Valvesprings provide the force that keeps the valvetrain together, which is a good thing in offshore performance boats. But how does one decide on the spring design he needs? Most people will ask the cam company they buy the cam from. They’ll get an answer, usually based on what has worked in the past. This Read more about Valvesprings: Use the Force – Part I[…]
Just a word on roller rocker arm tips: they are sold to guys under the premise that they reduce friction. They are really there to make up for suboptimal geometry and inferior guide materials. As the rocker pivot moves to either side of its optimal position, the amount of relative motion between the wiper-style valve tip contact feature (called the pallet) and Read more about Tips on Roller Rocker Arm Tips[…]
Many people view cams as a commodity. One cam from this company is just as good as another from another company, right? Wrong! There is a dirty little secret floating around that many people don’t know. There are a number of companies, notable companies, that have based their businesses on copying other people’s cam profiles. These Read more about Offshore Powerboat Cams[…]
The second limitation of the extruded aluminum arm is the material. With aluminum, the clock starts ticking on it from the first load cycle. Every aluminum part loaded structurally will fail at some point. Yes, that goes for you saltwater boaters with your aluminum trailers, too! Many of us are familiar with how shaft mounted aluminum Read more about Aluminum: Not all it’s “Cracked” Up to Be[…]
So you like performance boating – great! If you look around you and observe how many people experience valvetrain problems in their big block equipped performance boat, you might realize that this duty cycle is taxing on that system. In fact, an engine that spends 600 hours at an average speed of 5500rpm will rack up nearly Read more about Main Failure Modes in Powerboat Valvetrain[…]
The first lesson in valvetrain is that it’s all about frequency. The frequency of any system is proportional to the square root of the stiffness divided by the mass. In pushrod engines, frequency is a challenge because the valves and the parts that move them are big and heavy. Drag racers have the option of Read more about Stiffness is King![…]
