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#1
08-08-2009, 09:02 PM
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How low is too low for oil pressure when idling?
Soo I took my LeMans out for a nice drive yesterday, highway and local. At fire up the oil pressure was good at 50+ psi, highway at 80ish cruising it was 60ish but when i got off the highway and stopped and let it idle for a bit, the pressure dropped to below 25 psi probably closer to 10-15psi, and when revving or getting back in it on the throttle it would go back up to normal pressure but not quite 50ish.
Should I be concerned about the low pressure at idle?(when fully warmed up obviously) I have a NEW autometer electric gauge so im pretty sure its accurate, motor is new and broken in, high compression, decent cam. Do I have a problem?
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1970 LeMans 462 E-heads, 400 trans, Moser 12 bolt rear with 3.73s, Pypes 3" X system/violator mufflers, BMR handling package with 275 Mickey Ts out back 94 TransAm couple bolt-ons 03 F150 SuperCrew Fx4 88 Mustang LX T-Top 5-speed |
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#2
08-08-2009, 09:38 PM
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the weight of oil will make a dif
i just switched from 20/50 to 10/30 and my hot idle pressure went from 40 to 20 and it is hard to get used to but im sure it is ok and i think your 10 to 15 is ok to as long as it goes up to 40 or 50 when you leave idle
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1980 TA 455 th400 2.56 posi 12.27@111.48 http://www.dragtimes.com/Pontiac-Tra...lip-29967.html http://www.youtube.com/watch?v=6X5XJ9PR1Qw https://www.youtube.com/user/hal101/videos |
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#3
08-08-2009, 10:08 PM
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I am running 10/30w should have written that
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1970 LeMans 462 E-heads, 400 trans, Moser 12 bolt rear with 3.73s, Pypes 3" X system/violator mufflers, BMR handling package with 275 Mickey Ts out back 94 TransAm couple bolt-ons 03 F150 SuperCrew Fx4 88 Mustang LX T-Top 5-speed |
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#4
08-08-2009, 10:11 PM
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Try Rotella 15/40..I bet it cures it.
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  Nothing is impossible if you break it down into possibilities. It's all a matter of "Want to". |
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#5
08-08-2009, 10:25 PM
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Yep!! X2 on the rotella 15-40! Also, hot, at idle in gear, check the gage, blip the throttle & watch the gage. If it allmost instantly jumps up in pressure, you are good to go. If it is slow to rise then you need to investigate what is causing the low pressure problem. I would also plumb in a mechanical gage just to double check the accuracy of the electrical gage.
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Keith Collier 61-63 Pontiac Tempest Tech advisor POCI.org |
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#6
08-09-2009, 07:03 AM
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Try the Valvoline VR-1 oil. Use the higher viscocity oil. Also has a higher zinc content.
 15 lbs id fine. If you are running a non stock rotating assembly,(Higher rod side clearance) I usually add a .060 shim inder the oil pump spring to move it another 10 higher. |
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#7
08-09-2009, 11:18 AM
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I had the same problem when I changed from 20-50 to 10-40. Its still ok. But next oil change, im going back to 20-50.
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#8
08-09-2009, 02:24 PM
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Yep once the oil heats up the idle oil pressure will drop especially with the lighter/thinner weight oils. The rule of thumb is having at least 10 lbs of pressure for every 1000 rpm's the engine is turning for adequate oiling. So having 10-15 lbs at say a 1000 rpm idle or slightly lower should be fine; if it's showing 10-15 lbs in gear idling at 600-750 rpm's it's even better! Sounds OK to me just keep an eye on it. JD
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Good luck to the new owner of the Ventura II! Sold the car after 13+ years. Look for it on the Hot Rod Power Tour in the future as it's currently being re-configured as a Pro-Touring ride! 
Last edited by 71 Ventura II; 08-09-2009 at 02:30 PM. |
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