Aftermarket Engine Blocks - CHP How It Works

The Top Block Manufacturers In The Industry Lend Their Expertise On Selecting The Best Casting For Your Project Car.

Stephen Kim Nov 18, 2010 0 Comment(s)
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Rocko Parker: "Production GM LS-series engines have an incredible track record for allowing customers to enjoy high performance as well as high efficiency from their production vehicle. Our engineering team took a look at the LS7 block specifically and adopted many of those features into the LSX Bowtie block, which is designed specifically for high-horsepower street and racing applications. The LSX block has several features that our customers demand for in their project car builds. It has six bolts per cylinder to assist in sealing the heads to the block for boosted applications, as well as priority oiling to the main bearings to assist in lubrication for high-rpm applications. It has additional bay-to-bay breathing, similar to the LS7, that production iron blocks do not require. Additionally, we have added two drilled and tapped holes in the front of the block for use with a front engine plate, and the LSX block has extra bulkhead material to endure greater crankshaft loads. The LSX block also features siamesed cylinder bores that allow for a larger piston than a production aluminum block. The LS7 aluminum blocks are also siamesed, but it has iron bore liners that limit the bore size to 4.125 inches."

Prep Work
Jack McInnis: "Every company takes its own approach to the amount of prep work their blocks receive before shipping, but Dart blocks are fully machined and only require a finish hone to suit your pistons and ring package. The only reason we don't finish the cylinders and lifter bores is because every piston and lifter manufacturer has their own tolerances, so there isn't a universal specification to finish to. Even so, we do offer custom machine work for specific purposes per customer request. A light deburring is a good safety precaution, and it is always important to thoroughly clean and inspect any block before assembling an engine. We also provide an option for completely finished and washed blocks based on customer supplied specifications. These are bagged, sealed, ready to assemble, and save you from having to drag your block to a machine shop and back. Some aftermarket blocks will require fairly extensive machine work before use, so that's an important factor to consider when comparing different blocks."

Rocko Parker: "The LSX block comes fully machined except in a couple areas, where engine builders perform their own prep work to suit their specific engine combo. The head deck surface is left at 0.020-inch taller than a production block, which allows the engine builder to fit the piston-to-deck surface to his liking. The crank main bores are also left with an additional 0.002-inch of material so that the engine builder can fit main bearing crush and clearance to his preferred values. All other machining is complete, and this adds a tremendous amount of value for consumers. When you start doing the math of a custom Gen III/IV engine build, our LSX Bowtie is a real value because of the extra machining we provide."

Block Reinforcements
Jason Neugent: "The materials and alloys used during the casting process plays a big role in block strength, but blocks must also be reinforced in high-stress areas to optimize strength. This is another huge perk of an aftermarket block, as stock castings seldom have sufficient ribbing. Brodix blocks have strengthening ribs in the lifter valley area of our blocks, which substantially reduces deflection. We also offer half-way filled water jackets to increase the lower end strength of a block. Ultimately, block integrity all goes back to using good materials, quality foundry work, and proper heat-treating. If any of these elements are absent, the casting quality will be compromised. To ensure quality and strength, Brodix continuously dissects its castings to properly place the correct amount of material in the essential places."


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