Ford SHO V8 engine

The 3.4 L SHO V8 was introduced in the spring of 1996. It incorporated many of the traits of the SHO V6, including the aluminum cylinder heads and 4 valves 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 manifold Runner Control opens the secondary plates at 3400 rpm. These secondary valves are called "secondaries" by SHO enthusiasts. Power was similar too, at {{cvt|235|hp|kW|0}} and {{cvt|230|lbft|Nm|0}} of torque.{{cite web |title=General Specifications|url=http://www.v8sho.com/SHO/genspecs.html}}

Bore and stroke were identical to the Duratec 25 at {{cvt|82.4|and|79.5|mm|2}}, 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.

Soon after the introduction of the SHO V8 engine, widespread problems with the cam sprockets began to surface. Yamaha had used a relatively unusual method, called "swaging", of affixing the cam sprockets to the camshafts.{{cite web |title=Cam Sprocket - Part 2|url=http://www.v8sho.com/SHO/camsprocket2.htm}} 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.{{cite web |title=More Cam Sprocket Photos|url=http://www.v8sho.com/SHO/MoreCamSprocketPhotos.htm}}

This method proved to be inadequate, and the cam sprocket could break loose from the camshaft and spin independently from the camshaft (or "walk").{{cite web |title=Picture Evidence of an Almost Cam Failure|url=http://www.v8sho.com/SHO/Picture%20Evidence%20of%20an%20Almost%20Cam%20Failure.htm}}{{cite web |title=Cam Sprocket Autopsy|url=http://www.v8sho.com/SHO/CamSprocketAutopsy.htm}} 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.{{cite web |title=Still Skeptical about Cam Welding|url=http://www.v8sho.com/SHO/StillskepticalaboutCamWelding.htm}} 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,{{cite web |title=Loctite TSB 03-14-1|url=http://www.v8sho.com/SHO/LoctiteTSB03141.htm}} but as SHO owners have experienced cam failure after the application of Loctite,{{cite web |title=Ernie Roberts - Loctited - Cam Failure #272|url=http://www.v8sho.com/SHO/ErnieRobertsLoctitedCamFailure272.htm}} most SHO enthusiasts do not recommend this fix.{{cite web |title=Owner Comments on Loctite TSB 03-14-1|url=http://www.v8sho.com/SHO/OwnerCommentsonLoctiteTSB03141.htm}}{{cite web |title=Analysis of Loctite Effect on V8SHO Camshaft Failures|url=http://www.v8sho.com/SHO/Bruce/Camfail_to_TW0904041.pdf}}

• Ford Taurus SHO
• Ford SHO V6 engine
• List of Ford engines
• List of Ford bellhousing patterns

{{reflist}}

• [http://www.v8sho.com V8SHO.com]
• [http://www.shotimes.com/php-bin/ SHO Times, with tech tips for the SHO]
• [http://www.shoclub.com SHO Club]
• [http://www.shoforum.com SHO Forum]

{{Ford Taurus}}

SHO V8

SHO V8 engine

Category:Yamaha engines

Category:V8 engines

Category:Gasoline engines by model