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Low oil pressure after rebuild

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Offline zuki1018

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Low oil pressure after rebuild
« on: October 26, 2011, 06:37:59 AM »
Hey folks.  As some of you know, I rebuild the 16v myself a few months back.  I have very little run time on it.

I have 50-60psi when the engine is cold. As the engine/oil warms the pressure starts getting lower.  At 800-1000rpms my guage shows little to no pressure.  When i rev the pressure does climb.

When people talk of "priming the oil pump", is this for lubrication on first cranking or for purging air from the pump or something along those lines?

Also i have a oil leak that popped up at my oil pump seal.  (my oil pressure is/was the same now as before the leak) Is there a suggested way to ensure I dont have to pull the front of my motor apart again??  The metal gasket that seals the pump should or should not have gasket sealer on it? ...should I just use oil resistant gasket sealer to start with and leave out the metal gasket? TIA

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Offline talonxracer

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Re: Low oil pressure after rebuild
« Reply #1 on: October 26, 2011, 06:52:14 AM »
New oil pump?

What were the clearances on the new bearings both mains and rod big ends?

What type and weight of engine oil?

As far as I know any and all metal gaskets should be used WITHOUT any sealant
« Last Edit: October 26, 2011, 06:55:22 AM by talonxracer »
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The only GOOD Commie is the commie taking a dirt nap....

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Offline zuki1018

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Re: Low oil pressure after rebuild
« Reply #2 on: October 26, 2011, 07:09:37 AM »
New oil pump?
Ya, everything is new (other than cam/head, crank/block)

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What were the clearances on the new bearings both mains and rod big ends?
I would have to look back. Do you mind explaining how tight bearings could cause this so i can comprehend.

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What type and weight of engine oil?
I 'think' I bought regular Valvoline 10-30... may be 5-30.  Will check later also.

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As far as I know any and all metal gaskets should be used WITHOUT any sealant
Thats what I thought also.  I did tighten the oil pump to block bolts to spec. 

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Offline lv2fsh

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Re: Low oil pressure after rebuild
« Reply #3 on: October 26, 2011, 07:16:19 AM »
It's possible that the little O ring on the oil pickup tube was damaged or left off. If you don't get a good seal, you start sucking air. As th oil gets warmer it gets thinner and the pressure will drop.

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Offline talonxracer

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Re: Low oil pressure after rebuild
« Reply #4 on: October 26, 2011, 09:29:13 AM »

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What were the clearances on the new bearings both mains and rod big ends?
I would have to look back. Do you mind explaining how tight bearings could cause this so i can comprehend.

 

I was only asking what the clearance were, didnt mention anything about tight bearings, I was thinking more along the lines that you may have too much clearance which would cause low pressures when at operating temps, and why I asked what the clearances were at. Just covering all the bases.
Tim "the toolman" Taylor is my HERO !!!

The only GOOD Commie is the commie taking a dirt nap....

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Offline mrfuelish

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Re: Low oil pressure after rebuild
« Reply #5 on: October 26, 2011, 09:34:10 AM »
could also be a stuck pressure relief valve.
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