Oil Pump Failure

[milit73]

So I installed my new carb, valley pan, a couple of other things, and getting everything dialed in. Now out on my test drive the car is running pretty good so I start heading back home and pulling into the driveway I start hearing tap, tap, tap look down and now oil pressure. I turn the engine off quickly, get the car back in the garage, check my oil level (all good), checked my coolant after it cooled down and all checked out. Now I am thinking oil pump which I removed, primed new pump, installed, and now all checks out good.

Ok so what makes an oil pump go bad? Is this a common problem? Should I check anything else? I did shut the car down very quick but should I be worried about the internals of the engine? It sounds very good now and the pressure at startup was 60. Specs 383/727 68 Superbee. Thanks

 

[benno440]

if you only just lost pressure and turned the engine off, i highly doubt there will be anything wrong internally, just keep an eye on pressure and temp for a day or 2 if its ok then you should be fine

 

[nothingbutdarts]

Was the old pump locked up? Take the old pump apart and look it over good, also look at the pressure relief valve in it.

 

[milit73]

No when I removed it it turned freely. I will inspect it when I have some time. So is it something worth saving for future (bebuild if it can be)?

 

[nothingbutdarts]

No, just trying to find out what the failure was caused by.

 

[RustyRatRod]

I have learned to never say never.....BUT.....I've been workin on and around cars since 1974. I have NEVER in all that time seen an oil pump "fail". I mean not without some other cause. Like no oil. Or something making it lock up. Neither of which is the pump's fault. Is it a high volume pump? If so, are you running a hardened intermediate shaft? If not, you're supposed to. The extra load of a high volume pump will twist a stock intermediate shaft into a pretzel. Oil pumps spend their entire lives either in the pan on a small block, or hangin on the block full of oil on a big block. Kinda hard for one to just "fail". There will almost always be some other outlying factor.

 

[milit73]

That is why I asked what would cause something like this as I could not think of a good answer. This engine did sit for a few years but I primed the system before starting the car. I have not driven the car much since putting this engine in so I was not sure of the normal oil pressure but now with the pump off the original engine it sits about 60 PSI and much more consistant but I also replaced the oil sending unit. I will also be adding a new gauge that is not electric at some point also as I hear they are not that reliable.

Oh and there was plenty of oil as I drained it so see if my dipstick was wrong as it did not seem to be reading properly.

 

[HEMI-ITIS]

Did you open the old pump??Were the rotors scored?How is the drive gear and tip?

 

[milit73]

I did not tear into the old pump so I have no answer there. As much as I could see the shaft to the pump it seemed fine but have not checked anything else. The gear drive I did not think to look at but should have now that you bring that up!!!!

 

[Meep-Meep]

The fact that you heard a tick, tick sound may indicate dry lifters from, as you found out, no oil pressure. I agree with Rusty about oil pump failures - as in there aren't any to speak of. I have pulled those apart where they looked like they were pumping sand and the engine still had oil pressure. Anyway, it's possible the pressure relief got stuck open somehow. I had a crappy oil filter cause me problems on start up but that wouldn't apply here. And it seems that you filtered out other possible causes. Another thing might be a heavily restricted oil pickup. But other than pieces of nylon from an old style timing chain sprocket I don't see what could do that.

- - - Updated - - -

I did not tear into the old pump so I have no answer there. As much as I could see the shaft to the pump it seemed fine but have not checked anything else. The gear drive I did not think to look at but should have now that you bring that up!!!!

That gear also drives the distributor so if there is a disconnect on the cam end the engine wouldn't run. There is also a pin that holds the cast iron gear to the shaft and same thing there. If the pin shears the gear may just spin on the shaft and not turn the distributor or oil pump.

 

[Stumper]

For the oil pressure to suddenly go to zero would indicate a complete shutdown of the pump, if it is the pump. Which would almost have to be a break in the shaft driving it. Scoring of the internals would not make it drop to zero like that. If this is not the case and the pump turns with the shaft then I would go to the next easy things to check and see if something suddenly plugged the pick up or if the gage is bad..
I am thinking though .... that you may find you answer under the valve covers? A sudden complete drop off in oil pressure might be a lifter out of the pocket, for several reasons. Hopefully not.

 

[dryheat]

I agree with Stumper about looking under the valve cover for a possible issue. Also ... I had an old Roadrunner 383 that spun a rod bearing out of nowhere and there was 0 oil pressure but it still ran like you described.

I seriously doubt that the pump failed ...

 

[RustyRatRod]

I have gotten both BRAND NEW oil pumps and rebuild kits and the rotor looked to be "scored". I think they are made like that for some reason. Perhaps to vary from a smooth surface much in the same way an unequal spaced fan will move more air. Every single new pump or set of rotors I've ever seen in my life was never smooth.

 

[68 HEMI GTS]

the relief valves can stick, if that the case with yours (i don't know) pull the cover apart and debur everything so it moves freely. what kind of oil filter you have? the orange can of death can cause loss of oil pressure too.:angry7:

 

[milit73]

I will take the car out soon and see how it goes. All I know is that after changing out the pump all is back to normal and even better pressure at this point but only ran the car for about ten minutes before having to leave and shut it down. As I said this engine sat for a few years so not sure that has anything to do with it. I hope that its fixed but lately its been a battle. I have been trying to get the car back to my house for about almost a year after giving my dad a ride before he passed (he bought this car in 1970) leaking trans fluid everywhere. Since then replace the original drivetrain with what is in there now so I can rebuild it in the future but enjoy it now. It just seems like it does not want to come home so it can get more attention as it is an hour away. Getting a little frustraited (spelling) at the moment as I want to be working on and driving it more. OK vent over sorry. Jim

Thanks for all of the help and I will keep updating......................

 

[RustyRatRod]

the orange can of death can cause loss of oil pressure too.:angry7:

That's a good one. And so true.

 

[milit73]

I bought a "upgraded" filter and it was black but for the life of me I cannot remeber the brand. What do you run?

 

[Stumper]

Sounds like a WIX filter. I run them on my hot rod exclusively.

 

[RustyRatRod]

Yup. WIX is good.

 

[Cranky]

Haven't bought a WIX in awhile but the ones left on my shelf are white and the Mobil 1 filters are black and I believe K&N's are black but it should have a name on em. I quit using Fram many moons ago after cutting a few open and seeing how cheap they are.