Here's a close up of Smeding's...
Here's a close up of Smeding's custom-ordered crankshaft built specifically for this engine and its piston and rod combination. It's made from forged 4340 steel and is precisely machined for superior oil distribution (check out the chamfered oiling holes).
All Smeding's engines are strokers because of their power curve. "Though peak horsepower is what sells someone on an engine, the torque curve is what is really important and makes the customer happy," Ben says. They get this impressive torque curve by using a long-arm crank. Along with the leverage advantage, they squeeze more torque out by making the engine as efficient as possible. That's where other builders falter-they throw too big of a camshaft at an engine and use the peak power gain to compensate for the torque loss.
Ben and his team of builders at Smeding only build small- and big-block Chevy, and small-block Ford motors. A machinist or engine builder who works on everything from Ferrari engines to go-kart engines won't have the intimate knowledge of any particular engine, just a general mechanical understanding.
Out of Smeding's four-model Ford lineup, we chose the most potent of the bunch: the 427 Cobra Special. The 427 Cobra Special is described as a quick-revving, maximum-effort performance engine that's not for the faint of heart. On dyno day, the combination made 566 hp at 5,600 rpm on pump gas. Even more impressively, the first torque reading on the dyno at 2,500 rpm was 442 lb-ft, and it never let up. This curve is what Ben Smeding has built his reputation on. He builds some of the most streetable, absurdly torquey, and reliable crate engines.
Everything you see here minus...
Everything you see here minus the rings and timing set were custom made for Smeding's 427s. What makes Smeding's engines so unique is that you couldn't re-create them anyplace else. The combination of parts and adjustments made are what give these engines so much power in such a wide-rpm band. Too bad they don't sell these parts individually too!
Rather than messing with a donor block, Smeding starts with a fresh Dart block with splayed four-bolt mains. These Dart blocks are extremely rigid; this strength allows the Smeding engine to have extremely tight clearances. The tighter clearances give them the ability to use a standard-volume oil pump and to keep the amount of oil flinging around the block down to a minimum. The Dart block comes fitted with a one-piece rear main seal, which has proven to seal better than the older two-piece design. Once they've decked, line honed, and clearanced the block for the stroker crank, it's onto installing the rotating assembly.
Before the crankshaft goes in, it's spun on a balancer and brought to within one gram of a zero balance. Most crankshafts are built with heavy counterweights to compensate for many different piston and rod combinations, and then are balanced at the machine shop. The problem with that is that the balancer can't tell you exactly where the unbalanced part is. Smeding's buying power has allowed him to have a 4340 forged steel crankshaft built with counterweights matched to their piston and rod combination for each cylinder.
Attached to this special crank are H-beam race connecting rods that are also made from 4340 forged steel. The rods are 6.2 inches long compared to the stock length (5.96 inch). The longer rod lowers friction because the reduced angle of the rod and piston places less stress on the thrust surface of the piston. The rod is connected to the crankshaft with ARP bolts, and installed with a tight clearance of 0.0018 inch. The main bearings are also given a tight fit at 0.0018-0.0022-inch. When this measurement is increased, the oil flow increases exponentially, requiring more oil volume to maintain pressure.
The pistons are forged units designed by Smeding. (They recommend using a forged piston when power levels exceed 500 hp.) For less powerful engines, Smeding prefers hypereutectic pistons because they expand less with heat, allowing the builder to fit them snugly. Our 427 needs the density of the forged piston not only because of its power, but also because of the piston's small size compared to a piston used with a shorter rod. These pistons were designed by Smeding, who owns the dies, and are manufactured by KB pistons. It's a full-floating piston, meaning that the wrist pin is assembled with snap rings rather than being pressed in. Any place Smeding can reduce friction, they do, since it's ultimately free horsepower and gives parts a longer life.
The Dart block comes with...
The Dart block comes with these billet steel four-bolt splayed main caps. The outward angling of the outer bolts directs them into a meatier part of the block, increasing their strength. Securing the crankshaft with anchors in multiple directions also helps to toughen the bottom end.
Just because they always use...
Just because they always use the same parts on their engines, doesn't mean they skip any measurement checks. Here, they measure the back and forth movement of the crankshaft, called endplay. Their spec is 0.002-0.004 inch.
Smeding never lets an engine...
Smeding never lets an engine out of their shop with an oil leak. One of the ways this is possible is because they use a one-piece rear main seal. The seal slips over the crankshaft between the end cap and the block without any sealant.