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Topic: Oil Pressure

in Forum: C3 Engines

Oil Pressure

Posted: 3/28/09 11:33am Message 1 of 7
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Elma, WA - USA
Joined: 6/25/2007
Posts: 692
Vette(s): Red 1973 Convertible. L-48 Auto #'s matching Red 1970 LT-1 Convertible #'s matching
So the  oil pressure gauge on the LT-1 goes to 70 pds.
The oil pressure needle goes way past that and I had them check it.
It is high.
Is this normal and did someone add a high pressure pump?
The folks say not to worry just keep the breathers clean.

I didnt get #'s but it must go up to 80 pds pf pressure or more.
What are your thoughts?

At least at this point I am most likely worrying bout nothing.



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Oil Pressure

Posted: 3/28/09 12:03pm Message 2 of 7
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Newland, NC - USA
Joined: 11/18/2008
Posts: 19
Vette(s): 1. 75 coupe 383 stroker, trick flow heads, eldebrock performer intake, roller rockers, cam, and780 hollery. 2. 05 Coupe w/Z51 options

Is that pressure cold or hot.  If it is hot.. could be your pressure relief valve is stuck.  Not sure... but one area to check.

Phil

 

 




Oil Pressure

Posted: 3/28/09 3:16pm Message 3 of 7
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Oil pressure depends on temp of oil, wt of oil, rpm of engine. Your oil pressure is quite high. The problem could be in the sending unit or gauge. There is an internal relief valve built into the oil pump, to allow excess pressure to return back to the crankcase. Hope this helps a bit. 


corvette440hp

Oil Pressure

Posted: 3/28/09 4:44pm Message 4 of 7
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Oceanside, CA - USA
Joined: 11/19/2003
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Vette(s): 1978 Silver Anniversary model. Original L82 engine, 700r4 trans, edelbrock intake, thorly headers, rack&pinion steering, mono rear and front spring, MSD 6A box
When I put on the 7qt oil pan I also put in a high presure oil pump.  The presure at crusing speed is 79 psi which is what it should be according to the oil pump instructions.  I would suggest you see if you  have the high presure pump.


Oil Pressure

Posted: 3/28/09 5:26pm Message 5 of 7
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Elma, WA - USA
Joined: 6/25/2007
Posts: 692
Vette(s): Red 1973 Convertible. L-48 Auto #'s matching Red 1970 LT-1 Convertible #'s matching
Looks like I will be pulling the pan to check that out.

Te pressure was checked with a remote gauge that backed up the gauge in the car.
It will give me a chance to change the oil so then I will know its fresh and what weight it is.

Those readings were with the motor warmed up.

As always thanks for the info. You all are great!



Oil Pressure

Posted: 3/28/09 5:58pm Message 6 of 7
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
If it is determined you have a high pressure pump, replace it with a high volume pump. There's no need for high pressure, unless you're running really loose bearing clearances for racing applications.
There's really no big downside to having overly high oil pressure other than more un-necessary drag on the engine. Some folks believe it leads to bearing "wash-out", but....that may simply be urban legend...
My '74 will peg the 80lb gauge on start up, and then settle down to 40psi at idle, hot.


Joel Adams
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Oil Pressure

Posted: 3/30/09 8:10am Message 7 of 7
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Mounds View, MN - USA
Joined: 5/24/2007
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Vette(s): 70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe
I agree with Adam.  Under extreme conditions, you should have up to ten pounds pressure per 1,000 RPM of regular use.So unless you regularly rev to 9,000 RPM, the stock 45 pound relief valve is the way to go.

Larry



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