Hi Jack93 & others.
Man, I tell ya with dealing with building 600 motors for 17 years now, this same subject has kept me awake many a night! but I think I can help.
First off Jack93, yes that pressure sounds pretty low, and you may well have internal problem, but also keep in mind many gauges don't read accurately below 10-15 lbs.
Secondly, turn that idle up....the cam chain doesn't like whipping around at low rpms either.
Thirdly, as far as internally changing the oil system all around? One thing I have learned in my 40 years of tweaking with motorcycle engines is that in most cases you can trust the Japanese engineers to know what they are doing. They know their stuff and usually have done their homework. Not saying that some things can't be improved for power or for specific use in a racecar, but on the whole you can trust their work. That goes for sizing the oil pump as well. All a bigger, badder oil pump will do is just loop and dump more oil out the oil bypass, just churning and heating it up worse. How do I know that? Just look at a data acquisition file such as a Mychron file that is setup for oil pressure. The oil quickly rises to max pressure then flat lines- well before 10000 rpms (at least on our motors)so that is taking all that excess hot oil and putting it right back in the pan to get even hotter. I can tell you first that the stock oil pump with a modified bypass can put out over 110lbs of oil pressure. We actually have to fight this, trying to get the pressure down when using our good oil. (too high pressure can actually force the rods "off center"- not good.)
put restrictors inside our motors, primarily diverting oil away from the transmission which is also carefully modified to keep from spraying oil all around. And we are really fussy about the oil pickups, pans and other parts of the system we modify. But I would NEVER even think of restricting the oil to the top-end, that oil provides the cooling to the hard working valve springs and cam lobes. plus it is already restricted usually by a tiny hole in the head gasket.
Lastly- if you put some really good oil in there it can make a big pressure difference. I don't believe these thin motorcycle and automotive oils pushed on people today have any business in something that is punished as hard as these microsprint motors. With trying to get 150hp out of a 100hp motor- plus adding on the load of dragging a racecar, the bearings loads go "off the chart"- well beyond what some hot street bike would normally see.
Having said all that, the real worry is not actually the oil pressure at all: basically enough pressure is plenty, more is not better. The big issue is actually the lubrication properties of the oil film between that bearing and the crank journal. The molecular rolling and shearing of that little thin layer of oil (called the hydrodynamic wedge) is really what keeps metal off metal- and disaster at bay. (It's pretty amazing really). Some specialty oils can support much higher loads than most other oils, and any oil will handle less as it's temperature rises. Much less, and your oil gets a lot hotter than you think.
All the oil pressure does is bring the oil "to the party", and carry away the localized heat. Once I had a clear understanding of this I fiercely sought out oils with the best high temperature properties, and also promptly developed the FTZ 600 Oil Cooler system, as the even best oil at 50 degrees hotter than some other oil, is no longer "the best".
One other factor involved is how the rod bearings are sized and fitted during assembly- which again effects that "wedge". We take this way past simply matching up factory "color codes", which can leave you all over the place on clearance. We have got to where we go thru sometimes dozen of bearings of the same color code, before finding and sizing up the very best one. (I guess that's the reason we had $5800 worth of just R6 bearings on our recent parts inventory! ouch...)
Hope this clears some of the fog, see the links below for more reading....
Jon@FTZ Performance, Inc.http://www.ftzracing.comhttp://www.ftzracing.com/600cooler.htmhttp://www.facebook.com/pages/FTZ-Perfo ... 4649170424