Supercharging a 2003 Explorer w Aviator DOHC Heads

[2000StreetRod]

This is a discussion thread regarding modifying the stock 4.6L SOHC (16 valve) V8 in a yet to be purchased 2003 Explorer with the heads from a 2003 Aviator 4.6L DOHC (32 valve) aluminum V8 I purchased and eventually installing a supercharger. The Aviator engine had two spun rod bearings that were ignored by the previous owner so long that the crankshaft and two rods are unusable so I'll use the Explorer short block instead of the Aviator block. The Explorer, Aviator and Mach 1 aluminum short blocks have a lot in common so some of this thread will apply to all three engine configurations. The 2003-2004 SVT Cobra came with a cast iron block and an Eaton M112 blower. It is the basis for most of the forced induction (FI) upgrades (Eaton, Whipple, Kene Bell) to the normally aspirated (NA) DOHC V8s.

The stock 2003-2004 SVT Cobra came with no knock sensors. It is speculated that Ford assumed knock sensors would respond to the blower noise resulting in false detonation spark retarding.

The PCM relies on the intake air temperature (IAT) to retard the spark advance to prevent detonation. The Cobra has a pre and post blower IAT sensor.

The Explorer SOHC V8 and Mach 1 and Aviator NA 4.6L DOHC V8s came with two knock sensors mounted in the block valley between the heads.

The PCM relies on the IAT and the knock sensor to retard the spark advance to prevent detonation. If I install a supercharger on an Explorer SOHC V8 with the Aviator heads I'll use the SVT Cobra lower intake manifold that has room for an intercooler.

The knock sensor bosses will have to be ground off because they interfere with the lower intake manifold. I prefer to retain the knock sensor retard function available in the Explorer strategy so I'll mount the knock sensors on the outside of the block as others have done. There are knock sensor sensitivity and threshold calibration constants in the PCM strategy that can be adjusted to reduce false detonation spark retard. On a stock Cobra block one sensor can be placed on the driver side of the block in an empty threaded hole near the motor mount.

Maybe I can find a spot on the passenger side for a second sensor.

 

[2000StreetRod]

Timing cover

Below is a photo of a 2002 Explorer SOHC V8 timing cover (2002-2004 P/N 2L2Z-6019-AA).

Notice how it differs from the 2003 Aviator DOHC V8 timing cover (2003-2005 P/N 2C5Z-6019-AA).

Which is similar to the SVT Cobra/Mach 1 DOHC V8 timing cover (2003-2004 P/N 2R3Z-6019-BF) but not identical.

 

[2000StreetRod]

water pump

The water pump for the 2003 Explorer is P/N 3L3Z-8501-CA which also fits the 2003-2005 Aviator. There appears to be a short (block to hub = 2.58 inch) water pump (P/N AR3Z-8501-A) and a long (block to hub = 4.125 inch) water pump (P/N 5W7Z8501AA) available for the SVT Cobra/Mach 1.

 

[2000StreetRod]

Oil pump

The stock cast oil pump in a 2003 Explorer is P/N 5L3Z-6600-AA. The DOHC V8 uses a higher flow oil pump. For the Aviator the P/N is F8OZ-6600-AA and is the same for the SVT Cobra and the Mach 1. Melling makes an oil pump (high volume SOHC, standard volume DOHC) with billet steel rotors (P/N 10227) that retails for $518 but can be found for about $405.

It fits an oil pickup tube outlet diameter of 15/16 inch (P/N F6ZZ-6622-CE for Cobra & Mach 1, P/N 2C5Z-6622-AA for Aviator).

I plan to replace the lower flow Explorer oil pump with an OEM Aviator pump and will use the Aviator pickup tube and oil pan.

 

[2000StreetRod]

Harmonic balancer

According to Tasca Parts data base:
The 2002-2004 Explorer harmonic balancer P/N is 1W7Z-6312-AA. The 2004 Mach 1 harmonic balancer is P/N 2R3Z-6312-BAA or F6ZZ-6312-AB. The 2003-2005 Aviator and the 2003-2004 Marauder harmonic balancer P/N is 2C5Z-6312-AA. Harmonic balancer P/N F6ZZ-6312-AB is used on 1996-2004 Mustang GT, 1996-1999 & 2001 Cobra and 2003-2004 Mach 1.

The cheapest way to upgrade a NA DOHC engine to FI 2003-2004 Cobra configuration is to purchase a complete upgrade kit from a salvage yard. That way I'll everything I need (relocation brackets, idler & drive pulleys, IC and engine cooling tubes, etc.) and it will all be compatible.

In the interim, after communicating with an experienced MKVIII seller I purchased the heaviest of the three harmonic balancer weights available for a MKVIII.

The heaviest one is supposed to be best suited for an automatic transmission. I need to compare it (pulley diameter, weight & wear) with the one on the Explorer.

 

[2000StreetRod]

crankshaft & flexplate

The cast crankshaft in the 2003 Explorer is P/N 2C5Z-6303-AA (Romeo block) which was replaced by 2C5Z-6303-BA and has a 6 bolt flange. The crankshaft in my 2003 Aviator (Windsor block) is P/N F65E-6303-BB. The Mach 1 with an automatic transmission should be the same. The forged crankshaft in the manual transmission Mach 1 and the 2003-2004 Cobra (P/N 2R3Z-6303-BA) has an 8 bolt flange. Finding an 8 bolt flexplate compatible with the 5R55S/W might be difficult and if one is available is probably expensive. Performance Automatic offers a 4.6L/5.4L 8 bolt 5R55S flexplate (P/N PA26478-58) that lists for $789 that I found new for $592. I think the stock cast crankshaft and stock flexplate should be able to handle 400 to 450 rwhp and is hardier than the stock 5R55S. I plan to save money to upgrade the transmission by using the Explorer crankshaft and flexplate. The local machine shop will clean, grind the main & rod journals to .010 undersize and polish the crankshaft for $115 with a one week turnaround. However, they said even with 180K miles the Explorer crankshaft may only need to be polished and not ground.

Below is a photo of the F65E-6303-BB crankshaft used in the 2002 Mustang GT.

It is identical to the crank in my 2003 Aviator.

It is readily identified by the "knife edge" counterweights.

Below is a photo of the F2LE-6303-AG crankshaft used in the 2002 Lincoln Continental.

It was replaced by 2F3Z-6303-AA which was replaced by the 2C5Z-6303-AA.

 

[2000StreetRod]

connecting rods

According to the Tasca parts database the Explorer connecting rods to 6/28/02 are P/N 2L1Z-6200-AA. After 6/28/02 the rods are P/N 8R3Z-6200-B, the same as for the Aviator and Mach 1. The 2003-2004 Cobra connecting rods are forged (P/N 2R3Z-6200-AA). If I purchase an Explorer with a build date later than 6/28/02 I'll have spare rods from my Aviator engine.

Edit: According to an article I found on the internet: Rebuilding The Ford 4.6L

"The 1999-’01 Romeo motors used a lightweight, press-fit rod (F1AE/F2AE) through ’01. It usually weighed around 575 grams. Ford put a heavy duty, press-fit rod that weighed around 615 grams in the Romeo motors in the 2002 models prior to 1/2/2002. The big end was beefed up, so all of the additional weight (35 to 40 grams) was rotating weight. It was a 2L1Z-6200-AA part number. The heavy rod was converted from a press-fit to a bushed design after 1/2/2002. It carried a 2C5Z-6200-AA part number and was later replaced by 8R3Z-6200-B.

The Windsor motors had the lightweight rods from ’99 through ’01, too, but they were always bushed instead of press-fit like the Romeos. There were very few 4.6L Windsors built in ’02, but they did get the heavy duty rods along with the heavy crank, just like the Romeos. The early ’02 Windsors should have been press-fit, just like the early ’02 Romeos, but we suspect that all the heavy rods that were used in the Windsor motors were bushed. All of the 4.6L Windsors built after 1/2/02 had the heavy, bushed rods, even if some of the earlier ones didn’t."

I purchased a couple used connecting rod/piston assemblies out of a 2003 Explorer to compare to my 2003 Aviator rods. The Explorer and Aviator rods have floating pins retained with circlips on each end.

I haven't weighed the rods yet but the physical dimensions are identical except for one noticeable feature. The left and right ribs on the I beams on each rod are different thicknesses.

But on the Aviator rod (left in photo) the thin rib is on the right and for the Explorer rod (right in photo) the thin rib is on the left. There is nothing in the Aviator or Explorer shop manual about the rods being different. But both manuals instruct to mark the orientation of the rods and caps before disassembly and to reassemble with the same orientation.

I'll check the rest of my Aviator rods to see if they are all the same.

 

[2000StreetRod]

pistons

According to Tasca's database there are two different grades of pistons for the Explorer. Grade 2 is P/N 1L2Z6108AA (discontinued). Grade 3 is P/N 2L2Z-6108-JA (discontinued/limited availability). I found a Jan 14, 2003 Mustang360 article that states the 4.6L piston dish was increased from 10.5cc to 18.5cc when Ford went to the Power Improved (PI) heads in 1999. The deeper dish pistons with the 2 valve heads result in a 9.5:1 compression ratio and a 8.5:1 compression ratio with the 4 valve heads. There are three different grades of pistons for the Aviator, Mach 1 and Cobra. Grade 1 is P/N 2C5Z-6108-AB. Grade 2 is P/N 2C5Z-6108-BB. Grade 3 is P/N 2C3Z-6108-CB. I would think the piston P/Ns for the NA Aviator and Mach 1 would be different from the FI Cobra which probably has a lower compression ratio. Below is a photo of one of my Aviator pistons which has a very slight dish. The stock compression ratio for the 2003 Aviator is listed as 10:1 and the engine requires premium fuel.

Below is a photo of 2003 Aviator piston compared to a 2003 Explorer piston.

The 2 valve pistons are compatible with the 4 valve heads but my compression ratio would drop from the Aviator 10:1 to 8.5:1. That would be fine if I installed the supercharger at the same time as the Aviator heads but I plan to upgrade in stages. With 8.5:1 I would have less power at low and mid engine speeds than the stock 2 valve Explorer engine. I need to determine if my Aviator pistons (which are reusable) are compatible with the Explorer rods. Hopefully, the build date for the Explorer is after 6/28/02. If it is, then I can install the Aviator pistons with the Explorer rods and crankshaft in either the Aviator or the Explorer block. It's probably best to use the Aviator pistons in the Aviator block.

 

[2000StreetRod]

heads

My 2003 Aviator engine heads (right P/N 2C5Z-6049-AG, left P/N 2C5Z-6049-DA) are the ones with only 4 spark plug threads and the coolant flow issues. The 2005 Aviator heads have 9 spark plug threads and the coolant flow issues have been corrected. Motor Trend reviews state that the 2003 Aviator has a 10:1 compression ratio and the 2005 has a 10.3:1 ratio with both requiring premium 91 octane unleaded fuel. When I removed the spark plugs on my heads I found that they had been properly torqued and there were no indications of stripped threads. There are workarounds available to correct the coolant flow issues. Since head and crankshaft main cap bolts, head and pan gaskets add a significant cost to piston replacement I need to decide which pistons to use and not change them later if/when I add a supercharger. Using the Explorer pistons with the Aviator heads only provides an 8.5:1 ratio which would be good for the strip with high boost but poor on the street for normal driving without boost. My Sport has a 9.7:1 compression ratio which works well for street driving with mild boost. So I'm going to use the Aviator pistons with the Aviator heads. I'll let the local head shop do what they think is appropriate for my application. I'll try to determine if the expense of higher performance head gaskets and bolts are justified for 8 to 10 psi of boost. I should be able to prevent detonation by adjusting the tune AFR and advance.

 

[2000StreetRod]

head gaskets

The 2002-2005 Explorer and the 2003-2005 Aviator use head gaskets P/N 4C2Z-6051-AA (right) and P/N 4C2Z-6051-BA (left). The 2003-2004 Mach 1 and Cobra use P/N 2R3Z-6051-AA (right) and P/N 2R3Z-6051-BA (left). I don't know why the gaskets are different. MLS gaskets would seal better for a cast iron block with aluminum heads (Cobra) but the Mach 1 block and heads are the same as the Aviator block and heads.

 

[87350gta]

Holy crap! Do not spend that much money on a flex plate. I am in the same boat with my new engine. I have a complete cobra engine from an '04. If you need to know anything specific or measurements let me know. I found that the v10 flex plate will work, but you have to use a non explorer starter. I am also considering cutting the center out of an 8 bolt flex plate and welding it to an explorer flex plate, then redrilling the other 6 bolts, since only 2 will match up from the 6 to 8 pattern. There is about 1/4" setback difference between an explorer flex plate and a non explorer one.

 

[2000StreetRod]

Eagle Rotating Assembly

I ordered an Eagle rotating assembly last fall with a 6 bolt crankshaft. That way I can use the stock flex plate. So far I've only received the pistons, rings and pins.

The delay is the availability of the ARP rod cap bolts to Eagle. The estimated delivery is now in May.

 

[2000StreetRod]

Today I checked out my garage after 9 months of landscaping my yard and also getting very actively involved in getting a third-party presidential candidate on the ballot in as many states as possible. My motivation to see if my Sport would start after sitting in the garage all that time without even an engine start was to eventually get my little trailer out so I could get some bark mulch. After partially charging the battery I flipped the switch to disable the Accusump from releasing its pressurized oil and then cycled the ignition on and off 3 times to get fuel pressure up to normal as read on the fuel pressure gauge. Then I enabled the Accusump and was pleased to see the oil pressure gauge read about 10 psi. The starter would just barely crank because of the low battery charge but the engine fired right up. While the engine was warming up and charging the battery with my 240 amp alternator I opened some boxes that finally arrived a couple months ago and took some photos. The stripped down 4.6L block is still sitting in the back of my Sport from my last trip to the machine shop in December to have it assessed as build worthy and bore required. Ballot access is winding down so in about two weeks the block will go to the machine shop for boring and the rotating assembly will be balanced. During the machine work the Sport will be hauling multiple loads of mulch. And then my automotive "tinkering" will resume.

 

[CDW6212R]

I love new pretty parts. I got a set of new Eagle rods myself recently, for a 275-300hp 306 I'm going to build. You will be done soon I'm sure, enjoy that engine build, go slow and appreciate it.

 

[Devan]

Today I checked out my garage after 9 months of landscaping my yard and also getting very actively involved in getting a third-party presidential candidate on the ballot in as many states as possible. My motivation to see if my Sport would start after sitting in the garage all that time without even an engine start was to eventually get my little trailer out so I could get some bark mulch. After partially charging the battery I flipped the switch to disable the Accusump from releasing its pressurized oil and then cycled the ignition on and off 3 times to get fuel pressure up to normal as read on the fuel pressure gauge. Then I enabled the Accusump and was pleased to see the oil pressure gauge read about 10 psi. The starter would just barely crank because of the low battery charge but the engine fired right up. While the engine was warming up and charging the battery with my 240 amp alternator I opened some boxes that finally arrived a couple months ago and took some photos. The stripped down 4.6L block is still sitting in the back of my Sport from my last trip to the machine shop in December to have it assessed as build worthy and bore required. Ballot access is winding down so in about two weeks the block will go to the machine shop for boring and the rotating assembly will be balanced. During the machine work the Sport will be hauling multiple loads of mulch. And then my automotive "tinkering" will resume.

View attachment 92195

View attachment 92196

So wat ended up happening with this thing i wish i had a 32 valve explorer. Id love to have an eaton 4.6 dohc explorer to tow my 01 eaton swapped cobra hahaha. Make this fit

 

[2000StreetRod]

The rebuilt Aviator long block is assembled.

I've decided to use the stock Explorer oil filter/coolant adapter instead of the Aviator and have purchased an On3 front crossover bypass delete kit.

I also installed a head cooling mod kit.

I purchased a 2003 Centennial.

I'm in the process of pulling the engine and installing a marine engine pre-luber.

I've about given up on supercharging the engine. I don't like Eaton blowers due to high inlet air temperatures. I don't like turbochargers due to lag and only minor low engine speed torque increase. I still haven't completely ruled out a belt driven centrifugal supercharger.

 

[JW]

Damn...

I wish I'd done the cooling mod on my new 4.6 while it was out.

 

[Devan]

wow very nice, that pre luber is def a good idea especially for a DOHC engine that you have spent a ton of time and money on. And I really like that oil filter adapter with the coolant lines going through it. Do you have a part number for that?, I may try to fit that to my cobra. I have that on3 crossover bypass on my Cobra but I don't have a thermostat in it. I still have the stock thermostat housing. I pretty much just used it to split the cooling lines and to get rid of that crossover tube so I could fit my saleen syle S/C tank. The only reason I even ended up doing an eaton swap on my 01 cobra instead of getting a kenne bell was so that I could get hellions compound boost twin turbo kit. but also at the time when I did it kenne bell only made a 2.1 blower for the 01 cobra and with the 03 04 cobra lower manifold I could have gotten a 2.6 or 2.8 mammouth kenne bell but I'm pretty sure they have even bigger ones now. you could go with a kenne bell. Or a procharger or a vortech would sound awesome on that thing as well with a blow off. Ill attach a cpl shots of my cobra engine so you can see what I did with my coolant hoses. The reason why I had to get rid of my crossover tube was to fit this saleen style supercharger coolant reservoir. I did have an 03 04 cobra style powder coated black supercharger reservoir however when I upgraded to a thicker radiator I ended up having to change the reservoir and move my abs module back and get rid of the coolant crossover pipe. Everything is so more difficult when your working with a 4.6 DOHC in a jam packed little engine bay like a 99-04 cobra but dam I wish I could fit that beautiful engine you built into my 01 Sport 2 door. Somebody has to do it already put a DOHC 4.6 in one of the 2 doors! Maybe Ill give it a go and see what I can do. BTW street rod what do you do for a living

View media item 53081Don't mind the blurriness of this first shot. I literally just took this picture, the camera on my phone is messed up. This is what my engine bay currently looks like. The rest of these pictures are old pics from when I was working on it. But you get the idea of what I did with my cooling hose setup. I have not yet done the rear head cooling mod like you have although I do have coolant goin to one of those rear ports however I will be pulling the freeze plugs out on the top backside of the motor by the intake ports and run coolant in that way. Like where the coolant hoses go in to the top front part of the motor by the front side of the intake ports I'm planning on doing that to the back side of the intake ports as well where those freeze plugs are.

20160309_231234

• Devan
• December 21, 2017

20160928_231245

• Devan
• December 21, 2017
• 1

Direct Port Methonal injection buildup-I didn't want methanol to go through my newely rebuilt stage 8 blower and take the finish off the rotorpack blades.

20160930_000241

• Devan
• December 21, 2017

20161003_020113

• Devan
• December 21, 2017

Where my coolant hoses go into the cylinder heads I used some MMR cylinder head water fittings instead of On3 Performances because the MMR fittings are one piece and the hold down is part of it whereas the On3 Perf fittings have that aluminum bracket to hold them down and it only covers half the fitting. Cooling System / Power Steering : Modular Motorsports, Home of the Worlds Fastest Modular Engines
My On3 Perf crossover delete kit came with 2 different types of cylinder head water fittings. One of them has 2 ports and the other only has one port but I do plan to use those for the backside cylinder head coolant ports where the freeze plugs are behind the intake ports

 

[2000StreetRod]

And I really like that oil filter adapter with the coolant lines going through it. Do you have a part number for that?, I may try to fit that to my cobra.

If you're referring to the 1st photo that's the stock Aviator oil filter/coolant block adapter that contains the cold temperature thermostat. I prefer the hot temperature thermostat configuration like the SOHC 4.6L implementation. I think the thermostat should be as close as possible to the head cooling outlet ports. That's why I purchased the On3 Performance crossover delete kit. It was the only commercially available one I could find that included a thermostat housing. See this for more info: 4.6L DOHC head cooling and crossover delete mods

Everything is so more difficult when your working with a 4.6 DOHC in a jam packed little engine bay like a 99-04 cobra but dam I wish I could fit that beautiful engine you built into my 01 Sport 2 door. Somebody has to do it already put a DOHC 4.6 in one of the 2 doors! Maybe Ill give it a go and see what I can do. BTW street rod what do you do for a living?

I put an M90 from a Thunderbird SuperCoupe on my 2000 Sport with the 4.0L SOHC V6. It has a mild boost of 6 psi to improve low engine speed acceleration. I think it would be difficult to put any 4.6L in my Sport but your 2001 Sport may have more room in the engine compartment. Your Cobra engine compartment is definitely dense. One of my goals is to reduce as many hoses and pipes I can. I'm using a 03 Mach 1 upper and lower intake manifold instead of the Aviator intake with intake runner control. I'm a retired electrical engineer who enjoys automotive tinkering.

 

[Devan]

Using a mach 1 upper and lower is a far better idea then using the runner control IMO, I think itll breathe better. You may also want to consider doing something like this if you wanna pickup a little more: Race Port Lower Intake HIgh Boost Twin Screw Only Posi Perf puts out a race porting job for the lower manifold. O wait your running mach 1 lower thas right. I forget what my 01 cobra lower intake manifold looks like but i dont think much porting can be done to it. I have an M90 in my sport running 6 pounds as well. I think explorer sports with the 4.0 SOHC from 96-2000 have pretty much almost an identical engine bay to that of the explorer sports from 01-03 with the 4.0 SOHC, I cant see any differences but if their are any let me know. The major problems I can currently forsee with swapping in a 4.6 would be the brake booster and the climate control box. I would definatly swap to a hyrdoboost (Ive seen that on other explorers and rangers and the mustang hydroboosts basically bolt right in) plus I would prefer hydroboost over a regular brake booster. And I also remember another guy with a ranger doing a 4.6 dohc swap where he cut up the climate control evaporator housing and fiberglassed it to the shape he needed it but he ditched the A/C system which I would not want to do. I would either try to relocate the evaporator or get a smaller one from another vehicle and make it work somehow. But those are the 2 most forseen problems I can see with a DOHC 4.6 swap into a sport. Of course Id prolly run into a ton of other problems like the steering shaft and exhaust manifolds. Heres the link to the 4.6 DOHC swap into a ranger. 4.6 DOHC Swap into 96 Ranger - Ford Truck Enthusiasts Forums He doesnt have torsion bars though hes got the coil springs in the front. Another thing that would be very important to me would that I would wanna retain my 4wd. I would prolly go with a built T5 with a borg warner shift assembly and an S10 tail housing so that I could bolt it to an electric shift BW1354 or BW4406 but with that much power I would feel a T56 would be much more reliable. But their are guys out there that can build the crap out of that little light weight T5 and I think the shifter would be right where your want it with the T5.

T5 4x4

• Devan
• December 23, 2017

Heres a rare modern 4x4 T5.

T56 4x4 Plate

• Devan
• December 23, 2017

Or better yet a T56 4WD adapter plate and you drill the holes whereever your want them