Because the Modular V-8 has so many different applications, it is impossible to detail all the removal and installation specifics here. However, I can touch on what you can expect across a broad range of Ford, Lincoln, and Mercury applications. Gone are the days when you could spend an afternoon pulling this and yanking that, and then wheel up a 1-ton hoist and remove the engine. Since the Modular engine is as large as the classic Boss 429 or 427 FE SOHC big-block, its sheer size creates all kinds of challenges for the weekend mechanic.
This Tech Tip is From the Full Book, 4.6L & 5.4L FORD ENGINES: HOW TO REBUILD. For a comprehensive guide on this entire subject you can visit this link:
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Based on what I’ve learned from Ford dealer technicians who do this every day, a few tricks of the trade make removing and installing a Modular engine easier. Although it’s straightforward to pull a small- or big-block Ford and transmission as a complete subassembly, this is rarely possible with the Modular V-8.
A 4.6L SOHC High Output from a 1996 Mustang GT is being used to illustrate proper procedures in this book. JGM Performance Engineering in Southern California purchased this engine as an experimental performance mule to learn more about the 4.6L SOHC V-8. Ryan Peart of JGM Performance Engineering has been assigned to tear down and inspect this engine. JGM will build it stock, dyno test it, and knock it down to evaluate what happened. JGM will also try different heads and cams along with carbureted induction just to see how this engine performs.
Be gentle during engine disassembly. When a part doesn’t come loose, there’s always a reason. Sometimes it’s just a sticky, stubborn gasket. Other times, it’s a fastener you’ve missed. Cover all bases and double-check your removal process. Never force any part.
If you’re going to pull an engine via conventional means, be mindful of items that may be in your way and easily damaged. Air conditioning condensers can impede engine removal. So can other subassemblies such as the compressor, power steering pump, power brake booster, coolant recovery reservoir, and other accessories. Always disconnect the battery before work begins. If possible, keep the air conditioning system sealed. If this is impossible, have an air conditioning shop responsibly remove the refrigerant. Do not just vent refrigerant into the atmosphere.
You must take an organized approach when disassembling the engine. This isn’t an engine you just rattle apart, toss all the parts in a box, and haul them to the machine shop. Catalog all parts and keep them in labeled containers. Stress to your machine shop how crucial organization is. Parts you’re going to reuse should return to their original location.
Always properly dispose of lubricants and coolants at recycle waste disposal sites. Don’t just toss old parts into the trash; recycle them at your local auto parts store or salvage yard. The days of mindlessly tossing old car parts are gone. Do the right thing and recycle.
1996–2009 Mustang GT, Cobra & Shelby
The engine can be removed in the conventional fashion through the top, with the hood removed or pinned back. Unfortunately, removing an engine and transmission as an assembly is nearly impossible. Here’s a tip: These engine/transmissions were installed at the factory through the bottom on a cradle. You can raise the car and remove the engine/transmission through the bottom using a floor or transmission jack. Of course, this means dropping the complete K-member assembly, including many front suspension components.
1991–2009 Ford Crown Victoria, Mercury Grand Marquis, Lincoln Continental
The engine can be removed in the conventional fashion, from the top.
Ford Thunderbird, Lincoln Mark VIII
The engine can be removed from the top or bottom by raising the vehicle.
Ford F-Series Trucks, Expedition, Excursion and Mercury Navigator
Ford dealer technicians lift the body off the chassis and remove the engine and transmission via conventional means with a hoist. You must have access to a lift to raise the body. Be sure to disconnect electrical and fuel lines before lifting the body away from the frame. If you’re unable to raise the body, the engine can be removed from above with the hood off, but the engine and transmission cannot be removed as an assembly.
Ford Explorer, Mercury Mountaineer and Aviator
The same strategy applies as with the F-Series and large sport utilities: Raise the body or pull the engine (only) out through the top.
The Noise Factor
Several years ago, this 4.6L engine was pulled out of a 1996 Mustang GT because of noise issues. During the teardown, I looked for noise sources, but sometimes they can never be determined because no amount of measuring can find them. Engine noise occurs for a variety of reasons because an engine has a lot of moving parts. One of the most common noise sources in the overhead cam Modular V-8 is the valvetrain.
If you like engine noise, the Modular engine makes a great sound thanks to its overhead cam design. As this engine revs, its valvetrain makes music on par with a high-performance racing engine. The sound comes from roller rocker arms riding on extraordinarily large composite cam lobes.
Through the years, Ford has tried in vain to silence much of the Modular engine’s noise, experimenting with nylon-coated cam sprockets. Ford even had one supplier rubber coat the cam sprockets to silence valvetrain issues; it was unsuccessful. So Ford has tried other things to contain engine noise: fancy engine hoods, hood blankets, different types of cam covers, you name it. Despite valvetrain noise, the Modular engine is remarkably smooth and relatively quiet at normal driving speeds.
Hydraulic cam followers (slack adjusters), rocker arms, and loose pistonto-cylinder wall clearances are the primary noise sources during cold start-up. Although Modular engines are fitted with hypereutectic pistons, they still have liberal clearances due to high operating temperatures, which makes them sloppy when cold. These loose clearances allow for piston expansion as the engine warms.
Piston clearances, coupled with hydraulic cam follower noise, make the Modular engine quite a chatterbox when cold. Some remain noisy when hot for the same reasons. Engine noise isn’t a reason to be concerned, because it’s a normal operating characteristic of these engines.
I’m convinced, based on what I found in this engine, that it was pulled for normal operating noise. I was unable to determine why it ran noisier than stock. All parts measured within limits, which indicates a perfectly healthy engine.
With all this in mind, you must first analyze why it’s necessary to tear down an engine before starting. It’s a good idea to determine noise sources (if any) before jumping into the deep end of the pool.
As you tear down a 4.6L SOHC engine, it’s easy to feel overwhelmed and intimidated because this engine seems very complex. However, taken one component at a time, the Modular engine is easy to understand. Building a Modular engine has to be viewed like taking a coast-to-coast road trip, which you do 200 miles and three hours at a time. Do not let this engine overwhelm you. Take many notes and shoot lots of pictures. Read this book thoroughly before you begin.
Start by photographing the engine while it is still in the car. Note and photograph electrical connections, hoses, brackets, and accessories. Once it’s out of the vehicle, take plenty of pictures, and record how everything goes together.
As you disassemble the engine, you should stamp reference letters in each casting: “L” and “R” for left and right. Do this with every part that has a left and right, such as camshafts and cylinder CHAPTER 2 33-50_ SA155 CH 2_Acura-Honda_5.QXD 1/23/15 11:59 AM Page 34 heads. If you’re tearing down a DOHC engine, mark left and right plus intake (“I”) and exhaust (“E”).
I stress marking cylinder heads so you don’t have to guess at left and right when it’s time for assembly. It’s also a good idea to mark galley and water jacket plug locations, which eliminates confusion later. Plug installation error could cost you sizable amounts of oil and/or coolant on the garage floor if you get it backward. Mark items, including wiring harnesses, with masking tape just in case photos become lost or illegible. Take plenty of photos and notes, no matter how obsessive it may seem.
As you disassemble the engine, closely inspect rod and main bearing journals (and bearings) for abnormal wear patterns that might indicate irregular connecting rods (meaning rods that are not straight or may be twisted). Connecting rods can arrive irregular from the factory or become bent or twisted as a result of poor machining technique during a prior rebuild.
Abnormal wear patterns appear from excessive wear on one side of a bearing or journal. This indicates that clearances were too tight on one side, driving out the oil wedge needed to prevent wear.You must have sufficient clearance between bearing and journal to allow proper oil flow (wedge). When clearances are too tight, oil flow across the bearing becomes limited, causing higher temperatures, oil breakdown (due to heat), and metal-to-metal contact. This is why all components must be square in their marriage with other components. A connecting rod must sit dead square on the rod journal to ensure a happy union with the bearing and journal. The same can be said for the crankshaft. If a crank is distorted (bent), nothing sits square, causing irregular wear and short engine life.
Engine teardown is a great learning experience and an opportunity to know how an engine performed during its service life. You also learn how it was maintained and how its many components functioned. Hammered rod bearings indicate hard use and abuse. Scuffed cylinder walls indicate oil starvation issues and high operating temperatures. Valves worn deep into the seats mean a poorly executed valve job or hard use. Blown head gaskets point to overheating or extremely hard use. Fouled spark plugs demonstrate improper fuel mixture, poor ring seating, or excessively worn valveguides and seals (oil consumption). Abnormal wear patterns date back to how the engine was machined and assembled.
When you examine main and rod bearings, for example, you learn how true the block, crank, and rods are. You see what kind of oil wedge and flow the engine has had across its bearings and journals. A narrow oil wedge shows in bearing wear. A clean wear pattern indicates a good oil wedge and flow. A good oil wedge avoids metal-to-metal wear. When the oil wedge becomes too narrow, you have extreme heat and wear. Remember that heat damages. Engine oil begins to break down at 260 degrees F. Synthetic engine oil begins to break down at 300 degrees F. When oil breaks down, it cannot lubricate and it cannot cool.
The area you should be concerned with most is the cylinder block. Ideally, you find a block with standard bores that has never been rebuilt and has never suffered from overheating. A 4.6L block that has been bored .020-inch oversize can go to .030-inch oversize, but that’s all, due to bore spacing and super-thin-wall casting techniques.
Step 1:Getting to Know the 4.6L SOHC
Our subject engine is a 1996 4.6L SOHC engine from a Mustang GT. This is a Romeo engine with passenger car induction and twin coil pack ignition. Coil pack ignition systems have spark plug wires, while coil-on-plug ignitions do not. Coil pack ignition systems were discontinued after 1998 to simplify the Modular engine ignition system. Everything from 1999–up has coil-on-plug ignition. Early V-10 engines also have coil pack ignitions with ignition wires.
Every Modular engine build should include sonic-checking the block before machine work begins. According to every Modular engine builder I’ve spoken with, taking bore size any farther than .030-inch oversize is courting trouble. Ideally, you have a standard-bore block and bore it .020-inch oversize and not beyond. When taking the bore size to .030-inch oversize, you drive compression higher, which raises operating temperatures and pressures. Because cylinder wall thickness is marginal at best at this oversize, you also risk entry into the water jackets. So take it from me: Do not go above .030-inch oversize with any 4.6L or 5.4L SOHC/DOHC Ford.
If you find a block that’s bored .020 or .030 inch, I suggest that you find another used standard-bore block or purchase a new block. Romeo and Windsor blocks are still available new from Ford. You can also buy one from an aftermarket performance source, such as Summit Racing Equipment or Mustangs Plus. If you’re tearing down a Romeo engine, order a Romeo block. If it’s a Windsor engine, order a Windsor block.
When it comes to selecting the best block, it’s a matter of personal preference and what equipment is in the engine. Aside from the main bearing side supports, there are few differences between Romeo and Windsor block castings. Romeo blocks have main cap jackscrews and cross bolts. Windsor blocks have hammered-in main cap dowels, which take less time to assemble. Aside from these items, little else is different.
As you begin the project, be very diligent and detailed in your block and head cleaning efforts and inspection. Oil galleys should be thoroughly scavenged with a long rat-tail brush and lots of soap and water. I stress this because you would be surprised how much debris is trapped in these passages even at the factory. All it takes is a stray metal fragment to score a bearing and do permanent engine damage. Ford’s casting and manufacturing techniques have improved a lot over 100 years; however, mistakes are still made and bad parts still find their way into new cars.
Modular engines sometimes create more questions than they answer. And Ford hasn’t been very effective at communicating technical information on these engines, so it is up to the enthusiast network to pass along information when possible. The Internet yields a wealth of useful information on these engines, as do engine building professionals such as Sean Hyland, Scott Sullivan, PowerHeads, JGM Performance Engineering, Modular Racing, and others.
As you progress through your Modular engine project, you learn a lot about this engine. In due course, you will begin to embrace the Modular engine, and awaken to the engineering marvel Ford has been putting in passenger cars and trucks for nearly two decades.
Step 2: Disassemble from the Outside In (professional mechanical tip)
First, remove exhaust manifolds. All parts should be cataloged, marked, and stored carefully. Take notes, shoot pictures, and mark parts with sticky notes. It’s a good idea to place fasteners in labeled bags that are very specific about where the fasteners go. Use a felt-tip pen to mark clearly where each fastener is located. If there’s any confusion, take pictures showing how each fastener came out. Exhaust manifold fasteners, for example, call for a 9/16-inch socket. Be prepared for both SAE and metric fasteners throughout this engine project.
I’m often asked whether to replace or keep electrical components during an engine rebuild. I recommend starting with all new sensors and other electrical components. When electronic engine control doesn’t do its job effectively, it can lead to engine failure. “Check Engine” or “Service Engine Soon” canmean anything from low oil pressure to overheating to an inoperative sensor to a loose fuel filler cap.
When sensors fail, they limit the electronic engine control module’s (ECM) ability to control fuel mixture and spark timing. A lean fuel mixture (short injector pulse width) causes combustion temperatures to increase. Early spark timing can cause detonation (pinging). These conditions can be caused by an ECM malfunction anywhere in the network. This is why your ECM should be checked during the rebuild for proper function and why you should use all new sensors. Because sensors are not cheap, you may be tempted to cut corners and avoid replacement. But consider this: What does engine failure cost? It certainly costs more than replacement of all electronics.
While you’re replacing sensors, also consider harness replacement. Underhood engine heat and ozone from air pollution causes deterioration of rubber and plastic parts. It contributes to the deterioration of insulation and copper/ aluminum wiring. Weak connections create the same problems experienced with inoperative or intermittent sensors. Of all an engine’s sensors, the oxygen, throttle position, and manifold air pressure (MAP) sensors are among the most vulnerable and failure prone.
Sensors are little more than variable resistors (potentiometers) or simple on/off switches. The oxygen sensors (four of them) monitor oxygen levels in the exhaust gases and help the ECM control the air/fuel mixture. Fuel mixture and burn activity determine oxygen levels in exhaust gas, and the more oxygen you have in the exhaust gas, the less fuel you have burned. The ECM responds by leaning the fuel curve. But if there’s another problem in the system, leaning the mixture can do more harm than good.
Step 3: Disconnect Cam Sensor
Disconnect the cam sensor and remove the accessory bracket using a 3/8-inch-drive, 8-mm deepwell socket. Although the exhaust manifolds had 9/16-inch fasteners, front dress accessory brackets have 13- and 18-mm fasteners (flange nuts). The coil pack must be removed first, and then the cam sensor.
Step 4: Remove Cam Covers
Remove the cam covers using an 8-mm deep-well socket and 3/8-inch-drive ratchet. Romeo engines have 11 cam cover bolts; Windsors have 14. Cam covers have factory-installed rubber gaskets that are virtually leakproof, but you need to replace them when it’s time for reinstallation. They are available separately or in a complete Fel-Pro engine gasket set.
Step 5: Disconnect Fuel Injectors (save money)
Carefully disconnect fuel injectors. Although this JGM Motorsports technician uses a screwdriver, it is unnecessary. Fuel injectors have virtually unlimited life if you keep them clean. Fuel injectors can be cleaned, tested, and reused, which saves you at least $100 each in replacement costs. Fuel rails are tied to the intake manifold in all applications with 8-mm fasteners.
Step 6: Disconnect and Remove Crank Sensor
Tools are not required for sensor lead disconnection. Use an 8-mm socket to remove the sensor from the timing cover. Take care not to damage this sensor if you intend to reuse it. You will need a new O-ring when it’s time for installation.
Step 7: Remove Cam Sensor
Use a 10-mm socket to remove the cam sensor. This is the crank sensor’s counterpart, tied to the electronic engine control module for pinpoint spark and fuel injection timing. The high spot on the cam gear triggers the magnetic pick-up sensor triggered. Because the cam sensor has an unknown lifespan, you can reinstall the old one and still enjoy satisfactory operation.
Step 8: Identify Temperature Sender/Sensor (critical Inspection)
It is easy to confuse temperature sensors and senders because they look alike. Here’s the easiest way to remember 4.6L Modular V-8 sensors: As you face the engine, the coolant temperature sender (to the coolant temperature gauge) is on the left, and the coolant temperature sensor (to the ECM) is on the right. The coolant temperature sender (for the gauge) is located near the thermostat housing, which is where coolant would be at its hottest. The cylinder head temperature sensor (where equipped) is also on the right beneath the intake manifold. Because Modular V-8s serve a variety of applications, I encourage you to purchase a Ford Service Manual for your particular vehicle because sensor locations vary according to vehicle type.
Step 9: Cylinder Head Temperature Sensor (critical Inspection)
On so-equipped engines, the cylinder head temperature sensor is found in this location. Expect to see this sensor primarily on truck and SUV applications. It serves as a backup for the coolant temperature sensor, which is positioned in the intake manifold. Coolant temperature activates intake and cylinder head temperature sensors, which are simple on/off switches. The primary sensor, located in the intake manifold, closes when engine coolant temperature reaches 195 degrees F, completing a circuit, taking the electronic engine control system into closed loop and normal operation. The cylinder head temperature sensor closes when cylinder head temperature reaches a predetermined overheat point, which makes the ECM go into “limp-home” mode to prevent severe overheat. The cylinder head temperature sensor protects your engine from extreme overheat and engine damage.
Two oxygen sensors upstream of the catalytic converters and two downstream adjust oxygen levels on both sides of the cats. Replace all of them. Because Bosch made most of Ford’s oxygen sensors, they’re readily available at AutoZone or NAPA Auto Parts stores for less than you usually pay at a Ford dealer parts department.
The throttle position sensor (TPS) is a variable resistor like the volume control on your sound system. Turn it up and you reduce resistance, allowing more power through. Turn it down and you increase resistance, allowing less power through. The same can be said for the engine’s MAP and MAF sensors. Both are variable resistors.
The coolant temperature sensor is little more than an on/off switch. When coolant temperature reaches 195 degrees F, the coolant temperature sensor closes, sending the ECM into normal closedloop operation. The ECM acknowledges all sensors and your engine resumes normal closed-loop operation.
Not every 4.6L SOHC Modular engine has the full complement of sensors. For example, not all Modular engines have knock sensors. Not all have the cylinder head temperature sensor. Take note of empty sensor bungs during disassembly.
It is important to understand how your engine’s ECM works. Not only does the ECM manage your engine’s electronic function, it programs the fueland-spark curve based on how and where you drive. It “remembers” driving habits. Disconnect the battery for an extended period of time, and the ECM has to start all over again. Expect rough, inconsistent operation until the ECM establishes a pattern.
If the ECM detects a malfunction from any of the sensors, including a misfire, the ECM triggers your “check engine” light. This light can result from a variety of sources. Any malfunction that affects exhaust emissions triggers it, meaning any faulty sensor or misfiring spark plug. When your technician interfaces with the ECM, it can be quickly determined where the fault is, right down to which cylinder misfired. This is a great benefit of today’s onboard diagnostics.
Another very important part of your engine’s electrical system is also part of the fuel system: fuel injectors. Fuel injectors become gummed up with varnish and carbon deposits in the course of normal use. When this happens, it adversely affects the injector’s spray pattern. A uniform spray fan is important for smooth, fuel-efficient, and powerful operation. Fuel injectors with an irregular pattern cause rough operation and poor performance. As long as they’re operational, a fuel injection shop can clean and service injectors for you.
Fuel injectors are little more than a low-voltage solenoid valve time-fired by your vehicle’s ECM. They malfunction when they become dirty or the electromagnet (solenoid) inside fails. Otherwise, fuel injectors can last indefinitely, and
I’ve seen them go beyond 200,000 miles in fleet use without service. Although this is impressive performance, I suggest regular fuel injection service (cleaning and inspection) every 100,000 miles. Service includes cleaning, electrical testing, and little else. Close inspection and test operation demonstrates whether they need to be replaced. Periodic cleaning and inspection costs less than replacement. A new set of eight fuel injectors can cost more than $800.
Fuel-pressure regulators, such as fuel injectors, have an unknown lifespan. Again, I’ve seen pressure regulators last more than 200,000 miles, but I suggest installing a new fuel-pressure regulator when performing a rebuild. The fuelpressure regulator controls fuel pressure through a vacuum signal and regulates return flow to the tank. Lean on the throttle and the vacuum signal drops. At idle, the vacuum signal increases.
Although emissions control devices aren’t popular with car enthusiasts, they are necessary for efficient operation and reduced emissions. To start with, replace the EGR valve because it can and does seize up from carbon deposits and excessive heat. In addition, the diaphragm, which is also exposed to excessive heat,tends to rupture, rendering the EGR valve inoperative. If the EGR valve sticks in the recirculation position, you experience rough idle or an engine that doesn’t idle at all.
Step 10: Remove Throttle Body
Back out the bolts with an 8-mm socket and extension to remove the throttle body. Expect the throttle body assembly to look like this on car and Explorer/Mountaineer applications, with a side-entry location similar to 5.0L SEFI pushrod V-8s. F-Series, Expeditions, and Excursions are completely different, with the throttle body pointed toward the front of the engine. On truck engines, the throttle body does not have to be removed unless you intend to completely strip the manifold.
The EGR valve receives its vacuum signal from a solenoid valve signaled by the ECM. EGR normally operates during deceleration when there’s a high vacuum signal and increased hydrocarbon emissions. Recirculation reduces hydrocarbon emissions.
Solenoid vacuum valves are on the engine and at the firewall. Two solenoid vacuum valves that serve evaporative emissions function on the firewall. It is important for you to determine proper function of these valves and your evaporative emissions canisters during the rebuild. They should be replaced while your engine is being rebuilt.
Step 11: Remove Intake Manifold (professional mechanical tip)
Although there are variations, this is the basic one-piece intake manifold for car and Explorer/Mountaineer applications. F-Series, E-Series, Expeditions, and Excursions have a twopiece intake manifold, with a cast-aluminum upper and plastic lower. Trucks and vans have the two-piece manifold with longer runners for better low-end torque. Always inspect the intake manifold for cracks and other irregularities. Plastic manifolds are notorious for cracking, especially early units. Inspect them closely for problems that will cause rough running (vacuum or coolant leaks) later on. Any electronics must be inspected and tested for proper operation. Use a 10-mm socket and extraordinary care when removing the intake manifold. Loosen bolts from the inside out to prevent warping or cracking. Keep bolts in their proper location for installation later. Do not reuse the intake gasket
Step 12: Non-PI Head Identification
This is the pre-1999 non-PI SOHC head, which does not have the high-flow design elements found in 1999 and later PI heads. Note the comma-shaped intake port. The PI head has a teardrop design for improved airflow coupled with an improved, smaller chamber. If your budget allows, consider an upgrade to PI heads, which calls for a PI intake manifold and exhaust manifolds/headers.
Step 13: Remove Valley Heater Hose/Tube (professional mechanical tip)
Romeo 4.6L SOHC applications have a heater hose located in the valley (shown). Truck applications have a solid pipe without the hose due to the challenging nature of large two-piece induction systems. Use only a reinforced Ford heater hose in this location. You may also use a heavy-duty braided hose (it will never have to be replaced). Use channel-lock pliers to remove hose clamps. I suggest using only Ford clamps because of the very precise clamping pressure required by Ford.
Step 14: Remove Timing Cover Belts (Documentation Required)
Remove timing cover bolts, using 13- and 18-mm sockets as required, and take note of their locations. Remember to take pictures and mark the parts for proper installation later. Two types of timing cover bolts are available: Studded bolts (18 mm) are for accessory mounting and are installed around the timing cover perimeter in most applications. Headed bolts (13 mm) are installed around the inside close to the water pump. Studded bolts, for example, hold ignition coils on coil pack engines.
Step 15: Take Off Belt Tensioner
Use a 13-mm socket to remove the belt tensioner and idler pulleys. The belt tensioner is spring-loaded and keeps tension on the serpentine belt. Replace it whenever you perform an engine rebuild. For good measure, change tensioner and idler pulleys every 75,000 miles because idler pulleys spin at very high speeds, and bearing wear is significant at 75,000 miles.
Step 16: Remove Water Pump Pulley (Important!)
The Mustang GT uses this special water pump pulley, which prevents belt derailment at high revs. Not all Modular engines are fitted with this pulley. For the rest, use a special fan pulley wrench combo (for engines with clutch fans) for fan removal. You need Fan Clutch Holding Tool 303- 239 (T84T-6312-C) and Fan Clutch Wrench 303-454 (T93T-6312-B). With an air-impact wrench, pulley bolt removal is easy. I suggest bolt removal with the serpentine belt installed to hold the pulley. Then, remove the belt and tensioner.
Step 17: Remove Water Pump (professional mechanical tip)
Modular engine water pumps don’t have a conventional gasket; they have an O-ring (included in the water pump kit, PN 8501). A gentle whack is required to knock the pump loose because there is no gasket. All front dress components, including water pump, call for a 14-mm socket for bolt removal. Pay close attention to bolt placement and take pictures as necessary. Replace the water pump while you’re at it and use only genuine Ford parts. Remove the bolts slowly, and look for corrosion in the bolt holes. Do not force a stubborn bolt: Flood the area with WD-40 and allow it time to soak in. Run the bolt in and out repeatedly to distribute the WD-40. Then, allow it to soak for an hour or two.
Oiling and Cooling Systems
The Modular engine is different from its Ford ancestors because of its 360-degree oil pan bolt circle. This means it’s a skirted block design without end gaskets and potential leak sources, which makes the Modular engine different than most Ford V-8s. At first glance, the Modular engine’s oil pan gasket patterns resemble those of older FE-Series big-blocks and Y-Block V-8s. Everything old becomes new again with the Modular V-8.
You will learn during teardown that gasket technology has come a long way in 40 years. Gone is the humble, archaic cork or rubber gasket, replaced by urethane, rubber, and silicone gaskets that hug precision-machined surfaces and keep fluids inside. The Modular engine has a onepiece rear main seal that eliminates leakage if it has been properly installed. This design is similar to a crankshaft front oil seal, except for size. The rope seal or rubber half-seals are gone. Ford takes it further with a rear seal retainer that bolts to the back of the block, making this engine virtually leakproof.
Why use this kind of seal technology? The environment. Fluid leakage from motor vehicles has been hard on the environment, forcing the mandate of vehicles that don’t leak. Examine any dip in the road, especially concrete, and you will see what I mean. Dips in the road are often discolored with engine oil, transmission fluid, or differential lube because fluids are thrown from underneath as you bottom-out in the dips. Building a leaky engine just isn’t acceptable anymore.
This is why you must determine why your engine had leaks to begin with. Leaks can indicate bad seals. But sometimes the culprit is a scored crankshaft or irregular gasket surfaces. It is your responsibility to ensure new seals and gaskets do not leak. Because Modular engines are blessed with advanced gasket technology, leakage is not a factor.
When you strip down the block and heads, leave no stone unturned. Remove every single core plug and every single oil galley plug. Strip all castings to the bone because you never know what’s hiding inside, such as a stray core plug knocked inside the block by a rebuilder or the factory, or iron particles trapped in oil galleys that can do engine damage. Mark each oil galley plug location for reassembly.
Use a thin layer of The Right Stuff from Permatex on those plugs when it’s time for installation. Use stainless steel plugs for corrosion protection. You may use brass or stainless steel plugs in the iron block. Aluminum heads should receive stainless steel plugs. Screw-in oil galley plugs should have Teflon tape on the threads.
Step 18: Unbolt Oil Pan
Once the oil pan is drained, it’s time for removal. Because this is a skirted block design, the 15 oil pan bolts go all the way around the pan. This is a flush, square installation designed to achieve a perfect seal. Use a 13-mm socket and a gasket scraper to remove the oil pan. Gently work the gasket scraper between pan and block to pop the pan, but don’t force it.
Step 19: Remove Timing Cover
Fifteen bolts retain the SOHC timing cover. Use a 3/8-inch-drive deep-well 13- or 18-mm socket for this step. Two types of bolts are used to retain the timing cover: Studded bolts (18-mm) hold accessories, and they are located toward the top and outside of the cover. Standard bolt heads (13 mm) are deep in the valley and toward the bottom. Two studded bolts are at the bottom on both sides.
Step 20: Remove Timing System
With the timing cover removed, things can look a little intimidating. The 4.6L SOHC is actually a simple SOHC design with two cam sprockets, two timing chains, four guides, two chain tensioners, a shutter wheel (for the crank sensor), and an oil pump (bottom center). Installation is simple if you follow the instructions.
Water jackets are a quick indicator of engine health. If your engine suffers from a blown head gasket or cracked casting, it tends to be apparent in the water jacket color. A blown head gasket or casting crack tends to discolor cooling system passages. Poor cooling system maintenance is apparent when the gray aluminum turns a rusty brown.
I’m often asked what should be replaced in the course of an engine rebuild. Ford designed and built the Modular engine to be extremely durable, so you would be amazed at what doesn’t need to be replaced. During disassembly, closely examine all valvetrain components, including camshafts, rocker arms, valvesprings, keepers, retainers, cam sprockets, chains, tensioners, and guides.
I’ve seen 200,000-mile engines that did not need chain guides replaced. I can say the same about tensioners, cams, and sprockets. Unless there has been oil starvation or a severe overheat (the latter engine electronics never allow it), camshafts last virtually forever. I suggest new chains, sprockets, guides, and tensioners for highmileage engines because it’s always wise to start with new components that you’re confident will last 200,000 miles or more. In any case, always replace valves, valvesprings, and seals.
Step 21: Remove Timing Chain Tensioners
Chain tensioners are retained with two bolts each. You need a 10-mm socket to remove both tensioners. Tensioners apply pressure only when the engine is running and there is oil pressure.
When you remove the oil pump, examine the pump rotor for abnormal signs of wear because the harmonic balancer sometimes loads the pump rotor on Modular engines. I’ve seen this in some teardowns, but not all. It has been most prevalent with DOHC engines. If you see abnormal wear patterns, I suggest harmonic balancer replacement or, at the very least, checking clearances at the crank snout and trigger wheel.
Two-Piece Truck Induction
It is important to note that F-Series and large SUVs have a different induction system than passenger cars, which have a single-piece plastic manifold. With trucks and big SUVs, you have a cast aluminum upper intake manifold and a plastic lower intake manifold, with a tuning valve designed to control runner length. This gives you short runners for wide-open throttle and long runners for good low-end torque. The manifold tuning valve is operated by the ECM, controlling runner length depending on load and throttle position.
Balancer Inspection and Service
The engine’s harmonic balancer is designed to absorb or dampen the crankshaft’s twist. As each cylinder fires and hammers out a beat on your engine’s crank, the crank twists a certain amount. The harmonic balancer dampens the twist, allowing the crank to bounce back smoothly. Because the harmonic balancer is a steel ring wrapped around an iron hub, separated by rubber, you need good rubber. As rubber dry-rots and hardens, a harmonic balancer has a tough time doing its job, making close inspection so important. Replace the balancer if necessary.
The 4.6L harmonic balancer is mounted differently than on older Fords, with just a slight interference fit at the crank snout. Inspect seal contact surfaces for scoring. You can sleeve it or you can replace it if contact surfaces are worn.
Chain Tensioners and Guides
The 4.6L SOHC’s overhead cam design automatically adjusts timing chain tension as you drive, and therefore, maintains itself. It does this in the same manner that hydraulic lifters maintain valve adjustment: through hydraulic pressure and mechanical interference. A 4.6L engine generates hydraulic pressure with its oiling system. As the chains and sprockets wear, tensioners maintain tension against the guides and chains, thanks to the engine’s oil pressure. When you rebuild, replace both tensioners and guides.
Prior to 2000, Modular engines had iron tensioners and steel chain guides. Steel chain guides weigh more, but appear to be more durable than plastic chain guides. Unfortunately, the plastic versions haven’t proven their worth yet.
Composite tensioners offer better chain tension than iron types. Iron types tend to lock into a tighter tension without making allowances, which can lead to unnecessary chain tension and failure. Seasoned Modular builders have their favorites, and some like the iron tensioner while others have embraced the newer composite tensioner.
During disassembly, be mindful of what you find in the valley. Although Romeo blocks are equipped with a valley drain at the rear of the block that carries away moisture and debris, others are not. The 1998 4.6L SOHC Windsor truck block does not have a drain, and I found coolant and even worms from some animal that had been nesting in there. Whenever you hose down an installed Modular V-8, make sure the valley does not fill with liquid because it can be corrosive. Use a wet or dry shop vacuum to remove all liquid when necessary. This is the knock sensor mid-valley. Some blocks are fitted with two knock sensors (DOHC engines) on each side of the valley, and others, such as the Mustang GT 4.6L engine, don’t have a knock sensor.
Step 22: Remove Cam Sprocket
Remove both cam sprockets next with an 18-mm socket and ratchet. Ford makes it easy to identify them. The driver-side cam sprocket has a sensor bump. The passenger-side sprocket does not.
Step 23: Identify Chain Guides (Documentation Required)
Mark the chain guides for reference purposes. Both of these will be reinstalled because they have been used very little. Chain guides call for the use of a 10-mm socket for removal.
Step 24: Remove Oil Pump (Documentation Required)
When Ford developed the Modular V-8, some basic shortcomings were eliminated. Instead of the oil pump being driven off the camshaft, as you see in most Ford engines, it’s driven off the crankshaft. Remove the retaining nuts with a 10-mm socket, taking note of where the hardware goes, and slide the pump off the mounting studs.
Step 25: Remove Cylinder Head Bolts (Important!)
Remove the cylinder head bolts with a 15-mm deep-well socket and ratchet. Because the Modular engine is a torque-to-yield engine, all cylinder head bolts must be replaced. Do not reuse them.
Step 26: Mark Left and Right Cylinder Heads
All Modular engines, except the 2004–up three-valve, have omnidirectional heads, so you have some flexibility with installation. However, I recommend marking “left” and “right” for reassembly because over time castings conform to the location where they have been installed. In other words, reinstall heads to the same banks they came from for best results.
Step 27: Identify Wear Patterns (Critical Inspection)
This 4.6L SOHC Mustang GT engine was removed because of noise issues, but it appears to be a healthy engine with no abnormal wear or combustion patterns. Under normal conditions and 100,000 miles, you can expect ridges and mirrorfinish cylinder walls. This is a lowmileage engine removed under warranty. Can you see the crosshatch pattern?
Step 28: Disconnect Oil Filter Attachment
Disconnect the oil filter attachment using a 13-mm deep-well socket. Because the Modular V-8 is fitted to many applications, expect wide variations. F-Series trucks, for example, have oil cooler connections. Passenger cars and Explorers/Mountaineers have yet other types of oil filter attachments. Retain the oil filter attachment from your Ford or Mercury just to be on the safe side.
Step 29: Inspect Crank Journals (Critical Inspection)
These crank journals look healthy and have virtually no scoring. The oil holes need to be modified and chamfered for improved oil flow.
Step 30: Remove Piston and Connecting Rod
Once the rod cap has been removed, gently remove the piston and rod. Connecting rod bolts call for a 13-mm socket. Do not reuse connecting rod bolts. Take extra care to ensure that the tool and rod do not strike the cylinder wall.
Step 31: Inspect Connecting Rods (Professional Mechanic Tip)
These rod bearings look good, with minimal wear. Even when bearings look healthy, never reuse them. Always throw them away and install a new set.
Step 32: Remove and Replace Oil Level Sensor (Professional Mechanic Tip)
The oil level sensor is located in the oil pan. When oil becomes low, you get a warning light. Replace this sensor along with the others.
Step 33: Remove Main Cap Cross Bolts
Remove the main cap cross bolts using a 13-mm (1999–up) or 10-mm (1998–back) socket. Expect to see variations of bolt-head size between Romeo and Windsor engines. Do not remove the main cap bolts first.
Step 34: Remove Jackscrews (Romeo Engines)
Use an Allen wrench to remove the main cap jackscrews. These jackscrews provide proper tension and stability against block skirts on Romeo engines only. Screw them clockwise (inward) to loosen or counterclockwise (outward) to tighten. Screw cross bolts into these jackscrews for additional security
Step 35: Remove Main Caps (Documentation Required)
Remove the main cap bolts last; begin working outward using a 13-mm socket. Expect main caps to be tight and challenging to remove.
Step 36: Take Note of Thrust Bearing Type (Important!)
Modular V-8s do not have a typical thrust bearing. Unlike most Ford V-8s, the thrust bearing is located at the number-5 main cap. Instead of a conventional two-piece thrust bearing, expect to see a four-piece affair where the thrust halves are of different thicknesses for easier endplay adjustment.
Step 37: Inspect and Determine Action for Crankshaft (Precision Measurement)
Remove the nodular iron crankshaft to check tolerances and examine journals. The main journal diameter should be 2.650 to 2.657 inches. The rod journal diameter should be 2.087 to 2.867 inches. This crank will be polished and chamfered before dynamic balancing.
Step 38: Remove Main Bearings
This is a low-mileage engine in good condition, so the main bearings look excellent. Because main and rod bearings are never to be reused, they must be tossed and replaced with new aluminum-shell standard bearings.
Step 39: Romeo/Windsor Thrust Bearing Differences
This is the Romeo number-5 thrust bearing. Notice the six-piece design with four crescent-shaped halves for the thrust and two conventional halves for the main bearings.
Step 40: Remove All Core/Galley Plugs (Important!)
Remove all core plugs so you can look inside the water jackets for obstacles that can cause overheating. Water jackets must be clear of all debris, core plugs, and more, or you face overheating and hot-spot issues.
Step 41: Take Nothing For Granted—Always Inspect (Critical Inspection)
Look what we found! This stray core plug was inside this new Ford block cast at the Cleveland foundry. When we knocked out all core plugs on this block, we found one that had been left inside during assembly at the factory. It was never removed and would have caused overheating.
Written by George Reid and Posted with Permission of CarTechBooks