RED2K

Ok I just dropped a 04 ls1 {22k miles}out of a gto in my silverado. I put a comp 220/224 (new) in it. I had oil pressure problem at first because i didnt replace the oring on the pick up tube. I have driven the truck about 25 miles and the oil pressure went from 40 to 30 lbs at idle. It sits at about 750 rpms at idle. If you bump it up to 1000rpm it climbs to about 38lbs. I have a nitrous tune from the old smaller cammed 5.3 in it. It still has the truck intake and 5.3 injectors. It has a bit of pinging under accel. { i think spark knock} I smelt the oil to make sure it isnt dumping too much fuel and maybe thinning the oil. It does have a fuel smell to it but not too bad. Any thoughts would help.

transamws6_97

iTrader: (5)

30 psi at idle is fine. The rule of thumb is 1 lb for every 100 rpm is acceptable

RED2K

YEah by why would it drop all of a sudden is what i am wondering.

ls1ws9ta

iTrader: (2)

heat?

RED2K

it was run the other day and held 40lbs even at full running temp

ls1ws9ta

iTrader: (2)

hmmmm.. what type of oil are you using? what kind of oil pump do you have?? maybe you have a pinched oring?

RED2K

5w30 mobile 1, stock ls1 pump, oring is new and engine was holding 40 lbs the day before. My 2001 z28 with 77k hols 40 all day long

ls1ws9ta

iTrader: (2)

hmmmm. i use german castrol which is 0-30. my hot idle oil pressure is 35psi. sometimes it will go down to 30psi...I am going to say that if you havnt replaced your oil sending unit that might be causing it. before my oil pressure dropped to 20psi out of nowhere and it was the sending unit..

RED2K

I talked talked to Dave at MTI and he said maybe some trash got intot he pickup tube. When ever my buddy put this in and fired it up the first time he ran it for like 25 seconds with no oil pressure. {when he told me i could have choked him} DAve said it is really doubtful that doing so hurt anything so i am saying my prayers. I priced a rebuild kit just in case. lol