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#1 |
Registered User
Join Date: Nov 2013
Location: wichita kansas
Posts: 6
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low oil pressure at idle on 383 sbc
hi im new on here and I cant seem to have anyone help me figure out my oil pressure problem on my 383 sbc in my 1982 c10. I just put this motor in about two months ago. im running 20/50w and at hot idle its running about 8-10 oil pressure. my dad bought this motor around two years ago unfinished. the pistions, rods, crank, and there bearings, and the cam bearings were installed and it came with a set of vortex heads that had work done to them. I bought it from my dad this summer and saved all my money to finsh it for my truck. its got a compcams 480. 480. lift roller rockers comp double roller timing chain and comp push rods. its got a high volume oil pump with the stock pan. im only seventeen and don't have a lot of money and this truck is my baby. thanks for time and help
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#2 |
Registered User
Join Date: Mar 2012
Location: Little Rock, Arkansas
Posts: 770
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Re: low oil pressure at idle on 383 sbc
If you have access to a good oil pressure tester gauge hook it up and see what you have. Then you can eliminate a bad gauge. Any leaks? Why are you running such a thick oil in a relatively new engine?
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1979 ![]() 1996 Silverado x-cab "the daily" |
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#3 |
Registered User
Join Date: Nov 2013
Location: wichita kansas
Posts: 6
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Re: low oil pressure at idle on 383 sbc
was recommended to by a friend that use to drag race. and just put a new oil pressure gauge on it. and there's no leaks that I can see. what weight would be better? and ill see if I can get my hands on a tester.
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#4 |
Registered User
![]() Join Date: Oct 2006
Location: Southern Kalifornia
Posts: 3,066
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Re: low oil pressure at idle on 383 sbc
What is it hot at speed? Did you put it together or someone else? Was the oil pump pick up set at the right depth and tack welded to the housing? I too think 20/50 is too much unless you have MASSIVE bearing clearances. We need more info on the build.
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#5 |
Registered User
![]() Join Date: Oct 2006
Location: Southern Kalifornia
Posts: 3,066
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Re: low oil pressure at idle on 383 sbc
And where are you taking the reading from?( on the block)
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#6 |
Registered User
Join Date: Mar 2012
Location: Little Rock, Arkansas
Posts: 770
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Re: low oil pressure at idle on 383 sbc
Also does your oil pressure increase much as rpm go up? Like manimal said I doubt you have so much clearance to warrant that oil. And thick oil will make your pressure increase so if you ran 10w-30 it would be lower which would mean you got a problem. Like I said get a good oil pressure tester and make sure its not the gauge. Check to make sure your top end is oiling correctly to see if theres a pump issue.
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1979 ![]() 1996 Silverado x-cab "the daily" |
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#7 |
Registered User
Join Date: Nov 2013
Location: wichita kansas
Posts: 6
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Re: low oil pressure at idle on 383 sbc
it runs around 190F and it gos up to around 30-35 psi at 40mph and its about 1750 rpms then idles just below 1000 rpms and drops to 10-8 psi when hot. I put the oil pump, cam, lifters, push rod, timming chain, and rockers in. the pistons, rods, crankshaft and their bearing were already installed before we got. we where told that it was a good motor and had no problems and that he was just going with a bbc and not the sbc. I had 10/40 in it but don't remember what the oil psi was. the pump I believe is the right depth and didn't tack weld it never heard of doing that. and its reading it from the back/top of the block behind the intake where they read on stock motors
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#8 |
Just here to tinker
![]() Join Date: Jun 2008
Location: Holland, MI
Posts: 3,692
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Re: low oil pressure at idle on 383 sbc
Is it an electrical sender? Might try replacing that if so. Least expensive thing to do. I agree with above about using a mechanical gauge installed directly to the engine to test pressure. Then you'll know if you have an internal problem or not.
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#9 |
Registered User
Join Date: Nov 2013
Location: wichita kansas
Posts: 6
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Re: low oil pressure at idle on 383 sbc
Alrighty I'll see if I can get hands on a tester and see what it says. It's got an aftermarket mechanical gauge on it. Thanks for the help i have more ideas on what to look at and look for. If it isn't the gauge and the tester reads low too. What should I do? Just drive it tell it gives? Or try and fix it? It's my only vehicle I have and like I said I don't really have a lot of money to but in it anymore cause I'm back in school now.
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#10 |
Registered User
Join Date: Aug 2013
Location: San Diego
Posts: 111
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Re: low oil pressure at idle on 383 sbc
sounds silly but what filter are you using? and is it new?
oil pressure when cold at start up? oil pressure when at operating temp at idle = 8-10psi? oil pressure @ ~1800rpm/40mph = 30-40psi? I run 15w-40 rotella in my 454 with no issues all it does is Tow my toys out to the desert though. |
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#11 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,602
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Re: low oil pressure at idle on 383 sbc
If you got a mechanical gauge now another mechanical test gauge won't show any difference.
You got a big cam in it, how well does it idle? If you smooth out the idle your oil pressure might come up. What's your initial timing at? Where's your vac advance hooked to? Manifold or ported? |
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#12 |
Registered User
Join Date: Apr 2012
Location: Murphy,NC
Posts: 212
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Re: low oil pressure at idle on 383 sbc
8-10psi per 1000 rpms is ok,not ideal,but ok, as long as it comes up with rpms, stays steady, and doesn't float around.
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#13 | |
Registered User
Join Date: Jul 2013
Location: The Woodlands Texas
Posts: 135
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Re: low oil pressure at idle on 383 sbc
Quote:
How long has your's been doing this 1982chevyc10383? Have you had any luck correcting the problem? Have you tried changing the oil and/or filter yet?
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#14 |
Registered User
Join Date: Jul 2009
Location: washington
Posts: 4,178
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Re: low oil pressure at idle on 383 sbc
Lately I've noticed issues with melling pumps having the oil pump pressure bypass binding up at times. The more expensive line of oil pumps from melling don't seem to have this issue.
Another cause possibly is sometimes builders forget a threaded plug underneath the main thrust cap. This can cause a low pressure situation too.
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#15 |
Registered User
Join Date: Jul 2013
Location: Rancho Cucamonga, CA
Posts: 27
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Re: low oil pressure at idle on 383 sbc
I would check the bearing clearances. Not sure how much time or miles are on the motor but definitely oil is a serious issue to address. I had the same problem on a recent BBC build. When I put the bottom end together I did not mic the crank. Sure enough the crank was .030 under and I used .0000 bearings. Changed the bearings, Bang, done. Motor runs stout. No oiling problem.
Had the problem on a SBC 400ci long to short oiling problem caused a broken crank shaft and destroyed #8 cylinder. I had heard lower psi at idle is ok when warm, but this is surely a sign of a problem. For me, to avoid any future problems and misreadings of a digital gauge, I have a mechanical hooked right up to the fitting at the oil filter. Just use about a 3 foot hose mount it right to the head. So if I see a low reading I go right to that gauge. I hope you figure out the problem. Definitely something to corner for sure. |
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#16 | |
Registered User
Join Date: Jul 2013
Location: Rancho Cucamonga, CA
Posts: 27
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Re: low oil pressure at idle on 383 sbc
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#17 | |
Master Hater
Join Date: Apr 2006
Location: Temple,Tx.
Posts: 402
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Re: low oil pressure at idle on 383 sbc
Quote:
Exactly , the old rule use to be 10psi for every 1,000 rpm. also just run like 10-30, no need for a thick oil, and use only good wix or napa ,,car quest filters, never use a pos fram. oil level doesn't affect oil pressure unless its so low it sucks the pan dry and starts sucking oil, then its bad news.
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#18 | |
Registered User
Join Date: Jul 2013
Location: The Woodlands Texas
Posts: 135
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Re: low oil pressure at idle on 383 sbc
Quote:
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#19 |
Registered User
Join Date: Jul 2009
Location: washington
Posts: 4,178
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Re: low oil pressure at idle on 383 sbc
The fram filters are ok but limeted in application. The issue with these filters are high rpm motors and motors with hv oil pumps. Also oils like synthetic can go extended intervals but a lot of filters do not. This is where extended mile filters come in handy. And even then they will only last 6months reliably being oil saturated.
If anything I would pull the motor and check everything like bearing clearances and the pump to make sure. It's time consuming and a pain in the butt. It that or risk your rotating assembly getting destroyed. And that's an even bigger pain
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377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511 |
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#20 |
Registered User
Join Date: Jan 2009
Location: Louisville,Ky
Posts: 5,811
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Re: low oil pressure at idle on 383 sbc
I'm thinking bad oil filter or maybe oil pump pickup tube is too close to the pan maybe.
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#21 |
Registered User
Join Date: Aug 2005
Location: Louisiana
Posts: 711
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Re: low oil pressure at idle on 383 sbc
Sounds like loose clearances to me. I would not be comfortable with those readings and 20w50 oil.
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#22 |
Registered User
Join Date: May 2012
Location: Ravenswood Wv
Posts: 86
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Re: low oil pressure at idle on 383 sbc
X2. He's probably under 5 psi with 10/30. Pull the pan and check bearings and replace them and the pump.
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#23 |
Registered User
Join Date: Jun 2008
Location: Lubbock, TX
Posts: 2,047
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Re: low oil pressure at idle on 383 sbc
Toss the junk cardboard Fram filter and get a Wix.
If you tear it down, double check those cam bearings (not just rods and mains) and the drive-in plug in the back of the block. |
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#24 |
Registered User
Join Date: Jul 2012
Location: Des Moines IA
Posts: 1,250
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Re: low oil pressure at idle on 383 sbc
I would not be worried about 10 psi under 1000 RPM idle on an aftermarket high volume pump. High volume pumps tend to be race ready for constant high RPM use and really don't come into their efficiency range until higher RPMs. Drop the 20/50 oil unless you have a rattle from loose clearances when using a 5/30, 5/40, 10/30, 10/40 oils first. 20/50 is fine for a race vehicle, but has no place on a properly built/assembled street engine because again, thicker oils are needed for sustained high RPM of a race engine (or really loose clearances of either an OLD engine with really high miles or a loosely assembled race engine).
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