denali_on_26's

iTrader: (26)

ok first of all..

ALL the internals are new and so is the oil pump... it's an iron block 6.0L standard bore..everything is standard

when i crank it up it has no oil pressure but if i rev it up 1 time to around 2500-3000rpm it builds oil pressure then keeps it at idle but it is only around 19psi then if i rev it up to 6k it will go to about 39psi then if it rest back at idle it stays back at 19...

i have tried 3 different oil pressure sending units and a manual gauge

please help!!!

sman

iTrader: (4)

Pinched the pickup tube o ring?

bczee

iTrader: (12)

Most of the no oil pressure problem from a new build or change that Involve the Oil pump are due to pinched o-rings or that the pickup tube is not seated fully or correctly.

Did you also check the pickup tube inlet, that it has enough clearence between the bottom of the pan and the inlet ?

I have found that while assembling, to fill the pump up with oil or light grease to help seal the rotors on start up and create a vacuum to suck the oil up faster.

98RedBird

iTrader: (77)

Probably not the problem but I just want to throw it out there because it happened to me... Barbell plug in the rear of the block? It can cause no cranking oil pressure and low pressure in the neighborhood of what you're describing while running. I know because I rebuilt a block a while back and failed to put the plug in...

Yeah, sucked to correct that problem but you can bet I'll never forget again lol

denali_on_26's

iTrader: (26)

were exactly is the barbell plug you are talking about and would i have to tear the motor back down to check it or replace it??

thanks for everyones input

98RedBird

iTrader: (77)

It's in the rear of the block. You don't have to tear the motor down but you do have to remove the trans and the rear cover to get to it. I don't have a picture of where it's at but I've seen one floating around the boards here. Maybe if someone else has it they can post it up to help you.

Basically what the plug does is when oil is pulled through your pump it is directed down the main drivers side galley towards the oil filter. The plug diverts oil down through the filter and then up to the oil pressure sending unit. Then it runs to your top end as well as your mains/rods. If this plug is missing like mine was it will just bleed a great deal of the pressure back off into the oil pan. You would understand it better if you were to see it.

Anyways, I hope that's not the problem for you because it is kind of a bitch to fix but it sounds like what my problem was to a T so I just wanted to throw it out there to you.

Good luck.

denali_on_26's

iTrader: (26)

also a guy from texas speed told me it could also be a gasket or O ring behind the cam retainer plate???

socmguy

iTrader: (18)

All of these are true. Be sure the oil pump pickup tube O ring is not pinched, the cam retainer plate is tight, and the oil galley plug behind the rear cover is present. I would start at the front and work my way back since you'll be able to check two things in the front at the same time.

726.0chevelle

iTrader: (17)

do these engines have a lot of probs. on first start up with oil pressure i just cranked mine up for the first time today and no oil pressure however i think my problem is my gauges my motor has never been apart is it possible for them to loose prime from setting up for a while

98RedBird

iTrader: (77)

This is a true possibility as well. I had a small piece missing off of my first LS motor and it dropped the oil pressure about 25psi. And it was a SMALL piece missing.

I would check the cam retainer plate and the oil pump O-ring first as they are both in the same relative place and you can check them both at about the same time.

The barbell in the rear of the motor you can check as well w/o pulling the trans/rear cover. You have to go in above the oil filter. It's an allen fitting and I cannot remember the size but once you remove it it will allow you to look up into the galley where the barbell is suppose to be. I can send a pic if you get to that point. Just let me know.

bczee

iTrader: (12)

If you research on the site, you will find many threads/post on this subject, I had the same problem.. not sur if it was the pump or pinched o-ring. I replace the pump with a LS6 pump and new o-right, I could not find anything wrong on the inspection of the old parts.

I filled my oil pump up with STP oil to let it create a better startup vacuum / suck to make sure that if everything is go. it got a better seal to start the pressure with. Other have used heavy oil, Grease, Vasaline, etc..

Most commond problem is the pinched O-Ring or the Oil pickup tube is too close to the oil pan bottom. But as stated, there are many other reasons.

denali_on_26's

iTrader: (26)

it was the bar bell plug

DaddySS

Thanks for the update. Hope the internals are fine after the lack of pressure.

denali_on_26's

iTrader: (26)

i put all new bearings in it and it has been running strong for a few months now