383 low oil pressure problem

**fastrthanurs** · 04-23-2007, 03:30 PM

just got the car and i'm having some problems. when the car is cold and idling i get 35 to 40 psi. then when it warms up it drops to 25 then 20 then to 10 and so forth. i thought maybe the sending unit. hooked up a manual gauge where the sending unit was and got the same readings. so i'm stumbled. the car is a 00 with a ls1 383 lunati crank, hbeam rods, je pistons 10.5 to 1 compression, 6.0 heads p&p, cammotion cam, jesel top end. the motor doesnt have many miles on it. the car was just put together. i'm stuck and i have no idea. i know there is a oring that can be damaged on the pickup tube i'm going to check into and i replaced the oil filter and oil with 10/30. i am just stuck and i have no idea what is going on. i woudln't think that it would be a bearing with the pressure being fine when the engine is cold! only does it when it gets hot. any ideas greatly appreciated.

**LETHALxLS1** · 04-23-2007, 03:43 PM

That sucks-maybe thats why they sold it. Dunno Whats the lowest reading when its hot?? When I went out looking for a newer camaro I came really close to buying a z28 convertable that was really nice. I looked at the oil pressure once it got hot and it said 15psi !!!! I told the guy if you put a new oil pressure sending unit in it and the pressure goes up I will buy it. He said no I cant do that. So I assumed there was more to it then a malfunctioning gauge. Did the car have low oil pressure when u bought it??

**Thorazine Shuffle** · 04-23-2007, 05:49 PM

I wouldn't say 35 to 40 psi cold is "fine"... My stock ls1 pushes around 70 cold, and 40 hot. I've had the same problem on two other older small blocks. One of them had a crack in the pick-up tube, which was easy to diagnose, because after you would drive it a bit the oil would be frothy from th air being mixed with it. The other had a spun cam bearing, that was blocking an oil journal.

Either way, I would get it fixed before you trash it.....

**fastrthanurs** · 04-24-2007, 03:24 AM

yea i'm going to work on it this weekend. i hope its something simple like the pickup tube or something. they guy that built the car is in jail for check fraud and the guy i bought it from owned a 4x4 shop and got the car for the lawyer fee's the people owed. so he didnt know what was going on with the car either.

**fastrthanurs** · 04-26-2007, 11:32 AM

anymore input or ideas?

**30transam948** · 04-27-2007, 07:50 AM

Brother I know what is wrong and you can call me if you would like when you stroke that engine you have to cut notches in the cylinder wall for the rods to clear at the same time if they are not cut at an angle then when the rod turns it throws the oil to the side of the block instead of up into the cylinder I have built around 5 of these and the first 2 I built had the same proublem until we figured out how to notch the block.

**fastrthanurs** · 04-27-2007, 08:29 AM

can you give me some more detail on it or some pics. do i have to pull the engine apart and notch the block or is there another route i can go. is the oil pressure really fine just not reading what is supposed to due to where the sensor is located? get back with me and thanks for the help.

**30transam948** · 04-27-2007, 08:36 AM

No way man the first engine lasted 1700 miles and the second lasted 2300 miles before the rods began to knock.You will have to take it out and have the block notched to do so you have to disassemble so when it is notched you do not get any metal into the engine I do not have any pics at this time.I had my Mechanics uphold my Warrantys on my engines and we tried everything that you are thinking about doing. The seal around the pickup tube only affects the oil by like 3 pounds. The only thing left would be they did not put in the windage tray. That could cause the same proublem.If the windage tray is there then get ready for a complete teardown. Jack

**fastrthanurs** · 04-27-2007, 08:38 AM

the car is suppsed to be a soild roller engine. so if it has solid lifters wouldnt that cause the pressure to read low since it doesnt have hydraulic lifters to push the oil up to the rockers and stuff?

**fastrthanurs** · 04-27-2007, 08:39 AM

whats your number jack i'm going to drop the k member and pull the pan tomorrow and see. if i have any ?'s can i call you?

**30transam948** · 04-27-2007, 08:41 AM

No the oil pressure is read at the back of the block with the oil pressure sensor the lifters only supply oil to the push rods then the oil travels throught the pushrods to the rocker arems that is how oil is supplied to the top of the engine.

**30transam948** · 04-27-2007, 08:43 AM

858-829-5107 Please I will help you as much as I can. Also one more incounter that we ran into is a oil plug that goes in the back of the block behind the rear main cover on the bottom left it is plastic if this piece is not installed you will have bad oil pressure also.

**fastrthanurs** · 04-27-2007, 08:49 AM

did your engines that did not have the notches cut into the block read fine oil pressure and just failed due to the notches not being cut? or did they read low also?

**30transam948** · 04-27-2007, 08:55 AM

You have to cut a notch to stroke the engine. When you stroke this block to a 383 when you turn the crank the rods hits the side of the block.U have to notch it at this point for thr rod bolts to clear. The proublem with new builders are that they are scared to open there block up much so they just notch it small enought for the rod bolt to clear , with this being done when you turn the engine the oil is thrown to the outer of the block instead of being thrown into the cylinder wall to lube the pistons. If you are following me then ask me more!

**fastrthanurs** · 04-30-2007, 08:36 AM

ok i dropped the kmember and pulled the pan and timinng cover. the oil pump didnt look good so i replaced that with a ls6 pump. the pickup tube was fine. has some gasket maker in the pan. cleaned everything up and reassembled the engine. cranked it up and same shit. 50 at idle and when the car reached 200 temp the oil pressure started dropping. when it droped it stayed at around 7 or 8 psi. i'm stuck. no noise coming from the engine. i'm thinking a cam bearing? any other ideas?

**30transam948** · 05-01-2007, 01:40 PM

Man i told u to check the block!!!!

**fastrthanurs** · 05-02-2007, 08:50 AM

i did check the block and it wasnt notched. but i still dont think that would have anything to do with oil pressure. that would keep the cylinders from being lubed well enough but not have anything to do with pressure. and it only does it when it gets hot. when it's cold for about 7 minutes it's fine. then it drops down. i'm thinking cam bearing.

**jigger1166** · 05-02-2007, 10:42 AM

Originally Posted by fastrthanurs

i did check the block and it wasnt notched. but i still dont think that would have anything to do with oil pressure. that would keep the cylinders from being lubed well enough but not have anything to do with pressure. and it only does it when it gets hot. when it's cold for about 7 minutes it's fine. then it drops down. i'm thinking cam bearing.

You're right. Throwing oil onto the cyl. walls, has nothing to do with the oil pressure.

**fastrthanurs** · 05-02-2007, 11:20 AM

but i can understand what he is talking about but it would cause premature ring and piston failure not pressure failure. for some reason when the engine gets hot the pressure is lost. all i can think is a bad cam bearing. maybe the redneck that put the engine together didnt lube the cam and the bearing seized or scarred up real bad. when the oil gets thin wallah! all i'm doing is guessing but whoever built the engine used waaayyyy too much gasket maker so i'm guessing they didnt know what they was doing! just a hunch tho.

**ls1maro99** · 05-02-2007, 11:44 PM

i had a lt1 camaro and it had an oil pressure problem and it was clearance between the crank and main bearings... they were wearing down and would hold enough pressure..... idk maybe could be your problem but maybe not just thought id try to help