Yes. Another low oil pressure thread. UPDATE 7/28
07-20-2011, 08:40 PM
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Yes. Another low oil pressure thread. UPDATE 7/28 Ok so Ive been searching and going through low oil pressure threads, but I haven't found any with my circumstances.
Forged 347 w/20 miles on it. Finally got to drive it today to work to fab up the exhaust.
Joe gibbs 5w30 break in oil
Mehling High flow/ high pressure pump
-4 feed line with NO restrictor.
My problem is that on cold startups I get 60-65psi oil pressure at idle.
While driving, still cold Im still seeing around 60psi
once it gets to operating temp on the highway it will sit at 40-45psi while cruising.
Now at a stop light on a 100*F day it will chill at 15psi. sometimes a tad lower. Oil pressure never makes it to the red on the gauge.
I keep reading everywhere that the bearings may be the culprit, but it runs fine and makes no noises. Also the fact that the oil pressure is so good on cold startup on mine compared to other threads I have read. But I read in previous threads that the sound of the engine doesn't mean jack.
Do you guys think this about normal?
I was suggested that I change the oil and filter first and try a higher weight oil while Im at it.
I was also thinking about adding a restrictor to the feed line.
Let me know what you guys think.
Forged 347 w/20 miles on it. Finally got to drive it today to work to fab up the exhaust.
Joe gibbs 5w30 break in oil
Mehling High flow/ high pressure pump
-4 feed line with NO restrictor.
My problem is that on cold startups I get 60-65psi oil pressure at idle.
While driving, still cold Im still seeing around 60psi
once it gets to operating temp on the highway it will sit at 40-45psi while cruising.
Now at a stop light on a 100*F day it will chill at 15psi. sometimes a tad lower. Oil pressure never makes it to the red on the gauge.
I keep reading everywhere that the bearings may be the culprit, but it runs fine and makes no noises. Also the fact that the oil pressure is so good on cold startup on mine compared to other threads I have read. But I read in previous threads that the sound of the engine doesn't mean jack.
Do you guys think this about normal?
I was suggested that I change the oil and filter first and try a higher weight oil while Im at it.
I was also thinking about adding a restrictor to the feed line.
Let me know what you guys think.
Last edited by NBM-LS1; 07-28-2011 at 11:32 PM.
07-20-2011, 09:25 PM
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I'd definitely try a higher weight oil. What are the bearing clearances? Call the engine builder if you don't have a build sheet and have them recommend an oil weight. Our FI engines tend to have looser clearances than the N/A guys. Yours being an aluminum block will do nothing but grow as it heats up which makes it even more noticeable. The fact that it makes good cold pressure makes me think the oil is way too thin. For instance my 390 is set up loose and I was recommended 20w 50 for break in with the same oil pump (used the blue spring though.)
07-20-2011, 09:31 PM
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I have a build sheet at my other house. Thanks for the input. Im going to change the filter and oil tomorrow. When I ran 5w30 with that pump when the engine was stock I had nearly 70psi on a cold start and 50-55psi cruising. Ill bump it up to a 10-40 tomorrow. I should use conventional, correct?
07-20-2011, 09:34 PM
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I have a build sheet at my other house. Thanks for the input. Im going to change the filter and oil tomorrow. When I ran 5w30 with that pump when the engine was stock I had nearly 70psi on a cold start and 50-55psi cruising. Ill bump it up to a 10-40 tomorrow. I should use conventional, correct?
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07-20-2011, 09:59 PM
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Agree heavier oil likely like 10/40.
I went thru a spun bearing problem with my 408. It was think always bit low on oil pressure even when new. But no build sheet since builder passed away in middle of my build.
I did get it to run 4000 miles or so then oil light came on. Oil pressure was zero.
After that you could start it ,it would have pressure then go to zero after 15 minutes or so. Pulled engine and it was fubared. Couple bearings were gone bye bye but luckily crank is fixable just turn it bit.
I think it was assembly error. Hopefully have better luck with the ERL engine. Almost got car running again on it.
If the heavier oil works you are likely ok. Don't think you should have to run 20/50 though.
I went thru a spun bearing problem with my 408. It was think always bit low on oil pressure even when new. But no build sheet since builder passed away in middle of my build.
I did get it to run 4000 miles or so then oil light came on. Oil pressure was zero.
After that you could start it ,it would have pressure then go to zero after 15 minutes or so. Pulled engine and it was fubared. Couple bearings were gone bye bye but luckily crank is fixable just turn it bit.
I think it was assembly error. Hopefully have better luck with the ERL engine. Almost got car running again on it.
If the heavier oil works you are likely ok. Don't think you should have to run 20/50 though.
07-20-2011, 09:59 PM
#11
did a quick search and found this, might be helpful, seems pretty easy and straight forward, https://ls1tech.com/forums/conversio...ure-gauge.html
07-21-2011, 12:44 AM
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i had the SAME problem, strong cold oil pressure, then dropped down to 20psi.. thought it was weird.. then the next day motor locked up while driving and wont turn over at all now
07-21-2011, 10:01 PM
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Just a little update. Drained the oil and it came out pretty clean looking. Removed the filter, cut it open and the oil at the bottom of the filter had metallic sparkles to it. Not rough or coarse. I as told the first oil change will be like that.
Was not able to get the mechanical oil gauge on it today but will tomorrow. One thing that is throwing me for a loop is the other morning on col start it was at 65psi. This morning it was at 40psi. Both of those times with 5w30. This afternoon on a warm start it started and idled at 40psi. After draining the oil and refilling it with 15w40, engine still warm at idle held just under 40psi.
After letting it warm up to nearly operating temp it was still holding steady at 40psi with the 15w40.
Now whats confusing is that I steadly keep raising the idle and the oil pressure will keep climbing. Oil pressure tops out at 70-75psi at 4k rpm. Let off the throttle back to idle and the gauge slowly creeps down to 65psi, stops, jumps right around 60-65psi and hold there. then a few seconds later the gauge will drop and then sit above the 45psi mark.
Im thinking that my new sending unit I put in there is junk?
Was not able to get the mechanical oil gauge on it today but will tomorrow. One thing that is throwing me for a loop is the other morning on col start it was at 65psi. This morning it was at 40psi. Both of those times with 5w30. This afternoon on a warm start it started and idled at 40psi. After draining the oil and refilling it with 15w40, engine still warm at idle held just under 40psi.
After letting it warm up to nearly operating temp it was still holding steady at 40psi with the 15w40.
Now whats confusing is that I steadly keep raising the idle and the oil pressure will keep climbing. Oil pressure tops out at 70-75psi at 4k rpm. Let off the throttle back to idle and the gauge slowly creeps down to 65psi, stops, jumps right around 60-65psi and hold there. then a few seconds later the gauge will drop and then sit above the 45psi mark.
Im thinking that my new sending unit I put in there is junk?
