In over my head with pickup motor

Trying to help out a friend but may have gotten in over my head.
10/97 build date F150 4.2 Motor hydro locked.
Friend bought a rebuilt long block from a national rebuilder and installed in truck. Died in a car accident before he could finish it so I told widow I would try and get it running.

Got it all buttoned up. Ran good with no noise but had no oil pressure. Thought it was the sending unit so I put a mechanical gauge on it.
0 pressure at idle and 20 lbs. when revved up per mechanical gauge.

Thinking it might be sucking air I pulled the motor back out to check pickup tube. Looks good. Pumps plenty of oil when run with a drill as oil streams from the area of each piston.
Put oil pan back on and removed gauge. Oil shoots out the fitting where the sending unit/ gauge installs about 2 or 3 ft.
Put gauge back on and run with a drill and get no pressure reading.

This has me stumped. Only other thing I can think of is pressure relief valve is stuck open. Do not know if he installed the new one that would have come with the new oil pump.

Any ideas???????????
Any one know where you can get that little freeze plug that holds pressure relief valve in without buying a new oil pump?????

most any REAL parts house should have a drawer full of different size welch plugs.
have you pulled bottom off pump to check clearance between gears? even with good flow,it's possible oil is bypassing gears under pressure. if you still have old pump i'd bolt it on and see if it makes any difference.
good luck

I've ran into this a lot too.

The builder or machinist has left a plug out of one of the oil passages.

Allan

One of my co-worker's had a 1962 Ford car with the 352cid engine. We were out looking for a used valve spring for my 57 Chevy that had a broken spring. When we turned into his driveway the oil pressure light came on. The hydraulic valves were getting noisy too. We pushed his car into his garage after installing the valve spring on my Chevy. We installed a pressure gauge and it showed zero oil pressure.

We quit for the night and he told me to put him on leave we got 26 days each year. He called me at work and told me to pick him up a new oil pump. I took it over after eating supper. He had already removed the oil pump and pan. The relief valve was open probably caused by sludge. The car was only driven on short runs. We installed the new pump after priming it and he had good pressure. He cleaned the old pump and
it was probably ok, but he didn't want to take a chance on using it. I have a 1981 Mercury Cougar XR7 and I only run it about once a month about 65 miles round trip on a dual highway to get it good and hot. Hal

possiblly a plug was left out of one of the oil galleries when engine was rebuilt. backside would leak into bellhousing and be apparent however front side would leak into timing chain housing. one way to check is to pressurize with air thru pressre sender hole and see where large amounts of air is leaking (oil pan would need to be off) possibly bad oil pump also.

I've seen that here on some of the tractor forums when the engine was hot tanked a plug was removed from the oil gallery and wasn't installed during the rebuild and they had no oil pressure. Hal

See if you can find a pressure OIL TANK. We use them on engines to prelube when you can't drive the pump. I have also used the tank with the pan, valve cover off to find oil pressure problems, galley plugs ,loose brgs. etc. Goodson Tools still has them available. Or you can build one, freon tank. Very good tool.

Earl

Coupla things I've run into. As others have said, a plug missing somewhere. Oil pump relief valve stuck.

Is there a gasket in the oil pump? I once couldn't get oil pressure after rebuilding a mid 80's Buick 3.0 engine. The engine was still on the engine stand and I was running the pump with a drill. Turned out there was a paper thin gasket where the oil pump bolts together. Only there were TWO gaskets stuck together and I didn't catch it when I assembled the pump. I removed one gasket and had plenty of oil pressure. You wouldn't think one gasket, maybe .003" thick, would make that much difference, but it did.

I was lucky. It was an external pump and the engine was still on the stand, so it was a simple fix.

Went out and took the timing cover off.
Pressure relief valve is mounted in timing cover and external pump mounts to cover.
You can move the pressure relief valve with a screw driver and in pops right back in place when you let it go. Looks to be a new welch plug so I would say he replaced the relief valve.

Poured some oil in the in port in timing cover that goes to the pump; put my finger over the exit port and spun the pump with a drill.
Pressure built up and blew my finger off spraying oil everywhere.

So I would say something is wrong in the block. Oil galley plug may be missing; or who knows what. That is the rebuilders problem now cause I am going to see how good the warranty is Tuesday morning.

If no factory made oil pressure tank is available, a very workable one can be easily made from a new, clean, $15.00 garden sprayer with several quarts of motor oil in it.

Drop the oil pan, connect the pressurized oil source to the oil sender port, pump 'er up, and look for the biggest leak!



<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/N%20Ford/OilPrimer.jpg">

I don't know about that engine, but I recall a small block chevy with no oil pressure; the builder had left out the drive shaft between the distributor shaft and the oil pump.

I have seen this three times on different engines. A Dodge 360 and a Ford 302 were two of them. Each time someone forgot to reinstall an oil galley plug after cleaning when machining was done. The installer is ALWAYS required to clean the engine prior to assembly and they were forgotten. Hope this helps. Gerard

Hey John,
Plug missing or even a cam bearing missing could be a possibility. Do they think the remanufacturer will still stand behind it after it has been sitting so long? Good luck. Remember "No Good Deed Goes Unpunished".
Ron

Hello Ron
Now that (cam bearing) sounds like a good guess.
The oil plugs are in behind the timing cover and by flywheel. There may be some plugs in the lifter valley but do not have intake off. May do that today.

The local installer paper work says 3 years with install and 1 year on self install. We are just out of the 1 year time frame. They did not rebuild the motor though. They bought it from a national rebuilder out of Dallas TX.
So I am hoping the local installer will cut me some slack. No harm to his pocket book as he will just send it back to Dallas.

This is getting way over my head but thinking and hoping my wife and kids would be treated the same when the time comes keeps me pushing forward.

Have a great holiday.
John