Decoding "350 Bored 60 Over": Understanding Engine Modifications
The phrase "350 bored 60 over" refers to a specific engine modification, primarily used in the context of internal combustion engines, often for motorcycles or cars. Let's break down what each part means:
350: This refers to the engine's original displacement in cubic centimeters (cc). This is the total volume of all cylinders when the pistons are at their bottom-most position. A 350cc engine is a fairly common size, particularly in some motorcycle models.
Bored: This signifies that the engine cylinders have been increased in diameter. The process of boring involves machining the cylinder walls to remove material, enlarging the cylinder's internal diameter. This increases the volume within each cylinder.
60 Over: This specifies the amount of increase in cylinder diameter. "60 over" typically means the cylinder diameter has been increased by 60 thousandths of an inch (0.060"). This is a common increment used in engine modifications.
The Combined Effect: By boring the cylinders, the engine's displacement increases. A 350cc engine bored 60 over will now have a larger displacement than 350cc. The exact increase depends on the original cylinder dimensions and the specific bore size achieved. This larger displacement generally leads to an increase in power and torque, but it also requires careful consideration of other engine components to maintain reliability.
Frequently Asked Questions (FAQs)
What are the implications of boring an engine?
Boring an engine increases its displacement, potentially boosting power and torque. However, it weakens the cylinder walls, and necessitates careful attention to piston-to-wall clearance. If not done correctly, it can lead to decreased engine lifespan or even failure. Often, the piston rings also need replacement to match the larger bore size.
Why would someone bore an engine 60 over instead of more or less?
The amount of overbore is a balance between increased power and maintaining engine longevity and reliability. Going too far overbore can lead to thin cylinder walls, which are prone to cracking. 60 over is often considered a safe limit for many engines, but this depends heavily on the specific engine design and material. The choice also depends on the availability of pistons for that specific overbore size.
What are the potential downsides of a 350 bored 60 over?
As mentioned, the thinner cylinder walls are a significant downside. Heat dissipation may become less efficient. The engine may also require adjustments to other components, like pistons, rings, and possibly even the crankshaft, to function correctly. Improper modifications can lead to engine failure.
How much horsepower will a 350 bored 60 over gain?
The horsepower gain is highly variable and depends on numerous factors beyond the bore size, including the specific engine design, the quality of parts used, the modifications to other engine components, and the overall tuning. It's impossible to give a precise figure without detailed specifications.
Can I bore my own engine 60 over?
This is strongly discouraged unless you have extensive experience and specialized tools. Boring an engine is a precise process requiring specialized equipment and expertise. Improper execution can severely damage the engine, leading to costly repairs or even total engine failure. This should only be done by trained professionals.
