Author Topic: What is normal oil pressure on a bbc?  (Read 11787 times)

Offline team39763

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What is normal oil pressure on a bbc?
« on: September 22, 2009, 05:23:01 pm »
My dually has been having really low oil pressure according to the gauge.  I haven't manually tested the pressure with a mechanical gauge yet, but I plan to.  I'm not sure how long the pressure has been reading low, it may have been like that since we bought it.  While driving along at 2100rpms, the pressure usually is 35-40psi.  When we come to a stop it drops to maybe 10psi.  The oil looks good, the motor sounds fine, never smokes, the temps are normal.  I was told to try thicker oil, so I did and it marked the same.  I was told to try 50wt next.  If it turns out that my gauge is correct, what should my next step be?

Offline malibu795

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Re: What is normal oil pressure on a bbc?
« Reply #1 on: September 22, 2009, 06:45:30 pm »
i have heard 10psi per 1000rpm..

i personally dont like that rule of thumb..

i have read stock oil presure at 800rpm should be 18psi...

i would get a cehap gauge from autozone...etc and double check it.

IMO its too low to effectively lube everything... i run 10w40 with HV pumps evg hot is 22-30psi on my block and idle ranged between 500-1000rpm. 60psi ar 2500rpm
adam wildman
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79 malibu 454/T56 305rwhp/432rwtq 15.6@92.8mph
02 2500HD D-max/allison best time 13.77 @ 99mph 463rwhp/930rwtq

Offline Captkaos

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Re: What is normal oil pressure on a bbc?
« Reply #2 on: September 23, 2009, 03:06:03 pm »
That is normal for a stock setup.
7 at idle and a pound for every 1000rpms is the general rule for minimum pressure.

Offline team39763

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Re: What is normal oil pressure on a bbc?
« Reply #3 on: September 23, 2009, 03:19:34 pm »
Ok, so it's not in bad shape then.  I'll still run a check on it to make sure my gauge is reading correctly.

Offline malibu795

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Re: What is normal oil pressure on a bbc?
« Reply #4 on: September 24, 2009, 08:09:32 pm »
That is normal for a stock setup.
7 at idle and a pound for every 1000rpms is the general rule for minimum pressure.
IMO if your running min pressure your looking for trouble... but thats me ona  DD aplication..

i know guys that only run 2.5-3qt of oil in a drag application..  since then shut down after the line.
adam wildman
75 K25 383/400
79 malibu 454/T56 305rwhp/432rwtq 15.6@92.8mph
02 2500HD D-max/allison best time 13.77 @ 99mph 463rwhp/930rwtq

Offline team39763

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Re: What is normal oil pressure on a bbc?
« Reply #5 on: September 25, 2009, 08:47:24 pm »
I think it only goes to minimum at idle.  During cruising it's around 40psi or a little less, so it's not too bad right.  I was too distracted to mess with the dually today...my race truck is alive once again.  I'll get that mechanical gauge on there next week.

Offline team39763

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Re: What is normal oil pressure on a bbc?
« Reply #6 on: October 10, 2009, 10:19:48 pm »
Just wanted to update this and let ya'll know that I fixed the problem by fixing a crankcase ventilation problem.  I put 2 breathers on the driver side valvecover and the squeaking/squealing went away and the oil pressure is much better.  Always at or above 30 and over 40 at cruise.

Offline VileZambonie

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Re: What is normal oil pressure on a bbc?
« Reply #7 on: October 11, 2009, 09:46:58 am »
Specification:
Oil Pressure (Fully Warmed Oil not Hot) 
10 psi at 600 rpm
25 psi at 2000 rpm

If below specification inspect for the following:
Engine oil diluted by moisture or unburned fuel mixtures
Improper engine oil viscosity for the expected temperature
Incorrect or faulty oil pressure gauge sensor
Incorrect or faulty oil pressure gauge
Plugged oil filter
Malfunctioning oil filter bypass valve

Remove the oil pressure gauge sensor or another engine block oil gallery plug.
Install an oil pressure gauge and measure the engine oil pressure.
If the engine oil pressure is below specifications, inspect the engine for one or more of the following:
Oil pump worn or dirty
Malfunctioning oil pump pressure relief valve
Oil pump screen loose, plugged, or damaged
Excessive bearing clearance
Cracked, porous or restricted oil galleries
Engine block oil gallery plugs missing or incorrectly installed
Broken valve lifters
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Offline Jim Rockford

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Re: What is normal oil pressure on a bbc?
« Reply #8 on: October 14, 2009, 09:10:30 am »
Like alot of FSJ guys say, stock gauges are for entertainment purpose only.... get a real gauge,  Aftermarket electric gauges are great nowadays, and no worries about hot oil spraying in the cab from a broken line.
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