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Written by Richard Holdener @ hotrod.com
Read the complete article at hotrod.com here. ©2019 hotrod.com.
What happens when a Mod Motor maniac and the King of Hemi horsepower get together and make chips fly – the new Accufab/BAE billet Coyote block. But does the Coyote market really need a race block? You bet it does! Don’t get us wrong, the 5.0-liter Coyote is certainly a force to be reckoned with. The combination of double-overhead cams, Four-Valve heads and variable-valve timing make the 5.0-liter pump out power (and torque) like a much larger 6.0-liter.
Coyote Mustang owners have also enjoyed plenty of aftermarket support, allowing the stock Coyote motors to easily eclipse the 1,000 horsepower mark with little more than bolt-ons and boost. In fact, it can be said that power production is the easy part of the equation, but so too does it present the ultimate problem.
Confused? Don’t be. Given the ease at which a modified Coyote makes power, you quickly reach the limit of one or more of the original performance components. After you build the motor with the necessary forged internals, add plenty of fuel and your choice of power adder, what’s left? Well, the limiting factor in terms of absolute power from a Coyote eventually becomes the block itself. Before the Coyote guys start storming the castle, know that this limit is quite high, but we are not talking about 1,000 horsepower street/strip stuff. We are talking about race cars with power outputs that start with a two before the comma, not a 1one.
For all the Coyote owners wanting to put this beautiful piece of billet hardware in their street car, look elsewhere, as the new aluminum race block from Accufab and Brad Anderson Enterprises (BAE) is exactly that, a race block. The dry block features no water passages, leaving cooling to the cylinder heads. What the billet block does provide is a combination of design features that allow it to not only withstand power levels that would easily kill a stock block, but actually help the combination produce and sustain those power levels.
Starting with the strength, each block begins life as a 20x20x14-inch, 600-pound chunk of 6061 aluminum. This same chunk is used by Brad Anderson Enterprises (BAE) to produce a blown Hemi block. For those new to the race game, these are the blocks used to build the 3,500 horsepower blown Hemi’s used in Alcohol Funny cars. Strength was obvious high on the list for these hefty Hemi Horsepower applications, so all that was necessary was to reprogram the CNC machine to spit out a Modular Ford block instead, right? Obviously, the design and programming took a great deal more effort, but working together, Accufab’s John Mihovetz and BAE’s Brad Anderson finally came up with a program to fulfill all the design needs.
Needless to say, the block features attention to detail at the most extreme level. Starting from the basic block, the 6061 aluminum was rough machined first, then heat treated to T6. According to John Mihovetz, aluminum suppliers cannot guarantee the core hardness of the any piece over 3-inches thick. Since the aluminum block measured nearly a couple of feet in each direction, that last thing they wanted was inconsistent hardness of the finished product. The cure was to rough machine the block to within .125-inch of the finished product, then harden to T6, then finish machine. The result was a block with consistent hardness (meaning strength) throughout. The strength was carried right through to the bottom, where they applied billet (4340) steel main caps.
The cast caps were naturally ditched, as were aluminum caps. According to Mihovetz, the aluminum caps are not as strong as steel and are prone to distortion, especially when using oversized fasteners that provide extra clamp load on the aluminum. The billet caps were secured by 7/16-inch studs to replace the factory 10mm units. They even went to great lengths on the design of the side bolts for the main caps. The block features counter bores for the press-fit, hardened washers, while the block and caps allowed extra thread engagement of the bolt.
You might notice from the photos that the billet block featured no motor mounts or water pump. Again, according to Mihovetz, the position of factory motor mounts on high-horsepower applications can cause distortion of the block. Besides, real race cars generally use motor plates. Also missing from the block were provisions for a water pump, as the dry block eliminated this need.
What was present was something that looked like a cam tunnel; this tunnel was actually designed to enhance communication between the cylinders, or more accurately the pairs of cylinders. The communication tunnel helped eliminate the build up of crankcase pressure, enhance oil drain and improve ring sealing. In fact, a great deal of effort went into the design of the block to improve oil drain and minimize aeration of the oil. The (de)aeration was critical for performance, especially on a motor equipped with hydraulic lifters (lash adjusters).
Further considerations in the design included revised oil drains, directional machining of the inside of the block, to channel oil down to the pan and contoured and radiused (and contoured) oil return holes. Naturally the block also featured air pressure equalization holes between the block and heads. They even went to the trouble of chamfering the ledge of the main web below each cylinder to minimize air resistance and the compression of oil off the ledge into the crank.
Obviously oil drain and aeration weren’t the only considerations given to the new block design, cylinder sealing and strength were also a priority. To ensure the block would survive the 40, 50 or even 60 psi of boost guys are currently running, the billet block received stepped, ductile-iron cylinder sleeves. To further enhance ring seal and piston support at BDC, the block featured .400-inch longer sleeves. The extra sleeve length combined with the internal (directional) machining of the block to allow the block to swallow stroke lengths up to 3.850-inches. Mihovetz was quick to point out that the raised main oil galley that was also partly responsible for the available stroke length. According to Mihovetz, the sleeves will accept up to a 3.700-inch bore size, but he recommended smaller bores to ensure sealing on ultra high-horsepower, turbo applications.
When supplied, the bores come unfinished (.005-inch under stock), while the deck height comes .020 tall. Sealing the heads to the new block were a set of hybrid studs that featured 9/16-inch (coarse) threads on the block side and ½-inch (fine) threads on the head side. Torqued to 125 ft-lb, these same studs are used on the BAE Hemi’s, so, again, they have been fully battle tested.
By accepting the factory oil pump, the race block was designed to be run as either a wet or dry sump. The block was not designed to be used with the factory oil filer adapter and instead featured a pair of AN-12 bosses for a remote filter. The AN-12 bosses can also be used for dry-sump oiling. The block will accept a number of stock components, including (of course) the cylinder heads, front cover, oil pan, bearings, starter and transmission (stock bell housing pattern). Obviously, an external water pump must be used to provide cooling to the cylinder heads. It should be pointed out that though the factory front cover will secure the timing chain (with screw-in studs to replace the factory press-in units), the block comes with a dedicated cover for the communication tunnel. The same can be said for the rear of the block, as a dedicated rear cover is used; one that includes a provision for the factory crank sensor.
Given the looks of the block and impressive credentials of the people involved, we can’t wait to see racers put this Coyote into action.
Accufab's Mod Motor Records:
World's Fastest Mod Motor - First Mod Motor Into 8's, 7's, 6's, 5's - First + 200, 210, 220, 230, 240; 250 Mph - World's Fastest Ford Lightning - Fastest Screw Supercharged Lightning - Fastest Screw Shelby - Fastest Turbo Mustang - Fastest Ford GT 1/2 and 1 Mile - Two Standing Mile World Records - PSCA Pro Street Champion - Eight PSCA Pro Street Wins - Seven Time NHRA Record Holder