HDF Tech
08-03-2005, 01:48 AM
Cooling & Lubrication for harley engines
V-Twin engines are designed for external air-cooling and internal oil-cooling. One feature of this scheme is that the front cylinder tends to run cooler than the rear cylinder because it receives more cooling air flow when the bike is moving. Air cooled engines span a range of operating temperatures due to state of tune, riding style and ambient air temperatures. Clearly, a V-Twin powerplant will run cooler in a Chicago winter than in a Florida winter, and that's okay as long as it is running within the proper temperature zone. It is wise to patiently warm-up a cold engine to allow all working metal parts to expand to their proper fit with one another since racing a cold engine dramatically increases wear and causes premature rebuilds.
There are several aftermarket oil coolers available that lower the average engine operating temperature by 20 degrees or more which is desirable for summer operation, especially in southerly climates. When oil reaches a critical temperature, it breaks-down and loses it's lubricating qualities. Much debate continues about the use of synthetic oils that have a higher resistance to thermal decomposition than petroleum-based oils, but, there are numerous high-powered Harleys that enjoy excellent longevity using synthetics. Also, proper oil levels should not be exceeded or problems may occur with blown gaskets and excessive seepage from engine breathers.
V-twin engines are pressure-driven devices that are sometimes referred to as heat pumps. Of all the heat produced from combustion, approximately 1/3 goes out the exhaust, 1/3 is dissipated through cooling and the remaining 1/3 is used to overcome friction and produce mechanical power. These percentages make it very clear that there is plenty of room for improved thermal efficiency.
Source: http://www.peganet.net/personal_pages/ironman1/harley.html
V-Twin engines are designed for external air-cooling and internal oil-cooling. One feature of this scheme is that the front cylinder tends to run cooler than the rear cylinder because it receives more cooling air flow when the bike is moving. Air cooled engines span a range of operating temperatures due to state of tune, riding style and ambient air temperatures. Clearly, a V-Twin powerplant will run cooler in a Chicago winter than in a Florida winter, and that's okay as long as it is running within the proper temperature zone. It is wise to patiently warm-up a cold engine to allow all working metal parts to expand to their proper fit with one another since racing a cold engine dramatically increases wear and causes premature rebuilds.
There are several aftermarket oil coolers available that lower the average engine operating temperature by 20 degrees or more which is desirable for summer operation, especially in southerly climates. When oil reaches a critical temperature, it breaks-down and loses it's lubricating qualities. Much debate continues about the use of synthetic oils that have a higher resistance to thermal decomposition than petroleum-based oils, but, there are numerous high-powered Harleys that enjoy excellent longevity using synthetics. Also, proper oil levels should not be exceeded or problems may occur with blown gaskets and excessive seepage from engine breathers.
V-twin engines are pressure-driven devices that are sometimes referred to as heat pumps. Of all the heat produced from combustion, approximately 1/3 goes out the exhaust, 1/3 is dissipated through cooling and the remaining 1/3 is used to overcome friction and produce mechanical power. These percentages make it very clear that there is plenty of room for improved thermal efficiency.
Source: http://www.peganet.net/personal_pages/ironman1/harley.html