I got this question posted to me
Thought you guys would like to hear the new motor. Got it done and it runs great.
Scat 900 crank, 6 inch scat I beams, kieth black forgings with 4 v relief, 11:1, 230 pro 1 heads, cam is 242/252 duration at .050, 565/540 lift, 112 LSA, RPM air gap intake, hooker super comp ceramic coated full lengths, holey 750 vac sec for street, pro form 750 for play, ls7 lifters, 4 bolt block, OE roller, fluid damper street damper, crower roller rockers...
Well, on the way to work today i had the oil presure fine till it gets into the RPMs, it will go up to 60 lbs and then start dropping to 40lbs while going up, and if i keep going it will drop to 20 lbs when i get closer to 6000. There is no noise from the motor so i hope it is a gauge problem. I bought another line kit in hopes it is from the small leak on the back of the motor where the tube goes in to the motor
thats FREQUENTLY a symtom of the oil pump pick-up being mounted too close to the oil pan floor or a restricted oil drain in the upper engine or too small of an oil pan capacity or no windage tray, ALL RESULT in restricted RETURN of oil flowing into the oil pump
THE OIL PUMP PICK-UP VIBRATING CLOSER TO THE OIL PAN FLOOR, OR LOOSE CRAP like bits of gaskets or sealants partly blocking the screen on that pick-up, COMES INSTANTLY TO MIND!
one of my friends had purchased a 1967 firebird 400 from a guy that had 120k on the orriginal engine it had good oil pressure at idle and up to about 3000rpm where it peaked then fell off if reved higher, the guy that sold the car said it had been that way for several YEARS, ever since he had the timing chain replaced? my buddy thought he was crazy, (thinking the timing chain had zero to do with oil pressure), but being more old school, I had a very good idea of the cause, and when I explained it too him he thought I was nuts, but I was correct, when we pulled the oil pan the oil pump pick-up was crammed full of plastic fragments from the orriginal aluminum and nylon timing set,and bits of gasket material clogged the oil pump pick-up screen
(similar to this)that had dropped into the sump as the old orriginal timing set had worn. replacing it with a cloyes true roller set and a baffled 8 qt oil pan, and a high voluum pump, instantly put the oil pressure curve back where it should have been[/b]
"It will idle at 45, when you rev it it will jump to 60-70"
ok the pump functions and the bearing clearances (SEEM) ok
"when you step into it and bring the RPM up slowly to 4000+ it starts dropping, in gear and without a load on it. I have a extra quart in her and it does nothing. "
then logically theres a restriction in the oil return flow too the sump,OR theres a restriction in the passages, in the block or oil filter, or pump feed/pick-up. if its a 4-5 qt oil pan your useing YOU could EASILY be having windage control issues where as the rpms increase the oil in the sumps beat to a froth, or a good percentage is being dragged around in the crankcase with the crank acting like a pump, impeller and you can,t get a solid supply into the pump stock pans seldom work on stroker combos above about 5000rpm, a decent pan/windage screen combo will cure that, and since I ASSUME youve checked or tested the other potential causes like your bearing clearances, oil pick-up clearance, and replaced the oil filter and verified the gauges, ETC.ETC, that seems like the most likey source & fix
http://www.moroso.com/catalog/categorydisplay.asp?catcode=11330
Thought you guys would like to hear the new motor. Got it done and it runs great.
Scat 900 crank, 6 inch scat I beams, kieth black forgings with 4 v relief, 11:1, 230 pro 1 heads, cam is 242/252 duration at .050, 565/540 lift, 112 LSA, RPM air gap intake, hooker super comp ceramic coated full lengths, holey 750 vac sec for street, pro form 750 for play, ls7 lifters, 4 bolt block, OE roller, fluid damper street damper, crower roller rockers...
Well, on the way to work today i had the oil presure fine till it gets into the RPMs, it will go up to 60 lbs and then start dropping to 40lbs while going up, and if i keep going it will drop to 20 lbs when i get closer to 6000. There is no noise from the motor so i hope it is a gauge problem. I bought another line kit in hopes it is from the small leak on the back of the motor where the tube goes in to the motor
thats FREQUENTLY a symtom of the oil pump pick-up being mounted too close to the oil pan floor or a restricted oil drain in the upper engine or too small of an oil pan capacity or no windage tray, ALL RESULT in restricted RETURN of oil flowing into the oil pump
THE OIL PUMP PICK-UP VIBRATING CLOSER TO THE OIL PAN FLOOR, OR LOOSE CRAP like bits of gaskets or sealants partly blocking the screen on that pick-up, COMES INSTANTLY TO MIND!
one of my friends had purchased a 1967 firebird 400 from a guy that had 120k on the orriginal engine it had good oil pressure at idle and up to about 3000rpm where it peaked then fell off if reved higher, the guy that sold the car said it had been that way for several YEARS, ever since he had the timing chain replaced? my buddy thought he was crazy, (thinking the timing chain had zero to do with oil pressure), but being more old school, I had a very good idea of the cause, and when I explained it too him he thought I was nuts, but I was correct, when we pulled the oil pan the oil pump pick-up was crammed full of plastic fragments from the orriginal aluminum and nylon timing set,and bits of gasket material clogged the oil pump pick-up screen
"It will idle at 45, when you rev it it will jump to 60-70"
ok the pump functions and the bearing clearances (SEEM) ok
"when you step into it and bring the RPM up slowly to 4000+ it starts dropping, in gear and without a load on it. I have a extra quart in her and it does nothing. "
then logically theres a restriction in the oil return flow too the sump,OR theres a restriction in the passages, in the block or oil filter, or pump feed/pick-up. if its a 4-5 qt oil pan your useing YOU could EASILY be having windage control issues where as the rpms increase the oil in the sumps beat to a froth, or a good percentage is being dragged around in the crankcase with the crank acting like a pump, impeller and you can,t get a solid supply into the pump stock pans seldom work on stroker combos above about 5000rpm, a decent pan/windage screen combo will cure that, and since I ASSUME youve checked or tested the other potential causes like your bearing clearances, oil pick-up clearance, and replaced the oil filter and verified the gauges, ETC.ETC, that seems like the most likey source & fix
http://www.moroso.com/catalog/categorydisplay.asp?catcode=11330