Monday, January 9, 2012

Explorer Engine Swap - Exploring Into the Mustang

Prior to choosing the Explorer engine to go into the Mustang, I told you I did a bunch of research into what it was going to take to put the engine in and what parts it would need to put it in there.  This is a quick compilation to that.

When researching the Explorer engine, the first thing I found out is that people like to take the heads and intake off of these engines and place it on their Mustangs.  I found this pretty interesting.  What is special about the Explorer intake and heads I asked myself.  Well after doing some research, I found out that Ford put GT40 heads on the Explorer.  This is the equivalent to the head that they put on some of the Mustang Cobra engines.  These heads allow more air into the air fuel mixture and results in added horse power.

The Ford Explorer came from the factory with about 225 horse power.  Well, that just a little more than what the factory Mustang GT comes with.  This engine should just bolt right in with no problems right?  Well, it will, but you won't get performance out of it like you would with the stock Mustang engine.

If you think about this for a bit you can realize why.  An Explorer is not meant to have speed.  It is built for torque.  Does that mean it won't work?  No.  All you need to do is stick a different camshaft in the engine.  

Now that you know the cam needs to be replaced, there is a little bit of a domino effect here.  Why?  It is pretty simple actually.  There are other parts that are relying on the camshaft to do their job.  One of these parts are the valve springs.  When you buy a cam from a dealer like Comp Cams or Summit Motor sports, they will usually inform you that you need to change the valve springs with the cam.  They are usually paired together.  Since you should at least install your Mustang GT cam into this engine, you will need to purchase a set of valve springs that match the cam from your engine.

The first thought that came to my mind was why can I not use the springs out of my mustang engine since I am already using the cam?  The answer to that is you can, but you shouldn't.  The reason you shouldn't do this is because your engine is already going to have some decent milage on it.  After a while your springs will start to get weak from the constant compression and release that happens while your engine is running.  So they are at the point that they are getting wore out.  Since you already have them off of the engine you might as well put new springs on there.  These aren't the easiest things to replace with the engine in the car.  So now is the ideal time to do it.

So why don't the springs from the Explorer work?  Well, that answer is pretty simple.  The cam for the explorer does not open the valves as much.  This means that when the springs were initially installed, they didn't need as heavy duty spring on it.  Since they didn't need it, it doesn't have it.  Will they still work?  This answer is debated over and over.  I am on the side of it will work, but the risks are too great to take to give it a shot.  This is where you have to ask yourself.  with all the time, effort, and money you are sticking into this, don't you think it is worth a new set of springs?  Do you really want to take the chance that one of these springs breaks while the engine is running?  That could result in a bent valve at the very least, and may end up destroying your piston and possibly your block depending on the damage that happens when the valve falls.

Ok, I have gone off on a little tangent and all you know right now is that you have to replace the cam and the springs.  I will get a little more in depth of what else you should change when I write up the "how to" for the change of the valve springs.

Now after this, you need to know that the upper intake for the Explorer is not identical to that of the 94-95 mustang (it is compatible in the fox body 86-93).  Because of this I needed to purchase an angle adapter to allow my cold air intake and throttle body to hook up.   There are several manufacturers of these angles and many different looks of them.  The one you choose is up to you.  I will give all the parts and vendors that I chose at the bottom of this post.

Once you are at this point, the last thing you need to have is a gasket kit.  You could buy all of the gaskets that you would need separately but it would get pretty expensive.  especially if you can get them all in one kit.

The last thing that you will need to buy is an oil filter bung.  The reason you need this is because of how the Explorer has its oil filter mounted.  you will need to remove that 90 degree angle piece and the bung that is in there and replace it with the new oil filter bung.  You could use the one out of your Mustang engine but they are pretty difficult to get broke loose.  They are pretty inexpensive, so save yourself the headache.

The one part that I have not seen anyone else ever recommend for this.  I am assuming it is because most just leave it off the car after they do the swap.  The strut tower brace.  Once you switch to the Explorer intake you will notice that it will sit a little higher than the stock GT intake did.  This causes a problem with the strut tower brace.  But don't fear, they do make a part that will work.  It is a Ford Racing part that will bolt on without problems.  I had to find mine on Ebay. There are some other performance parts companies that make them, but they tend to get pretty expensive and I am cheap.  :)

Here is a quick list of the parts you will definitely need:

1.  Camshaft - this can be the one from your Mustang engine.
2.  Valve springs - I recommend buying a Trick Flow kit TFS2500100  (LMR)
3.  Intake Elbow Adapter - I went with the Professional Products one.  I wasn't real impressed with it and ended up having to drill a little on my intake to get the thing to bolt up and also had to remove a good chunk of the aluminum where the throttle body bolts up and a sensor plugs into it. PP54151 (LMR)
4.  Gasket set - Felpro KS2371 (AA) One thing I ran into with this kit was that for some reason the water pump gasket was not the right one and neither was the upper intake gasket.  It may have just been that I got a defective set, but when I when to Advance Auto parts, I brought them in and they gave me the correct ones so no harm no foul.
5.  Oil Filter Bung - LRS-6890A (LMR)
6.  Strut Tower Brace - Ford Racing M-20201-A51
7.  Oil pan and pickup tube - this can come off of your Mustang engine

AA =

I will go into more of the other items that you may need for this and some things you will want to change but are not required in the article "Better to Be Safe Than Sorry"


  1. I'm not sure if you did or did not mention it, but there was a moderate amount of surface rust on the engine block of my explorer motor when i stripped it down. Did you encounter that?

    I spent an evening with a wire brush and naval jelly, just to get the block acceptable. The next evening I painted the block.

    1. My block was rust colored, but wasn't overly rusty. By this I mean I wasn't going to be able to brush chunks of rust off of the block. I did contemplate cleaning the block and painting and whatnot, but elected not do do it due to the time commitment that would have been involved to get it to a point where the paint would stick and not peal off. If I had rebuilt the core of the engine, I would have done so.