Forgot to Prime Oil pump

xtrabolts

Registered User
I replaced a 93 engine (180k) with a 90 engine (160k). It is supposed to be only a temporary situation so I can rebuild the 93 engine at my liesure, but the 90 has 175 pounds of compression, so I figure I can take my time. I did replace the head gaskets and timing chain for the heck of it, but other than that, I did bascially nothing else. I did pull the oil pump apart though and forgot to prime it before I reassembled everything.

My question is whether or not the unprimed pump will prime itself and if it won't will putting oil down the sending unit fitting prime it?

Thanks in advance for any help.
 
I can back it up because it primed itself for me whenever I put my motor in earlier this year.

If you're concerned then unplug the coil pack and hold the starter and let it turn over for about 5-10 seconds. When the motor is turning over the oil pump gear drive creates a vacuum through the pickup and takes oil from the pan and disperses it throughout the motor. So all you need is rotation to get oil pressure.
 
you have to fill your filter correct cause i turned mine over for 20 seconds overall and oil fillter was dry as a bone
 
Yes it's self priming...just disable the fuel pump and crank it for about 10-15 seconds a few times before starting the motor. Filling the filter won't help prime the pump. It picks up oil from the oil pan, then goes out into the filter then from the filter it goes back into the motor and is pumped to several areas.

David
 
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It will help to fill it, but you don't necessarily have to. Whenever you get the motor started stare at the oil pressure gauge and see if it will come up within 5-10 seconds. The starter may not be providing enough RPM to move the oil very far.
 
What about the old drill on the oil pump shaft thing.

I rebuilt a n/a ford 3.8. Took at least a minute or two of running before it got enough pressure to activate the gauge. scared me, first motor I ever did.

I don't see how just cranking it over without the car starting would be any better for the motor then just starting the car and letting it idle??
 
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If you hold the throttle to the floor it will shut the injectors off so you won't get any fuel going into the motor while you are just turning it over.

If you pull the plug for the fuel pump you still have excess fuel in the lines that will be injected into each port.
 
What about the old drill on the oil pump shaft thing.

I rebuilt a n/a ford 3.8. Took at least a minute or two of running before it got enough pressure to activate the gauge. scared me, first motor I ever did.

I don't see how just cranking it over without the car starting would be any better for the motor then just starting the car and letting it idle??

I did this to verify that i had oil pressure on my 92NA when i swapped a motor in from a 94 mustang after i threw a rod. (the oil light was on when i had pressure, musta went through a relay and operated an on/off gauge like the one in the SC in the mustang)
The bolt that covers the hole where the distributor would be has a securty torx on it (it has one of those nipples in the middle). Then you will need a shaft about 2 feet long and you'll have to grind/file/machine down the end to properly fit. I can't even rememer whether it was 4 or 6 sided, let alone size. This would be a reasonable option of you are worried about running the top end without oil while the pump primes.
 
I always use an old distributer shaft...

Its more then just priming the oil pump. You want to assure everything is lubed up before starting your engine...

Dry cranking an engine is NEVER a good thing
 
Its relatively easy to remove the pump, pour oil in it and reinstall it. Years ago, mine didn't want to prime itself and I didn't want to risk running the engine any longer than 1-2 seconds w/o oil pressure. :rolleyes: I removed it, filled it, reinstalled it, and had oil pressure right away on the next start. :)
 
Pull out cam sensor....

Put in 4 or 5L of oil into the motor through the opening for the cam sensor...

Using a paint mixer (the ones you can buy for cheap at home depot for use with a drill, and then cut off), spin the oil pump. If you hear bubbles in the oil pan, spin it the other way so it's sucking rather than blowing. I believe it's supposed to be clockwise...

Watch the rockers, when oil starts coming out of ALL of them, then the motor is primed.

Check for leaks and proper oil level in the crankcase.

This has worked for me three times in a row. You don't have to pre-fill the oil pump or filter.
 
Old distributor with cam gear removed and drill works every time. Definatly don't crank motor to prime it.

Filling the oil filter is optional, it will shorten the amount of time you have to spin the oil pump with the drill, so its not a bad idea.

Oh, and high speed air drills work awesome at this.
 
another thing with using a drill is, you don't have to go full bore with it. It doesn't take much to get 60psi of pressure pumping through. I just get a nice and slow consistant pace for about 5 minutes.
 
Using a paint mixer (the ones you can buy for cheap at home depot for use with a drill, and then cut off),


Careful now, when I primed my motor i remember reading a post where somebody sheared one of those cheap hex paint mixer things inside the timing cover...had to take it out and clean all the small pieces of metal out. I went to the junk yard and took appart an n/a 3.8L distributor and took the shaft and used that autozone extension thing with a drill.
 
I just use the shaft from the cam synchro in the car, a socket, a long 1/4" (12-14") extension, and a cordless drill.
 
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