Oil Cooler Assembly for Royal Enfield Thunderbird 350 AVL
May 9th, 2011
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The performance of a IC engine is directly dependent on the difference between the ambient temperature and the exhaust temperature. If you had learned about IC engines, it is apparent that the power generated is proportional to the temperature difference between the inlet and the outlet feed for the engine. So, it is critical to operate the engine under low temperature such that maximum power is generated by the engine. To keep the engine cool, engine oil is used, which also serves as the lubricant for the moving parts. Engine oil is the blood for an engine and it’s circulation is crucial for maintaining the temperature and low frictional loses. There is no oil cooler assembly for TB, or for that matter any RE bikes in India.
Chinmay Dhangre from Pune generously offered to supply a modified oil cooler. I was excited to read a blog post by Chinmay at http://www.indiancarsbikes.in/automotive-technology/royal-enfield-avl-engine-oil-cooler-update-real-world-data-4175/. When I contacted Chinmay at macasp@gmail.com, he was readily helping me to get the necessary fitments and hardware.
The reason for keep the inlet at a higher position than the outlet is to ensure that some oil is pre-stored in the oil cooler compartment all the time. When the engine is started, it takes >10 seconds for the oil to reach the rocker, tappet assembly through the Y pipe. If I had put the oil cooler in the middle, it would take more time to fill the oil cooler and then reach the rocker assembly. Having this inverted connection helps the oil start its circulation faster.
The oil cooler assembly and the Y pipes are connect via a nylon coated reinforced rubber tube. While fitting so, care should be taken for keep the pipes away from the silencer tube. Also, it is to be ensured the the joints don’t leak after they are secured by clamps. In the above picture, one clamp is missing!
I had used one clamp to offset the nylon pipe from the silencer tube. I will have to use some other method for this offseting, as I am indeed wasting a good clamp!
While draining the oil during oil replacement, one has to take care of removing the oil in the oil-cooler compartment by opening the bottom vent. Otherwise, sludge can start to accumulate inside the oil cooler assembly, which could eventually block the oil flow later. So, it should be practice that the oil cooler assembly is cleaned every time the engine is serviced.
The completed bike is able to keep the engine oil temperature lower by allowing the natural air flow cooling off the oil through the oil-cooler fins. Do mind that while the bike is stationery, the oil cooler cannot provide any help as it needs air flow for cooling.
