SOHC 4.6L engine swap from Mustang to Explorer

[jayton]

Hello guys,

I have a 2002 Explorer 4.6L with a spun bearing and chewed up crankshaft with 186,006 miles on the clock. I have decided to do a swap for a similar engine that will not require a new pcm.

The salvage yards around me only have trash for Explorer engines. I have a Mustang shop close by that can source me a complete Romeo 4.6L from a 01-04 Mustang, complete with accessories, run tested, and a 90-day warranty.

I see that the opposite of what I am trying to do is a very common upgrade on the 2001-2004 Mustang for the purpose of weight savings. There are many threads on the Mustang sites that explain swapping an 02-05 Explorer engine into a Mustang. They cover which parts need to be changed over from the old engine, including: headers, front timing cover, oil filter housing, oil pan, oil pickup tube, flex plate, etc.

I will be leaving my power steering pump and a/c compressor intact in the vehicle.

Would I be correct to assume that this would be just as easy a swap the other way around? I am not concerned about adding the extra weight of an iron block to the front of the vehicle.

What are some issues that I may run into and what will I need as far as tools to correct those issues.

Thanks,

[jaydez]

I'd assume if it can one way it can go the other. Just swap the parts the mustang boards have swapped to make is successful.

[rocket 5979]

Yes you can reverse swap without much issue. I swapped to an iron GT block engine because that is what I chose to build my built engine off of to ensure max strength. There will be a few things to do to make it work. First off, your motor mounts will need to be modified a little bit. Basically you will need to weld these little extension tabs onto your existing ones to reach the last hole that is a little further back then the ones found in the WAP alum blocks. You will either have to drill and tap the cast, but not used, knock sensor bosses on the iron block piston valley area for your knock sensors or have them deleted in the tune. I suggest retaining them if you can. I deleted mine but that was only because they would not fit with the Kenne Bell supercharger on top of the engine and they pick up interference from the supercharger anyways. I would swap as much of the stuff from your Explorer engine onto the Mustang longblock if you can when it comes to front drive accessories, and other stuff to keep it simple. Your serpentine belt idler pullies may have to rearranged a little bit but that is no big deal, but may require you to purchase a different length 6 rib belt than either a Mustang or Explorer take which will mean you would need to take a direct measurement to fit the right belt. Again no big deal for a DIY'er. That is about all I can remember right now. Overall it is not a terribly complex swap to do.

[jayton]

Originally Posted by rocket 5979

Yes you can reverse swap without much issue. I swapped to an iron GT block engine because that is what I chose to build my built engine off of to ensure max strength. There will be a few things to do to make it work. First off, your motor mounts will need to be modified a little bit. Basically you will need to weld these little extension tabs onto your existing ones to reach the last hole that is a little further back then the ones found in the WAP alum blocks. You will either have to drill and tap the cast, but not used, knock sensor bosses on the iron block piston valley area for your knock sensors or have them deleted in the tune. I suggest retaining them if you can. I deleted mine but that was only because they would not fit with the Kenne Bell supercharger on top of the engine and they pick up interference from the supercharger anyways. I would swap as much of the stuff from your Explorer engine onto the Mustang longblock if you can when it comes to front drive accessories, and other stuff to keep it simple. Your serpentine belt idler pullies may have to rearranged a little bit but that is no big deal, but may require you to purchase a different length 6 rib belt than either a Mustang or Explorer take which will mean you would need to take a direct measurement to fit the right belt. Again no big deal for a DIY'er. That is about all I can remember right now. Overall it is not a terribly complex swap to do.

Excellent info. Thank-you. I will have more questions in the days to come.

What about the Intake manifold, fuel rails, injectors, etc? Should I swap that over from the Explorer engine or leave those on from the Mustang?

Do you have any pictures of how you did the welding of that tab on the mounts?

What about coolant inlets and outlets? Any differences there?


Thanks!

[rocket 5979]

Originally Posted by jayton

Excellent info. Thank-you. I will have more questions in the days to come.

What about the Intake manifold, fuel rails, injectors, etc? Should I swap that over from the Explorer engine or leave those on from the Mustang?

Do you have any pictures of how you did the welding of that tab on the mounts?

What about coolant inlets and outlets? Any differences there?


Thanks!

Just keep things simple and swap your intake manifold and rails on over. The intake on the Explorers positions the alternator slightly different than the Mustangs so reuse your Explorer mani. The rails are different on your Explorer than on a Mustang because the Mustangs have an electronic FRPS whereas the 02 Explorer does not.

I do not have any pictures of how I modified the tab on the motor mounts. But it is really simple when you see it in person. If you or a buddy of yours has some basic welding and fabrication skills it should be no problem at all to get your motor mount modified to accept the other block.

The coolant passages are the same within the blocks and the cylinder heads. As long as you keep your stock intake manifold and water pump then it will be a simple swap. Yes there are ways to use aftermarket Mustang intake manifolds and all that, but it sounds that you want to keep this swap simple so just keep your stocker Explorer stuff for that.

Use the Mustang shortblock, heads, and cams (if the cams have the bolt on cam sprocket), and probably the oil pump too as long as it is in good shape since your stock one may have metal in it. Reuse your front stock accessories from your Explorer, intake manifold, throttle body, fuel system components, timing chains guides, sprockets, reluctor wheel, front engine cover, cam covers, PCV system, vacuum lines, throttle linkage, oil pickup, oil pan, and so on.

[joecrna]

Exactly, use the Mustang Long block. Use everything else from the Explorer, if your desire is to keep it simple.

[jayton]

Originally Posted by rocket 5979

I do not have any pictures of how I modified the tab on the motor mounts. But it is really simple when you see it in person. If you or a buddy of yours has some basic welding and fabrication skills it should be no problem at all to get your motor mount modified to accept the other block.

I am very thankful to have your insight. I do have a couple of neighbors that can weld.

I will be starting this swap later this week.

Thanks!

[jayton]

My new engine arrived today! It is from a 2003 Mustang GT and had only 51,000 miles.

Now the work begins. I will be working on it maybe one or two days a week. So it will be a couple weeks before I am finished.

Here are the pics. New engine arrives

[jayton]

Do I need to remove the transmission cooler lines to get the last starter bolt (the b*tch bolt)? Also, what's the trick to get to the top two bellhousing bolts?

I'm hoping to have the old engine out tonight.

[rocket 5979]

Originally Posted by jayton

Do I need to remove the transmission cooler lines to get the last starter bolt (the b*tch bolt)? Also, what's the trick to get to the top two bellhousing bolts?

I'm hoping to have the old engine out tonight.

I cannot remember about the trans cooler lines interfering with the starter bolts removal. With the top two bellhousing bolts you can take take about 3' worth of ratchet extensions with a wobble joint on the front to reach on up there and undo them. You can go from the top too so long as you have the intake manifold off to give yourself some extra working room.



I just noticed that you have a 96 Mustang GT too. If your cylinder heads in the Explorer are still good you can take those plus the 03 GT intake manifold and accessories and do a PI heads/intake swap for a good power gain on the 96. You will pretty much have all the required parts laying around already after the Explorer swap.

[jayton]

I have wanted to do the PI swap on that car for many years. I hope the old heads are still good. It was obvious that I had a failure in the right side of the engine, so it is possible that the right side head may be bad. See pictures here: Engine failure

Things are moving right along!

I am now to the part where I need to figure out what I am going to do about the two raised bosses for the knock sensors.

I am a somewhat experienced DIYer, but the drilling and tapping I do not have enough experience with. I do not know how close to the original locations I would need to make the hole. I may need to get someone to help me or start thinking about having it tuned out. I would at least like some practice at drilling and tapping first, as my cast iron mustang block should definitely not be my first attempt.

Can the engine still run without a tune? I understand that there would certainly be the "Check Engine" light, but would it still run normal temporarily until I do get a tune?

What if the sensors are plugged in but are left dangling there on the valley? Is there a specific event that this sensor is measuring or is it only a monitor of failure?

[rocket 5979]

Originally Posted by jayton

Things are moving right along!

I am now to the part where I need to figure out what I am going to do about the two raised bosses for the knock sensors.

I am a somewhat experienced DIYer, but the drilling and tapping I do not have enough experience with. I do not know how close to the original locations I would need to make the hole. I may need to get someone to help me or start thinking about having it tuned out. I would at least like some practice at drilling and tapping first, as my cast iron mustang block should definitely not be my first attempt.

Can the engine still run without a tune? I understand that there would certainly be the "Check Engine" light, but would it still run normal temporarily until I do get a tune?

What if the sensors are plugged in but are left dangling there on the valley? Is there a specific event that this sensor is measuring or is it only a monitor of failure?

Does the block you got have those two bosses cast into it in the piston valley? If it does then just take a 4.5" grinder with a flapwheel disc and grind the roughness of the cast down on the top where the knock sensor would mount to. Once you have ground it down enough to make a smooth mounting surface for your sensor (about 1/8") then select your tap based on the size of the bolt that mounts the knock sensor. I cannot recall what size it is but I am guessing it had to be around 8mmx1.0 or so. Make sure that you get a bottoming tap which has a flat tip instead of a pointed one. The side of the tap will tell you what size drill bit to use with it. Then mark the center of the boss with a marker, mark the depth of drill on the bit with some tape. Then hold the drill bit as perpendicular to the boss surface as possible and drill to depth. Cast iron is VERY easy to drill so you won't have to push hard. Now get your tap out and put some motor oil on it. Make sure you hold it perpendicular to the boss surface to get it started straight. Tap in about a turn or two and then back out to remove the metal chips. Keep putting oil onto the tap and into the hole every time you reinsert it so that the cast iron doesn't flake or gall. You will have it done in no time and without much hassle. Just blow the hole out with compressed air and admire your work.

If you would feel more comfortable you can buy a piece of steel or something from Home Depot to practice your tapping skills on until you feel comfortable. The good thing is that cast iron is about the easiest to tap, followed by steel, and then aluminum in my opinion. Nothing real hard, except that aluminum will really gouge into itself bad if you don't lubricate the hell out of the tap.

If you want to eliminate the knock sensors you can do so. I eliminated mine because of the false knock they would have picked up from the Kenne Bell supercharger. But in your truck you won't exactly have the problem. If you can keep them then I suggest it. I forget if it threw any codes that had to be tuned out in the PCM tune or not. It was so long ago I cannot remember. I doubt it would throw a code if you just unplugged them considering that they are a passive sensor.

Do not leave the sensors plugged in and dangling in the valley. They would probably rattle around so much that they would pick up all sorts of false knock which would cause your PCM to pull spark timing advance and kill your power. Either fully install them or fully unplug them.

The only specific event that these sensors monitor is knock which is not supposed to be happening under normal circumstances.

[jayton]

Originally Posted by rocket 5979

Does the block you got have those two bosses cast into it in the piston valley?

The two bosses are absent: 2003 Mustang valley 2002 Explorer valley

Originally Posted by rocket 5979

If it does then just take a 4.5" grinder with a flapwheel disc and grind the roughness of the cast down on the top where the knock sensor would mount to. Once you have ground it down enough to make a smooth mounting surface for your sensor (about 1/8") then select your tap based on the size of the bolt that mounts the knock sensor. I cannot recall what size it is but I am guessing it had to be around 8mmx1.0 or so. Make sure that you get a bottoming tap which has a flat tip instead of a pointed one. The side of the tap will tell you what size drill bit to use with it. Then mark the center of the boss with a marker, mark the depth of drill on the bit with some tape. Then hold the drill bit as perpendicular to the boss surface as possible and drill to depth. Cast iron is VERY easy to drill so you won't have to push hard. Now get your tap out and put some motor oil on it. Make sure you hold it perpendicular to the boss surface to get it started straight. Tap in about a turn or two and then back out to remove the metal chips. Keep putting oil onto the tap and into the hole every time you reinsert it so that the cast iron doesn't flake or gall. You will have it done in no time and without much hassle. Just blow the hole out with compressed air and admire your work.

If you would feel more comfortable you can buy a piece of steel or something from Home Depot to practice your tapping skills on until you feel comfortable. The good thing is that cast iron is about the easiest to tap, followed by steel, and then aluminum in my opinion. Nothing real hard, except that aluminum will really gouge into itself bad if you don't lubricate the hell out of the tap.

Thanks for the info. I realize I am making a bigger deal out of tapping than it really is. I need to figure out where to drill these two holes now.

Originally Posted by rocket 5979

If you want to eliminate the knock sensors you can do so. I eliminated mine because of the false knock they would have picked up from the Kenne Bell supercharger. But in your truck you won't exactly have the problem. If you can keep them then I suggest it. I forget if it threw any codes that had to be tuned out in the PCM tune or not. It was so long ago I cannot remember. I doubt it would throw a code if you just unplugged them considering that they are a passive sensor.

Wow, so you are saying that because they are passive, that I could maybe leave them unplugged and would not need to do any programming? That would be nice. However, if it was looking for a ground, continuity, or something else, could something to serve the purpose of an eliminator be wired in?

Originally Posted by rocket 5979

Do not leave the sensors plugged in and dangling in the valley. They would probably rattle around so much that they would pick up all sorts of false knock which would cause your PCM to pull spark timing advance and kill your power. Either fully install them or fully unplug them.

Yeah, I guess that would be kind of dumb. Nevermind that.

[rocket 5979]

Knock sensors can operate well whether they are located inside the piston valley or on the outer side of the block near where your exhaust manifolds would be. Some vehicles will place their knock sensors in the valley while others will place them on the exterior face of the block. One piece of guidance for placement would be to try to locate in the middle of the block when looking at in a forward and aft positioning.

I would suggest against drilling into the block anywhere there is not a protruding boss. There may be some existing area to which you could mount the knock sensors but I cannot recall any exact location. If worst comes to worst then just unplug them and call it a day.

[jayton]

Originally Posted by rocket 5979

I would suggest against drilling into the block anywhere there is not a protruding boss. There may be some existing area to which you could mount the knock sensors but I cannot recall any exact location. If worst comes to worst then just unplug them and call it a day.

From what I see, this seems to be a good idea. I'm going to move on.

[2002GreyHD150]

Jayton, did you get your swap all finished? how'd the no-knock sensor situation pan out?

any new pics or final pics?

thanks
Rob

[jayton]

Originally Posted by 2002GreyHD150

Jayton, did you get your swap all finished? how'd the no-knock sensor situation pan out?

any new pics or final pics?

thanks
Rob

Not even close to finished yet. Yesterday was the first day that I got to work on it in about 2 weeks. However, I was able to get a lot of cleaning done on the old parts and the engine bay. I also painted the valve covers a silver aluminum-looking color. They came out better than I thought as it was my first time trying to paint something.

The knock sensors are just going to be a trial and error thing when I get to it. I have a number of things I want to try and test as far as an eliminator, but I have more to learn there. The 2002 Explorer 4.6L has two sensors and 4 wires. Once it is time, I will tap on them to see if I can measure what signal they send, and then hopefully wire in something to make it think its never knocking. The end all solution if none of that works will be to pay to have it retuned.

I am just now starting to piece things back together.

[jayton]

This is one of my favorite references of all for the Ford 4.6L:

http://www.enginebuildermag.com/Arti..._ford_46l.aspx

Near the bottom of the article, they talk about knock sensor holes in iron blocks, and they mention 12mm holes and using 8mm Timeserts. Any idea which 12mm holes they are talking about?

[jayton]

I had to swap heads on my new engine due to the discovery that the previous owner had the bright idea of upgrading his spark plugs when he didn't know what he was doing. It looks like one of them were over tightened, and then they used a thread insert that was installed improperly, causing the head to be unusable. Luckily the salvage yard allowed me to exchange the heads for a really nice looking set.

My current issue is that I can not get the head mating surface on the block smooth enough. There is a lot of crud that has been very difficult to remove. I'm not sure if I am getting anywhere with it or if I am just making things worse. I have used acetone, lacquer thinner, and Permatex Gasket Remover with no luck. I am using aviation plastic scrapers and a Dremel with carbon steel wheel brush #428 with no luck.

Any ideas or tricks to getting this smoothed out without milling? I don't want to grind or mill it down because I fear changing the height of the heads will cause the new head bolts to bottom out, or that spark timing would be slightly effected, as mentioned on every source I read (such as near the bottom of the page at http://www.aa1car.com/library/ar396.htm)

[2002GreyHD150]

jayton, can you post a pic (use imageshack.us) of the stuff you are trying to clean? is it old head gasket material?

Im knuckles deep in my swap too.. found an '03 Explorer 4.6L in Eldon, Missouri (Branson area) for $1,500 delivered to Dallas, NO core, 65,000 on the clock. got to hear it run over the phone before they shipped it... LOL. All the engines locally were a joke: 156,000 for $1,250 + a $500 core!!...86,000 mile Mustang engine (80lbs heavier) for a "deal" of $1,600 + $ 600 core penalty... idiots...

I'm down to the top 2 trans bolts, the starter and dropping the A/C & PS off the sides, then out comes the old engine... same problem, right around same miles (ours has 182,183).

I have completely stripped, painted, dressed and got everything moved over to the new engine.. I I'm going to be stripping the old tape and crud off the wiring harness and re-wrapping the harness tonight in my living room watching DVR... LOL.. my wife would normally kick my azz, but since the Monty is HER truck I'm doing the way I usually do all MY stuff... She's not so crabby about my O.C.D this time since its HER truck getting the full treatment...

I will grab the link to my post and put it in here. I have a bunch of pics, I just haven't posted them yet.

http://www.explorerforum.com/forums/...=1#post2861014

Rob