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Subject: 454 oil pressure low

Original Message
Name: Rick B
Date: February 24, 1998 at 18:48:31
Subject: 454 oil pressure low
Guys, I have a 454 in a 71. The problem is the oil pressure is only 40-45 when cold and 35-40 when hot (10w-30) at speed. The pressure also bounces around afer its hot, some times 15-20 lbs. A friend told me the pressure relief valve can cause that (old age) and can be replaced. OK, where is it and can it really be replaced?
Or, maybe I have a real problem, (worn out main or cam bearings)? The motor runs strong with no hint of knocking or excessive oil consumption.

Response Number 1
Name: Leo
Date: February 25, 1998 at 01:12:54
Subject: 454 oil pressure low
The pressure relief valve is located in the oil pump cover plate. If you are going to replace the valve and spring you will be better off changing the oil pump as an assembly. If the valve is really sticking then the bore it slides in is also worn. Change the oil pump and eliminate that as a problem. Your main and cam bearings could cause a drop in pressure but not likely a pressure that jumps around and then is steady. Bearing wear will generally be higher when cold and after warm up drop some and be fairly steady. The valve in the oil pump is a more likely culprit.


Response Number 2
Name: fred ont canada
Date: February 25, 1998 at 05:52:08
Subject: 454 oil pressure low
Rick the oil pressure reading you quote are within specs for a stock engine.
The jumping around is not normal.
If you are running a high volume pump high pressure the reading sound low,also if you are running a high volume pump with a stock oil pan this could cause the fluctuations in pressure readings."IE"cavitation,too much oil in the engine not enough in the oil pan...FRED

Response Number 3
Name: Keith Tedford
Date: February 25, 1998 at 08:19:38
Subject: 454 oil pressure low
I think Fred is on the right track. Big block Chevies don't need high pressure as do other engines with poorly designed oiling systems. Mine never went much over 55 psi. Under hard acceleration in low gear I've seen the oil pressure dip slightly. Down only a pint would cause this. Spend the money on a large capacity oil pan. A lot of engines would be still alive if they had had one in the first place. Five quarts are just barely adequate under normal conditions.

Response Number 4
Name: ray
Date: February 25, 1998 at 14:27:58
Subject: 454 oil pressure low
Is gage is OK? If you have a friend with the same type of gage, switch gages. If the problem goes away, you've found the problem.

If not, well it was a simple and inexpensive check.

Response Number 5
Name: ray
Date: February 25, 1998 at 23:20:21
Subject: 454 oil pressure low
remove your oil filter...unbolt oil filter adapter from the block....clean the little round screen,and blow it out really good...re-install adapter...filter..re-fill oil...start car be amazed you fixed your problem at the cost of a quart of oil and 30 minutes time.

Response Number 6
Name: ED
Date: February 27, 1998 at 22:11:30
Subject: 454 oil pressure low
Rick, check out your wiring to your oil pressure sender and the guage at the left side of dash behind tach. Sometimes the conection at the printed circuit will loosen up because of the weight of the wiring harness will pull down on it. Rapid fluctuation usually is electrical 'short', slow rise and fall could be sender unit. Check your ground wires too!!! C U ED

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