low oil pressure

[sdryde]

.060 bore
10.25 cr
.054 head gasket
zero decked
24lb injectors
stock renix fuel pessure reg
comp cam
comp lifters
mopar spings and retainers
7120 head polished and gasket matched
99+ intake
STOCK renix tb
renix computer

33" tire
4.88:1 gears spooled


I did not replace the oil pump durring rebuild and after the motor fully warmed up ie oil temp up the oil pressure slowly crep to 0 psi and the lifters were clacking the next step was replacing oil pump..after replacing the oil pump,..I now have pressure of 13-16 psi at full temp @idle in gear..and now only one lifter is complaining...While i replace the pump I did pull all the rod caps and observed good bearings wear.....


help me please....this is my first rebuid---justin

[wolfpackjeeper]

What oil are you running? Did you prime the pump before starting?

[sdryde]

started with
maxima break in oil (high zinc)
changed the oil to:
valvoline racing 50 wt High zinc)
changed the pump
pump helped a little bit but not the answer to the problem

at cold start up oil pressure 65psi then once the motor warms up it creeps down to 12-15 at idle give a little throttle and it goes back to 30-40psi

[Talyn]

What is your bearing clearance like?

[wolfpackjeeper]

at cold start up oil pressure 65psi then once the motor warms up it creeps down to 12-15 at idle give a little throttle and it goes back to 30-40psi

This is within specs is it not?

[Talyn]

Minimum at idle is 13psi. At 1600rpm and above 37-75psi. For a new engine his numbers are low. Are you reading the pressure using the stock gauge or a mechanical gauge?

[sdryde]

the oil gauge is aftermarket electric....I am looking through my old stuff to find my mechanical gauge to verify the reading, but so far can't find it

[CherBear]

0331 head?

[Talyn]

7120 head polished and gasket matched

0331 head?

Good job there Watson

[CherBear]

Good job there Watson

I have a knack for missing the obvious. :banghead:

[sdryde]

I drove it to Wholesale Automotive Machine aka WAM in San Diego (by the way great shop and excellent customer service, A 5 star shop imo) I had one of the engine builders listen to it and he told me to:

#1) verify oil pressure with meachanical gauge

#2) bring him the pump with out seperating the pickup so he could check it out

he seems to think that maybe it is sucking a bit of air between the pick up tube and the pump. hopefully tomorrow I will have time to do this.

[activeshooter1]

during ur rebuild did you replace the cam bearings? if not well........
if so is it possible that you didn't get the oil jurnals lined up?

screw it put lucas in it and run the poooo out of it

[wolfpackjeeper]

screw it put lucas in it and run the poooo out of it


Because lucas will fix anything right? I am a firm believer in lucas but this is just a retarded statement. The idea is to fix the problem, not to just cover it up.

[Talyn]

screw it put lucas in it and run the poooo out of it

That is awesome advice for a newly rebuilt engine.

[JJacobs]

Hell yeah, throw a little Slick 50 in there too and screw the oil! Oil pressure is for sallies. Do they still make Slick 50?

Did you put the plug in the oil galley underneath the front cover? I've forgotten that before.. once. It's the kind of thing you don't do twice.

[eflores]

that much loss in oil pressure when warm and running VR1 50wt scream main bearings to me...Jacobs is spot on also. leaving an oil galley plug out will do it every time....but i think you would see far less oil pressure with a half inch hole in your oil galleys

[live24wheel]

Hell yeah, throw a little Slick 50 in there too and screw the oil! Oil pressure is for sallies. Do they still make Slick 50?

Did you put the plug in the oil galley underneath the front cover? I've forgotten that before.. once. It's the kind of thing you don't do twice.

X2 I just read about a guy over on JeepStrokers that forgot that plug. Seemed to be about the same issues. Threaded oil galley plug behind the timing cover.....

[JTwthaXJ]

Hey! hey! hey! You have what sounds like the same issue I am having! Please trouble shoot first dont pour in these magic elixirs and think its as permanent fix. I had my 4.7L in for about 4 months and 1500 miles before I had to snatch it out again for a new timing chain. Had the same engine shop go through it replace bearing etc. Got it back in and I have the same problem still. NO TO LOW OIL PRESSURE (5-30 tops.) I replaced the oil pump with a Hesco Blueprinted pump and still no worky. Moral of the story is get more than one opinion before taking a major investment to an engine builder. I am going to check bearing clearances and look to see if the oil galley plug is there. Reputable engine builder in Raleigh that builds strokers for fun and another one here in FV said run 15-40, no zinc additive need. They both do it for race engines and in their daily drivers. My two cents...

[sdryde]

live24wheel,

I just looked for that thread could'nt find it could hook me up with a link?

[Talyn]

There isn't much to it. Guy had low oil pressure and it turns out he forgot to put in the oil galley plug that is under the cam cover at the top, under the cam gear.

[wolfpackjeeper]

I know JT and have been trying to help him trouble shoot over the phone from 500mi away. But I think his problem is going to end up being that his engine builder turned the crank too much on at least one surface and it now probably has one or two bearings just enough out of spec to cause that drop.

He has removed and replaced the oil pump twice
From the bottom end he has checked the cam for free play as much as can be done without pulling it.
I could see a potential that if you grooved the lifter bores maybe, but it does not seem to likely.
He removed his oil cool and remote setup, which did provide a marginal increase.

I believe he is going to drop the pan and plastigauge the bearings to see if maybe one or all are just out of spec. He said that he thought the oil plug was in, and it is topped off. I also have him checking while he can to make sure he has the right pickup clearance with the bottom of the pan. Too much can cause it to drop pressure as well. I know I beat mine out to about 1/8th to 1/4 in clearance.

I'll throw up his findings here in case he doesn't, that way it may help someone else.

[Talyn]

Also, take a look at the cam bearings and make sure they aren't pushed out and crap.

[wolfpackjeeper]

Also, take a look at the cam bearings and make sure they aren't pushed out and crap.

he said it looked pretty good when he checked it out last time. I am sure he will look at it even more after I told him I think it is an out of spec bearing somewhere.

[sdryde]

if I was missing the oil galley plug sounds like I would not have 75psi @ cold start up, Right? or no

[wolfpackjeeper]

no, I don't think so. Jeff gets low pressure throughout the spectrum. Which makes me think that plug could be it, but even then it is a slight maybe.

[sdryde]

yea I get good oil pressure cold and then when the oil temp comes up then the pressure go down

In other words the oil pressure is indirectly related to the oil temp

oil temp up = oil pressure down

Thefore I am ruling out the oil galley plug

I still have not ruled out:
bearing clearence
oil pump pickup tube to oil pump connection maybe sucking air

[wolfpackjeeper]

yea I get good oil pressure cold and then when the oil temp comes up then the pressure go down

In other words the oil pressure is inversely related to the oil temp

oil temp up = oil pressure down

Thefore I am ruling out the oil galley plug

I still have not ruled out:
bearing clearence
oil pump pickup tube to oil pump connection maybe sucking air

fixed. Yea, I would check bearing clearances and your pickup between the bottom of the pan and the oil pickup. It's a pain in the ass to do, but might be well worth it.

[sdryde]

A little update

I checked the oil galley plug in the front of the motor behind the timing cover, IT WAS THERE.

I had a machinest/engine builder from Wholesale Automotive Machine of San Diego come to my house to check the motor out. By the way he offered to come to my house and refused the money i offered when he left. He and I took all the rod and two of the main caps of and found no smoking gun. he concluded the only way to find the problem is to pull it out and put it on the engine stand at the shop.

Spring break is next week and also the last chance I will have to go to the desert this season so I am going to put half lucas and half oil in it, bump up the idle to1300 rpm and run the shit out of it in ocotillo wells then pull the motor....