OIL WARS !

Slowly I turn step by step .................

On the Savage - your gauge shows that it is obvious we don't need Oil Pressure......we need some flow to the bearings and cam.  Those nearly zero pressure readings at your gauge are scary to see - however it is proven that as long as you keep the idle speed up enough to provide a bit of flow......the cam and rockers will survive just fine. (Provided the oil has a good amount of ZDDP).

I don't know that any benefit would be achieved by using an oil cooler, as the engine doesn't get overly hot when it is moving - and when it is not moving (traffic) there will be little air flow through the oil cooler.  The hottest my engine has ever been was a head temperature of 300 degrees - once was a slow 1st gear climb up a gravel mountain road, and the other was a grueling ride on Main Street in Gatlinburg (both of those events had 95+ degree air temperature).

And in support of the "Oil Wars" theme - I don't have any problem with using 10W-40 or 20W-50 or 15W-40 or 5W-40....if the oil is suitable for wet clutches and has around 1,200 ppm of ZDDP.  The differences in viscosity in summer riding conditions are minimal...none of them are going to result in an oil related failure or overheating.

I did some looking and poking....and here is what I believe happens.

The oil comes out of the filter and then goes to the left and of the crankcase - and - a second passage goes up to the top gasket surface of the right cover.  The cover has a passage that carries the oil to the passage that leads up to the head/head cover.......and a second passage that goes to the transmission.

The only passage that has a brass restriction is the passage to the transmission - the flow to the crankshaft and head are only limited by the size of the passages themselves.

The oil that goes into the right side of the crankshaft oils the lower end of the rod.....then the oil gets splashed to the cylinder/piston/upper rod bearing.

The oil that drains from the head to the left front cylinder stud drop out in hole that is directly over the left crankshaft web - and it appears the web will provide an oil spray using the drained oil.

The oil that stays inside the cam either comes out the holes in the lobes, or feeds out the right side and oils the cam chain.

It also appears the bearing on the left side of the crankshaft gets oil from the random oil spray going into the hole in the left side of the crankshaft.

So I believe the crank and cylinder head are not restricted...just the gearbox (which probably doesn't need much oil at idle or very low speeds).

batman wrote on 06/09/19 at 15:20:12:


I don't want to prolong, extend or exaggerate the oil discussion -  but I don't ride when it is -10, -20....or -30, and I doubt that DBM does either.

The folks who commute year round on their bikes are likely affected by the winter rating of an oil - but the cold weather flow of oil has no affect on my motorcycle....if I can't walk out to the garage in a T-shirt, it is likely not a day I will start up the motorcycle and go riding.  

I suspect that at summer temperatures of 60-90 degrees, the viscosity difference of the oils at start up is negligible.  I suspect most of us will never experience enough engine wear to justify worrying about these "top shelf" oils.  It took Youzguyz 160,000 miles to wear out his valve guides to the point he needed to do something about it.  I believe the first 60,000 miles was using Valvoline and the last 100,000 miles was Rotella.

So I took it out this morning for an early morning spin.  Ambient temp was pretty cool.  I would estimate about 65 degrees.  That makes a significant difference in oil pressure.  I was surprised.  It ran about 10 psi on the freeway, whereas previously it ran about 3 psi with ambient around 85 degrees.  I figured it would eventually heat up and drop to 3 or 4 degrees but it didn't.  Held steady at 10.  That 20 degrees drop in ambient makes a bigger difference than I anticipated.

About 15 years ago I fabricated an oil cooler.  Never used it.  I dug it out of my junk bin.  Seems to me I could hook it up to the two ports Versy marked in his oil system diagram.  If I did that, I could give it a whirl and see what effect it has on the pressure.  Easy enough to remove if the pressure goes in the tank.  

From what I can gather from the diagram and the picture, it looks to me like there is one horizontal passage off the pump discharge in the engine case.  That passage runs fore/aft.  There is another vertical passage to the oil filter in the clutch cover running up/down.  And last there is a short horizontal passage running right/left in the cover and case that connects the pump discharge passage to the filter passage.  Seems to me if I want oil running out to the cooler and returning to the filter I would have to plug the passage running right/left that connects the pump discharge passage to the filter passage.  The cooler would essentially connect the pump discharge to the filter.  Do I have that right?

It would be an interesting test and I think we could learn a few things from it.  I noticed there is an outfit that sells temp gages that replace the filler cap.  Anyone know anything about those?  Do they work OK or do they fall apart and wreck your engine?  With the pressure gage and the temp gage I think I could get some decent info on the cooler and how it affects the system.  If it works lousy restoring to stock would be easy (just don't forget to remove that plug).

Typically, you want an oil cooler downstream of the filter, not upstream.  Only way I could pull that off on the savage would be to tie the cooler into the drain system somehow.  I don't see that happening any time soon.  Maybe when I yank the head off again to try the larger valves.

Here's a shot of my old poor man's oil cooler.  I think it might work OK.

Wow, a 7 psi difference in pressure in the top end , The hottest part of the motor  when FULLY WARMED at highway speeds , with only a 20 degree difference in outside temperature. I wonder what the cooler temperature of the bottom end did to the pressure/flow. My statement that no oil fully protects the bike at cold startup where 80% of wear occurs,  isn't B.S. no matter what the outside temperature ,it's merely the truth. 20w oil will be molasses,5w or 10w will be maple syrup. You'd be better of installing a block heater,  than an unneeded oil cooler.