An engine with a strong bottom end of high-quality parts is foundationally key for making horsepower, but you also need to ensure the bottom end is going to be securely held in place. The main caps you select and how they’re fastened to the block will determine how long your engine will live when you start cranking up the power.
If you plan on using a power-adder with your engine, it would be a good idea to look at strengthening your main caps and upgrading the fasteners. Forced induction and nitrous add a substantial amount of stress to the crankshaft and main caps, and the more stress you add, the greater the chance the main caps will start to move on their saddles. That movement will change bearing clearances and alignment, which will lead to premature wear along and engine failure. If you have an OEM block, using a high-grade fastener from ARP with your main caps will add strength.
Jack McInnis from World Products has some words of wisdom about the kind of main caps you want to use, and what form of retention is the strongest.
“For high horsepower applications, especially if you’re using a power-adder, you want the whole deal. The caps must be beefy, strong in their design, and made of good materials. You need to select high-grade fasteners, and the caps must be in an ideal location. The common methods for making sure the mains will stay in place are stepped registers at the ends of the caps, and dowels pinning the caps to the block. The block itself must also be made of high strength alloy, and the main webs must be robust and thick.”
A stock block is only going to take so much punishment before it fails. Moving to an aftermarket block will add plenty of general strength, but it will also beef up the area around the main caps. You’ll also have options for stronger methods to attach the main caps to the block itself.
“World Products blocks use either cast nodular or billet steel caps with the splayed four-bolt design for maximum strength. The nodular caps are fitted with ARP bolts and the billet caps with ARP studs. We use ARP fasteners exclusively for their high quality and strength. All of World’s main caps use a deep stepped register and ring dowels to locate the caps securely and prevent walking. Our blocks are designed with extra material in the webs and pan rails to strengthen the bottom end, and are cast from high strength schedule 40 iron alloy,” McInnis states.
If you’ve got more questions about main caps and blocks make sure you check out the World Products website right here. You’ll find plenty of information about how you can maximize your engine’s strength top to bottom.