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Author Topic: Low oil pressure reading  (Read 4651 times)

Offline ITSANSS

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Low oil pressure reading
« on: November 05, 2010, 07:45:26 pm »
Just replaced the old worn out 350 for a rebuilt one.  Old engine had low oil pressure and now I'm not so sure if it was the junk engine or if it could be the wiring, sensor, or gauge because the new engine is only reading 15psi.  Seems like it would be reading more than that...?

What is the rule of thumb for oil pressure on an old carbureted 350?

Thanks
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Offline screamin86

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Re: Low oil pressure reading
« Reply #1 on: November 05, 2010, 07:47:32 pm »
10lb per 1000rpm is what I've always heard. My rebuilt 350 does similar 15ish hot idle in gear but 50+ at cruse or wot
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86 k10 lwb 4x4:350 .040 214/224 444/466 112lsa performer rpm 1406 lt's summit racing th350 2800stall
03 yukon xl:tint debadge full boltons
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Offline ITSANSS

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Re: Low oil pressure reading
« Reply #2 on: November 05, 2010, 08:16:56 pm »
10psi/1,000 RPM.  Hm, ok.  I'll check tomorrow what kinda' fluctuations I get with RPM.  Thanks

If it doesn't change, could a bad sensor or a worn out gauge cause a low reading?

Thanks
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Offline Lt.Del

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Re: Low oil pressure reading
« Reply #3 on: November 05, 2010, 08:32:49 pm »
the sending units, usually just behind and right of distributor, do get clogged and do malfuntion.  I replaced them on both my trucks through the years. They're cheap.   
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Offline screamin86

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Re: Low oil pressure reading
« Reply #4 on: November 05, 2010, 08:37:50 pm »
Yes. My truck when I got it the factory gauge was hooked up after about 2weeks it droped to zero one day I put a sunpro oil psi gauge on it and it would hold atleast 10-15 at idle and go to about 30-35 cruise. Then I busted a ringland off a piston and I swaped in amild 350 with hv pump and like I said before hot its 15ish in gear idle with my mech gauge and 50+ crusie and wot

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86 k10 lwb 4x4:350 .040 214/224 444/466 112lsa performer rpm 1406 lt's summit racing th350 2800stall
03 yukon xl:tint debadge full boltons
86 ta:lm7 hot cam boltons

Offline Irish_Alley

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Re: Low oil pressure reading
« Reply #5 on: November 06, 2010, 02:51:07 am »
im running about 25-30 hot and 40-50 at speed. if im creepin it will drop to the teens
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Offline bobcooter

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Re: Low oil pressure reading
« Reply #6 on: November 06, 2010, 09:29:14 am »
Mines about the same. Idle, in gear, hot about 15 psi. Running 60 mph, hot, around 45 to 50 psi.
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Offline ITSANSS

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Re: Low oil pressure reading
« Reply #7 on: November 10, 2010, 06:33:52 am »
I must have a bad gauge.

New engine.

New oil pressure sender.

Only reads about 10 PSI idle and about 20 PSI goin' down the road.

By the way, the new oil pressure sender (bell shaped thing) is twice as big and half the weight of the one that was on there.  Figured the old one probably had some sludge in it like the old engine did.  lol

Thanks
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