Miniaturized is the best way to describe the tiny Coyote roller rocker arms, "finger follo
Another seemingly simple choice was to make the block aluminum, as the Blue Oval mandate is to save weight. However, the Coyote will inevitably be supercharged. The team didn't want to have to re-engineer the block later, so it was designed with forced-induction loads in mind.
This extra material is best seen in the main-bearing bulkheads, which are now a couple millimeters thicker. Fastener sizes are larger too. All are generous, and should prove absolutely bulletproof in naturally aspirated trim. They also pack the reserve strength to withstand us hot rodders bolting on blowers. This bodes well for modular engine building as we've just gained a strong, lightweight aluminum block with production engine economies of scale. Too bad the connecting rod isn't as over-built, but that's getting ahead of the story.
Something Ford has identified as important in its new 6.2 truck engine and the Coyote 5.0 is crankcase bay-to-bay breathing. This is managing air pumped by the pistons sliding up and down in their bores. This constantly changes the shape of the crankcase volume, creating powerful pulses, especially in the area where opposing cylinders share a "bay" between main bearing bulkheads.
Coyote team members go on and on about how huge the Coyote cams lift at 12mm (0.472-inch)
Research shows either sealing the bays to minimize breathing, thus forming "air springs," or opening the bays to allow liberal communication have advantages. The Coyote team chose liberal bay-to-bay breathing, with limber holes strategically placed in the main bearing bulkheads and credits this as an important power builder. It no doubt has a positive effect on ring seal.
The Coyote team says the forged. powdered-metal connecting rod is the least robust link in the 5.0 chain. Engineers noted it is absolutely strong enough for its naturally aspirated application in the Mustang, but just absolutely strong enough. It's worth noting that while the Coyote rod shares its big- and small-end diameters plus its center-to-center length with the 4.6 rod, the Coyote rod has been redesigned to more evenly distribute bearing loads and is definitely an improved piece.
Most ominously, supercharging will require a stronger forged rod, so we expect to see those, and, no doubt, a short-block in the FRPP catalog before long. This adds a whole new layer of commitment to bolting a blower on a Coyote. We'll have to let the brave among us prove the standard Coyote rods' boost tolerance. For those planning on a rod-exchanging teardown right away, Ford says the Cobra's Manley forged rod will just fit, but you must be careful. No word on how to package a forged piston and rod combination.
Coyotes use the same type of multi-plate silent-link chains as other modulars. However, wi
Because a fully populated Coyote crankcase is packaged tightly as coach airline seating-the already abbreviated piston skirts come close to the crankshaft counterweights-there is no room left for stroke increases.
You may also think "weak" when viewing the Coyote's racy-looking but hypereutectic pistons. But there's a twist: oil-cooling jets. A fine mist of oil is squirted continuously from jets in the block's main webs. This oil sprays directly on the underside of the piston, at the vulnerable piston boss and bottom of the crown. The engineers sold the expense of oil jets to management by telling them it speeds engine warm-up (which is true), but the real reason was for piston cooling, hence longevity. This means the lighter, quieter, tighter-fitting, less-expensive hypereutectic piston can be run in this demanding high-rpm, high-load application.
Benefits of the squirters are extensive. Testing shows the crankshaft runs 25 degrees cooler with them, and they help with octane sensitivity. Combined with the heads superior water-jacketing they are one reason the high-compression Coyote can feed on 87-octane gasoline. Interestingly, adding piston-cooling oil jets was one thing engineers on the original Four-Valve modular-the 280hp Lincoln Mark VIII's 4.6-told us they would do if asked to increase performance. That was 17 years ago, so it's been a long wait for this fundamental improvement.
When it came time to fit the dipstick the usual path through the headers proved restrictiv
While perhaps not as sexy as the zoomy new cylinder heads, the Coyote short-block is a comprehensive re-think and re-engineering of the modular V-8 and is clearly poised as the all-new performance Ford engine foundation for years to come.