Title says it all,

I just put my new 383 in a few weeks ago and have been carefully driving it around town breaking it in. I have a mechanical roller cam in it. Tt has a Milodon 6 qt oil pan with windage tray and what i believe is the correct pickup for this pan. I am also running a Melling high volume oil pump recommended by my engine builder as he did some clearancing around the oil filter passages and rear main cap. I started out with some mobile 1 conventional 5w-30.

It has been doing fine for the majority of the break in, holding around 40 psi idling and up to 60 when cruising or on power. recently though it dropped to 10 psi cruising and refused to go up with RPMs. I took it home cut the filter open and had zero metal shavings in it. Changed the oil for some Castrol 5w-30 synthetic blend.

I cranked the engine over with no ignition and had zero pressure on the gauge. I fired it for just a few seconds and still zero pressure. I am beginning to think the pickup fell off my pump. what do you guys think?

 

might be worth trying a new oil pressure sending unit or gauge first?

 

It has a mechanical gauge, one on the dash and one in the engine compartment. both are showing zero. I guess it is possible that the line going to the gauge got clogged.

 

you could pull the fitting off the block and start it for a second. oil should shoot all over.
if you think the pick up fell off, try adding an extra 2-3 quarts of oil and see if pressure comes back.
just a few ideas.

 

I added one quart of oil, it is now showing a little above the full line on the dipstick, pulled the distributor and turned the pump with a priming tool on a drill. that showed over 20 psi on both gauges. I would think one quart wouldn't make that big of a difference if the pickup was attached right? especially with a deep pan like this.

 

i guess its possible the pick up fell off. it happens. i'd add another quart and start it up. if the pressure increases, chances are its a pick up issue.

 

Ok, now i am confused. dropped the oil pan and the pickup is on tight. my dipstick is a solid 2 - 3 inches above the bottom of the pickup. I feel like it should be pumping good even without oil showing on the dipstick.

 

No oil pressure with the distributor installed. Oil pressure with a drill motor and priming tool.

Have you turned the distributor over and looked at the "blade" end of the distributor shaft?

 

I believe I would pull the #1 main and #1 & #2 rod caps off and have a look.

 

I did look at the distributor, definitely engaging the oil pump.

here are the pictures for #1 journal as well as #1 and 2 rods

the bearings definitely have some scratches but the journals all still look smooth

 

Also I forgot to mention after seeing pressure when turning the pump with the drill I reinstalled the distributor and fired it up, pressure was good then but that was with around 8 quarts of oil in it.

 

i wonder if the plug under the rear main cap moved? not sure it would have anything to do with it?
http://www.crankshaftcoalition.com/w..._rear_main_cap

maybe you need to run 8qts? is the pressure good at 8 qts?

 

http://garage.grumpysperformance.com...it-works.3536/

I think my problem is pickup length. see this article they state a HV pump is longer than a standard pump. my pickup is probably doesn't have the clearance.

 

Alright guys I swapped my pump and pickup for the combination recommended my Milodon, Pickup # 18316 and pump #18750 with oil pan 30908. Now we went from one extreme to the other. Fired it up and both gauges get pegged at over 100 psi.

 

I am not surprised that is a high volume and pressure pump. Mildon says it will hold 65-70PSI at HOT so cold I am not surprised you are pegging or nearly pegging the gauge. If you have a pan big enough for high volume I would probably have gone 18755 which is just high volume and about 50 psi hot.

 

I think we can close the book on this one, i ran it for a little and revved to around 2000 rpm and it dropped to 70 psi and held cold. not sure what that was about but happy it has good pressure again.