Can anyone tell me what the proper oil pressure should be on a 1971 LS-5? The car had a rebuild about 10K ago, but has been sitting for the past 6 months. I changed the oil when I got it back and noticed what I think is a bad lifter. However, the oil pressure is pegging my guage at over 70 lbs and three days after changing the oil I had about a quart of oil come out of the top of the oil filter. The oil filter was tight, but it appears that the pressure was too great and it blew out. After driving a while, the pressure drops back to 45-50 and the lifter noise is far less noticable. To me it sounds like a blockage in one of my oil passageways, but what confuses me, is that the pressure comes and goes and from what I know about blockages is they are either blocked or they are not, they don't come and go. I have tried 10W-30 and 10W-40 and neither makes a difference. Besides a complete breakdown I am wondering if anyone has any other ideas.
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Re: 71 454 Oil Pressure
The usual oil pressure for a hyd lifter BB is about 60 PSI @ cold startup, about 30 PSI at warm idle and 50 - 60 PSI warm at approx 2000 to 3000 RPM. Is this a new problem? It is common for rebuilders to use the Melling High volume pump with the high pressure relief spring but you should then have seen the same pressure all along. Is the gauge accurate (try an aftermarket one temporarily to verify the reading).
Good luck,
Mark -
Re: 71 454 Oil Pressure
Tom,
Sounds like there is a possibility you left the old rubber seal on the block when you changed filters. Then with the two seals it blew out. When you take the filter off check with your fingers or look on the old filter to make sure that the oil seal did not stick on the block side.
This has happened to me and others on this board. It will only happen once as it makes a mess and you will always remember.
As for your oil pressure, it sounds great and I would not worry about a thing. Just be happy you have oil pressure.
Regards,
JRComment
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Re: 71 454 Oil Pressure
Thanks for the info. Ever since the rebuild the pressure was exactly like you said it should be...about 60 at start up and about 40 warm. Now it seems to be higher than that even warm. What really scares me is the tapping noise I hear at high pressure now and the lack of noise at lower pressure.
One thing I didn't mention originally is the pressure sky rockets when it is accelerated, which I guess is common to increase with added rpms, but it really pegs the needle.Comment
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Re: 71 454 Oil Pressure
I thought that as well, but there was only one seal on the filter and nothing on the block. Do you think there is a connection with the tapping noise and the high pressure? I thought about adjusting my tappet, but that may only mask the real problem of oil starvation someplace.Comment
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Re: 71 454 Oil Pressure
Tom:
Something doesn't sound right. My low mileage original '71 LS-6 doesn't peg the gauge needle when climbing in rpm's. The oil pressure reading rises when driving at accelerated speeds, but no way doesn't it peg the needle and stay there.Comment
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Re: 71 454 Oil Pressure
sounds to me like you may have the bypass plunger in the oil pump sticking.Comment
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Re: 71 454 Oil Pressure
This sounds like a sticking plunger in the bypass relief system in your pump. Maybe a metal shaving has jammed it. Time to pull the pan......CraigComment
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Re: 71 454 Oil Pressure
yeah something is not OK, need to drop the pan an check out.Comment
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