Tom Wilson
August 9, 2010
Photos By: Courtesy of Ford Motor Company

Ford's newest gasoline V-8, the 6.2-liter, is an interesting development. Architecturally it doesn't much resemble other Ford engines once above the head gasket. Its production debut is in trucks and yet it already has a performance background on the dragstrip. But most interestingly, the more you study the new 6.2, the more potential you see.

Just to underscore that point-even though Ford certainly hasn't-the 6.2 is landing on dealer lots at 1.02 hp per cubic inch, in 5,500-rpm truck trim, no less. There's power lurking in this big engine.

Obviously designed to deliver the one thing modular V-8s can't-cubic inches-the 6.2 has an indirect development history. Originally codenamed the Hurricane and rumored to be a cool Mustang mill, the engine dropped off the radar for a while before resurfacing as the Boss. But now it's officially just called the 6.2 and, so far, is purely a truck engine.

What sets the 6.2 apart is its 115mm (4.53 inch) bore spacing. Modular V-8s such as the new Coyote 5.0 are limited to 100mm bore spacing by their production machinery. So to break the modular displacement barrier, Ford has gone to a fundamentally larger architecture. In the 6.2, that translates into a 4.02-inch bore.

We've come to think of the 6.2-liter as a big-block modular. Of course, the only modular architecture making it through to the 6.2 is the bellhousing bolt pattern. We suppose the deep-skirted block, cross-bolted mains, and gerotor-style oil pump are modular thinking, but it's best to remember the 6.2 as its own engine family.

What a Bore
That large cylinder bore does wonderful things for the 6.2. Most basically, it allows larger displacements with less friction, weight, and length than the modular method of adding cylinders.

Secondly, it allows large valves with reduced valve shrouding, so breathing is well supported. And while it may seem retrograde thinking to consider Two-Valve cylinder heads, the large bore allows good breathing with Two-Valve heads, which helps contain costs.

Other than the larger bore, we don't see anything fundamentally innovative in the 6.2's short-block compared to other modern Ford engines. The block is cast-iron for durability, the deep skirts and cross-bolted mains are typical modern practice, and the gerotor oil pump is also typical. We also like the piston oil squirters.

There is mention of improved bay-to-bay breathing in the 6.2. This is something Ford is big on, as it's mentioned by the company as a factor in the 3.5/3.7 V-6 family, the Coyote 5.0, and now the 6.2. In practice, it means the crankcase is ventilated, with windows through the main bearing bulkheads, so air pulses generated by piston movement can move more freely in the crankcase. Ford says there is good power from the technique; we guess it helps with ring seal.

About the only gamble Ford took with the bottom end was simply the large displacement. No one knows where the economy or fuel prices are going (well, they're going up, but how much and when are open questions), so the cross purposes Ford is addressing with the 6.2 are delivering a large-enough gasoline V-8 in trucks, while not spending too much money in case the engine is driven into obscurity by $7-a-gallon gas.

Shaft Rockers
Where the 6.2 goes off on its own is in the valvetrain. Unlike any other Ford V-8 since you're granddad was buying muscle cars, the 6.2 uses a single overhead cam with splayed valves and shaft-mounted rocker arms. As we'll see, this is a cost-effective way of making good power, and it's definitely interesting in that it doesn't resemble any other Ford engine.

What reasoning led to such a valvetrain? Well, the overhead-cam layout is flexible from a manufacturing standpoint because different cylinder head layouts can be easily bolted to the same short-block. Much as Two-, Three-, and Four-Valve cylinder heads have been used with essentially the same 4.6 modular block, Ford engineers were careful to design the 6.2 short-block so it could readily accept twin-cam heads. And that's sounding interesting to us: a big-block V-8 with DOHC, Four-Valve heads? Tasty.

Overhead camming also frees up cylinder-head real estate because there's no need to accommodate push rods. That gives the cylinder-head designer more leeway in laying out the intake ports, exhaust ports, water jacketing, and head bolts. And sure enough, the 6.2 has large, symmetrical ports, the better to feed its large valves.

A single camshaft per cylinder head is less expensive than dual cams, weighs less, and is more compact than a twin-cam head. The downsides are you have to work harder to package anything other than inline valves with a single overhead cam, and there are fewer variable-cam-timing options available because the intake and exhaust lobes are in a fixed relationship to each other on the single bumpstick.