"I have a strange oil pressure problem on my mildly built 454. It only has about 250 miles on it. Starts up with 65psi and then quickly drops to 40 psi within 90 seconds. It will then drop to about 20 psi. If I slowly rev to 1800rpm the pressure does not increase. If I put it in gear it stays at 20psi. If I then drive it, it drops to 10psi. I am thinking bad bearing but not sure on an engine built with high quality parts and with such little mileage. Other ideas? Bad oil pump spring? "
sounds more like the oil pump pick-up moved to close to the oil pan floor or possibly fell off to me, the bye pass spring has zero effect on low pressure it only effectively limits max pressure.
I,d suggest verifying the oil level on the dipstick is correct and that the oil filters not defective, be sure the engines got at least 5 quarts of oil minimum.
Id suggest checking the pressure with a second test gauge before you panic as gauges can be defective also.
BTW a tool like this that can be used thru the oil pan drain can save you a ton of guess work here
http://www.amazon.com/Vision-Flexible-B ... B000BHO28S
read these
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=1800
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=3536
viewtopic.php?f=54&t=64
sounds more like the oil pump pick-up moved to close to the oil pan floor or possibly fell off to me, the bye pass spring has zero effect on low pressure it only effectively limits max pressure.
I,d suggest verifying the oil level on the dipstick is correct and that the oil filters not defective, be sure the engines got at least 5 quarts of oil minimum.
Id suggest checking the pressure with a second test gauge before you panic as gauges can be defective also.
BTW a tool like this that can be used thru the oil pan drain can save you a ton of guess work here
http://www.amazon.com/Vision-Flexible-B ... B000BHO28S
read these
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=1800
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=3536
viewtopic.php?f=54&t=64