It’s a known fact that reduced weight equals more speed, which is why aluminium engines are the next big thing in motorsport. Bill Mitchell Products tells us why.
For performance enthusiasts looking to hop up a Chevy, Ford or Chrysler, today’s aluminium engines offer several advantages that can no longer be ignored. The decreased weight and increased performance of well designed aluminum blocks, heads and intake manifolds combine for a complete aluminum engine that was previously unattainable and only possible with cast iron. At the same time, improved casting and machining of modern aluminum engines has yielded enhanced durability.
“My customers are mainly seeking more performance—in terms of horsepower and torque—without sacrificing reliability and reparability, and with aluminum they get it all,” says racing legend Nick Arias Jr., a recent inductee into the SEMA Hall of Fame and owner of Nick Arias, Jr. Racing Components.
Aluminium is now proving so popular that successful racers in a wide range of motor sports rely on it for a competitive advantage at all levels: from drag racing, track racing, off-road, rally, and drifting to powering monster trucks, racing tractors and speedboats.
With aluminium parts designed with the latest technology and built to the tightest tolerances, you gain both power and lightness.
The winning edge
By itself, aluminium gains a “hole shot” advantage over steel by virtue of its lightness. At 27 on the periodic table, the molecular weight of this element is less than half that of iron (56). As the famous founder of Lotus Cars, Ltd., Colin Chapman, once said, “Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere.”
But if every competitor runs aluminium, then the only way to stay ahead of the race is with more power. This is where the materials and craftsmanship of an aluminium block, whether short or long, make all the difference. With aluminium parts designed with the latest technology and built to the tightest tolerances, you gain both power and lightness.
“Our customers primarily come to us for more power for their cars and trucks,” says Arias, whose Gardena, CA shop, Nick Arias, Jr. Racing Components, makes a name for itself selling racing engines and components such as Arias designed pistons and hemispherical heads for Chevy and Ford motors. “We start with aluminium blocks supplied to us from Bill Mitchell Products because it is a quality product that consistently delivers the goods.”
Bill Mitchell Products, based out of Ronkonkoma, NY, specializes in building state-of-the-art aluminium blocks, heads, and intake manifolds with a focus on high performance. The company’s street cred’ dates back to 1988 when Hot Rod Magazine named its small block Chevy heads Product of the Year for increases of 30-70 horsepower over stock heads. Its current range of parts ranges from: Ford Windsor 302/351 Windsor blocks capable of building as much as 460 c.i.d.; a highly refined version of the original Chrysler 426 Hemi block; to a 632 c.i.d. big block Chevy drag race package that produces well into the 1500+ hp range.
“The proof of these aluminium engines shows on the dyno,” says Tucker Caven, lead project designer and engine builder for TCB Engine Development out of Murietta, CA that specializes in developing high performance engines for racing. “We’re currently working on an Arias project that makes in the neighborhood of 1,000 hp from an LS motor with a hemi head, and we will be using Bill Mitchell Products aluminium blocks exclusively.”
Attention to detail gets the checkered flag
Stratospheric output from aluminium engines only comes about through meticulous design and construction. Yet, it’s the attention to detail in the machining process that duplicates design advantages right through to the finished product.
By itself, aluminium is a much better material to work with than steel because it is easer on the cutting tools, allowing jewelery-like precision. But that’s not always enough.
“One of the biggest things you have to keep in mind is that just because someone brags that their products are built on a CNC machine, that qualifies them as being perfect; that’s not entirely correct,” explains Caven. “The machining process starts with the pallet the part is bolted to. If it’s not fixtured correctly, then the best designed tolerances don’t mean a thing. You could get a set of cylinder heads from a low quality manufacturer where the center line of the bores is 5-10 thousandths off. Most people don’t catch those slight differences, but it shows up on the track.”
“Whereas you take a manufacturer like Bill Mitchell, who maintains machining integrity by fixturing the part correctly,” continues Caven. “We check the position of everything—cylinder bores, lifter bores, necks, the cam tunnel, etc.—and we can quickly tell when everything has been made to spec’. That’s a big plus for our racing customers because if you buy a cheap engine block, but have to put $2000-3000 of machine work back into it, you are shooting yourself in the foot. We save money by starting with a quality part.”
By itself, aluminium is a much better material to work with than steel because it is easer on the cutting tools, allowing jewelery-like precision.
Greater endurance with aluminium
Gone are the days when aluminium was considered a weak sister to iron under harsh motoring conditions. Today’s high tensile compounds and improved casting techniques now allow aluminium to match or exceed the durability of iron. Additionally, aluminium is superior by virtue of its cooling properties.
In the case of a manufacturer like Bill Mitchell, 356 grade aluminium is employed for cylinder heads and 357 T6 on blocks—the strongest grade used in the industry. This material is carefully cast to reduce porosity issues, further improving durability.
“A well cast aluminium block draws heat faster and gets rid of it faster, too, so you get a strong resistance to warping or cracking,” notes Arias. “Not only that, but aluminium won’t rust like iron. That all adds up to greater durability.”
“Another advantage of aluminium is its repairability,” continues Arias. “If the worst happens and you throw a rod out of it, you can repair it easier. Aluminium is readily welded. For hardcore racing, it really is the better application.”
“Quality aluminium parts manufacturers go to ‘nth’ degree to start with the highest quality material and castings,” explains Caven. “The result is aluminium blocks that are just as tough as iron blocks, but without all the weight.”
Packaged efficiency lowers ETs
Maximum gains come from assembling an engine—block, heads, intake manifold—all from quality aluminium. A top-quality, cohesive package can lower lap times at the track and increase terminal speeds through the “traps” by way of improved efficiency.
“A well produced aluminium engine frees the engine up and helps it to work easier, and that’s the best kind of horsepower because it’s free,” points out Caven. “When you put the lifters, cylinders, cam tunnels, etc. exactly where they belong in terms of geometry, then friction and other parasitic losses are decreased and horsepower numbers go up.”
“In this sense you’re not hurting the engine, you’re relaxing it,” continues Caven. “For example, Bill Mitchell makes a small block, LS, Chevy engine that is bullet proof right down to an improved oiling system, which the factory block lacks. We have no trouble extracting big horsepower out of it with high compression pistons, a big lift cam, solid lifters and all, simply because the motor isn’t working against itself. So at the end of the day, those torque numbers go up.”
For performance enthusiasts who ascribe to football coach Vince Lombardi’s famous quote, “Winning isn’t everything; it’s the only thing,” then aluminium stands out as the clear choice to bring home a trophy, or maybe even a pink slip.
