Ford 6.7L Power Stroke Engine: Specs, Problems, and Reliability. The 6.7 L Power Stroke is a 6.7-liter V8 turbocharged diesel engine. Starting with a clean sheet, in 2008 Ford Motor Company began to develop a new diesel engine for the Ford Super Duty in-house. During its developmental stage, this new product has codenamed the Scorpion, and when Ford officially introduced it in 2011, the engine was already designated as the 6.7 Power Stroke. Ford’s 6.7 L Power Stroke changed the 6.4 L Power Stroke and became the first Power Stroke engine not manufactured by International Navistar (nearly 30 years of partnership).
While the majority of current diesel engines use heavy cast iron, the 6.7 L Power Stroke has a cylinder block made from compacted graphite iron (CGI). Its deep-skirt block also has nodular iron six-bolt main caps highly common on the 7.3 L Power Stroke instead of the 6.4 L’s bed plate. This block layout along with the CGI material provides significant weight savings over the 6.4 L predecessor.
The 6.7 Power stroke also presents a steel crankshaft, powdered-metal cracked-cap connecting rods made by Mahle, and Federal Mogul cast-aluminum pistons. The connecting rods have an end cap that is rotated 45 degrees to increase strength. The engine was outfitted with piston cooling jets for lower piston and combustion temperatures. This affects positively on engine longevity. All 6.7 L blocks are manufactured by American foundry company, Tupy.
For the truck segment, Ford’s 6.7 L Power Stroke uses cast-aluminum cylinder heads. They present the reverse-flow design. Each cylinder has for valves (two intake and two exhaust valves; 32 valves total). Every valve is geared up with its own rocker arm and pushrod. The intake air experiences ports inside the valve covers, while the exhaust gases into exhaust manifolds located in the lifter valley (in a traditional V8 engine, the exhaust exits from the outside).
In engine valley, there is also a Garrett GT32 DualBoost changeable geometry single sequential turbocharger (SST). The exhaust volume of this system is smaller, providing a much more dynamically cooperation of the engine. The compressed and hot intake air is cooled by a water-to-air intercooler which is connected to a secondary cooling system of the engine. This powertrain secondary cooling system is also used for cooling of EGR circuit, transmission fluid, and fuel cooler. The primary and powertrain cooling systems have their own water pump, thermostats, degas bottle, and radiator.
Ford 6.7L Power Stroke Engine: Specs
|Manufacturer||Ford Motor Company, Chihuahua, Mexico plant.|
|Cylinder block material||Compacted graphite iron|
|Cylinder head material||Aluminum|
|Fuel system||Common rail direct injection|
|Number of cylinders||8|
|Valves per cylinder||4|
|Bore, mm||99.1 mm (3.9 in)|
|Stroke, mm||108.0 mm (4.25 in)|
|Displacement, cc||6,700 cc (406 cu in)|
|Type of internal combustion engine||Four-stroke, turbocharged|
|Power, hp||270-450 hp (201-335 kW)/2,400-2,800|
|Torque, lb ft||675-935 lb-ft (915-1268 Nm)/1,600-1,800|
|Engine weight||970 lbs (440 kg)|
|Engine oil weight||CJ-4 or CJ-4/sm;
SAE 10W-30 – normal use;
SAE 5W-40 or 15W-40 – for severe duty or biodiesel applications.
|Engine oil capacity, liter||12.3 l (13 qts) – with oil filter|
|Oil change interval, mile||7,500 (12,000 km)/12 months|
|Applications||Ford F-250, Ford F-350, Ford F-450, Ford F-550, Ford F-650, Ford F-750|
The 6.7 L Power Stroke is equipped with a high-pressure common rail direct injection. The Bosch CP4.2 fuel pump supplies fuel under a 30,000 psi for the 19 mm Piezo actuated Bosch injectors with 8 hole nozzles. The fuel injectors are capable of pulling off five events per combustion cycle.
In 2015, the GT32 SST turbocharger was switched out by the Garrett GT37 with single VGT. The GT37 includes a larger 88 mm compressor wheel along with increased turbine wheel to 72.5 mm up from 64 mm in the GT32. The fuel system also was upgraded with a higher-flowing Bosh CP4.2 high-pressure fuel pump with a larger stroke and optimized injector nozzles. With made improvements, the engine is able to produce even more power.
6.7 Power Stroke Engine Problems and Reliability
Ford’s 6.7 L Power Stroke diesels are solid engines, extremely durable, and reliable, with just a few problems/issues. Among the big improvements in regard to reliability is that the 6.7 L Power stroke no longer would rely on four bolts per cylinder holding down the cylinder heads. There are six bolts per cylinder now. That will reduce the risk of head bolt stretch and head gasket failing – blown head gasket and coolant/oil inside cylinder.
Turbocharger failure is the biggest what can happen to the 6.7 Power Stroke. The first years of production, engines have a fairly complicated turbocharger with ceramic bearings (the tiny GT32 SST), which were prone to premature failure. Latest engines are fitted with another turbocharger unit, which has more reliable steel ball bearings on the turbo shaft. Turbo failures are reported so far mostly on 2011 and 2012 models.
Engines produced in 2011 had weak glow plugs, which can potentially break off and lead to massive engine damage inside the cylinders. It is safe to switch out them with the updated ones. There are also problems associated with some soot clogging on the EGR cooler and EGR valve, issues with EGR temperature sensor, and plugged DPF filters as well. Coolant leakages are feasible around the turbocharger area and from the primary radiator of the cooling system.
Overall the 6.7 Power Stroke engine has proven to become a very robust engine. It is highly important to do regular oil changes and using high-quality motor oil that meets Ford’s lubricity requirements for this diesel engine. With proper maintenance, the engine will last thousands of thousand miles.