Originally posted as Blowin' Smoke article
Volume 15; February 03: 6.0 PowerStroke and Torqshift Transmission
Click here for 6.0 Bulletins
Engine Features:
The 6.0 is the next generation PowerSroke engine, which is designed to meet the more stringent emissions requirements for diesel engines, while not compromising performence. This is accomplished using more sophisticated electronics, cooled exhaust gas recirculation, catalytic converter, four valves per cylinder and an elecrtonic variable geometery turbocharger. The results are less tailpipe emission from an engine producing 325 horsepower at 3300 RPM, and 560 ft/lbs of torque at 2000 RPM. Maximum engine speed is 4100 RPM.
The 6.0 has a cast iron cylinder block and heads, but instead of having a familiar one-piece block, the 6.0 has a split crankcase. The main part of the block contains the cylinders and upper main bearings. The lower part, called the bedplate, is one piece that contains all of the lower main bearings. Below the bedplate is the aluminum upper oil pan assembly, which acts as a windage tray (baffle) and contains a passage to supply oil from the pickup tube to the lube oil pump--no more long pickup tube to leak and suck in air. The lower oil pan is the sump and bolts to the upper oil pan. The engine oil cooler is intergrated with the oil filter base and is now in the valley of the block instead of being bolted to the side.
In order to have four valves per cylinder in the heads with an in-block camshaft, it was necessary to have one rocker arm actuate two valves. To do this, a bridge is installed between each set of two companion valves. This reduces the available room under the valve cover, and required having a rocker carrier bolted on top of the head. The rocker carrier is aluminum, and has passages drilled through from the outside to for the glow plug and injector harnesses. The valve cover gaskets no longer contain circuits for the injectors and glow plugs.
Like the 7.3, the 6.0 uses a gear to gear timing sets to drive the camshaft and high pressure oil pumps. But on the 6.0, the timing gear set in on the rear of the engine. This positions the high pressure oil pump for the injectors at the rear of the engine, under the turbocharger. What would normally be a timing cover on the front of the engine only houses the water and lube oil pumps.
The 6.0 still uses electronically controlled high pressure engine oil to operate the injectors. On the 7.3 the injector solenoids would open a valve to allow HP oil into the top of the injector, and spring pressure would close the vlave. On the 6.0, the injectors work more like power door locks, in which the injector solenoid is powered on briefly to move a shuttle valve to the open position, then powered off briefly to return the valve to the closed position. This reduces the noise of the injectors actuating. On the 7.3 the Powertrian Control Module would make fuel injection calculations based on sensor data. The PCM computer would then send commands to the Injector Driver Module for which injector to actuate and for how long. The 6.0 uses a Fuel Injection Control Module that receives sensor data over a communication network from the PCM, and the FICM makes the fuel injection calculations and actuates the injectors.
The high pressure oil system on the 6.0 is now completely internal. The HP oil pump reservoir in built into the block and the HP oil lines route inside the valley under the pump cover to the heads. The injectors are no longer supplied oil through passages inside the heads. They now have a rail on top of the injectors under the valve cover. These two designs prevent both external HP oil leaks and leakage between the HP oil and fuel passages. Unfortunately, it also means the turbocharger and intake manifold need to be removed to access the HP oil pump.
The 6.0 has glow plugs to aid in cold weather starting and reduce emissions. Due to the limited space under the valve covers, the glow plugs needed to be moved outboard of the valve sets. This arrangement allows the glow plugs to be removed through the holes through which the the harness connectors pass without having to remove the valve cover. It also means the glow plugs have to pass through the water jacket, so they now have sleeves similar to those on the injectors. The glow plugs are actuated by the same Glow Plug Control Module found on the 2000 and up California 7.3.
The most significant change to the PowerStroke in terms of performance is the variable geometry turbocharger (VGT). A valve on the turbo directs oil flow to vanes inside the turbine housing. The vanes adjust the width of the passages through which the exhaust gases pass into the turbine housing. By changing the passage widths the velocity of the gases increase or decrease. The smaller the passage, the higher the velocity and backpressure. On cold engine start-up the computer closes the vanes to increase backpressure and help the engine warm up, like the EBP valve was used on the 7.3 PowerStroke. At low engine speeds the vanes are narrow to allow for better acceleration and less lag. As engine speed increases under acceleration the vanes are opened to reduce backpressure while maintaining sufficient boost--up to 25 PSI--to meet the load demand on the engine. This is similar to the function of a wategate. The computer monitors the volume of air entering the turbo through a mass air flow sensor, boost pressure in the manifold with a manifold absolute pressure sensor, as well as intake air and manifold air temperatures and exhaust backpressure to determine how to adjust the turbine vanes.
Another addition to the PowerStroke is the cooled exhaust gas recirculation (EGR) valve. The EGR valve introduces exhaust gases into the intake manifold at cruising speeds to lower the combustion temperatures, which reduces oxides of nitrogen (NOx) emisions. Exhaust gases pass through a cooler to reduce their temperature before reaching the EGR valve. The only way the exhaust gases can flow into the intake is if the exhaust backpressure is higher than intake manifold pressure, so the computer adjusts the VGT to provide the necessary backpressure when EGR flow is needed.
The 2003.25 Super Duty and Excursions with the 6.0 use a Visctronic Drive Fan to cool the radiator. The fan has a viscus clutch similar to older models, but instead of being locked up by a thermostatic spiring, it has an electronic actuator controlled by the PCM based on ambient air, coolant and ATF temperature and fan speed.
Engine Service:
The 6.0 oil filter is a cartridge design, and is mounted on top of the engine for accessability. Loosening the oil filter lid opens a valve that allows the oil to drain from the filter housing back into the pan. The oil filter replacement procedure is similar to replacing a cartidge fuel filter. The oil filter lid is loosened a couple of turns (use a 36mm socket or 3.5"-4" oil filter wrench) to drain the filter housing. Remove the oil drain plug and let the crankcase drain. Once the oil draining from the pan slows down, fully unscrew the oil filter lid and remove the filter with the lid. The filter element snaps onto the lid, and the lid is reusable. Remove the old element from the lid, install the new element and o-ring, lube the o-ring and reinstall the assembly into the housing. Torque the filter cover to 18 ft/lbs. Reinstall the drain plug and refill the engine with 15 quarts of oil.
Due to the cooler EGR system, a new oil requirement has been developed. Use only oils that are API service rated CI-4 or higher, prefered viscosity SAE 15W-40.
I have verified the following oils meet CI-4:
Synthetics:
Ford is recommending to use the following oils for the listed operating temperature:
SAE 15W-40 is the preferred oil above 30 degrees, but it is acceptable for use down to 10 degrees, and is recommended for towing down to this temperature.
SAE 10W-30 is the preferred weight between -10 to 30 degrees.
SAE 5W-30 and 5W-40 is acceptable for use below 30 degrees, and 0W-30 is acceptable below zero.
(All temperatures are in Fahrenheit)
To provide better air volume into the engine, the 6.0 uses a Donaldson PowerCore air filter. This is a new filter design comprised of parallel rows of triangular cells. Alternating rows are sealed at the fresh air or the engine end of the cell. Air enters an open cell at the fresh air side, but has to pass through the media to an adjacent cell to go on to the engine. The air cleaner housing and element are one piece. To remove the air filter from the vehicle, I have found it is easiest to remove the two screws securing the coolant expansion bottle to the cowl so there is enough room to disconnect the mass air flow sensor assembly from the air cleaner. There are two spring latches at the top and two tabs at the bottom. Once the MAF sensor is out of the way, disconnect the air inlet from the air filter--again, two latches and two tabs; and remove the air filter from the engine compartment.
Info on the PowerCore air filter can be viewed at Donaldson.com (Requires Adobe Acrobat).
The fuel pump on the 6.0 in the pickups and Excursion is a frame mounted electric pump that also contains the primary fuel filter, the fuel heater and the water separator. The water separator is drained by loosening a plug on the side of the assembly with a 6mm allen wrench. The secondary fuel filter is on the pressure regulator next to the oil filter housing. The primary filter traps particulates down to 10 microns; the secondary down to 4 microns. Both filter elements are replaced at the same time. The primary filter lid uses the same tools as the oil filter lid, but the secondary filter uses a 1/2" ratchet.
Trucks with the 6.0 engine only use the Motorcraft Premium Long Life Gold Antifreeze, Zerex G05 (gold bottle), Peak Global Lifetime (gold bottle) or Peak Extended Life CF-EXL (silver bottle). These coolants are fully-formulated using hybrid organic acid technology (HOAT) and do not require SCA/DCA*. Do not use "universal" products that claim to be replacement for any color antifreeze. The coolant should be checked every six months for pH balance and freeze protection**. The service life on the Premium Gold coolant is five years or 100,000 miles on the initial factory fill. If the cooling system is repaired or serviced and tap water is used to dilute the coolant, the service life is reduced to 45,000 miles***. To maintain the 100,000 service life, only use distilled or demineralized water to dilute the Gold coolant.
The cooling system must be completely full and purge of air to prevent EGR cooler damage.
Ford does not recommend using propylene glycol-based coolants in any of their vehicles. They also have not approved the use of any organic acid tecnology (OAT) extended life coolants (ELC) in the PowerStroke cooling system.
*Trucks subjected to severe duty/special operating conditions should now have the gold coolant checked for nitrite level using the same test strips as for testing SCA in green coolant (disregard molybdate pad), and adjusted with FW-16 as needed. Levels should be more than 800 ppm/0.8 units per gallon. If the level is below 300 ppm/0.3 units/gallon, the coolant should be changed.
**Testing under severe duty/special operating conditions is six months/15,000 miles.
***Service life under severe duty/special operating conditions is 45,000 miles.
TorqShift Transmission:
The 5R110W, or TorqShift, automatic transmission is a redesign of the E40D/4R100. Basically, the gear ratio for first gear was lowered from 2.71 : 1 to 3.09 : 1. To get second gear the overdrive clutch is engaged to give a ratio of 2.2 : 1. Third gear is now the same ratio as the old second gear, 1.54 : 1. The TorqShift is advertised as being a 5 speed automatic, when actually it has six forward speeds. On cold engine operation (below 0 degrees) the overdrive clutch is engaged in third gear for a ratio of 1.09 : 1. The transmission will shift directly to sixth from fourth and fifth is skipped. On a warm engine the shift pattern would be 1st, 2nd, 3rd, 5th (direct drive), 6th.
Shift performance has been improved through completely redesigning the control valve bodies. The E4OD/4R100 used an electronic pressure control solenoid to adjust apply pressures to the clutches and band depending on load and throttle position. This would give you soft, slipping shifts on light acceleration and harsh shifts on hard acceleration. There was no feedback to the computer for EPC--it was also assumed that the EPC was operating as commanded.
There were two shift solenoids that would divert fluid flow to various shuttle valves to engage the clutches and band for each gear. There were also solenoids to control torque converter clutch and coast clutch operation. The problem with this design was having to time the disengagement and application of each apply component so as to not have too long of a lag between gears, or even worse, two gears applied at one time. There was also limited feedback to the computer as far as whether the components were operating as commanded, other than electrical faults. The computer could see if there was no RPM change at the shift points and set a code, but it could not determine if the problem was hydraulic or mechanical in nature.
On the TorqShift there are pressure control solenoids that directly control each hydraulic apply component with no shuttle valves. There is also pressure sensors to provide feedback so the computer knows whether it needs to increase current to a specifc solenoid to get the necessary hydraulic pressure, making each solenoid its own EPC. Since the computer is directly controlling and monitoring the hydraulic flow and pressure to each component, there are no lags between shifts and each shift is very positive without feeling harsh.
Another new feature on the TorqShift is the Tow/Haul mode. Unlike previous transmission models, this does not deactivate overdrive and immediately turn on the coast clutch. You still have all five active gears. Tow/Haul is a second transmission strategy in the computer. When activated, upshifts will occure at a higher road speed for a given accelerator position for better acceleration. Also, when releasing the accelerator on an upgrade, upshifting is delayed to prevent shift hunting.
The torque converter clutch will lock up at a lower vehicle speed for a given accelerator pedal position to provide improved transmission cooling. It will also stay locked longer on deceleration to provide engine braking. Engine braking is also provided on deceleration through the coast clutch. On the older transmissions EPC would always be minimal with the accelerator in the idle or coast position. This would result in slippage during deceleration on steep down grades, especially with a load. When the Tow/Haul mode is selected on the TorqShift, the computer commands sufficent pressure to the apply components to prevent this slippage.
Finally, to help maintain vehicle speed when desending a grade and help increase brake pad longevity, the transmission will downshift automatically. If the computer senses vehicle speed increase with the accelerator released, it will downshift to the next lowest gear. If vehicle speed continues to increase, the computer will command the transmission to downshift again. The grade braking downshift mode will be deactivated if the Tow/Haul mode is deactivated or the accelerator is depressed.
The TorqShift transmission uses a new fluid--Mercon SP*. This is not interchangeable with Mercon (Dextron), Mercon V, or synthetic Mercon. Since there is no torque converter drain, servicing is ment to be done by automatic flush machine. The external filter--mounted on the cooler lines near the radiator--needs to be replaced at the service. Ford has no service interval for the internal pickup filter. I think it is a good idea to replace the internal filter at the service intervals as cheap insurance against a failure. There is a second transmission filter screen that is part of the valve body gasket, but it does not need to be replaced unless the transmission is being repaired. If a flush machine is not available, the trans pan does have a fluid drain. You can either drain and refill the transmision pan, start the engine to circulate the fluid, then drain and refill again. Or, drain and refill the pan, then remove the cooler return line and direct it to a drain pan. Start the engine and as fluid is expelled from the cooler line, add fluid to maintain the level in the pan. It may be more advantagious to have a someone helping you for this method. Replace the external filter after changing the fluid. The external transmission filter is installed on a by-pass, so it only filters 10% of the fluid flow. I would be advantageous to install a secondary filter to capture any contaminates the factory one misses.
*Mercon SP has now been superceded by Mercon LV.*
Charles David Ledger; dieselmann©2003
Links to other sites on the 'Net
www.thedieselstop.com; (The Ford Diesel Website/Ford-Diesel.com) information and discussion for Ford diesel owners
International Truck and Engine (Navistar)
Amsoil product information--lubricants and filters.
Diesel Injector Service;
For all of your diesel engine needs: Injection systems, filters, O-ring kits,
accessories and fuel conditioners
PowerStroke Mail List;
Information and discussion on 1999 and up Ford F Series Trucks & Ford Vans with the
Ford/Navistar Power Stroke 7.3L Direct Injection Turbo diesel engine.
Click to subscribe to PowerStroke mail list
Power Stroke Registry
An organization for PowerStroke owners; quarterly publication
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