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Building a Better Cobra Jet Coyote

Livernois Motorsports

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Dearborn Heights, Michigan
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www.livernoismotorsports.com
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S550 HQ
Vehicle(s)
2016 Mustang GT (TVS 2650) (6R80)
There is little doubt that the Coyote engine is one of the best platforms ever developed by Ford. With over 400hp on hand in a stock Mustang GT, and the stock block and crank capable of handling over 800hp, there are few engines that rival it in terms of power handling capability.

With insane power levels being made by the Coyote and Ford also utilizing the block as the engine foundation in the Cobra Jet program, eventually some additional work needs to be done. Whether that work is for more cubic inches, strength in a naturally aspirated combination, or to endure the brute-force capability of a forced induction combination, there are a number of reasons why a Coyote block could need some additional work – mainly in the realm of sleeving the cylinder bores.

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After measuring the block, each block is bored by a CNC boring machine. This process cuts the stock thin wall sleeves out of the block.

Sleeving a modular engine platform block is nothing new, obviously. We’ve been doing this since shortly after the DOHC 4.6 made it’s debut in the SVT Cobra in 1996. The Coyote blocks respond very much like their 4.6 and 5.4 liter predecessors. We began sleeving Coyote blocks first at the request of some manufacturing companies.

The sleeving process takes approximately two days to complete. This is in part due to tight controls that Livernois has in place to prevent damaging the aluminum block and to make sure the sleeves are fixed into position properly and won’t shift later.


Left: The CNC boring machine determines exactly how much material to remove. Right: After boring the blocks they are thoroughly cleaned.

So why sleeve the Coyote block? The simplest answer is strength. The distance between the cylinder walls are tight and the separation to the water jackets on the top of the bores can give way with a lot of boost. Also, when boring the block the thin wall sleeves are not ideal for high power output applications. By installing the sleeves, the block can maintain integrity and benefits from increased strength over stock due to the much thicker iron sleeves. We’ve sleeved approximately 40 blocks at this point and we have customers with these blocks making 1,400-1,500 hp in some instances. Try doing that with many other stock blocks, and sleeved or not you’ll end up with a failure in many cases.

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We have a large selection of sleeves to choose from with varying inside and outside diameters. The majority of these blocks will have a 3.700-inch inside diameter bore, while a few higher output applications will get a slightly smaller 3.660 inside diameter sleeve.

All of the work on each block is done by CNC equipment. A CNC milling machine first measures to determine the existing dimensions of the block in factory form. The CNC machine allows Livernois to precisely locate the bore centers in the block. Schropp says, We use block blueprint data from Ford to ensure that the bore centers are located exactly where the blueprints call for. The factory machine work is usually close, but we make it perfect. This prevents the aluminum from being compromised by over boring the blocks and also ensures the best possible assembly as the bore centers remain in-tact.

After the blocks are bored they are then heated slowly with our proprietary process for several hours. This process takes the better part of the day. Once the proper temperature is achieved, the block is removed from the oven and technicians install the specified sleeve size. The sleeves are made from centrifugally cast spun material. Sleeve selection is dictated by what the block can be bored to and what the customer’s application is. Higher horsepower applications will use a smaller diameter bore with a thicker sleeve, while naturally aspirated applications can typically run a larger bore and sleeve with a thinner wall thickness. Around 95% of the blocks will receive the 3.700 inside diameter bore, while a few of the very high powered applications get the slightly smaller inside bore diameter of 3.660, that uses a thicker outside diameter sleeve for higher strength.


Left: Blocks are placed in an oven and slowly heated before being removed for sleeving. Right: With the block still hot, two technicians carefully install all eight sleeves.

Once the sleeves are installed, a special fixture is put in place to keep tension on the sleeve and prevent it from shifting in the bore. The block is then placed back in the oven with the fixtures installed and brought back to room temperature slowly. These strict temperature controls not only prevent the sleeves from slipping or shifting, but they also protect the aluminum from cracking during the process.

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The block goes back in the oven for a slow, controlled cool down with these fixtures attached to prevent the sleeves from shifting or slipping during the cool down. Once cooled the sleeves are set, the deck will be milled to ensure a uniform surface.

The final step in the sleeving process is to mill the surface of the deck to ensure the sleeves and deck are parallel and square. The milling usually removes .002-.003 of an inch from the block surface giving a final deck height of around 8.934 to 8.936 inches.

Livernois also offers other machining services on the blocks including the typical line-honing and line boring. About 75% of the blocks we complete this process on are then built into complete, short or long block assemblies. The remainder are shipped to professional racecar facilities, performance shops, engine builders, customers and machinists across the country.
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