still drives straight, but i have a chance to get a pretty close to mint 84 bronco II 4X4 with an auto tranny and no engine (was 2.8). Sense i love bronco II's, manual trannys and low mileage engines, i'm wondering how hard it would be to swap the 2.9 into the 84. i just lost my license a week ago so i got 6 months of free time on my hands, a good set of tools, some fair mechanical experience, and an engine that has all the wireing and everything to make it run like it just came out of the box. (remember, the truck is complete 'cept for the front end frame damage) i'm wondering how much time it would take to do in my front driveway with a few friends, and how hard it would be to convert to manual tranny. would the engine mounts match up? tranny mounts? and how to do whatever i need to do to make it seem like it came that way stock. thanks for any help you can provide.

 

I would be shocked if it wouldnt work. When you pull the 2.9L dont unplug anything electrical just remove it entirely from the truck. Also take alot of closeup digital pic's. before you start. Also keep in mind you will need the entire fuel system gas tank and all. If it were me I would swap the entire drive train. Engine tranny and tcase. I would look under the dash and see if you can just add the clutch pettal to the auto B2 cuz it will probably be a pain to change out everything. Too bad the frames bent cuz you could just change out body's. Just do it! RB

 

That almost sounds like the project I undertook about 6 months ago. I first got for $500 a California '84 with EPA 2.8L carburated V6, that was shot due to the previous owner neglecting to keep oil in it, mated to a earlier 5-speed than your version. Later, I picked up a Pacific Coast-rusted '88 Sport Bronco-II with 2.9L EFI V6 mated to a newly rebuilt and fine running A4LD auto tranny, for $600.

Using the '88 as the parts donor, I sold the A4LD for $325 to another FTE member who's A4LD had started to fail. On ebay, I sold the "Ground Effects" package for about $150 (plus S&H).

Finally, after cleaning and repainting the 2.9L, I replaced the old worn out 2.8L, including (engine) wiring harness and EEC-IV module with that from the '88. It mated perfectly to the '84's manual transmission. The only trick that was needed was in fooling the 2.9L's EEC into thinking it was mated to the A4LD, so it wouldn't report any transmission (shift) errors, and possibly go stupid on me. (If I could find the EEC-IV from an '88 2.9L with 5-speed, that would eliminate any need for that modification.)

Since I left the 2.8L's engine mounts "blocks" (the parts mounted to the frame crossmember), I also had to use the 2.8L's mount brackets on the 2.9L. But, one could use either set, as long as both the engine brackets and frame blocks are from the same original set. The 2.9L's original exhaust plumbing had to be transferred along with the engine.

In addition, the entire fuel delivery system for the EFI was transferred; including:

-> the fuel tank with its internal low-pressure pump,
-> the high-pressure (frame-rail-mounted) pump with its bracket (some drilling req'd),
-> both feed and return fuel lines,
-> first and second stage fuel filters (some drilling was required on the frame rail),
-> charcoal cannister (next to radiator),
-> and the wiring harness that runs down that frame rail, as it sends power to the tank's fuel pump. Included in that harness is the wiring to the vehicle's rear lights. Ford changed the connectors at the back end of that harness, going to the lights' wiring harness, from '84 to '88. I felt it was easier to also swap the rear light harness, than to try to splice in the new connectors to the old wiring. In your case, you'll have to see what happens as you go along.

Since the Mazda 5-speed might be about an inch longer than the '84's automatic, you'll probably have to swap both drive shafts, too. But, unless the U-joints and/or CV-joints are going bad, or the CV-joint boots are cracking, that should be no major problem. You may also find that you'll have to transfer the transmission rear mount crossmember, or to use the '84's crossmember, drill a few holes to reposition it.

By the way, a trick I learned from an old U.S. Navy man in dealing with unyieldingly rusted fasteners (bolts, nuts, etc). Since it's assumed they're going to have to be replaced with new parts anyway, heating them until they're at least almost glowing red, with a propane torch or better, will make them easier to bust loose, after the PBlaster and Liquid Wrench rust dissolvers have proved ineffective. Work them lose while they're hot. The only thing one has to bear in mind; be careful around fuel containers and fuel vapors, as well as other things that might catch fire or be damaged by the heat.

My project also involved swapping the rear axle and front differential, due to my '84's final drive gears being wasted when a bevel gear tooth that was left inside punched a hole in the rear diff cover, draining out all the oil when I was about 60 miles from civilization.

Working meticulously by myself, the project took me about 20 8-hour days to complete. You'll probably be doing about half the work I did, and therefore should take about half as long; even less if you have good help and the right "pro" tools!

Finally, when I was finished and had saved some of the good excess parts, I rented a tow dolly and hauled off the '88's hulk to a sell at a salvage yard for scrap metal with my upgraded '84 Bronco-II. I may have made one mistake, though. Without thinking, I probably used 5th gear while towing. The owner's manual cautions against doing that for good reason. It's TOO WEAK for towing, and doing that may have damaged a bearing on the countershaft. It's driveable until I can replace the bearing; I just have to avoid using OD.

So don't YOU make that mistake! When you're towing, stay out of overdrive!!