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Discussion Starter #1 (Edited)
Hi, All

I picked up a 1990 Ford Bronco that has a 4BT on June 1st.





The build is documented on here, but since I'm new this site won't allow me to post a link to the thread. Search "Bronco 4BT" and look for the thread started by redman. That's the one.

I picked it up with the intention of making it my daily driver. It's all there, but it's a little rough and there are some things I want to change to suit my tastes.

This isn't my first diesel, but it is my first converted 4bt engine swap. I'm going to need some guidance and answers to questions, so I thought I'd post a quick Hello! and introduction.

:smokin:
 

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Welcome.
I have a 4bt Bronco also It works well I have had the 4bt in it for 8 or 9 years.
Looks like you need some fuel line holders before the lines fail from vibration.
 

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Discussion Starter #4
Thanks for the replies.

The custom lower radiator hose hanger is one of the issues that I want to address.

Good eye on the lack of fuel line holdes, dieseldude! I hadn't noticed that before.

I'm working swings for the next week and I've got some other stuff I need to take care of around the house. My hope is by the end of June I'll have all of my other loose ends tied up and I can focus more of my energy on this Bronco. I'd like to have it DD ready by the end of October... we'll see how that goes. :D
 

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At least that yellow nylon cord isn't supporting the engine. Looks like it could use a better larger air cleaner. Everything else looks pretty normal.
 

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Discussion Starter #6
Looks like it could use a better larger air cleaner.
Yep, that's another issue that I want to address. I'd like to install an intercooler and redo the intake pipe and filter.

The PO also disconnected the boost gauge line. He said it made a "ticking" sound when it was hooked up. Investigation necessary.
 

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Welcome.
Looks like you need some fuel line holders before the lines fail from vibration.
Great catch.

At least that yellow nylon cord isn't supporting the engine. Looks like it could use a better larger air cleaner. Everything else looks pretty normal.
Absolutely, I've found an air filter that small restricts power.
 

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On the intercooler, the early Powerstoke model can fit that body style depending on the width of your radiator.. Have to rework the hood latch support brace. Those came in 2 designs, one all aluminum and the other with plastic end tanks. You'd want the all aluminum version. Of couse there are probably many others that will work. Hadn't noticed the missing injector line clamps. That should be a first order fix. Don't want to be cracking injector lines. Makes a terrible mess under the hood. Here's a couple of photos of the IC.
 

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Also, if you get intake air from in front of the radiator, etc., the engine will have more power, no-one needs pre-heated intake air.
 

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Discussion Starter #10
I actually have an all-aluminum 7.3 PowerStroke intercooler. I was thinking it was a little too big for the small Holset that's on the 4BT. Maybe not?

Having a cold air intake would be nice. Probably worth the time to put that in.
 

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1989 Jeep Wagoneer, 360v8, 727, stock for now,
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I actually have an all-aluminum 7.3 PowerStroke intercooler. I was thinking it was a little too big for the small Holset that's on the 4BT. Maybe not?
Having a cold air intake would be nice. Probably worth the time to put that in.
No such thing as too big when it comes to the intercooler, unless it won't fit. I'm only using a 92 Dodge intercooler in my Scout.
 

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Discussion Starter #12
No such thing as too big when it comes to the intercooler, unless it won't fit.
I've been under the impression that if you oversize an intercooler, you will reduce the air density to the point where it will negatively impact engine performance.

Maybe that's not too much of a worry with most of the intercoolers we're likely to run since they are all (relatively) small in terms of area?
 

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I've been under the impression that if you oversize an intercooler, you will reduce the air density to the point where it will negatively impact engine performance.
cut……..
The more you cool the charge air the greater the density.
 

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Discussion Starter #14 (Edited)
The more you cool the charge air the greater the density.
Sorry, I should have use the word velocity.

The reason an air-to-air intercooler cools the charge air is because the energy (heat) in it is transferred to the aluminum of the intercooler itself. This energy is then transferred to the outside (ambient) air. This results in a cooler, denser air charge. The more air molecules that contact the aluminum of the intercooler, the more heat transferred.

The disadvantage is the air also loses velocity. This is the reason you see a pressure drop. You're going from a 2" intake tube from the compressor straight into the intake manifold to more tubing and an intercooler. Obviously, the more restrictions you add to the charge air stream, the more velocity you lose.

If you oversize your intercooler to the point where there are more restrictions than your compressor can push past efficiently, the drop in air velocity would be too much. I'm pretty sure a Ford 6.0 intercooler would be a bit too big for the tiny hairdryer that's feeding this 4BT... at least, that's what I gather from the research I've done. Maybe I'm misunderstanding something.
 

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i put a speedway double pass radiator on my 71 dodge to get both inlet and outlet on the right side--also increases cooling----bob
 

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Brandon, you won't see a lot of pressure drop caused by the intercooler. As was said, bigger is better. Member Camccardell is running the 6.0 intercooler on his F150 with no probem. See photo. That one has the plastic tanks, but those didn't crack as bad as the 7.3 model. On the 6.0 you have a different size inlet and outlet. On the 7.3 they are both 3.25". Can't see in your photos, but I suspect your engine has the small H1C turbo. That isn't the greatest turbo if you want any kind of performance. Change it to an HX30W and it would be a whole different engine.
 

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Discussion Starter #17
Thanks, char. I'll bolt the intercooler I have on and see what kind of EGT difference that makes.
 

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For reference:
The 130hp 4bt (Freightliner) CAC core is 357 sq in.
The 92 dodge CAC core is 379 sq in, 160hp
The 94-98.5 Dodge CAC core is 525 sq in, 160-215hp
Remember These are MINIMUM sizes that the engineers said will work.
 

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Discussion Starter #19
I've been looking forward to tearing into this Bronco since I bought it.

Here's where it was this morning:



And here's where it is after a few hours of work:



Started cleaning a 7.3 all-aluminum intercooler I got from a friend from another board a couple of years ago:

 

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Discussion Starter #20 (Edited)
After a month and a half without any real forward progress, I finally made time last night to do this:



The way the front motor mounts are designed, the engine kept getting hung up on them. After struggling for a couple of minutes I realized they needed to come off. Once I pulled them out of the way, it was pretty simple.

After I got the clutch assembly and flywheel off, this is what I saw:



Assuming that the rear main seal needed to be replaced, I pulled the adapter plate off:



And here's a closer look:



It appears that this plug is leaking. Is this basically just a freeze plug that seals the oiled area of the block? I've got a Cummins service manual that covers complete tear down and rebuild, but I can't find a reference to removing and reinstalling this plug. Any pointers?

EDIT: I got the 4BT mounted on the engine stand:



And here is the engine bay now:



Lots of work to do in there...

As far as the engine is concerned, I just plan on doing a reseal and upgrading the turbo to a HX30W, so (hopefully) the engine will be done shortly.
 
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