Low oil pressure on new 427 build
09-12-2009, 03:46 PM
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Low oil pressure on new 427 build I recently installed a LS2-based 427 in my car. After buttoning everything up I cranked the car over with no fuel or spark for 20 seconds at a time to prime the oil system. I did this about 10 times giving the starter motor 30-60 seconds to cool off each time.
My oil pressure gauge is hooked up to an ACC +12 that switches off during cranking, so I didn't see what pressure I was getting until I fired up the motor the first time. As soon as the gauge cycled on I could see that I was only getting about 10psi of pressure so I switched the motor off.
I re-wired the oil pressure gauge so it stays on during cranking. I then removed the serpentine belt and the spark plugs (and disconnected fuel). I cranked the engine for about 30-40 seconds. Each time, my SPA digital oil pressure gauge showed only about 1.5psi. The gauge sender is mounted at the top of the motor in the valley cover. I've checked over the car and there are no leaks.
Before I pull the subframe apart and drop the oil pan (which takes about 2-3 hours on my car) I wanted to make sure that there isn't something else I should check. My sense is that there is might be a problem with the pickup tube o-ring, but I'd love to know if there are other possibilities that I should think of.
This is immensely frustrating. Any help or advice would be greatly appreciated. Thanks,
-ch
My oil pressure gauge is hooked up to an ACC +12 that switches off during cranking, so I didn't see what pressure I was getting until I fired up the motor the first time. As soon as the gauge cycled on I could see that I was only getting about 10psi of pressure so I switched the motor off.
I re-wired the oil pressure gauge so it stays on during cranking. I then removed the serpentine belt and the spark plugs (and disconnected fuel). I cranked the engine for about 30-40 seconds. Each time, my SPA digital oil pressure gauge showed only about 1.5psi. The gauge sender is mounted at the top of the motor in the valley cover. I've checked over the car and there are no leaks.
Before I pull the subframe apart and drop the oil pan (which takes about 2-3 hours on my car) I wanted to make sure that there isn't something else I should check. My sense is that there is might be a problem with the pickup tube o-ring, but I'd love to know if there are other possibilities that I should think of.
This is immensely frustrating. Any help or advice would be greatly appreciated. Thanks,
-ch
09-12-2009, 04:16 PM
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are you certain the dumbell galley plug was installed at the back of the block? If it's not there the oil is pumped straight out of the block underneath the rear cover and back to the pan.
09-12-2009, 05:40 PM
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I'm not completely sure. The motor was built by Katech so I feel pretty confident, but it's a great suggestion that I will have to investigate if the pickup tube is not the issue.
It's worth noting that the oil pump is new as well.
I'm wondering, however, if a problem with the pickup tube can really result in only a few psi of pressure during cranking?
-ch
It's worth noting that the oil pump is new as well.
I'm wondering, however, if a problem with the pickup tube can really result in only a few psi of pressure during cranking?
-ch
09-12-2009, 07:29 PM
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JFM is right. Talk to Katech, there's no way they missed the galley plug, but they'll know where to start looking. They know their stuff, did they build the whole motor or short/long block?
09-12-2009, 07:57 PM
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-ch
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09-12-2009, 09:47 PM
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The problem was confirmed after pulling the plugs out and disconnecting the fuel and cranking (about 150 RPM according to HPTuners) for 30 seconds or more. I repeated this step about four times. I could get no higher than 1.5 psi.
I just pulled the sensor out and tested it against my air compressor line. It is working normally--so there is definitely a pressure issue in the motor somewhere.
Next step: pull the pan and inspect the pickup tube, I guess.
-ch
09-12-2009, 10:48 PM
#9
There are a few plugs that need to be checked. I also bought a built short block. I bought one of those how to build an LS1. I checked the barbell and plugs.
Take the valve covers off and see if you got oil up there. If you don't, I read about a guy here who posted a no psi and no oil up top. He found the front oil plug was missing. It was the one under the front cover.
Take the valve covers off and see if you got oil up there. If you don't, I read about a guy here who posted a no psi and no oil up top. He found the front oil plug was missing. It was the one under the front cover.
09-13-2009, 03:03 PM
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I pulled the head covers off and it's bone dry up there except for the assembly lube.
I looked at some pictures that I took of the motor during build and I can see that the oil plug on the front is in place. Unfortunately I didn't photograph the back of the motor so if it comes to that I'll need to pull the trans and the rear cover...
-ch
I looked at some pictures that I took of the motor during build and I can see that the oil plug on the front is in place. Unfortunately I didn't photograph the back of the motor so if it comes to that I'll need to pull the trans and the rear cover...
-ch
09-13-2009, 05:08 PM
#11
I pulled the head covers off and it's bone dry up there except for the assembly lube.
I looked at some pictures that I took of the motor during build and I can see that the oil plug on the front is in place. Unfortunately I didn't photograph the back of the motor so if it comes to that I'll need to pull the trans and the rear cover...
-ch
I looked at some pictures that I took of the motor during build and I can see that the oil plug on the front is in place. Unfortunately I didn't photograph the back of the motor so if it comes to that I'll need to pull the trans and the rear cover...
-ch
Good luck to ya.
09-13-2009, 05:21 PM
#12
If you dont have any oil in the top of the motor then its definatly the rear plug or the o ring, most likely the plug, if the o ring is pinched you should have decent pressure at start up and pretty low when up to temp as the oil thins out. Where the plug is located is where the oil makes a vertical turn to oil the camshaft and lifters, basically the oil has nothing to convert the flow and pours down the inside of the rear cover.
09-13-2009, 06:40 PM
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Is there any way to test to see if the dumbbell plug is missing other than by pulling the rear cover? For instance, if I took the oil cooler block off the side of the oil pan and ran a feeler into the aft port towards the back of the motor, wouldn't I hit the barbell pretty quickly? (I'm running a F-body pan.)
-ch
-ch
09-13-2009, 06:40 PM
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Is there any way to test to see if the dumbbell plug is missing other than by pulling the rear cover? For instance, if I took the oil cooler block off the side of the oil pan and ran a feeler into the aft port towards the back of the motor, wouldn't I hit the barbell pretty quickly? (I'm running a F-body pan.)
-ch
-ch
09-13-2009, 07:09 PM
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not sure that will work for you - the bypass plate is a few inches below the gallery if memory serves. Then you have to make a right turn. But what the hell, it's worth a try.
09-21-2009, 04:08 AM
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I will know tomorrow, but 99% it's the dumbbell plug. There are great ways to learn about these little details. I'm not feeling like this is one of them...
-ch
-ch
09-24-2009, 06:28 PM
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Well, mystery solved. What's missing from this picture?
Okay, so just because I never want to open this cover up again, I want to make sure I get the install of the dumbell plug right. Do I:
Thanks!
-ch
Okay, so just because I never want to open this cover up again, I want to make sure I get the install of the dumbell plug right. Do I:
- Push the plug in as far as it will go,
- Lightly seat it and let the cover press it in, or
- Something else?
Thanks!
-ch
