Most of us only want to pay...
Most of us only want to pay to rebuild the engine in our Mopar once, so we want it done properly. This month we'll show you some techniques we used when building an all-out race Hemi, and these same methods can be applied to your engine as well.
When it comes to the engine in our Mopar, we all want an abundance of power (isn't that why we drive Mopars?), but there are other important aspects regarding the powerplant that sits between the frame rails of our car. For a powerful engine to last, it must be able to withstand the forces placed on it during its life, especially in high-rpm or high-load applications, without over-stressing itself or breaking an internal part that would lead to engine failure. Chrysler did a pretty good job designing their high-performance V-8 engines to withstand their rated power levels, and stock Mopar muscle car engines often lasted far longer than the engines in their competitors' vehicles. Engine technology has come a long way in the past four decades though, and by today's standards the engines in our muscle cars definitely utilize outdated technology.
To properly build a high-performance engine, it takes a good selection of the right parts, as well as accurate inspection, machining, and assembly techniques, to result in an engine that is not only powerful, but durable as well. And while durability isn't usually the first thing that comes to mind when building an engine, it is vitally important if you want to be able to properly enjoy your vehicle. Durability means that at the track, you're the racer who runs quick, consistent elapsed times or lap speeds, without having to open the hood of your car during an event. On the street, durability means not worrying about driving on that long cruise or taking your car on a trip or to the track, because you're confident nothing will break. But while knowing the importance of engine durability is one thing, actually achieving it is an entirely different matter. It takes the proper tools, techniques, and parts to build an engine that lasts, and often the experience needed is gained by testing parts and theories on the dyno or at the racetrack.
Starting with quality parts...
Starting with quality parts will ensure the motor is not only powerful, but durable as well. We chose an Indy Maxx aluminum, water-cooled block from Indy Cylinder Head because of its light weight and its ability to sustain high loads without failure.
One of the reasons we do so much racing is because we know the rigors of racing are the ultimate test of engine parts, and the technology used in race engines can often be applied to street or dual-purpose engines as well. This is no secret, as auto manufacturers have been utilizing this theory for many years, applying cutting edge racing technology to the engines they produce for their street cars and building more powerful and robust production engines each year. So, while we know most of you won't get the chance to build your own all-out race Hemi, we thought we'd let you follow along while we build one, showing you the parts and techniques we used, many of which can be applied to your street engine as well.
The subject of our build is a 540 cubic inch all aluminum Hemi we're putting together for a friend and local Mopar enthusiast who lives on the West coast of Florida. This engine is a full-blown race motor, which will eventually reside in a tube-chassis '68 Dodge Dart. Due to its power potential, this engine will be built using all aftermarket parts, including an Indy Maxx aluminum, water-cooled block, Indy CNC ported aluminum cylinder heads, a Comp roller cam, Milodon oil system, and a mixture of forged and billet internals from Summit Racing. Experience tells us that this high-compression race engine has the potential of nearly 1,000 horsepower and 8,500 or more rpm if equipped with tunnel-ram induction, but Joe chose a cross-ram intake manifold which will limit the engines output to around 900 horsepower. Even so, the loads and pressures on the internal and external engine parts will be immense, so only the best parts, and the most precise machining techniques, will ensure this engine's longevity.
Another advantage on an aluminum...
Another advantage on an aluminum block is that if the engine does suffer an internal parts failure that damages the block, the block can quite often be repaired by Tig-welding.
The Indy block comes with...
The Indy block comes with extra gusseting, and billet steel main caps. Factory Hemis had cross-bolts in the center three main caps, the Indy block has them in all five. Combined with ARP Main studs and cross bolts, these caps will virtually eliminate cap walk, keeping the crankshaft as true as possible in the main journals.
The power an engine makes...
The power an engine makes is directly related to the flow of the cylinder heads. To ensure our big Hemi gets plenty of fuel and air, we chose Indy's CNC ported 426-1 cylinder heads to top this engine.
These heads are made of lightweight...
These heads are made of lightweight aluminum, are capable of nearly 1000 horsepower out of the box, and have the rocker stands already conveniently cast into the head.
We ordered our heads bare,...
We ordered our heads bare, and then installed Manley severe duty stainless steel valves along with Comp Cams' valve springs, titanium retainers, and locks. Since the stem-to-guide clearance is kept to a minimum, keeping the valve true to the seat, no valve guide seals are necessary on this "race only" engine.
The crankshaft takes a lot...
The crankshaft takes a lot of abuse in a race engine, so we're using an American-made Crower forged-crankshaft with a 4.5-inch stroke. While less expensive forged crankshafts may be satisfactory for a moderately powered engine, we've found American-made crankshafts like this Crower are generally stronger, lighter, and machined more accurately.