I agreed to install a remanufactured engine for the daughter of a board member. Old engine had knocking #3 rod and low oil pressure. Car is a 68 Dart.

I got the engine installed and broken in today. I was using a hand held electronic oil pressure gauge to monitor oil pressure during break-in. Oil pressure was about 25-30. Seemed low for a rebuilt engine, but OK.

Break in run completed, oil changed, valves adjusted, timing and idle set. I reconnect the stock oil pressure idiot light. I start the car and get the bright red oil light shining at me. My heart sinks. I rev the engine and the light goes out, but at idle the lights comes on and stays on.

I think I made a stupid mistake. The new engine came with a Melling five hole oil pump. After reading about the sealing issue and the drive gear failure issues with selling pumps, I decided to reuse the original early 70s factory oil pump that was in the motor with the knocking rod.

Well, it looks like a worn out oil pump was the cause of the failure of the old motor, and I just transferred that problem to the new motor.

And, to top it off, I was supposed to have this done and ready to go by this evening.

Is there anything I can do short of pulling the pump? Can I clean out the relief valve with the oil pump installed in a wide A body? Worst case scenario- I know I can remove the pump with the engine in the car, but can I install the Melling pump with the engine in the car?

I feel very stupid and want to kick my own ass right now. Any suggestions are appreciated.

Don't kick yourself too hard. We've all made them. If I've made my last thoughtless error, I'll be dead before tomorrow morning.
Quickly and quietly get the rebuilder's oil pump back on the engine, then quickly and quietly delete this thread. As a previous poster in your other thread mentioned, the rebuilder's warranty is probably contingent on no parts-swapping.
Probably.
Probably, with DusterIdiot's procedure.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Good advice on all points. I just hate giving someone an engine with a known problematic oil pump.

I am going to try changing the sending unit on the off chance that the unit on the car is bad. If that doesn't fix it, off comes the old pump, on goes the new. I doubt I can get that done in a few hours, but I am going to try.

Thanks for the advice and support.

And even easier with the 1967-1972 motor mounts than the 1973-1976 spool mount ears on the K-member... The only one that really isn't easy is the 7/8" HP oil pump swap...that just ain't good (another reason to not use one...unless absitively necessary)

Good luck, Reed we are rooting for ya!!!!!

I forgot to look at your other posts, did you pull open the old pump and check the ring and rotor for any nicks or damage, and the housing bore?
Did you break open the FSM and check to see the clearances between the rotor and ring to see how loose they were?

Wrong neck of the woods or I'd give you a hand. Good luck in getting it done.

This dart has had the later 73-up spool mount k-frame installed, so it has spool motor mounts.

Before I installed the engine, I had the oil pump in my hand, thinking, "Maybe I should open it up and check all the clearances," but I was in a rush so I decided not to do it. Yet again, I learned the truth of the saying, "an ounce of prevention is worth a pound of cure."

I can confirm that it is possible to get the relief valve plug off with the engine fully installed a wide A body. Not fun, but possible. Shimming the spring did not help in my situation.

I need to talk to the owner and see what she wants to do. Off idle it has OK pressure, but at idle the light comes on. Only option at this point is to install a new/different oil pump, and that means loosening the motor mounts, draining the radiator, and hoisting the engine up. That won't happen until this weekend.

Thanks for the support and advice.

Maybe just maybe it's the pressure switch..............

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

That was the first thing I replaced. Believe me, I am fundamentally lazy, so I try all the easy solutions first. New switch didn't fix it, shimming the pressure relief valve didn't fix it. All that is left is swapping out the pump. Maybe I can get my self a hair shirt while I am at it.

Anyone in the Puget Sound area who feels like lending a hand can drop by my place this Saturday morning....

Messed with it, didn't you... Put the original oil pump back and hope for the best. If no improvement make a warranty call. Hopefully the remanufacture doesn't read this forum.

If your in a hurry - you can remove the pressure relief valve, clean it out, put a washer under the spring, maybe stretch the spring a bit, and reassemble. This will up the pressure until you can find the time to swap the pump proper.

The pressure relief valve shouldn't make a difference at idle unless it's stuck open.

I doubt increasing the spring pressure would help at idle.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Are the gears themselves interchangeable between the Melling pump and the stock pump? If so, and if the stock pump clearances are out of spec, maybe drop the outer gear from the Melling pump into the stock pump and see if the clearance is any better. Unless there's a difference in hardness between the gears, or any other reason this would be a stupid idea.

Also, I can confirm that you can also remove the pressure relief valve with the pump installed in an early A-body. I did it in my '64 when I was paranoid about low oil pressure while spinning the rebuilt engine over the first time. Turned out my battery was just too low to turn it over fast enough.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

The original oil pump is what I installed. I am going to install the Melling pump. I didn't mess with anything, just swapped the oil pump, water pump, oil pickup, oil pan, valve cover, fuel pump,,manifolds, etc... My mistake was using the original oil pump and not the replacement Melling pump. No messing was done.

Tried that. If it did anything, it made it worse.

The Rotor and outer pump ring are different thicknesses between makes...The melling ring and center rotor are thicker than the stock
set anywhere from 1/8" on the normal melling to 3/8" or so on the HP pump,
so no swap there. Also the melling guts are a little softer than the OEM
pump parts innards and drive gear...