K1 is flush with LS stroker crankshafts to take your block from boring to big-inch.
Ready to feel old? The LS engine turned 21 this year. If it were human, it would have a high-school diploma and could legally down a six-pack of beer. After two decades of LS swaps, builds, records, and race wins, it's as popular as ever, and there more of cores than ever to go around.
If you've picked up an LS core for your project, there's a good chance it has considerable miles on it. A bore, hone, and hot tank almost always work into the build plan, but what about the crank? The stock LS crankshaft is a stout and admirable piece, but one of the many strong points of the LS architecture is its taller deck height (over the gen I small block) and the ability to stroke it to torquier cubic inches.
That's where K1's line of LS stroker crankshafts come in. Currently available in 4.00in, 4.125in, and 4.250in, strokes, these longer arms can add invaluable displacement to your build. Better yet, they are also available as rotating kits prepackaged with the correct rods and pistons for an easy inch increase.
A Sum Greater Than The Parts
K1 built their reputation around crankshafts and rods that deliver quality at an affordable price, offering value that your average imported parts can’t match. However, they've teamed up with Wiseco pistons to provide complete rotating assembly kits that pair professionally-matched components into a single part number to make ordering simple.
“We currently offer Chevy LS applications as an off the shelf rotating assemblies,” K1’s Nick DiBlasi explains. “However, many of our customers make their own combinations with our pistons, rods, and cranks daily. We found it easy for our customers to pick and choose any combination they wanted and we could suit their needs.”
It’s no surprise that the LS engine family would be the first target on K1’s radar for complete kits; factory blocks are so ubiquitous and cheap that they’ve become the hands-down favorite for racers and hot rodders looking for a solid foundation for a high-horsepower build. Though the stock LS components can definitely take a beating, upgrading the internals is a sure-fire way to create a durable, powerful race or high performance street engine.
Crank it Up
K1’s LS rotating assemblies start with a high-quality crankshaft, with a number of options. Both 58 and 24 tooth reluctors are available, and customers have a wide selection of crank throws from stock to stroker. Per DiBlasi, “The K1 LS cranks are all forged 4340 steel and are designed for the latest demands of our customers. We offer strokes from factory 3.622 all the way up to 4.250, in 3.622, 3.900, 4.000, 4.100, 4.125, and 4.250 throws.”
A nitrided finish improves crank strength and bearing life, and the large-radius fillets remove potential areas of stress concentration and potential failure. K1 employs a straight hole oiling system for superior bearing lubrication, and tolerances are held to plus or minus one ten thousandth of an inch.
The second ingredient in the successful recipe is a robust connecting rod, and K1 has that covered as well. “We offer our K1 H-beam 4340 forged rods with our kits,” DiBlasi explains. “They are designed specifically to be matched with our crankshafts and clear all the stroker applications. They feature ARP2000 bolts and have seen over 1,500 horsepower on many of our customers’ race cars.”
Many racers will debate the relative benefits of an H-beam versus an I-beam design in terms of ultimate strength, but for applications where shaving grams isn’t absolutely critical, the H-beam delivers additional rigidity and better load distribution than a comparable I-beam connecting rod, and makes perfect sense for K1’s rotating assembly kits. Dual reinforced ribs add strength on the big end, while radiused sides maximize clearance. A shot peened finish is the finishing touch, placing the outer surface in compression and removing any potential locations for stress riser formation.
Slugging it Out
When it comes to pistons, Wiseco offers a wide selection, no matter what bore or compression ratio you’re shooting for. Per DiBlasi, “Our main rotating assemblies come packaged with Wiseco pistons. We offer various popular compression ratios based off the combinations we know work best.” Depending on combustion chamber volume, the shelf stock LS rotating assemblies range from 9.3:1 to 13.0:1, suitable for boosted or naturally aspirated builds.
Wiseco’s Professional Series forged pistons also utilize their proprietary ArmorGlide skirt coating that reduces friction, increases horsepower, and improves wear resistance. “If you are looking for a compression ratio that we do not offer [in a stocking part number], we can gladly build a rotating assembly with the same components and another piston combination that we offer,” DiBlasi adds.
When you order up a rotating assembly from K1, you’re getting all the other matched components you need to round out the engine internals as well. “They come with pistons, pins, locks, and rings,” DiBlasi explains. The goal is to provide everything you need under a single part number, so that you can order with confidence, knowing that there won’t be any bits and pieces that you need to figure out before you start putting everything together. “All of our kits come with rod and main bearings,” he adds.
“Our kits are designed to go together and have been tested on our in-house dyno,” DiBlasi says. “We have an in-house engine dyno just for LS-based engine testing. Everything was designed to work together. We take the work out of ordering parts from different places, and do the testing for you. Creating rotating assembly kits for the LS family was simply a no-brainer."