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Oil pressure light when just cranking after engine rebuild


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11 replies to this topic

#1 rallynutdon

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Posted 19 November 2013 - 08:37 AM

Just rebuilt engine with new bearings. Cranking for approx 1 minute and the oil light doesn't go off. In the past, knowing everything was lubricated well, I've never tried this, just left it fire and if oil light didn't go off after 2 or 3 seconds (always did) I'd be prepared to shut it off.  Anyone ever tried this method to make sure the pump is pumping oil? Should the light go off with just normal cranking after a minute? TIA



#2 ocei77

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Posted 19 November 2013 - 08:53 AM

The light won't go off until it's running for constant pressure.

As long as the oil leve is good, fire it up!

 

O.



#3 Gloyale

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Posted 19 November 2013 - 12:44 PM

Just rebuilt engine with new bearings. Cranking for approx 1 minute and the oil light doesn't go off. In the past, knowing everything was lubricated well, I've never tried this, just left it fire and if oil light didn't go off after 2 or 3 seconds (always did) I'd be prepared to shut it off.  Anyone ever tried this method to make sure the pump is pumping oil? Should the light go off with just normal cranking after a minute? TIA

 

Yeah.....the oil pump will take a bit to prime.

 

It is a good idea to do that way though.

 

Just crank a few more times till it goes out before reconnecting the coil and running.

 

If it REALLY doesn't want to prime, you can jack the rear of the car up as high as you can to tip the oil forward into the pump cavity.



#4 RallyKeith

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Posted 19 November 2013 - 01:31 PM

Yeah.....the oil pump will take a bit to prime.

 

It is a good idea to do that way though.

 

Just crank a few more times till it goes out before reconnecting the coil and running.

 

If it REALLY doesn't want to prime, you can jack the rear of the car up as high as you can to tip the oil forward into the pump cavity.

It's actually my motor he's talking about. I cranked it for about a minute. 10 seconds of cranking, 5 second pause, repeat, for a total cranking time of about 1 minute. Light never went off. Before putting the oil pan on I filled the oil pump and pickup tube to try and get oil in the pump. 

 

The switch for the light is supposed to go out when it's above 2.1psi. If I do some math and assume a linear relationship between the speced RPM and pressures in the manual I should be able to get around 10psi while cranking. 

 

I will probably try starting it and if the light doesn't go out within about 5 seconds I'll kill it.



#5 Gloyale

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Posted 19 November 2013 - 01:49 PM

Crank it for more like 20-30 secs at a time.

 

I would not want it to be firing and running without oil pressure.  Don't kill your new bearings for impatience.

 

Crank it until the light goes out.



#6 RallyKeith

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Posted 19 November 2013 - 02:24 PM

BTW, I've got the coil pack unplugged and fuse to the fuel pump pulled. Last thing I need is to be dumping tons of fuel into the exhaust or risk having it get past the rings and dilute the oil.



#7 MilesFox

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Posted 19 November 2013 - 07:54 PM

Fill up the oil filter if you haven't already



#8 Crazyeights

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Posted 19 November 2013 - 08:29 PM

If you pull the spark plugs out when you are doing the initial cranking it will spin the engine much faster. Also, it will put less load on the starter motor so you can crank a little longer. This should start the prime pretty quickly.



#9 RallyKeith

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Posted 20 November 2013 - 08:11 AM

Miles, Oil filter always gets filled up.

 

It was just an issue with priming. It wouldn't build pressure or flow at all. Finally got it to flow and build pressure on the starter by filling the pump through the where the oil pressure switch goes. Once I did that it built pressure just from cranking. Started it up and everything is fine.



#10 ivans imports

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Posted 20 November 2013 - 10:09 AM

I installed a rebiuld engine yesterday took 10 seconds for oil light to go out I do not crank them at all just fire it dont want to push all are assembly lube out cranking with no oil preshure is bad thing just fire it remember pump is trying to pull oil up hill and you dont make mutch rpms cranking



#11 Fairtax4me

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Posted 20 November 2013 - 05:53 PM

Pull the plugs out (also unplug the injectors) and it only takes 10-15 seconds of cranking for the light to go out, and there is no load on the bearings.

#12 ivans imports

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Posted 21 November 2013 - 11:15 AM

If you have faith in your work just fire it if not crank it






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