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How to Check Oil pressure, on the engine stand

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Old 05-10-2009, 01:01 AM
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Default How to Check Oil pressure, on the engine stand

If you have ever installed a LS motor and had oil pressure problems, you know it is not fun. The usual suspects are: O ring on the pickup tube, metal plug in the front of the block, barbell in the back, and my favorite; the pickup is too low in the pan. Here is a simple solution that is worth trying. With the short block together, oil filter on, 5 qts of oil in the pan, lifters installed, and no rockers or sparkplugs. Hook up a mechanical gauge, put a breaker bar on the crank and crank it over as fast as you can. Link to oil pressure video.

http://www.youtube.com/watch?v=YT-yCLo2dos

In the video it gets oil pressure really quick because we tried it a few minutes before. When the motor was dry, it took at least 30 or 40 cranks to get pressure. All of that noise is from the spark plug holes.
I would never install a motor without trying this first.
Old 05-10-2009, 06:19 AM
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Originally Posted by racecar
If you have ever installed a LS motor and had oil pressure problems, you know it is not fun. The usual suspects are: O ring on the pickup tube, metal plug in the front of the block, barbell in the back, and my favorite; the pickup is too low in the pan. Here is a simple solution that is worth trying. With the short block together, oil filter on, 5 qts of oil in the pan, lifters installed, and no rockers or sparkplugs. Hook up a mechanical gauge, put a breaker bar on the crank and crank it over as fast as you can. Link to oil pressure video.

http://www.youtube.com/watch?v=YT-yCLo2dos

In the video it gets oil pressure really quick because we tried it a few minutes before. When the motor was dry, it took at least 30 or 40 cranks to get pressure. All of that noise is from the spark plug holes.
I would never install a motor without trying this first.
Starter motor works ok too .
Old 05-10-2009, 06:34 AM
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That's good oil pressure to be turning the engine by hand.
Old 05-10-2009, 11:51 AM
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I was happy with 40 psi cranking by hand. I can't explain why it stops at 40. When I try to crank faster, it stays on 40. LS6 ported pump with shim.

Starter will do the same trick, if you have the right battery cables.
Old 05-10-2009, 04:35 PM
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Originally Posted by racecar
I was happy with 40 psi cranking by hand. I can't explain why it stops at 40. When I try to crank faster, it stays on 40. LS6 ported pump with shim.

Starter will do the same trick, if you have the right battery cables.
The relief valve probably operates at 38-40psi with the shim, limiting the pressure if you are still ramping up the rpm.
Old 05-11-2009, 12:01 AM
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OK i just tried this Didnt see anything on my short block. if i do this should i be able to see oil pumping in the back hole of block with gauge out ?
Old 05-11-2009, 02:35 PM
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I pulled my oil filter off it pumped oil out of where the oil filter screws on. Maybe im just not turning it fast enough?
Old 05-11-2009, 02:46 PM
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Originally Posted by BigRich954RR
I pulled my oil filter off it pumped oil out of where the oil filter screws on. Maybe im just not turning it fast enough?
use an impact wrench
Old 05-11-2009, 07:57 PM
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The first time that I tried this was with the new motor, oil passages dry, filter full. With the oil pressure gauge in the back top of the block I cranked for 15 revolutions, nothing, cranked another 15, nothing. I pulled the plug on the side of the block, next to the oil pump, oil ran out. Put the plug in, cranked another 15, Got Pressure, then I could hear it gurgling inside the motor. The oil has to fill the passage from the pump all the way back to the filter, then up to the top, and fill both passages by the lifters before you will have any pressure, that's a lot of oil. Keep cranking, from my experience, it took 45 turns the first time to get pressure. We shot the video, AFTER it had been pressured one time.
Old 05-30-2011, 02:41 PM
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Good info!!
Old 05-30-2011, 09:44 PM
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How about some pics of where you hooked up your mechanical gauge and what kind?

Please and thankyou!
Old 05-30-2011, 11:57 PM
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You should avoid putting an impact on your crank if you can help it. It beats the **** out of the bearings.

Also if you want a faster prime, pull the oil pressure sensor out of the back of the block and pour oil down it.
Originally Posted by slayerized6
use an impact wrench



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