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05-25-2010, 06:13 PM
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#1 |
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Registered User
Join Date: May 2010
Location: Webster, MA
Posts: 17
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low oil pressure!!!!
hey,
i got a rebuilt 350 i put in my gmc. all new bearings, right clearances that i know of, new heads cam etc. etc. etc. heres the deal. At cold start it runs between 40-60 psi. at normal running temp, driving it gets anywhere between 30-50 psi. at a warm idle it drops to almost 0, more like 5 psi but instantaneously comes up when i hit the throttle. is this the bearings(which are new)? ive heard of oil filters causing this??? oil was just changed after the break in with no signs of metal really and there are no n oises fromthe engine. |
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05-25-2010, 08:07 PM
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#3 |
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Registered User
Join Date: Jun 2007
Location: Cape Coral, Florida
Posts: 1,123
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Re: low oil pressure!!!!
If its only low at idle, but at spec at 2k or whatever the specified rpm is, I've been told its normal. I have a GMPP 350 in my Caprice that has about 5psi at idle(550rpm) but comes right up at the hit of the gas. Been 3 years 15k miles and no issues.
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05-25-2010, 08:39 PM
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#4 |
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OL BLUU
 
Join Date: Mar 2004
Location: WICHITA, KS.
Posts: 1,065
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Re: low oil pressure!!!!
The one I just had installed in my Blazer runs about 20psi at idle... and maybe 45 at the highest point. I say your normal...
But my 87' runs 50-60 constantly... I don't know if I helped ya any! lol
__________________
More Drop and pics... whatch'a think?: http://67-72chevytrucks.com/vboard/s...d.php?t=249927 My recent 2wd Blazer progress thread: http://67-72chevytrucks.com/vboard/s...d.php?t=393427 http://67-72chevytrucks.com/vboard/s...d.php?t=394870 |
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05-25-2010, 11:51 PM
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#5 |
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Registered User
Join Date: Mar 2009
Location: TN
Posts: 410
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Re: low oil pressure!!!!
It's fine. Your driving pressure is right where it should be. If it drops when you hit the gas, then you have problems.
__________________
'69 Dodge Charger R/T 440, 727, 3.55 Sure Grip '68 Plymouth Road Runner 383, 727, 3.23 Sure Grip '89 Dodge Diplomat ex cop car 408, 727, 3.55 Sure Grip '77 Dodge Monaco ex cop car 440, 727, 2.71 '79 Dodge 'Lil Red Express pickup 360, 727, 3.55 Sure Grip '12 Dodge Challenger SRT8 392, M6, 3.92 '85 Chevrolet C-10 SWB 2wd 305, TH350, 2.73 |
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05-26-2010, 06:56 AM
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#6 |
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Registered User
Join Date: May 2010
Location: Webster, MA
Posts: 17
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Re: low oil pressure!!!!
thanks guys
it dont really drop when im cruising or on the throttle. just comes down at idle but blips right up. im running a fram filter and have been told those are junk. two people actually said they had this same problem, put on a different kind of filter and were all set. we'll see, ill let ya'll know. |
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05-26-2010, 07:42 AM
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#7 |
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Registered User
Join Date: Jun 2008
Location: Lubbock, TX
Posts: 2,047
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Re: low oil pressure!!!!
5psi at idle is too low, regardless. Particularly on a new engine with what should be NO bearing wear.
I have about 20K on the last 350 I built. Pressure never goes below about 30 psi at idle and I'm at about 60psi at 2500. Sounds like you have bearing clearance issues that are only going to get worse. Who built it and what were the clearances? 5psi at idle would be what I'd expect from a worn out engine, not a rebuild. |
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05-26-2010, 09:47 AM
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#8 |
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Registered User
Join Date: Jul 2005
Location: Saskatchewan
Posts: 189
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Re: low oil pressure!!!!
Could be the sender. I put an external gauge on mine because mine would be pegged at startup and drop to near 0 after 20 miles. My sender was shot so I replaced it.
    Hope that's all yours is.
__________________
Stu- 1981 GMC Sierra Classic LWB 355- original 2 bolt block, 10.2:1, vortec heads, Comp XE268 cam, built by self in 1992 700R4-2000 stall with lockup, shift kit, Corvette servo 3.07 open diff- I need a 3.73 posi! 2nd owner since 1986 - 388,000 km and counting. 100k by the first owner and the rest by me. |
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