Oil pressure loss

carlmb · #1 (**permalink**) 06-02-2009, 10:44 AM

Good afternoon. I have a new 347 wth about 5 miles on it that lost oil pressure. Had 50 pounds at cold start, would level off to about 40 at idle. Driving it for the 1st time and pressure dropped off to just above 0 after 3 miles. Pulled distributor and pump shaft not broken and pump spins freely. No external oil leaks. I read it could be 1 of the galley plugs at the front of the motor that popped out. Does this make sense and would it cause total loss of oil pressure. Thanks for any help.

FWB · #2 (**permalink**) 06-02-2009, 10:49 AM

if there really is no oil pressure, there would be quite a bit of noise. if the motor sounds fine i would bet its the gauge or sender.

Fred

carlmb · #3 (**permalink**) 06-02-2009, 10:53 AM

I forgot to mention I know it lost pressure because of the immediate racket from the new hydraulic roller after losing pressure. Gauge is fine.

blykins · #4 (**permalink**) 06-02-2009, 12:14 PM

Probably a good time to call your engine builder.

carlmb · #5 (**permalink**) 06-02-2009, 12:16 PM

That would be the guy in the mirror.

blykins · #6 (**permalink**) 06-02-2009, 12:20 PM

Ok...

Lots of possibilities. Some that come to mind....broken oil pump shaft, oil pump bolts loosened up, oil pickup fell too close to pan, etc.

Here's what I would do first to rule some things out.

Take an electric drill and a pump primer, yank the distributor out, and prime the oil pump. Pull the valve covers, and see if you get oil to the top of the engine and watch the oil pressure gauge.

Jac Mac · #7 (**permalink**) 06-02-2009, 12:28 PM

1. Call your builder.
2. Gallery plugs at front or at single rear plug high up in valley.
3. Pickup tube/screen fell/broke off pump.
4. Relief valve in pump stuck open.
5. Cover plate on pump loose.

Those are the obvious ones that 'can' happen, you can remove the fuel pump to observe while you hand prime with an old dist shaft to check if its the front gallery plugs, if you cannot get a continous flow while priming by hand then its likely the pump/pickup scenario, if you get flow & its not at front then remove intake to check that rear plug & or lifters.

DAVID GAGNARD · #8 (**permalink**) 06-02-2009, 02:38 PM

Quote:

Originally Posted by blykins

Ok...

Lots of possibilities. Some that come to mind....broken oil pump shaft, oil pump bolts loosened up, oil pickup fell too close to pan, etc.

Here's what I would do first to rule some things out.

Take an electric drill and a pump primer, yank the distributor out, and prime the oil pump. Pull the valve covers, and see if you get oil to the top of the engine and watch the oil pressure gauge.

That's the first thing I would do and the easiest, be sure to spin the drill counter clockwise or in reverse.......

Then if you have pressure,check the "pin" on the gear on your distributor shaft, it could have sheared and you can't hardly tell by just looking at it....check the simple things first, then move on......

David

blykins · #9 (**permalink**) 06-02-2009, 02:40 PM

My money's on the roll pin.

DAVID GAGNARD · #10 (**permalink**) 06-02-2009, 02:42 PM

Quote:

Originally Posted by blykins

My money's on the roll pin.

Mine too...............

David

Jerry Clayton · #11 (**permalink**) 06-02-2009, 02:57 PM

If the engine continued to run, it won't be the pin

Jac Mac · #12 (**permalink**) 06-02-2009, 03:24 PM

Quote:

Originally Posted by Jerry Clayton

If the engine continued to run, it won't be the pin

Plus one!- the gear via the pin drives the dist shaft & oil pump drive.

blykins · #13 (**permalink**) 06-02-2009, 03:39 PM

Ah, good point guys.....forgot it was running.

olddog · #14 (**permalink**) 06-02-2009, 05:53 PM

Did you pull the dip stick and check the oil? On a similar problem, my son said he knew it was full of oil, as he had just filled it, and wasn't stupid. I said humor me, I'm old. Pulled the dip stick to find a gallon of gasoline in it. Seems that new diaphram fuel pump had a hole in it. You could have water or other issues.

If when spinning with the drill the pump turns freely (no load on drill) and you don't see oil flowing out the gallery plug, I think I would suspect a pick up tube problem.

Do you have any shop rags missing? A friend found out that the rag is too fine a filter for the pickup tube.

Good luck.

Rick Parker · #15 (**permalink**) 06-02-2009, 07:04 PM

Relief Valve in the pump.

carlmb · #16 (**permalink**) 06-03-2009, 05:06 AM

Thanks for all the replies. It is a brand new Melling pump. I hope it is not the relief valve. I will know this evening.

Rick Parker · #17 (**permalink**) 06-05-2009, 06:52 AM

Survey says.......(extended drumroll)???

Clois Harlan · #18 (**permalink**) 06-05-2009, 07:55 AM

I am thinking galley plug, did you put a little nick in the block after you installed your galley plug to keep it from coming out? Maybe your oil pump is loose or it is the relief valve. As the others stated pull the valve covers and spin you oil pump counter clockwise with a drill, I think the 302 base engine takes a 1/4" drive shaft on the oil pump. Do not start your engine again until you have this issue resolved.

Keep us posted on what you find.

Clois

eschaider · #19 (**permalink**) 06-05-2009, 08:10 AM

I would check the pressure relief built in to the pump. If it picked up a piece of trash that is holding it open then your oil pressure problem is easy to fix.

I think you will find some foreign material holding open the pressure relief. Pull the pan take the pump relief apart look it over wash it out reassemble and I bet your oil pressure is back to normal.

In the oh by the way category you might want to consider what some people call an external wet sump. The system uses the pressure stage only off of a dry sump and draws oil through a pickup that goes through the side of the pan. The pump is easily rebuildable, easily serviceable and in the end quite a nice upgrade to the engine.

I forgot to mention, it looks sort of cool also.

Ed

RedBarchetta · #20 (**permalink**) 06-05-2009, 09:26 AM

Quote:

Originally Posted by eschaider

...Pull the pan...

If it was my motor, that was my initial thought (after pulling the dist. and verifying that the pump isn't generating oil at the valve rockers). I would also be thinking, while the pan is out, to pull the main caps and insure the bearings didn't get scored. You already have too much time and energy building the motor...I would always be wondering whether or not the incident hurt the bearings. It doesn't take much and they don't cost a whole lot in the end.

-Dean