Mustang V8 Engine Swap

[Travis Brown]

Background
The timing phaser and/or chain went bad in my '06 4.6 with 213k and rather than throw parts at an old engine, I tracked down a '08 Mustang engine with 79k miles from a local wrecking yard for about $1000. The Mustang engine is an aluminum block version of our 3V V8s, so it should save a whopping 80-100 lbs. I figure that weight savings will help to offset all of the off roading gear I'm about to add to this rig and the lower mileage is awesome. The Mustang engine is rated for more horsepower and torque than our engines due to different exhaust, intake, and tuning, but for now I'm just going to swap the long block and keep everything else stock.

Removing the old Engine
I've done engine swaps before, but this one is not for the faint of heart. You have to basically disassemble the whole truck to get the engine out. I was following the factory shop manual, but it failed to mention a few key steps, leading to a lot of head scratching. Here's the process:

* Remove front and rear drive shafts
* Remove frame cross member (the shop manual didn't mention this, but it's absolutely critical)
* Remove transfer case

* Remove exhaust Y-pipe - This was very tricky because the down-stream cat and muffler were in the way. I wound up having to unhook the rubber muffler hangers to get enough clearance

*Remove starter

* Remove transmission - This is pretty tight, but doable if you have about 3ft of wobble extensions

* Remove cooling fan, hoses, and upper intake manifold

* Detach power steering pump, and A/C compressor - The A/C is held to the block with studs, which I wasn't able to remove before pulling the engine. I just hoisted the engine and let the compressor slide off the studs
* Unbolt the motor mounts
* Pull the engine

Engine Accessory Swap
Here's the old engine next to the new one

I haven't really gotten started on this yet, but I've identified quite a few difference between the two engine setups

• Upper intake manifold and throttle body
• Coolant-heated PCV (Explorer only)
• Oil pan shape
• Oil temperature sensor in the oil pan (Explorer only)
• Engine Mounts
• Pump-mounted cooling fan (Explorer only)
• Coolant tubing

This last one has me stuck. There's a cooling line that is attached (brazed?) to the block on both engines, but it's not the same between them.

Any thoughts on what to do with this line?

 

[boominXplorer]

That line is just bolted to the head on the back and will twist off towards the back of the engine. It is sealed by 2 o-rings. I feel your main hurdle might be bolting on the motor mounts.

 

[Travis Brown]

That line is just bolted to the head on the back and will twist off towards the back of the engine. It is sealed by 2 o-rings. I feel your main hurdle might be bolting on the motor mounts.

Dude, you're an oracle! I ran out to check the engine mount holes and you're right, they're not all the same. On the passenger's side, it's not too bad. I'll just need to drill one new hole in the Explorer mount bracket. On the driver's side, the Explorer bracket doesn't cover the fourth hole, so I'll need to break out the welder and extend the engine mount.

How did you know they were different? Did Ford change the modular block layout sometime between 2006 and 2008? Or are the Mustang blocks just special?

 

[boominXplorer]

I have a 01 mustang gt (iron block) and have been considering the aluminum block swap myself. There's a few ways around it just depends on your platform.

Some expeditions in 2003-2004 came with the aluminum block 4.6s as there was a casting issue in 2002 with the iron blocks. The mustang had iron blocks until 2004. You might be able to source the mounts from one of those expeditions, can't remember how similar they are to the 06+ explorer.

The aluminum block castings are the same from 2v and 4v but I'm not certain about 3v. If it starts with 3LXX then it's the same.

 

[Travis Brown]

Well, I got around to pulling the oil pans today and found some surprises. Here's the explorer on the left and the mustang on the right

It looks like the mustang comes with some pretty aggressive baffling. Not surprisingly, the oil sumps are different to account for different oil pan shapes. I would love to keep the mustang baffling, but it physically interferes with the explorer oil pan baffles shown here:

Also note the timing chain tensioner shrapnel at the bottom, probably the root cause for the engine's timing issues. Maybe this is to be expected after 213k miles...

Anyway, what do you guys think? Cut off the wimpy explorer baffles and leave the mustang baffles in place or unbolt the mustang baffle and run a stock explorer oil pan?

 

[loooney2ns]

I don't know if you will have clearance for the Mustang pan and pickup. If the windage tray will fit with the Explorer pan and pickup. then use it.

 

[boominXplorer]

Either way you do it you must keep the oil pump pickup with the correct oil pan.

 

[Travis Brown]

Ok, I cut down the oil pan baffles on the Explorer so that I can mount it on the Mustang engine without hitting the windage tray. The mustang oil pickup is about a half inch shallower than the Explorer, so I carried over both the pickup tube and the pan.

Here are the motor mount brackets after drilling a hole in the right side and welding on an extra flange on the left.

 

[Mbrooks420]

How did you know they were different?

He’s the man.

 

[Travis Brown]

I finally got around to finishing up this swap and ran into a few more minor issues. Part of the wiring harness leading to the sensor on the oil pan attaches to three pan bolts and one of the timing chain cover bolts. On the aluminum block, these bolts don't stick out the back of the hole far enough to attach the harness. It's easily fixed with some longer bolts.

I also had a heart attack when I pulled the spark plugs and saw that they're totally different from the old ones, because I was told that the heads were all the same between 3V 4.6 engines. Happily, it turns out that the dreaded stuck spark plug problem was fixed in '07+ Mustangs, and my new engine (thankfully) has the newer head design.

Overall, I'm super happy with the results. The front end sits a little higher from the reduced weight and the engine runs much nicer than the one it replaced. I really think that this is the engine that should have come in this thing from the factory. Here's a final pic of the engine before I put it in.

 

[Harley McIntyre]

I finally got around to finishing up this swap and ran into a few more minor issues. Part of the wiring harness leading to the sensor on the oil pan attaches to three pan bolts and one of the timing chain cover bolts. On the aluminum block, these bolts don't stick out the back of the hole far enough to attach the harness. It's easily fixed with some longer bolts.
View attachment 314704

I also had a heart attack when I pulled the spark plugs and saw that they're totally different from the old ones, because I was told that the heads were all the same between 3V 4.6 engines. Happily, it turns out that the dreaded stuck spark plug problem was fixed in '07+ Mustangs, and my new engine (thankfully) has the newer head design.
View attachment 314705

Overall, I'm super happy with the results. The front end sits a little higher from the reduced weight and the engine runs much nicer than the one it replaced. I really think that this is the engine that should have come in this thing from the factory. Here's a final pic of the engine before I put it in.
View attachment 314706

Does it drive any nicer now?

 

[Bklein711]

I finally got around to finishing up this swap and ran into a few more minor issues. Part of the wiring harness leading to the sensor on the oil pan attaches to three pan bolts and one of the timing chain cover bolts. On the aluminum block, these bolts don't stick out the back of the hole far enough to attach the harness. It's easily fixed with some longer bolts.
View attachment 314704

I also had a heart attack when I pulled the spark plugs and saw that they're totally different from the old ones, because I was told that the heads were all the same between 3V 4.6 engines. Happily, it turns out that the dreaded stuck spark plug problem was fixed in '07+ Mustangs, and my new engine (thankfully) has the newer head design.
View attachment 314705

Overall, I'm super happy with the results. The front end sits a little higher from the reduced weight and the engine runs much nicer than the one it replaced. I really think that this is the engine that should have come in this thing from the factory. Here's a final pic of the engine before I put it in.
View attachment 314706

Did you have to do anything to the computer or put in the mustang computer for the engine?

 

[Travis Brown]

Does it drive any nicer now?

I'll admit that I didn't have my Explorer long enough before doing the engine swap to do a fair comparison, but there is one place that I really noticed a difference. There's a street near my house that has about 6 huge speed bumps in a row. With the old cast iron block, going over these bumps was a little like going on a roller coaster. It really freaked me out the first time I went over them because whole truck pitched so violently. After performing the engine swap, it feels more like a normal car where you glide over them, laughing about people's futile attempts to slow you down.

Did you have to do anything to the computer or put in the mustang computer for the engine?

No, I'm using the stock computer. I do wonder if there's a difference in tuning or programming between the two blocks, but it runs fine and I worry that there might be some major compatibility issue if I try to change the PCM.