Oil pump gear material
Oil pump gear material
One of the main things that interested me would be getting them made with high strength metal gears. The stock gears are sintered metal and are known to fail on high RPM builds. There is enough middle ground between what the stock pump can handle and the need or budget to go full dry sump that there is a market for high strength gears.
Here is an example of some that I currently sell. http://www.todaracingusa.com/catalog/pc/viewPrd.as...
I really thought these were made of chromoly but I might have been mistaken as I can't find anything about that now so perhaps it's another alloy.
When I thought they were made of chromoly I asked the company about having them make chromoly gears and they said it would wear the aluminum housing much faster. This seemed odd to me but it did get me wondering about what the best material would be and if there would be any other concerns like that. I don't really see how something like chromoly would cause it to wear faster but this level of metal engineering is well beyond me.
Does anyone have any thoughts on what desireable alloys might be and if there would be any concerns of using these other alloys?
If anyone is curious about the failures or has any input on that I would be very interested to hear that as well.
At extended high RPMs they have been known to break. I don't know if this is due to force, wear, or harmonics or possibly some combination.
As the gears get older they definitely get some pitting in them and in the high RPM motors this pitting is more severe. Some of this may be due to the sintered metal not being held together very well but I suspect that it at least partially has to do with cavitation though I have heard that the high strength aftermarket gears don't really get this or at least not as significantly. Unfortunately I haven't gotten to inspect used ones yet. At some point I would like to do a little research to test pressure at the inlet of the pump as well as play with some porting to see if it's possible to reduce pressure drop on the inlet side. If there is significant pressure drop this would definitely contribute to more cavitation.
I have also wondered about the interface between the gear and the crank. This is not a terribly tight fit and I have wondered if it could actually clatter a little bit. I have wondered if something like a very thin delrin or similar sleeve could prevent this from happening but then I have wondered if it's better that the gear has a little room to float and if attaching it to the crank more rigidly could cause problems.