What You Need to Know to Build a Motor

[MS6_Newb]

This post is very useful and full of info. However, you asked if there are any more pros and cons on overboring an engine. There is one massive con when it comes to overboring. If you overbore you increase the chance of overheating your engine. Your cylinder walls act like a heatsink to spread the heat around evenly to all the coolant passages. If you overbore the is less material to spread the heat so hot spots occur and boils the coolant. Another thing is when you overbore the heat generated during the power cycle is greater which acts as a multiplier to the above. If your wondering why I say/know this, well, I talk from experience. I overbored a honda .020 over and ever since then the car ran hotter than normal. It over heated a few times until I upgraded the cooling system. I don't want to discourage anybody but let this be a fair warning to not go to big.

[TWOptSL0W]

Originally Posted by MS6_Newb This post is very useful and full of info. However, you asked if there are any more pros and cons on overboring an engine. There is one massive con when it comes to overboring. If you overbore you increase the chance of overheating your engine. Your cylinder walls act like a heatsink to spread the heat around evenly to all the coolant passages. If you overbore the is less material to spread the heat so hot spots occur and boils the coolant. Another thing is when you overbore the heat generated during the power cycle is greater which acts as a multiplier to the above. If your wondering why I say/know this, well, I talk from experience. I overbored a honda .020 over and ever since then the car ran hotter than normal. It over heated a few times until I upgraded the cooling system. I don't want to discourage anybody but let this be a fair warning to not go to big.

thanks, op updated