I have a fresh 383 ls1 with 15 mile on it. When I first started it up I only had 20 psi of oil pressure. No problem, replaced the pump with a ported slp one and a stiffer spring. Everything was good for 15 miles! 15 miles then i noticed it dropping again so I changed the oil sending unit and nothing. Is it the pump again or should I what ? Any help is greatly appreciated.

 

Is the barbell plug in the back of the block. New OP o-ring and are you sure it is not pinched??

 

Mine was doing same thing. Ito was my sending unit

 

Did you check it with a mechanical gauge?

 

Oring may be pinched.

 

This comes first.
If a mechanical gauge mimics the electronic gauge, you have a problem.
Was the 'fresh' engine working well before?

 

I am going to check it with a mechanical gauge. I changed the sending unit with the same results. The motor was fine before all this started. even to pull it in the garage it was running fine.

 

I might be a noob for asking this, but what barbell on the back of the block?

 

its an oil galley plug near the flywheel area and if its not in the block, or the oring is bad, little to no oil pressure. and a royal PITA to get to (ie drop the tranny and all that =/ )

 

ok so I installed a mech gauge last night and the oil pressure reading was at 20 psi at 2000 rpm. so Im stuck. should I tear the front apart to check the oil pump o-ring or dig into the back of the block for the barbell plug?

 

if you had good oil pressure for the first 15 miles, the barbell is not your problem.

 

I'd start by cutting open the oil filter...

 

What will cutting the oil filter accomplish? I'm not being funny I really want to know.

 

You'll open it up and find out if you have bearing material or metal shaving ect. inside of it.

 

I'd put money on a pinched o ring. Seems to be fairly common to cam swapers when they do the oil pump. One of the reasons I just left mine alone.

 

I'm thinking if he got 15 miles out of the 2nd pump and then had problems, it wasn't the 0-ring, but bearing material in the system due to either the low oil pressure from the 1st pump or "other" problems...

 

So basically change oil pump again, or...

 

Nope, he's saying that you bearings could have gottend damaged with he low oil psi with the first pump.

 

Did you cut the oil filter open?

 

I had to work all weekend and I have school tonight but when i get home Im going to try and cut the filter open to determine what my next move is going to be