Differences

This shows you the differences between two versions of the page.

--- techtalk:ref:oil05a [2019/06/04 17:55]
hippysmack [Feedback from installing this mod]
+++ techtalk:ref:oil05a [2021/04/07 20:06]
hippysmack
@@ Line 1: / Line 1: @@
 [[:techtalk:menu|{{  :techtalk:gototechnicalmenu.jpg|}}]]
 ====== REF: Oiling & Lubrication - Sub-05A ======
-====== Homemade Oil System Bypass  ======
+====== High Pressure Oil Bypass ======
+**This is a Race Only Mod - Install this mod at your own risk!**. \\
+This mod can also be installed on motors with EXTREME wetsumping issues. \\
+Generally speaking, if a street motor wet sumps bad enough to NEED this mod, there are many more items to check off that might need attention instead. \\
+\\
+**Theory behind installing a high pressure bypass**: \\
+The supply side of the oil pump is over supplying oil to the crank case during sustained high RPM running. \\
+The motor is designed to run with a dry sump. ((rob@robertsystems.com of the XLFORUM http://xlforum.net/forums/showthread.php?t=59421&page=40)) \\
+(with only enough oil in the crank case to lubricate the bearings, not a 'splash' wet sump lubrication design) \\
+When the sump gets wet, the crank sees a lot of resistance due to the oil pooling there. \\
+This generates a lot more heat meeting the power demands while overcoming the added drag of the oil on the flywheels. \\
+Just adding a cooler may not solve this problem. \\
+You need to get the oil out of the crankcase so it does not interfere with motion of the crank and cause the heating problem in the first place. \\
+To regulate the oil pressure you have to bleed some of it off. ((aswracing of the XLFORUM http://xlforum.net/forums/showpost.php?p=4341107&postcount=6)) \\
+-speeds have a spring loaded pressure regulator built into the oil filter pad that does exactly that. \\
+There's a passage from the filter pad into the cam box. \\
+If the pressure gets high enough, the regulator opens and bleeds off some of the pressurized oil, dropping it into the cam box. \\
+Then it eventually drains down to the crankcase and gets pumped back to the tank. \\
+They did away with the pressure regulator on 92 and up 5-speed XL's though. \\
+Evo Big Twins have a spring loaded bleed-off regulator, as do Twinkies, XR1200's, and 08-up Buells. \\
+Some have found it useful to build bypass circuits to bleed off excess oil pressure and send it back to the tank. \\
+Such that the scavaging side of the pump will be able to evacuate the oil from the crankcase before it starts to wet sump and generate the added heat. \\
+But this does reduce oil pressure across the board, as opposed to opening a bypass when the pressure exceeds a certain point. \\
+{{:techtalk:ref:oil:oil_pressure_bypass_mod_14_by_aswracing.jpg?direct&300|}} ((photo by aswracing of the XLFORUM http://xlforum.net/forums/showpost.php?p=4341107&postcount=6))
+====== Homemade Oil System Bypass (OSB)  ======
 Article by aswracing of the XLFORUM ((http://xlforum.net/forums/showthread.php?p=754838#post754838))
@@ Line 11: / Line 42: @@
   * I run the bejeezus out of my bike and this has caused no issues.
   * I did not invent this idea by any means. Probably the first guy who ever raced a Sportster came up with it. Wet sumping has been an issue on high rpm Sportsters for forever, and for some reason, with the oiling system changes on the '04, it got a whole ton worse, we're even seeing it on mildly modified street bikes.
+  * I learned it from Ron Dickey (of Axtell). ((aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073512&page=6)) \\ By the way, when Ron told me about it, he also described dyno testing it. \\ He has a Stuska water brake dyno with a strain gauge and DePac instrumentation and he can do steady state torque and power measurements. \\ He said he could watch the power rise as he lowered the oil pressure (I think he had a valve on the bypass so he could adjust the oil pressure). \\ He threw out a number, in terms of HP gain. It was a big number, relatively speaking.
+  * Of course, much depends on how badly the motor is wet sumping to begin with. \\ I've seen wet sumping motors that were literally 30hp down on the dyno. \\ They literally came up 30hp when the wet sumping issue was solved.
+  * Another thing I've noticed, a badly wet sumping motor often shows extreme motor braking. I once worked on a bike that would literally chirp the rear tire when you chopped the throttle. Felt like it wanted to throw you over the bars.
   * Your oil pump consists of two sections, a "pressure" section and a "scavenge" section. The pressure section is the bottom area of the pump. On the lower left is the feed line, coming from the oil tank and into the pressure section inlet. We won't be touching this line, just leave it hooked up. On the lower right is the pressure section outlet. This goes through a hose up to the oil filter. On a rubber mount, the pressure side hose is quite a bit shorter than this one (this is a '99 motor), but it's the same deal. From the oil filter, the oil under pressure goes into the engine.
   * Above the pressure section is the scavenge section. The scavenge section's job is to pump the oil back out of the engine and send it back to the tank. A Harley uses a "dry sump" oiling system, meaning that the oiling system is designed to keep the oil in an external tank, and the pump is always trying to keep the engine sump dry, or at least nearly dry. The problem with Sportsters is that sometimes the scavenge section doesn't keep up, and the engine starts filling with oil, which we call "wet sumping". This is what we're trying to fix.
@@ Line 152: / Line 186: @@
 ====== Feedback from installing this mod ======
 **Bike**: 2005 1200C: \\
 **Condition trying to fix**: High oil temps at high rpm. \\
@@ Line 162: / Line 197: @@
 Also I let the bike idle for some extended periods and never had any excessive noises. \\
 </blockquote>
+\\
+**Bike**: assumed rubbermount: \\
+**Condition trying to fix**: High oil temps at high rpm. \\
+<blockquote>Have had the fix in now for about a week. No problems. ((bubbas1 of the XLFORUM http://xlforum.net/forums/showthread.php?t=59421&page=41)) \\
+Wife and I took bike on interstate yesterday and were cruising at about 80 for a good distance. \\
+Temp got to 200. No problem. \\
+Then took back roads for about 30 miles. Wife then pulls over because there is to much racket coming from the top end. \\
+Sounded like there was no oil getting to the lifters. \\
+Called some friends and trailered bike home. Removed the "fix" and put bike back to normal. No more noise. \\
+</blockquote>
+====== Conclusions ======
+**Understand why you would need to install this mod**: \\
+This mod is __not__ meant as a cure for high oil temps at or above highway speeds. \\
+It was designed as a fix for wet sumping during high revs in the interest of gaining (or rather not losing) horsepower due to wet sumping. \\
+Some ride reports are above from XLFORUM members trying this mod to solve oil temp problems. \\
+Reported were cooler temps at higher RPMs but lifter noise (presumed from oil starvation) during low or idle conditions. \\
+So this mod reportedly does work to control wet sumping and temps at higher RPMs due to wet sumping. \\
+**Speed and RPM**: \\
+You can run highway speeds in 4th or 5th gear, sometimes 3rd. \\
+Naturally the lower gears raise the RPMs higher than 5th gear would at the same speed. \\
+Plus 883's, being geared differently, hit the same speeds as 1200s at higher RPMs. \\
+So, it's not the speed that contributes to wet sumping but rather the RPM range instead. \\
+**Blowby and crankcase pressure**: \\
+Piston ring flutter at a certain RPM range will contribute to ring blowby which raises crankcase pressure. \\
+Higher crankcase pressure contributes to higher engine temps also. \\
+and up bikes are prone to higher oil temps at high RPMs. \\
+Crankcase pressure was increased by the MoCo in 2004. \\
+This mod was deemed unsuitable for a fix for the sole condition of rubbermount high oil temps. \\
+Later, a cam chest breather mod was discovered by Deimus of the XLFORUM that was deemed a fix for better crankcase venting. \\
+That mod did reduce crankcase pressure allowing for lower engine temps.
+You can read about it here in the Sportsterpedia: [[techtalk:ref:engmech05d|Installing the Ultimate Crankcase Vent]]. \\
+**Coincidence**? \\
+This mod is not so different than what the MoCo has already done to 92 and up engines. \\
+When the factory got rid of the 86-91 oil pressure regulator, they introduced an oil bleed passage (tiny hole) in the oil feed galley of the right case. \\
+This relieves some of the pressure while giving some extra oil to the cam gears by way of splashing #2 cam from the feed galley. \\
+So, on 92 and up engines, one could also say this mod will add a second pressure relief to the feed oil system. \\
+The jet size for this mod may need to be adjusted for these engines. \\
+(to make sure there is still enough pressure to keep proper oil to the lifters during hot idle or low speeds) \\
+|  98 cam chest. ((photo by isiahstites of the XLFORUM and labeled by Hippysmack http://xlforum.net/forums/showthread.php?t=51598&page=5))  |
+|{{:techtalk:evo:oil:98_cam_chest_by_isiahstites.jpg?direct&300|}}|
 \\

Trace:

Differences

Navigation

Search

Toolbox