Ford Yamaha V8 engine
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| Ford SHO V8 | |
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| Manufacturer | Ford Motor Company |
| Also called: | Volvo V8 |
| Production: | 1996–1999 2005– |
| Predecessor: | SHO V6 |
| Similar: | Jaguar AJ-V8 Ford Modular V8 GM Premium V Mercedes-Benz M113/M115 BMW M62/S62 BMW N62 Toyota UZ Nissan VH Nissan VK |
Ford Motor Company had worked with Yamaha Motor Corporation to develop the compact DOHC V6 Ford SHO V6 engine for the 1989 Ford Taurus SHO "Super High Output". When the time came to replace that engine, the company again worked with Yamaha to build a new V8 based on their successful Duratec V6. This partnership created the 3.4 L V8 for the 1996 Taurus SHO. That engine went out of production after 1999, but was resurrected and modified by Ford's Volvo marque for use in the Volvo XC90 SUV in 2005.
Now at 4.4 L, the V8 engine is unique in Ford's wide range of V8 engines in that it is designed for transverse use and has a V6-like 60° bank angle.
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[edit] SHO V8
The V8 SHO appeared in spring of 1996. It was at 3.4 L and continued many of the traits of the SHO V6, including the aluminum cylinder heads (the V8 SHO engine has an aluminum block, V6 SHO engine has an iron block), 4-valve per cylinder DOHC design, but no variable length intake manifold. The V8 SHO has a split port style intake valve setup. The primary valve is exposed all the time and has the fuel injector spraying on it and 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 ft·lbf (312 N·m) of torque. This version was retired in 1999 because of changes to the base Taurus it was based upon for the 2000 model year, and the lack of a manual transmission as was available with the prior generation SHO.
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. One sign of such similarity is that the two engines share the same bell housing pattern.
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 valve train 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 (see section below).
[edit] Cam trouble
Soon after the introduction of the SHO V8, widespread problems with the cam sprockets began to surface. Ford had used a relatively unusual method, called "swedging", 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 thus on some engines, 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 (see above section). 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 [1]. Another such fix is "pinning" the cam sprocket, or inserting a pin in the sprocket to keep it aligned on the camshaft. There were calls for Ford to provide a recall, though none ever happened, potentially because it was a limited-production vehicle. Aside from this issue, the engine itself is considered to be fairly dependable and a good example of Yamaha engineering.
[edit] Volvo V8
Volvo began offering the 4.4 L V8 version of this engine in its large P2 platform automobiles in 2005. The engine is made by Yamaha in Japan and was initially offered in the Volvo XC90 SUV. It is also available on the Volvo S80 and possibly a future Lincoln all wheel drive luxury car.
The engine is a 4.4 L aluminum DOHC V8 which produces 311 hp (232 kW) and 325 ft·lbf (441 N·m). Officials of all three companies involved insist that the Volvo V8 is not related to the SHO engine, but insiders dispute this claim.
The 4.4 L engine was likely to find its way to Lincoln's new D3-based models in 2008 and beyond with production beginning in Lima, Ohio. Since this platform is designed for transverse engines, none of Ford's other V8 engines would easily fit. The engine was used in the 2006 Lincoln MKS concept car because of the engine's V6-like 60 degree V angled cylinder banks; V8 engines usually have a 90 degree V. However, it was revealed[1] in mid-August, 2006, that Ford's Way Forward plan would not allow the low-volume engine to go forward.
[edit] See also
[edit] External links
- Pinning versus welding
- Discussion of the cam sprocket problem
- More cam failure links
- Class action lawsuit
- Who is responsible for the poor camshaft design
- SHO Times, with tech tips for the SHO
- SHO Club
[edit] References
- ^ (August 21, 2006) "Lincoln V8 Axed". AutoWeek.
