take the time and effort to read thru the links if your interested in knowning a bit more about bearings
there are oil pump testers available commercially or if your mechanically inclined you can fabricate one with reasonable care, after a bit of measuring and purchasing a gauge
http://cvrproducts.com/oil-pressure-test-kit/
Melling 55070
70 psi, Steel, Pink, Pins, Chevy, Small Block, Kit
Melling 77070
Oil Pump Springs, 70 psi, Steel, Pink, Pins, Chevy, Big Block, Kit
Melling 55058
Oil Pump Springs, 58 psi, Steel, Yellow, Pins, Chevy, Small Block, Kit
Melling 55078
Oil Pump Springs, 78 psi, Steel, Green, Pins, Chevy, Small Block, Kit
Melling 77060
Oil Pump Springs, 60 psi, Steel, Black, Pins, Chevy, Big Block, Kit
Melling 55049
Oil Pump Springs, 49 psi, Steel, Green, Pins, Chevy, Small Block, Kit
Melling 77052
Oil Pump Springs, 52 psi, Steel, Purple, Pins, Chevy, Big Block, Kit
Melling 7770M
Oil Pump Springs, 70 psi, Steel, Pink, Chevy, Big Block, Set of 5
Melling 5556F
Oil Pump Springs, 55 psi of Force, Steel, Chevy, Small Block, Set of 5
Melling 5570F
Oil Pump Springs, 70 psi, Steel, Pink, Chevy, Small Block, Set of 5
Melling 7760M
Oil Pump Springs, 60 psi, Steel, Black, Chevy, Big Block, Set of 5
Melling 7752M
Oil Pump Springs, 52 psi, Steel, Purple, Chevy, Big Block, Set of 5
http://www.thirskauto.net/BearingPics.html
http://www.babcox.com/editorial/ar/ar20128.htm
http://www.babcox.com/editorial/cm/cm99828.htm
http://www.thirskauto.net/Engine_Thrust_Bearings.html
http://www.aptfast.com/Flyer_HowTo_Dir/HowTo_Folder/Cam_Bearing_Install/Install_Cambearings.htm
http://www.babcox.com/editorial/us/us90126.htm
http://www.circletrack.com/tipstricks/4636_crankshaft_rod_bearing_installation_tips/index.html
http://garage.grumpysperformance.com/index.php?threads/repair-or-replace-350-crank.14181/
http://www.stockcarracing.com/techarticles/scrp_0509_coated_bearings/index.html
http://www.engineparts.com/motorhead/techstuff/brgclear.html
http://www.engineparts.com/motorhead/techstuff/bearingfailures.htm
http://www.engineparts.com/motorhead/techstuff/clrcode.html
http://www.babcox.com/editorial/ar/ar10180.htm
http://www.popularhotrodding.com/tech/0711phr_bearing_clearance_control/index.html
http://www.tpub.com/content/engine/14076/css/14076_73.htm
http://mahleclevite.com/techbulletins/CL77-1-205R.pdf
http://www.chevyhiperformance.com/t...rain/0707ch_main_bearing_clearance/index.html
BTW beariing shells rarely fit the block EXACTLY ,its comon, for the bearing shells to need TWEAKING/FITTING to the application, a differant brand of bearing MIGHT fit/line up better but its not a big deal or unknown, use a dremel tool to teardrop, and SMOOTH/RADIAS the block port to a depth of about 3/16" -1/4" so as too match the bearing shell opening which can, and should also be opened slightly where it blocks part of the port ,with part of the bearing shell ,if your careful to further open access to the port in the block too allow full oil flow to the bearing shells oil port opening.
DON,T forget to totally clean up any chips or grinding dust and wash the area till its clean with solvent, little things like that are why its called ENGINE BUILDING vs ASSEMBLING engine PARTS
and why EXPERIANCE COUNTS.
BTW avoid the urge to just use a big drill bit to open up the block as it COULD cause stress points in the block that WON,T show untill the blocks under stress
remember the upper bearing has far less stress that the lower bearing shell, but it needs to maintain the oil wedge , pressure and flow rates supporting the cranks main journals.
ITS comon to need to open that feed port, BUT its best to smooth the block feed port and the bearing feed port to maximize the flow
heres a MINIMALLY TEARDROPPED PORT enterance
thats the idea! but the TEARDROP being ground into the port exit should be DEEPER to ease flow restriction, and any part of the bearing shell that overlaps the port exit needs to be removed and smoothed
http://www.circletrack.com/tipstricks/4 ... index.html
http://www.circletrack.com/howto/1815_c ... index.html
http://www.babcox.com/editorial/us/us90126.htm
http://engineparts.com/Motorhead/techst ... stall.html
your bye-pass spring controls the pressure at which the pump starts to bleed off excess oil pressure, if it reaches 65 psi and then drops to 58 psi its NOT the pumps bye-pass circuit, as it will close at pressures below 65 psi, and shimming the spring will only effect the peak pressure you reached, before it opens,... below that point it has no effect, on the pressure the pump puts out ,you must keep the pumps pick-up covered in a significant level of oil in the sump, a running engine can keep 2 or more quarts in the upper engines, lifter gallery and heads, if the oil drains are not clear or the spinning cranks preventing drain back, into the sump. the fact that its dropping pressure at high rpms indicates an oil supply or control issue, in most cases its a control issue if you have at least a 7-8 quart baffled oil pan and a properly installed windage screen, if your running a 5-and in some cases a 6 quart factory style oil pan, without baffles and a windage screen, its potentially a problem with the supply.
if the oil pump pick up is mounted to close to the oil pan floor it can cause a restriction at higher rpms, if the oil doesn,t drain back to the pan because its rotating with the crank assembly, as its dragged around, or if your not running a pan and windage screen that allows the spinning crank assembly to sweep returning oil into the sump for re use,it is a potential problem.
a quick test is adding one-two more quarts of oil to the sump, if the oil pressure curve changes with the extra oil and doesn,t drop at the same rpm point you've proved its a supply or control issue, if it remains exactly consistent with the current set up, it could be a control issue if you don,t have the baffled pan and windage screen,but its unlikely to be a supply issue
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=615
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=64&p=1394#p1394
