|
|
Ishihara-Johnson crank scrapers and other windage control products are a very simple but effective way to improve the performance of your engine! What are some of the benefits? ˇ Less rotating mass for the engine to accelerate because of the removed oil ˇ Less loss of power because of excessive drag caused by the windage cloud ˇ Helps reduce engine damaging oil-foaming ˇ Helps avoid oil starvation by keeping the oil in the pan during hard braking and turning as well as during off-road driving ˇ Helps to cool critical engine parts by quickly returning heated oil to the sump ˇ Helps to prevent the cylinder walls from being overloaded with oil ˇ Can help with fuel efficiency
During normal engine operation a significant amount of oil adheres to or becomes entrained in a cloud surrounding the spinning bottom end.
This oil eats up horsepower your engine is making by increasing the rotating mass and also creating parasitic drag. A crank scraper mechanically strips off excess oil by coming close to, but not touching*, the moving crankshaft and rods. It also interferes with the pressure differential that draws oil into the so-called windage cloud. Here is a short video clip made by one of our customers showing a rotating assembly and crank scraper from a Mitsubishi 4G54.
Our crank scrapers are constructed from steel unless noted and include installation instructions. The scrapers are installed in a variety of positions but generally between the oil pan and engine block or along the main bearing caps. Some fitting to your individual engine may be required and the procedure for carefully checking this is explained in the installation instructions. Here is a pictorial of the crank scraper installation on the earlier scraper for the Suzuki G10 engine. Here is a pictorial of an installation on an AMC V8 -- very typical of two piece scrapers.
Do they really work? Yes! Crank scrapers in various forms have been in use in stock passenger car engines for at least 45 years! More importantly, they are currently in use in a variety of OEM engines of both large and small displacement -- from relatively low RPM V8 engines to high RPM straight fours. Most auto enthusiasts are surprised to learn just how common they really are. In short, it is an extremely well-proven technology that is often simply not recognized. The modern trend is to have many more oil control devices in engines. Crank scraper technology is OEM equipment on various modern engines from Nissan, BMW, Chrysler, Ford, Mazda, Honda, Toyota, VW, Porsche, GM, Pontiac, Chevrolet, Mitsubishi, Mercedes and many other manufacturers. For example, here are a couple quotations from a recent patent held by General Motors:
Some pictures of OEM crank scraper technology in passenger car engines...
Is a windage tray the same as a crank scraper? No, a windage tray serves a different but related basic function. It is present to act as a physical barrier between the rotating assembly and the sump reservoir. A crank scraper actively removes excess oil and returns it to the sump. Some windage trays do have scraper technology built into them but even then a scraper will approach the moving parts much more closely.
Above: Honda B-series engine showing an installed TeflonŽ scraper on the left and the factory windage tray covering the entire assembly on the right. The windage tray shields the rotating assembly from splashing sump oil while the scraper actively removes excess oil. Before 6000 RPM the standard steel version of this scraper returned a 1.5 % to 2 % hp gain and from 6000-8900 RPM the hp gains averaged 2.5 %. Remember that this was on a statically mounted engine already having a full windage tray as with the Suzuki G10 mentioned below. A windage cloud will still form on a statically mounted engine with a full windage tray. For example, roller dyno testing of a scraper in the Suzuki 993 cc three-cylinder G10 engine with a full windage tray still showed an average 3 % hp increase (over four pulls data ranged from 2.4 % to 3.5 %). Power began growing at about 2750 rpm and peaked at 5300 rpm (the maximum for that economy cam). Here are the dyno charts. In a moving car the oil would be sloshing around and making at least partial contact with the rotating assembly creating larger windage losses -- consequently the gains would be greater when using a scraper. Will my engine still get enough internal splash lubrication? Yes. The rod and main bearing journals are constantly spraying large amounts of oil in all directions when the engine is operating. Much of this oil lands directly on the cylinder walls and other internal components which depend on splash lubrication. The scraper removes oil directly only from portions of the surface of the crankshaft and the rod big ends, neither of which depend upon lubrication of any sort. These components, as well as the pistons, do depend upon a flow of oil to cool them. By constantly removing oil that has contacted these hot surfaces and allowing fresh oil to re-wet and cool them the thermal efficiency of the engine is enhanced. Hopefully, too, the user is reassured by over four decades of the successful and dependable use of scrapers in OEM stock engines as well as competition engines of all sorts. Many enthusiasts remember splash lubricated engines where the big ends of the rods dipped directly into the sump reservoir for lubrication. This is essentially pre-WWII technology and does not apply to modern engines with positive pressure bearing lubrication from an oil pump.
General answers: What is windage and what are the differences between an oil baffle versus a windage tray versus a crank scraper? Windage:
What about dry sumps: do they eliminate windage? There are many levels of dry sump technology as well and windage is still an important issue in their design. Dry sumps are primarily intended to deliver an uninterrupted supply of quality oil to the bearings under all reasonable types of vehicle movement (aircraft systems are more complex). Oil aeration is reduced but not eliminated. The faster the engine spins the higher the quality of the oil supply needed and so in F1, for example, many more stages and/or scavenge points could be in use along with active versus passive oil deaerators. F1 engineers have remarked that up to 8% of the output of an engine is available (and, at great expense, presumably achieved). Here is a company that makes dedicated vacuum pumps to lower the crankcase pressure in a wet sump:
Contact Information
|
|
Copyright 2002-2008 All rights are reserved on our product designs -- a great deal of hard work goes into each one. TeflonŽ is a registered trade mark of E.I. du Pont de Nemours and Company. Only DuPont makes TeflonŽ resin sourced by Ishihara-Johnson Crank Scrapers from authorized DuPont licensees. We
Ship
|
Left: Gen III Dodge
Viper V10.
World Wide!
