re windage trays
Edit: For some reason my new posts to the thread do not seem to be showing up. Yes, Crane states this -- I checked before posting. It is under 1. A) at cranecams.com/?show=faq&id=1
A constructive solution might be to add the often seen OEM oil ejector slots on rod faces that are aimed at the thrust surfaces of the piston bores. The oil ejected from these slots would include the cam in their upper quadrant sweep. This is an extremely simple mod to do.
Windage control devices help keep the oil running cooler and in a way that dedicated oil coolers do not. This is certainly critical in cooling the camshaft efficiently.
Once the energy from the rotating assembly is transferred to the oil by hitting it or moving it the oil rises in temp. That is energy that is lost forever to make your engine perform better. It is also allowing the exact opposite of the dual (lubrication/cooling) function of oil.
Windage trays are meant to prevent this sort of parasitic loss from oil splashing onto the crank and to shield the sump oil from windage effects. Many trays have scraper louvers built into them that strip away oil from the windage cloud. The louvers also help disrupt the pressure differential that forms around the spinning crank (the differential allows the windage cloud to form). Disrupting the pressure differential allows more oil -- not less -- to be directly and immediately ejected in the upper two quadrants where the SBC camshaft sits -- thereby cooling and lubricating it. This oil would otherwise be drawn into the cloud. The windage tray operates in the lower two quadrants of crank rotation. The windage cloud is self-renewing from oil ejected from the mains, rods and draining down from the lifter valley and heads.
It is a common misperception that a windage cloud will not form because of a windage tray and that a windage cloud comes primarily from splashing oil in the sump. The latter might be true during abrupt manuevers but during steady driving a windage cloud will form with or without a tray in place. It will increase in oil entrainment as a function of rpm because of the higher pressure differential formed. To increase oil entrainment volume it will simply capture a larger amount of ejected and draining oil before reaching equilibrium.
Once the oil has absorbed heat from the camshaft and lifter it needs to be removed as quickly and efficiently as possible so that new, fresh -- and cooler -- oil can take its place. Just like the water cooling system in a car -- circulation is needed.
If still additional oil flow is needed to cool the lobes or lifters then dedicated passages or devices need to be devised to do so. This is just like using oil to cool the underside of pistons in turbo or highly tuned NA engines. In those applications windage trays are typically seen more often rather than subtracted as the tech tip logic would dictate.
Windage control helps keep sump oil temps down as mentioned in the beginning but running a dedicated oil cooler will help keep oil that is moving through the galleys -- then to the cam and lifters -- cooler. An oil cooler, though, cannot give back the energy lost when it rejects it to the atmosphere -- as windage control devices can by preventing the energy loss/transference in the first place. Both cooling approaches are valuable.
Also the "do not use a windage tray" advice contraindicates any sort of dry sump system as it removes much more oil from the crankcase and more quickly as well. Think about it.
I think the cams are clearly pushing the limits of the materials and design of the components and many plausible sounding things are being thrown out in an effort to lengthen that life. This advice, though, appears to be a step backwards.
Last edited by Kevin_Johnson; 09-16-2007 at 11:35 AM.