Guys,
I found this very interesting today. I installed a new ZZ4 shortblock in my 63 in May this year with a STOCK front sump oil pump and Pan. At first start up when engine not warm I would get 35-40 pounds oil pressure at 800 rpm idle. When the car got good and warm around 190 degrees and running for 20 plus minutes under driving conditions the oil pressure droped to 7-8 pounds ONLY AT IDLE but goes right back up to 20-40 pounds when engine rpms increase so I always have at leat 10 pounds per 1,000 rpms once past idle.
I have called GM and 3 certified GM Dealers who tell me this is NORMAL! They actually have some ZZ4's that are running 3-4 pounds at idle. Said that as long as the oil pressure is increasing with engine rpm up to 25-40 pounds based on rpm range that all is fine! Good rule of thumb is 10 psi per 1,000 rpm...above idle.
This very much surprised me to learn that they are seeing engines actually have 3 pounds of oil pressure at idle!
I found this very interesting today. I installed a new ZZ4 shortblock in my 63 in May this year with a STOCK front sump oil pump and Pan. At first start up when engine not warm I would get 35-40 pounds oil pressure at 800 rpm idle. When the car got good and warm around 190 degrees and running for 20 plus minutes under driving conditions the oil pressure droped to 7-8 pounds ONLY AT IDLE but goes right back up to 20-40 pounds when engine rpms increase so I always have at leat 10 pounds per 1,000 rpms once past idle.
I have called GM and 3 certified GM Dealers who tell me this is NORMAL! They actually have some ZZ4's that are running 3-4 pounds at idle. Said that as long as the oil pressure is increasing with engine rpm up to 25-40 pounds based on rpm range that all is fine! Good rule of thumb is 10 psi per 1,000 rpm...above idle.
This very much surprised me to learn that they are seeing engines actually have 3 pounds of oil pressure at idle!