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Problem with new oil pump (sbc)

18K views 20 replies 10 participants last post by  delawarebill 
#1 ·
I just installed another oil pan and changed the Melling Select HV oil pump (10550) for a Melling Select stock volume (10553). Now everything is back together, I just went to prime the pump using a priming tool and the pump is noisy and the shaft doesn't turn smoothly. I removed the priming tool and stuck a flat blade screwdriver on the end of the oil pump drive shaft and I could feel the jerkiness in the shaft as I turned it with the screwdriver. It was generating healthy pressure for the brief time I ran the drill with the priming tool, but obviously something is definitely not right. It's worth noting I did turn the shaft before installing the pump and it was perfectly smooth. I also had the cover off to change out the pressure spring. Anyone have any ideas?
 
#2 ·
v8hed said:
I just installed another oil pan and changed the Melling Select HV oil pump (10550) for a Melling Select stock volume (10553). Now everything is back together, I just went to prime the pump using a priming tool and the pump is noisy and the shaft doesn't turn smoothly. I removed the priming tool and stuck a flat blade screwdriver on the end of the oil pump drive shaft and I could feel the jerkiness in the shaft as I turned it with the screwdriver. It was generating healthy pressure for the brief time I ran the drill with the priming tool, but obviously something is definitely not right. It's worth noting I did turn the shaft before installing the pump and it was perfectly smooth. I also had the cover off to change out the pressure spring. Anyone have any ideas?
May have picked up something from the screen if it was not cleaned out good before installation. Or it may have had something in pump. It really don't matter it's gotta come back out one way or another. Then you will find the problem.
 
#4 ·
DoubleVision said:
I've never had a oil pump turn smoothly. Every last one I ever installed had hard spots in the revolution. This is to be expected since the gear mesh between the two is tight. However I none of them made any noise that I recall.
Really? Interesting. Unfortunately, my only frame of reference was an old oil pump with a few thousand miles on it... that turned smooth as silk, hence my concern when this new pump wasn't the same way.

Before this new pump was installed, the gears turned perfectly smoothly (of course, it wasn't working against oil pressure).

With a long screwdriver turning the oil pump drive shaft by hand, I can distinctly feel some pretty bad 'notchiness' in the pump drive as I turn it slowly with the screwdriver. The noise might be simply because the drill is turning this notchy/jerky drive shaft at a couple of thousand RPM and is causing a lot of vibration through the drive shaft and drill. It really doesn't feel right, but this is the first new pump I've installed and primed.

Anyone else with a few new oil pump installs under their belts care to comment? I'll tear everything down again if I have to, but it's a major PITA and I'm not keen to do all that when this might be perfectly OK.

Do oil pump gears 'wear-in' to each other in a short amount of time? Is there some kind of bedding-in that happens?

f
 
#5 · (Edited)
I just went out to the garage and tried again, this time with a quieter (cordless) drill. I took a quick vid with my phone (forgive the awful quality; it's dark here and my phone battery was too low to use the flash). Guage is a dash-mounted gauge on the end of a long capillary tube just propped-up inside the windshield...

http://youtu.be/-5tLWd7owVs

With the quieter drill, I can now say the oil pump doesn't make any unusual noises... it just doesn't turn smoothly and there's a lot of vibration felt through the drill when priming it. Pressure rises quickly to 65psi however (I think it would've gone to 70, which the pressure relief spring is rated for, but my drill battery needs charging).

What do you think? Normal?

I also found this vid and this guy's oil pump sounds similar to mine (pretty noisy)...

http://www.youtube.com/watch?v=jPSPwLMlLB0

Hard to tell though.
 
#6 ·
Do you actually drive this car or spend all of your time worrying about meaningless things? Why would you even change out the oil pan and what would possess you to prime the engine's oiling system again? The things you come up with are just unbelievable. Start posting your stuff in the basics forum.
 
#7 · (Edited)
Are you pushing down towards the pump with the drill? There shouldn't be any downward force applied to the oil pump shaft, or the gear attached to it will be forced into the oil pump cover and drag/bind.
Also the engaugement between the priming tool and the pump shaft is not exactly a precise fit that may create some clatter/vibration.
I'm sure youve seen/heard of spacer/washers that are installed between the intake manifold and the distributor collar to make sure when the distributor is tightened that it is not binding the pump. You can tell its not binding if you can insert the distributor without a washer and the collar sits all the way down on the intake. If it doesn't sit flush on the intake you can use a feeler gauge to measure seperation and install a washer thats about .050" thicker.
IMHO/FWIW
ssmonty
 
#8 ·
ssmonty said:
Are you pushing down towards the pump with the drill? There shouldn't be any downward force applied to the oil pump shaft, or the gear attached to it will be forced into the oil pump cover and drag/bind.
Also the engaugement between the priming tool and the pump shaft is not exactly a precise fit that may create some clatter/vibration.
FWIW
ssmonty
Not pushing down... just the weight of the drill. The priming tool is the type with the valley collar, which I believe would prevent any undue downward pressure on the drive shaft. The drive shaft does not turn smoothly... if I stick a screwdriver on it and turn it slowly by hand, I can feel the shaft kinda jerking in steps rather than being buttery smooth. No other symptoms. I'm starting to think maybe it's normal, but I was just expecting the shaft to turn smoothly.
 
#10 ·
ssmonty said:
The weight of the drill is too much pressure.
ssmonty
The collar on the prime tool limits the engagement depth (I think), so the weight above that should be a non-issue? I just tried again taking the weight of the drill and it's exactly the same. As I said, the pump drive shaft is jerky when turning it by hand with a screwdriver.
 
#11 ·
v8hed said:
The collar on the prime tool limits the engagement depth (I think), so the weight above that should be a non-issue? I just tried again taking the weight of the drill and it's exactly the same. As I said, the pump drive shaft is jerky when turning it by hand with a screwdriver.
so go buy another pump and try it with the screwdriver.
 
#13 ·
v8hed said:
Really? Interesting. Unfortunately, my only frame of reference was an old oil pump with a few thousand miles on it... that turned smooth as silk, hence my concern when this new pump wasn't the same way.

Before this new pump was installed, the gears turned perfectly smoothly (of course, it wasn't working against oil pressure).

With a long screwdriver turning the oil pump drive shaft by hand, I can distinctly feel some pretty bad 'notchiness' in the pump drive as I turn it slowly with the screwdriver. The noise might be simply because the drill is turning this notchy/jerky drive shaft at a couple of thousand RPM and is causing a lot of vibration through the drive shaft and drill. It really doesn't feel right, but this is the first new pump I've installed and primed.

Anyone else with a few new oil pump installs under their belts care to comment? I'll tear everything down again if I have to, but it's a major PITA and I'm not keen to do all that when this might be perfectly OK.

Do oil pump gears 'wear-in' to each other in a short amount of time? Is there some kind of bedding-in that happens?

f
It should turn smoothly from the get go.

Bogie
 
#14 ·
I think I might know what's causing the problem...

I'm using ARP mains studs and the oil pump housing needs grinding to clear the stud adjacent to the pump on the rear main cap. I thought I had clearanced the housing sufficiently, using the pump I removed as a template to work to. Unfortunately, it's virtually impossible to get eyes on the stud/pump relationship with the engine in the car and working under the car on axle stands. I tried as best I could to inspect this area with an articulated inspection mirror and a bright light and I thought it looked OK. However, I now have a theory that the pump housing is hung-up ever so slightly on the stud as perhaps I didn't quite remove enough material from the housing when I clearanced it. This would cause the oil pump drive stub to be at a v.slight angle relative to the oil pump prime tool. Under load, this slight (probably only 1* or less) angle would show-up as vibration through the prime tool into the drill.

The only problem with this theory is I can't figure-out how that could cause the pump to feel very notchy/jerky when simply turning it slowly by hand with a screwdriver. Perhaps interference between the drive shaft collar and the oil pump drive stub, since the collar is a fairly snug fit? Although I can't think of anything (without the distributor installed) that would constrain the oil pump drive shaft in a dead straight line.

I'll drop the pan again and see what I can see (damn PITA).
 
#15 ·
When in doubt, pull the pan and pump; disassemble the pump and inspect the two gears for any evidence of debris passing between the gears. If there has been, you will see small gouges left by the debris. Hope you don't find any!

Another item if you have a 400 SBC is that the 400 takes a necked-down oil pump drive shaft to avoid rubbing on the rear main bearing cap.
 
#16 ·
UPDATE...

Dropped the pan and pulled the pump.

Turned the pump shaft with it off the motor while it still had some oil in it and it felt horrible... not smooth at all and turning in really jerky steps. Emptied the oil out and now it feels smooth again when I just spin the shaft with my fingers.

I pulled the pump cover and inspected the gears... there's no damage, but I can see shiny and dull patches on each gear where they've been meshing. The black idler gear has some of the black coating partially worn away from this. Also, the gears have worn a few shiny patches on the inside of the housing, but nothing you can feel with your finger.

Does this all sound normal?

It's amazing how much difference there is in the smoothness of the pump between it being empty and it being full of oil.... perfectly smooth when empty and notchy as hell when there's oil in there.

At least this hasn't been a complete waste of time, as I discovered the front and rear seals were weeping, so I'll replace the gasket when I reassemble.
 
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