1990 Ford Bronco 4BT swap

[lotzagoodstuff]

Quick update:

I have changed directions on the upgrades that I'm performing on this Bronco. I bought it because it was complete AND had a five speed. QUOTE]

Ditching the 5 speed for an auto. I'm sure your left foot might thank you during traffic, but I gotta say I miss my ZF.

It's awesome that you are making it your own. That's still the best part about this country: you really can have it your way

 

[BrandonMag]

Ditching the 5 speed for an auto. I'm sure your left foot might thank you during traffic, but I gotta say I miss my ZF.

Yeah, I feel kinda like a traitor to myself. ALL of the vehicles I have DDed have had manual transmissions until the Accord I currently drive. I guess I'm getting old.

It's awesome that you are making it your own.

Thanks, RJ. It won't be the fastest project completion, but it will be done correctly to my specs.

 

[BrandonMag]

I've been mulling options for axles because Ford's TTB front suspension design is the engineering equivalent of Chernobyl. I have a 1985 F350 4X4 that I bought a little over four years ago. It had a blown 460, so I picked up a first-gen Cummins with the intent of swapping it in. Then, after it had sat for about three years, I got the idea to swap in an International DT360. Now, I realize it would be a better option for my long-term plans to buy an early Super Duty F550 chassis to swap the DT360 in to. Props to SuperHatch on PSN, I'm essentially copying his idea.

Because of this shift in priorities, I have a perfectly usable dually F350 4X4 crew cab that I can snag whatever I want from. And the first thing is axles.

One of the changes that is needed is gearing. The F350 axles are 4.10 and the Bronco axles are 3.55. I really liked how the Bronco behaved on the freeway with the higher gearing, so I will change the Sterling and Dana 60 gears to 3.55s. Since the axles will be out from under the frame, I'll give them a thorough going-through as well.

I went out to the garage this morning to take some measurements to see how close the front and rear axles are in width between the Bronco and the F350. I also measured the M5OD length to compare it to the E4OD I just picked up this past weekend.

Here's what I came up with (these measurements are all fairly close but not exact):

1. The M5OD is 29 1/2" long, while the E4OD is 31 3/4". I think this will work out in my favor, because of the now-needed change in front axle clearances. I will cut the front crossmember off (that the nightmare of a front axle currently pivots from) and fab up a DOM crossmember in its place further forward to carry the weight of the 4BT. My idea is to shift the 4BT forward the 2 1/4" difference. (Truthfully, I think the only thing that will be an issue with where my engine eventually ends up is the oil pan to D60 pumpkin clearance.)

2. The D44 TTB is 58 1/4" wide and the D60 is 60 3/4" wide. I measured from the inside of the dust shield to the inside of the dust shield, but I think it's a close enough measurement for my purposes. The F350 is a dually, so I will need to change out the hubs and spindles. I figure I can find these easily enough on any '80s or '90s F250 4X4 in the junkyard. I'm also going to keep my coil sprung front suspension, so I have some reading, thinking and fabrication work to do on the Dana 60.

3. The 8.8 rear in the Bronco is 60 1/8" wide and the Sterling 10.25 is 62 1/2" wide. This surprised me, because I read that the dually Sterling rears are four inches wider than the non-dually Sterlings. I had assumed that the 8.8 in the Bronco was going to be the same width as the non-dually Sterlings, but I guess not. This measurement was taken from the inside of the drum brake flange welded on the end of the axle tube to it's counterpart on the other side.

Really, it just boils down to choice. Would you rather have this:

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or this?

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Pretty much a no-brainer, IMO.

EDIT: This Bronco has an 8.8 rear axle.

 

[BrandonMag]

With some more reading and measuring under my belt, I have realized the DRW Sterling hanging from the rear of the '85 F350 is not a good option for the Bronco. I measured the SRW Sterling in my '89 F250, and it measured only 57 1/4". The DRW in the F350 measured a whopping 62 1/2"! That's a difference of 5 1/4" between the DRW and the SRW.

Because I need a VSS for the E4OD to function correctly, I am going to find a 1993 to 1998 F250 4X4 to snag the SRW Sterling and the hubs and spindles from. Here's an informative article about the Sterling family of rear axles: http://www.fourwheeler.com/how-to/transmission-drivetrain/129-0506-ford-1025-1050-inch-axle-tips/

And here is a very useful quote I just found from Snicklas that I want to keep for future reference:

"Early E4OD's had a mechanical provision for a speedometer drive. The Bricknose 87-91 E4OD Equipped trucks had a cable driven speedometer, with a provision for a VSS inline for cruise (if equipped) and to feed vehicle speed to the TECA (Transmission Computer). In 92 when the release of the OBS, the speedometer is electronic (as is all them through current) and the speedometer feed is from the VSS in the top of the read differential. The VSS is fed to the PSOM (the electronics that feed the digital odometer and the speedometer) and the TECA for the Transmission.

The late E4OD's and the 4R100's behind the 7.3PSD's also use the VSS in the rear diff for speed, but it is fed to the PCM and it controls the transmission and the instrument cluster."

 

[F350camper]

This 8 lug bronco is going to be bad ass! the end!

 

[BrandonMag]

I got the chance to work on the spaghetti mess of wires that Ford installed this weekend.

Here's what the engine bay looks like now:

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It may not look much different from a couple of weeks ago, but here's the current size of my scrap wire pile:

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I had a brainstorm today and ordered a weatherproof Bussman 20-slot ATC fuse holder, similar to this:

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I'm considering relocating all of the fuses from the factory fuse panel location to under the hood, somewhere near the corner of the engine bay where the two main electrical plugs for the EEC and all of the chassis wiring are located. I need five slots for the fusible links I removed and I have a total of 11 fuse slots being used in the factory fuse block. By rewiring all of this, I will end up with less than 16 fuse slots used. I will have room for future expansion, which is always a bonus. The exact details of how, where and exactly what are a little fuzzy at this point. I can say for sure that my pile of scrap copper will get bigger.

The PO mounted the control boxes for the tach and pyrometer on an aluminum plate, which I like. The location however, I'm not a big fan of:

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The tach would occasionally die when the clutch was pushed in. I realize now the reason is because the wires coming from the Dakota Digital interface were getting pinched by the clutch arm. I'm not sure where I'll relocate these two electronic gizmos to yet, but where they are now isn't working.

On a good note: crawling around under the Bronco earlier today, I realized the factory Ford 8.8 rear has a VSS. And it's mounted to the top of the diff. I was just informed on 4BTswaps that the 8.8 rear has a 108-tooth tone ring and the Sterling has a 120-tooth tone ring. That information will probably come in handy during the transmission programming phase of this build, but it will be awhile.

 

[BrandonMag]

Look what showed up today:

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I also took a couple of shots with other turbos for comparison. Here it is on the 4BT:

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Look at the difference in the size of the turbine housing. It's no wonder the baby H1C is known as being laggy. The housing on the HX30 is half the size!

And here it is with a "real" H1C off a 6BT that came in an '89 W350.

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I wonder how well the H1C from the 6BT would work as the atmosphere in a compound setup?

 

[F350camper]

Nice looking piece of hardware Brandon. Are you going to be able to stuff it in the stock location? Looks like it will fit fine, even with the larger compressor housing.

 

[BrandonMag]

Yeah, I'm planning on putting it in place of the 'baby' H1C... for now.

EDIT: I nixed the idea of using the Bussman weatherproof fuse block in the engine bay. Once I got my hands on it, I realized it wasn't going to work. It was pretty nice, but it was for the mini fuses. I thought it was a full-size fuse holder. Oh, well.

It would be nice to have more than just standard sized fuses available. I've got next week off, so I plan on hitting up a couple of JYs and seeing what I can come up with.

 

[F350camper]

I think you will be really happy with that turbo. My baby h1c will make more boost than I can use, and that was just by swapping in a 12cm gated exhaust housing. Your setup with the smaller exhaust and larger compressor should clean up just about any amount of fuel you can dump in.

 

[BrandonMag]

Your setup with the smaller exhaust and larger compressor should clean up just about any amount of fuel you can dump in.

That's my hope. I'm thinking about sending the VE pump to Mel for some Moose treatment. With that combo I shouldn't be lacking in the power department.

 

[BrandonMag]

Got the chance to spend a solid ten hours in the garage today. Here is my favorite part so far:

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No more EEC wires!

I've spent at least 15 hours working on the wiring and I still have many more to go. But it's moving in the right direction... slowly, but surely.

When I started removing the transmission/transfer case, the first thing I did was remove the rear driveshaft. The flanges had only three of the four bolts installed and only one was tight! I'm surprised I didn't notice more driveline vibration. I took this before I removed anything:

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I won't be removing the transmission and transfer case as an assembled unit again, it was a bear. But I got it out, and here it is:

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I noticed something odd on the front of the Dana 44 TTB. The first pic is the passenger side and the second is the driver's. Does anyone have any idea what these are?

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I thought at first they were adjustable steer stops, but the threads don't go through the radius arm. They just thread in to the nipples that are welded on the radius arms. I can't figure out what they're for.

I've got to do some figuring as to how exactly I'm going to mount the DOM crossmember to take the weight of the front of the 4BT. I'm thinking about installing a removable crossmember in front of the steering box. (Please excuse the third grade Paint photo editing. I am not an artist.)

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Recommendations welcome on the DOM crossmember.

Here is where the Bronco sits now:

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I've got the next week off. We're heading up to the Tacoma area for Thanksgiving, but I should have a few days between now and then to get more done.

 

[bbjordan]

Those sure look like shock absorber mounts to me.

 

[F350camper]

Those sure look like shock absorber mounts to me.

yeah, those look exactly like the shock studs on my dana 35 ttb. Maybe they are for some sort of quad shock option?

 

[laserjock]

I was thinking the same thing that they look like shock mounts. My dads half ton 4x4 had dual front shocks I think. It was a 91. I don't remember if my 88 did or not.