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techtalk:ref:oil24 [2024/04/11 03:25] – created hippysmacktechtalk:ref:oil24 [2024/04/20 05:32] (current) – [Reflections on K Model Oil Temperature] hippysmack
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 ====== Reflections on K Model Oil Temperature ====== ====== Reflections on K Model Oil Temperature ======
-Despite the generous supply of oil passing through the KHK engine, under real-world operation, very little engine heat is bled off through the oil, as evidenced by the fact that the oil tank temperature remains in a very low range of 130-150°F. In any Harley flathead engine, it is challenging to get a continuous flow of oil on the piston crown, where all the heat is. Although KHK piston squirters exist to help address this issue, their 0.040” dia oil stream is directed straight across the base of the cylinder bore, so no oil is directed upward to the piston crown. Simply stated, the heat is up top in the piston and head, and the oil is down low in the bottom end. Piston squirters, found on the majority of modern engines, provide a continuous strong stream of oil that impinges on the piston crown and carries off a tremendous amount of piston heat. Although privateers have incorporated piston squirters for WL, KH, and UL engines and report good results, the majority of stock flatheads have very cool oil and very hot engines. \\+Updated 4-20-2024 \\ 
 + 
 +Despite the generous supply of oil passing through the KHK engine, under real-world operation, only minimal engine heat is bled off through the oil, as evidenced by the fact that the oil tank temperature remains in a very low range of 130-150°F. In any Harley flathead engine, it is challenging to get a continuous flow of oil on the piston crown, where all the heat is. Although KHK piston squirters exist to help address this issue, their 0.040” dia oil stream is directed straight across the base of the cylinder bore, so no oil is directed upward to the piston crown. Simply stated, the heat is up top in the piston and head, and the oil is down low in the bottom end. Piston squirters, found on the majority of modern engines, provide a continuous strong stream of oil that impinges on the piston crown and carries off a tremendous amount of piston heat. Privateers have similarly incorporated piston squirters on WL, KH, and UL engines and report satisfactory results. \\  
  
 Speaking from my own experience, the KHK oil tank temperature remains at almost exactly the same temperature as the nose of the heavy aluminum primary cover. If a KHK is started at 70F, and ridden for 5 mi, the primary cover and oil tank are each barely getting lukewarm at that stage. After 30 mi they are both about 135F, and nothing but dramatically higher air temp or dramatically harsher use pushes the temp of either component much higher. In all the KHK driving I’ve done, I’ve never observed an oil temperature over 165° F, and that was on a 95F day after 30+ miles of travel. To move as much oil as possible through my engine, I have tightened the bypass slug spring to be almost solid, thus the large majority of oil exiting the pump should be directed through the engine, not bypassing. \\ Speaking from my own experience, the KHK oil tank temperature remains at almost exactly the same temperature as the nose of the heavy aluminum primary cover. If a KHK is started at 70F, and ridden for 5 mi, the primary cover and oil tank are each barely getting lukewarm at that stage. After 30 mi they are both about 135F, and nothing but dramatically higher air temp or dramatically harsher use pushes the temp of either component much higher. In all the KHK driving I’ve done, I’ve never observed an oil temperature over 165° F, and that was on a 95F day after 30+ miles of travel. To move as much oil as possible through my engine, I have tightened the bypass slug spring to be almost solid, thus the large majority of oil exiting the pump should be directed through the engine, not bypassing. \\
  
-The scavenging efficiency of a K/XL engine can be assessed by draining the crankcase to see how much oil remains in the case. An engine in good mechanical condition will retain ~ 4 oz of oil in the crankcase and it is challenging to reduce this much further. With the by-pass circuit essentially removed from my pump, via the high bypass circuit spring force (engine sees full oil pump capacity), draining the crankcase after 2 mi, 10 mi or 30 mi of use, when the engine is hot, cold, or in-between, I have never observed more than 3 - 4 oz of oil retained in the case. Thus there is certainly no scavenging issue with this particular pumping system in this particular engine. \\+The scavenging efficiency of a K/XL engine can be assessed by draining the crankcase to see how much oil remains in the case. An engine in good mechanical condition will retain ~ 4 oz of oil in the crankcase and it is challenging to reduce this much further. With the by-pass circuit essentially removed from my pump, via the high bypass circuit spring force (engine sees full oil pump capacity), draining the crankcase after 2 mi, 10 mi or 30 mi of use, when the engine is hot, cold, or in-between, I have never observed more than 3 - 4 oz of oil retained in the case. Thus, there is certainly no scavenging issue with this particular pumping system in this particular engine. \\
  
 ====== Appendix  ====== ====== Appendix  ======

Trace: • EVO: Oiling & Lubrication