Ford Yamaha V8 engine
Encyclopedia
The Ford SHO V8 engine [super high output] was designed and built by Ford Motor Company
in conjunction with Yamaha Motor Corporation for use in the 1996 Ford Taurus SHO
. It was based on the successful Ford Duratec engine rather than its predecessor, the compact Ford SHO V6 engine
developed by Yamaha for the 1989 Taurus SHO. The engine was retired in 1999 when production of the third-generation Taurus SHO ended.
, including the aluminum cylinder heads and 4-valve
per cylinder
DOHC design, but differed with an aluminum rather than iron block and no variable length intake manifold
. A chain is also used to time the camshafts to crankshaft instead of the belts that the SHO V6s used. The SHO V8 has a split port style intake valve setup. The primary valve is exposed all the time and has the fuel injector spraying on it, while the secondary valve is only exposed when the Intake Runner Manifold Control opens the secondary plates at 3400 rpm. Power was similar too, at 235 hp (175 kW) and 230 lb·ft (312 N·m) of torque.
Bore and stroke were identical to the Duratec 25 at 82.4 mm and 79.5 mm, respectively. The engines shared other traits as well, and insiders report that the designs are related, though not closely. Notably, the two engines share the same bell housing
pattern and 60° V angle. The 60° angle makes it compact and more suitable for transverse
mounting, but it is not ideally balanced—V8s are typically 90°—necessitating the use of a counter-rotating balance shaft
.
Manufacturing was also a shared process. Ford manufactured the aluminum engine blocks, using a patented Cosworth process, at their Windsor, Ontario
plant, then shipped them to Japan for finishing by Yamaha. The finished engines were shipped back to the Taurus plant in Atlanta, Georgia
for installation.
Unlike the SHO V6, the SHO V8's valvetrain
was an "interference" design, one that is shared by many engines built today, meaning that the piston
will collide with the valves if the camshaft
or timing chain
fails. Due to some cam sprocket failures, the engine acquired a reputation for potentially catastrophic failure.
This method proved to be inadequate, and the cam sprocket could break loose from the camshaft and spin independently from the camshaft (or "walk"). This would result in the camshaft stopping and thus not activating the valves, allowing the pistons to hit the valves, ruining the engine. The preventive measure of welding the cam sprocket to the camshaft soon proved to be a fix for engines that had not suffered such a fate yet. Another such fix is "pinning" the cam sprocket, or inserting a pin in the sprocket to keep it aligned on the camshaft. Ford issued a TSB (TSB 03-14-1) prescribing the application of Loctite to the cam sprocket to lengthen the life of the camshafts, but as SHO owners have experienced cam failure after the application of Loctite, most SHO enthusiasts do not recommend this fix.
Ford Motor Company
Ford Motor Company is an American multinational automaker based in Dearborn, Michigan, a suburb of Detroit. The automaker was founded by Henry Ford and incorporated on June 16, 1903. In addition to the Ford and Lincoln brands, Ford also owns a small stake in Mazda in Japan and Aston Martin in the UK...
in conjunction with Yamaha Motor Corporation for use in the 1996 Ford Taurus SHO
Ford Taurus SHO
The Ford Taurus SHO is a full-size performance sedan based on the Ford Taurus that was originally produced by the Ford Motor Company from 1989 until 1999. It returned in 2009 for the 2010 model year....
. It was based on the successful Ford Duratec engine rather than its predecessor, the compact Ford SHO V6 engine
Ford SHO V6 engine
The Ford SHO V6 is a family of DOHC V6 engines fitted to the Ford Taurus SHO from 1989 to 1995. The designation SHO denotes Super High Output....
developed by Yamaha for the 1989 Taurus SHO. The engine was retired in 1999 when production of the third-generation Taurus SHO ended.
3.4 L
The 3.4 L SHO V8 was introduced in the spring of 1996. It incorporated many of the traits of the SHO V6Ford SHO V6 engine
The Ford SHO V6 is a family of DOHC V6 engines fitted to the Ford Taurus SHO from 1989 to 1995. The designation SHO denotes Super High Output....
, including the aluminum cylinder heads and 4-valve
Poppet valve
A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...
per cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
DOHC design, but differed with an aluminum rather than iron block and no variable length intake manifold
Variable Length Intake Manifold
In internal combustion engines, a variable length intake manifold , or variable intake manifold is an automobile internal combustion engine manifold technology...
. A chain is also used to time the camshafts to crankshaft instead of the belts that the SHO V6s used. The SHO V8 has a split port style intake valve setup. The primary valve is exposed all the time and has the fuel injector spraying on it, while the secondary valve is only exposed when the Intake Runner Manifold Control opens the secondary plates at 3400 rpm. Power was similar too, at 235 hp (175 kW) and 230 lb·ft (312 N·m) of torque.
Bore and stroke were identical to the Duratec 25 at 82.4 mm and 79.5 mm, respectively. The engines shared other traits as well, and insiders report that the designs are related, though not closely. Notably, the two engines share the same bell housing
Bell housing
"Bell housing" is a colloquial/slang term for the portion of the transmission that covers the flywheel and the clutch or torque converter of the transmission on vehicles powered by internal combustion engines. This housing is bolted to the engine block and derives its name from the bell-like...
pattern and 60° V angle. The 60° angle makes it compact and more suitable for transverse
Transverse engine
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the long axis of the vehicle. Many modern front wheel drive vehicles use this engine mounting configuration...
mounting, but it is not ideally balanced—V8s are typically 90°—necessitating the use of a counter-rotating balance shaft
Balance shaft
In piston engine engineering, a balance shaft is an eccentric weighted shaft which offsets vibrations in engine designs that are not inherently balanced...
.
Manufacturing was also a shared process. Ford manufactured the aluminum engine blocks, using a patented Cosworth process, at their Windsor, Ontario
Windsor, Ontario
Windsor is the southernmost city in Canada and is located in Southwestern Ontario at the western end of the heavily populated Quebec City – Windsor Corridor. It is within Essex County, Ontario, although administratively separated from the county government. Separated by the Detroit River, Windsor...
plant, then shipped them to Japan for finishing by Yamaha. The finished engines were shipped back to the Taurus plant in Atlanta, Georgia
Atlanta, Georgia
Atlanta is the capital and most populous city in the U.S. state of Georgia. According to the 2010 census, Atlanta's population is 420,003. Atlanta is the cultural and economic center of the Atlanta metropolitan area, which is home to 5,268,860 people and is the ninth largest metropolitan area in...
for installation.
Unlike the SHO V6, the SHO V8's valvetrain
Valvetrain
Valvetrain is an all-encompassing term used to describe the mechanisms and parts which control the operation of the valves. A traditional reciprocating internal combustion engine uses valves to control air and fuel flow into and out of the cylinders, facilitating combustion.-Layout:Valvetrain: The...
was an "interference" design, one that is shared by many engines built today, meaning that the piston
Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...
will collide with the valves if the camshaft
Camshaft
A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.-History:An early cam was built into Hellenistic water-driven automata from the 3rd century BC. The camshaft was later described in Iraq by Al-Jazari in 1206. He employed it as part of his automata,...
or timing chain
Timing belt
A timing belt, or cam belt , is a part of an internal combustion engine that controls the timing of the engine's valves. Some engines, such as the flat-4 Volkswagen air-cooled engine, and the straight-6 Toyota F engine use timing gears...
fails. Due to some cam sprocket failures, the engine acquired a reputation for potentially catastrophic failure.
Cam trouble
Soon after the introduction of the SHO V8 engine, widespread problems with the cam sprockets began to surface. Ford had used a relatively unusual method, called "swaging", of affixing the cam sprockets to the camshafts. The cam sprockets were fastened to the hollow camshafts by forcing a metal ball which was slightly larger than the interior diameter of the camshaft through the center of the camshaft, thus expanding the metal slightly and creating a mechanical bond between the cam sprocket and the camshaft.This method proved to be inadequate, and the cam sprocket could break loose from the camshaft and spin independently from the camshaft (or "walk"). This would result in the camshaft stopping and thus not activating the valves, allowing the pistons to hit the valves, ruining the engine. The preventive measure of welding the cam sprocket to the camshaft soon proved to be a fix for engines that had not suffered such a fate yet. Another such fix is "pinning" the cam sprocket, or inserting a pin in the sprocket to keep it aligned on the camshaft. Ford issued a TSB (TSB 03-14-1) prescribing the application of Loctite to the cam sprocket to lengthen the life of the camshafts, but as SHO owners have experienced cam failure after the application of Loctite, most SHO enthusiasts do not recommend this fix.
See also
- Ford Taurus SHOFord Taurus SHOThe Ford Taurus SHO is a full-size performance sedan based on the Ford Taurus that was originally produced by the Ford Motor Company from 1989 until 1999. It returned in 2009 for the 2010 model year....
- Ford SHO V6 engineFord SHO V6 engineThe Ford SHO V6 is a family of DOHC V6 engines fitted to the Ford Taurus SHO from 1989 to 1995. The designation SHO denotes Super High Output....
- List of Ford engines
- List of Ford bellhousing patterns